wip

2025-10-06 19:59:41 +07:00 · 2022-01-13 15:22:11 +01:00 · 2022-01-13 15:18:41 +01:00 · 2022-01-13 15:15:47 +01:00 · 2022-01-13 15:02:11 +01:00 · 2022-01-13 10:17:47 +01:00
312 changed files with 55681 additions and 83841 deletions
@@ -0,0 +1,27 @@
 # This workflow will do a clean install of node dependencies, build the source code and run tests across different versions of node
 # For more information see: https://help.github.com/actions/language-and-framework-guides/using-nodejs-with-github-actions
 name: Node.js CI
 on:
  pull_request:
    branches: [ master, owl-next ]
 jobs:
  build:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        node-version: [12.x, 14.x, 16.x]
    steps:
    - uses: actions/checkout@v2
    - name: Use Node.js ${{ matrix.node-version }}
      uses: actions/setup-node@v1
      with:
        node-version: ${{ matrix.node-version }}
    - run: npm install
    - run: npm run test
    - run: npm run check-formatting
@@ -15,6 +15,7 @@ yarn-debug.log*
 yarn-error.log*
 package-lock.json
 yarn.lock
 #ide's
 .vscode
@@ -23,4 +24,11 @@ package-lock.json
 node_modules
 # Extras temp file
-/tools/owl.js
+/tools/owl.js
 release-notes.md
 .rpt2_cache
 # useful in some cases
 /temp
@@ -0,0 +1,612 @@
 # Changelog
 This document contains an overview of all changes between Owl 1.x and
 Owl 2.x, with some pointers on how to update the code.
 Note that some of these changes can be magically implemented (for example, by
 patching the `setup` method of `Component` to auto register all the lifecycle
 methods as hooks). This will be done for the transition period, but will be
 removed after.
 ## Changes
 **Components**
 - components can now have empty content or multiple root nodes (htmlelement or text) ([details](#31-components-can-now-have-arbitrary-content))
 - new `useEffect` hook
 - new `onDestroyed`, `onWillRender` and `onRendered` hooks
 - breaking: lifecycle methods are removed ([details](#1-component-lifecycle-methods-are-removed))
 - breaking: can no longer be mounted on detached DOM ([details](#2-components-can-no-longer-be-mounted-in-a-detached-dom-element))
 - breaking: standalone `mount` method API is simpler ([details](#4-mount-method-api-is-simpler))
 - breaking: components can no longer be instantiated and mounted by hand ([details](#5-components-can-no-longer-be-instantiated-and-mounted-by-hand))
 - breaking: components can no longer be unmounted/remounted ([details](#6-components-can-no-longer-be-unmountedremounted))
 - breaking: template name is no longer inferred from the class name ([details](#7-template-name-is-no-longer-inferred-from-the-class-name))
 - breaking: components no longer have a `shouldUpdate` method ([details](#8-components-no-longer-have-a-shouldupdate-method))
 - breaking: component.el may be a text node, and is no longer `null` ([details](#9-componentel-may-be-a-text-node-and-is-no-longer-null))
 - breaking: style/class on components are now regular props ([details](#10-styleclass-on-components-are-now-regular-props))
 - breaking: components can no longer be mounted with position=self ([details](#11-components-can-no-longer-be-mounted-with-positionself))
 - breaking: `t-on` does not work on components any more ([details](#12-t-on-does-not-work-on-components-any-more))
 - breaking: `t-component` no longer accepts strings ([details](#17-t-component-no-longer-accepts-strings))
 **Portal**
 - portals can now have arbitrary content (no longer restricted to one single child)
 - breaking: does no longer transfer dom events ([details](#13-portal-does-no-longer-transfer-dom-events))
 - breaking: does render as an empty text node instead of `<portal/>` ([details](#14-portal-does-render-as-an-empty-text-node-instead-of-portal))
 **Slots**
 - breaking: `t-set` does not define a slot any more ([details](#3-t-set-will-no-longer-work-to-define-a-slot))
 **Miscellaneous**
 - improved performance
 - much simpler code 
 - finer grained reactivity: owl 2 tracks change per key/component
 - finer grained reactivity: sub components can reobserve state
 - new App class to encapsulate a root Owl component (with the config for that application)
 - new `Memo` component
 - breaking: `Context` is removed ([details](#15-context-is-removed))
 - breaking: `env` is now totally empty ([details](#16-env-is-now-totally-empty))
 - breaking: most exports are exported at top level ([details](#18-most-exports-are-exported-at-top-level))
 - breaking: properties are no longer set as attributes ([details](#19-properties-are-no-longer-set-as-attributes))
 - breaking: `t-foreach` should always have a corresponding `t-key` ([details](#20-t-foreach-should-always-have-a-corresponding-t-key))
 - breaking: `EventBus` api changed: it is now an `EventTarget` ([details](#21-eventbus-api-changed-it-is-now-an-eventtarget))
 - breaking: `Store` is removed ([details](#22-store-is-removed))
 - breaking: `Router` is removed ([details](#23-router-is-removed))
 - breaking: transition system is removed ([details](#24-transition-system-is-removed))
 - breaking: no more global components or templates ([details](#25-no-more-global-components-or-templates))
 - breaking: `AsyncRoot` utility component is removed ([details](#26-asyncroot-utility-component-is-removed))
 - breaking: `useSubEnv` only applies to child components ([details](#27-usesubenv-only-applies-to-child-components))
 - breaking: `env` is now frozen ([details](#28-env-is-now-frozen))
 - breaking: `t-ref` does not work on components ([details](#29-t-ref-does-not-work-on-component))
 - breaking: `t-on` does not accept expressions, only functions ([details](#30-t-on-does-not-accept-expressions-only-functions))
 - breaking: `renderToString` function on qweb has been removed ([details](#32-rendertostring-on-qweb-has-been-removed))
 ## Details/Rationale/Migration
 All changes are listed in no particular order.
 ### 1. component lifecycle methods are removed
 There was two ways to define hooks: the component methods (`willStart`, `mounted`, ...) and the hooks (`onWillStart`, `onMounted`, ...). In Owl 2, the component methods have been removed.
 Rationale: it makes the implementation simpler and slightly faster. Hooks are more composable
 than component methods. It enforces a single entry point to check all the useful lifecycle
 calls (instead of it being scattered in the component definition). It feels more "modern".
 Migration: lifecycle methods should be defined in the `setup`:
 ```js
 class MyComponent extends Component {
  mounted() {
    // do something
  }
 }
 ```
 should become:
 ```js
 class MyComponent extends Component {
  setup() {
    onMounted(() => {
      // do something
    });
  }
 }
 ```
 ### 2. components can no longer be mounted in a detached dom element
 Nor document fragment.
 Rationale: it is actually very difficult to do it: this implies that a component
 can be mounted more than once, that we need to check every time different status,
 that some elements is in the dom, and was a cause for bugs. Also, we don't use it
 in practice. Removing this means that we have a much simpler mental model of what
 happens.
 Migration: well, not really easy. The code needs to be refactored in a different way.
 ### 3. **`t-set` will no longer work to define a slot**
 The `t-set` directive cannot define a slot anymore. Only the `t-set-slot` directive
 can do it.
 Rationale: it was left for compatibility reason, but was deprecated anyway.
 Migration: `t-set` should be changed to `t-set-slot` (when defining a slot)
 Example:
 ```xml
 <SideBar><t t-set="content">content</t></SideBar>
 ```
 should become:
 ```xml
 <SideBar><t t-set-slot="content">content</t></SideBar>
 ```
 ### 4. `mount` method API is simpler
 Before, the `mount` method was used like this:
 ```js
 await mount(Root, { target: document.body });
 ```
 It is now simpler and takes the root component and a target argument:
 ```js
 await mount(Root, document.body);
 ```
 Rationale: the `mount` method is only useful anyway for small toy examples,
 because real applications will need to configure the templates, the translations,
 and other stuff. All complex usecases need to go through the new `App` class,
 that encapsulates the root of an owl application.
 ### 5. components can no longer be instantiated and mounted by hand
 In Owl 1, it was possible to instantiate a component by hand:
 ```js
 const root = new Root();
 await root.mount(document.body);
 ```
 Now, it is no longer possible. All component instantiations should be done by
 the owl framework itself.
 Rationale: the `mount` method does not make sense for all non root components.
 Also, the fact that it was possible for a component to be sometimes root,
 sometimes a child made for a weird constructor signature. This changes makes it
 simpler.
 Migration: all code doing that should use either the `mount` method (if the use
 case is simple enough, or the `App` class):
 ```js
 const app = new App(Root);
 app.configure({ templates: ..., ...});
 await app.mount(document.body);
 ```
 ### 6. components can no longer be unmounted/remounted
 Rationale: this is a very difficult feature to implement (it adds a lot of possible
 state transitions), compared to its benefit.
 Migration: all code using it should find a way to export and reimport the state
 ### 7. template name is no longer inferred from the class name
 Before, it was possible to define a component without specifying its template:
 ```js
 class Blabla extends Component {
    // no static template here!
 }
 ```
 with the `Blabla` template. It also worked with subclasses. But then, this means
 that the code had to look up all the super classes names to find the correct
 template.
 Rationale: in practice, it is not really useful, since all templates are usually
 namespaced: `web.SomeComponent` anyway. All the trouble to do that was just not
 worth it.
 Migration: simply explicitely defines the template key everytime:
 ```js
 class Blabla extends Component {}
 Blabla.template = "Blabla";
 ```
 ### 8. components no longer have a `shouldUpdate` method
 Rationale: `shouldUpdate` is a dangerous method to use, that may cause a lot of
 issues. Vue does not have such a mechanism (see https://github.com/vuejs/vue/issues/4255),
 because the reactivity system in Vue is smart enough to only rerender the minimal
 subset of components that is subscribed to a piece of state. Now, Owl 2 features
 a much more powerful reactivity system.
 Migration code: remove the `shouldUpdate` methods. Then, maybe the following
 ideas may help:
 - try to organize the state/architecture to minimize the number of state updates
 - take advantage of the finer reactivity system. For example, if we have a list
  of items, with a component for each item, we can write this:
  ```js
  class Item extends Component {
      setup() {
          this.item = useState(this.props.item); // and only use this, not props.item
      }
  }
  ```
  Doing so will make it that each `Item` component will register itself as an
  observer of its own item, and will be the only component being rerendered when
  its item object is updated.
 - use the `Memo` component to wrap some piece of template. `Memo` memoize its
  content, and only update itself if its props are different (shallow comparison):
  ```xml
    <Memo a="state.a" b="state.b"> 
        <t t-esc="state.a"/>
        <t t-esc="state.b"/>
        <t t-esc="state.c"/>
    </Memo>
  ```
 ### 9. component.el may be a text node, and is no longer `null`
 This comes from the fact that Owl 2 supports fragments (arbitrary content). When
 it is not defined, it was `null` in Owl 1 and is `undefined` in owl 2.
 ### 10. style/class on components are now regular props
 Before, it was possible to do this in a template:
 ```xml
 <Child style="..." class="..."/>
 ```
 (or with `t-att-style` and `t-att-class`). This does no longer work, as they are
 now considered normal props.
 Rationale: with the move to fragments, the semantics of where the style/class
 attribute should be set is unclear. Also, it is actually very hard to implement
 properly, in particular with higher order components. And another issue is that
 it (slightly) breaks the encapsulation of behaviour from the `Child` component
 perspective.
 Migration: each component that wishes to be customized should explicitely add
 the `class` and `style` attributes in its template. Also, the parent component
 should be aware that since we are talking about props, it should be a javascript expression:
 In parent:
 ```xml
 <Child class="'o_my_god'"/>
 ```
 and in child:
 ```xml
    <div t-att-class="props.class">
        ...
    </div>
 ```
 ### 11. components can no longer be mounted with position=self
 Rationale: this is due to the implementation of owl 2 virtual dom. The hack
 necessary to support position=self does not work. This position also is not
 compatible with the fact that a component can have a root `<div>` then later,
 change it to something else, or even a text node.
 Migration: no real way to do the same. Owl application needs to be appended or
 prepended in something, maybe a `div`.
 ### 12. `t-on` does not work on components any more
 In owl 1, it was possible to bind an event listener on a component tag in a
 template:
 ```xml
 <SomeComponent t-on-some-event="doSomething"/>
 ```
 This does not work any more.
 Rationale: with the support of fragments, there is no longer a canonical html
 element that we can refer. So, this makes it difficult to implement correctly
 and efficiently. Also, we noticed in practice that the event system was an issue
 in some cases, when components need to communicate before they are mounted. In
 those cases, the better solution is to directly use a callback.  Also, another
 conceptual issue with this is that it kind of breaks the component encapsulation.
 The child component kind of leak its own implementation to the outside world.
 Migration: a quick fix that may work in some cases is to simply bind the event
 handler on a parent htmlelement. A better way to do it, if possible, is to change
 the component API to accept explicitely a callback as props. 
 ```xml
 <SomeComponent onSomeEvent="doSomething"/>
 ```
 ### 13. Portal does no longer transfer DOM events
 In Owl 1, a Portal component would listen to events emitted on its portalled
 child, and redispatch them on itself. It no longer works.
 Rationale: Portal now supports an arbitrary content (so, more than one child,
 and potentially no html element), so it is already unclear what it should listen
 to. Also, redispatching events was an hack. And this changes allows the portal
 to render itself as a text node, which is nice. This is also in line with the
 fact that modern Owl moves toward using callback instead of `t-on` for communication.
 Migration: use callback if possible to communicate. Otherwise, use a sub env.
 ### 14. Portal does render as an empty text node instead of `<portal/>`
 That is pretty nice. No real migration needed.
 ### 15. Context is removed
 Context was an abstraction in Owl that was used to define some reactive state
 and to let some components subscribe to it, then only them would be rerendered
 if the context was updated. This has been removed.
 Rationale: first, the Context api and code was kind of awkward, which is a sign
 that the abstraction is not well thought. But the good news is that it is actually
 completely replaced by the new reactivity system, which is even more powerful,
 since it can tracks changes key by key.
 Migration: replace all uses of Context with the new reactivity system.
 ```js
 // somewhere, maybe in a service, or in the global env
 const context = observe({some: "state"})
 // in a component that would previously get a reference to the context:
 setup() {
    this.context = useState(context);
    // now the component is subscribed to the context and will react to any
    // change for any key read by the component, and only those changes
 }
 ```
 ### 16. `env` is now totally empty
 In Owl 1, the `env` object had to contain a QWeb instance. This was the way
 components would get a reference to their template function. It no longer works
 that way: the `env` object is now totally empty (from the perspective of Owl).
 It is now a user space concept, useful for the application.
 Rationale: first, there is no longer a QWeb class. Also, this changes simplifies
 the way components works internally.
 Migration: there is no proper way to get an equivalent. The closest is to get
 a reference to the root App using `this.__owl__.app`. If you need to do this,
 let us know. If this is a legitimate usecase, we may add a `useApp` hook.
 ### 17. `t-component` no longer accepts strings
 In owl 1, we could write this:
 ```xml
 <t t-component="Coucou"/>
 ```
 This meant that Owl would look for the component class like this: `components["Coucou"]`,
 so, essentially equivalent to `<Coucou/>`. In Owl 2, the `t-component` directive
 is assumed to be an expression evaluating to a component class:
 ```js
 class Parent extends Component {
  static template = xml`<t t-component="Child"/>`;
  Child = Child;
 }
 ```
 Rationale: it simply seems more consistent with the way directive works. Also,
 the implementation is slightly simpler.
 Migration: simply using `constructor.components.Coucou` instead of `Coucou` will
 do the trick.
 ### 18. most exports are exported at top level
 Most exports are flattened: for ex, `onMounted` is in owl, not in `owl.hooks`.
 Rationale: this makes it easier to work with, instead of importing stuff from 
 `owl`, then `owl.hooks` and `owl.tags` for example.
 Migration: all import code simply need to be slightly adapted.
 ### 19. Properties are no longer set as attributes
 Formerly, html properties `<input type="checkbox" t-att-checked="blah"/>` were
 set as property and as attribute, so, they would be visible in the DOM:
 `<input type="checkbox" checked="blah"/>`. Now, they are treated as property only:
 `<input type="checkbox"/>`.
 Rationale: this is actually simple to do, is faster, and makes more sense to me.
 ### 20. `t-foreach` should always have a corresponding `t-key`
 It was possible in Owl 1 to write a `t-foreach` without a `t-key`. In that case,
 the index was used as key.  Since it was clearly a possible bug, Owl 1 had a
 warning in some cases, when it could detect that there was definitely not a `t-key`.
 However, this was imperfect, and in some cases no warning was displayed. In Owl 2,
 the tag with a `t-foreach` has to have a corresponding `t-key`.
 Rationale: this makes it easier to avoid bugs.
 Migration: simply move the `t-key` to the tag with the `t-foreach`. If this is
 a situation where there is really not a need for a `t-key`, you can still add
 it with the `_index` suffix:
 ```xml
 <div t-foreach="items" t-as="item" t-key="item_index">
  ...
 </div>
 ```
 ### 21. `EventBus` api changed: it is now an `EventTarget`
 In Owl 1, the `EventBus` class was done manually, with a custom API. In Owl 2,
 it simply extends `EventTarget` (the native Dom class), so its implementation
 is basically only 5 lines long. This means that it has now the usual DOM interface:
 ```js
 bus.addEventListener('event-name', callback);
 ```
 Rationale: it makes it easier to have just one interface to remember, it makes
 the code simpler
 Migration: most bus methods need to be adapted. So, `bus.on("event-type", owner, (info) => {...})` has to be
 rewritten like this: `bus.addEventListener("event-type", (({detail: info}) => {...}).bind(owner))`.
 Do not forget to similarly replace `bus.off(...)` by `bus.removeEventListener(...)`
 ### 22. `Store` is removed
 The Store system had been abandoned in owl 2.
 Rationale: first, it was complicated to maintain. Second, it was not really
 used in Odoo. Finally, the new reactivity system seems to be a pretty good basis
 to write a store, and it should not take much work. Also, this can be done in
 user space (so, not necessarily at the framework level). Another point is that
 the store API was invented before the hooks, then was still a little awkward.
 Migration:
 - rewrite the code not to use a store
 - probably use the reactivity system instead and build a store class and a few
  hooks on top of it.
 ### 23. `Router` is removed
 Rationale: Router was not used that much, and it felt like it did not fit in Owl 2.
 Its API needs to be reworked, and we are not confident that it is a good
 experience to use it. Also, it can be done in userspace (it does not need specific
 integration at the framework level)
 Migration: reimport all missing piece from the code in Owl 1.
 ### 24. transition system is removed
 Rationale: this was a high ratio cost/value, with a lot of potential for bugs.
 We feel like there should be a way to reimplement in userspace the simple cases.
 Maybe something like: add a `t-ref` in the template, and define a hook `useFadeOut`
 that takes the ref, and add a fadeout class at initial render, then in mounted,
 wait for a micro tick and remove it.
 Migration: try to reimplement it manually. 
 ### 25. no more global components or templates
 It was possible in Owl 1 to register globally a component or a template. This is
 no longer the case in Owl 2.
 Rationale: first, this was a tradeoff: ease of use was gained, but at the cost
 of a higher complexity. Users had to know that there was a magic mechanism. Also,
 it was not used much in practice, and the cost of having to import manually components
 is low.  Finally, this can be mostly done in user space (for example, by subclassing
 `Component`).
 Migration: import manually all required global components, or find a way to organize
 the code to do it.
 ### 26. `AsyncRoot` utility component is removed
 Rationale: it was difficult to understand, never used, and not really useful.
 It seems better to control the asynchrony of an application by simply controlling
 how/when the state is updated, and how each component is loading/updating itself.
 Migration: remove the `AsyncRoot` component, then possibly, reorganize the code
 to fetch data in a higher order component, and using a `t-if/t-else` to display
 either a fallback when the data is not ready, or the actual component with data
 as props.  If there is no escape, and `AsyncRoot` is needed, please reach out to
 us so we can study this usecase.
 ### 27. `useSubEnv` only applies to child components
 In Owl 1, a call to `useSubEnv` would define a new environment for the children
 AND the component. It now only defines an environment for the children.
 Rationale: This was a subtle cause for bugs: some code had to be rrun
 before the call to `useSubEnv`, otherwise it could interfere with the sub environment.
 ### 28. `env` is now frozen
 In Owl 2, the `env` object is frozen. It can no longer be modified (structurally)
 arbitrarily. 
 Rationale: it seems like the `env` object purpose is to have a global channel of
 communication between components. It is however scary if anyone can add something
 to it.  The usual use case is to add something to the environment for some child
 components. This use case still works with `useSubEnv`.
 Migration: use `useSubEnv` instead of writing directly to the env.  Also, note
 that the environment given to the App can initially contain anything.
 ### 29. `t-ref` does not work on component
 Before, `t-ref` could be used to get a reference to a child component. It no
 longer works.
 Rationale: the possibility of having a ref to a child component breaks the
 encapsulation provided by Owl components: a child component now has a private
 and a public interface.  Another issue is that it may be unclear when the ref
 should be set: is the component active on setup, or on mounted? Also, it is
 kind of awkward to implement.
 Migration: the `env` and `props` should provide a communication channel wide enough:
 the sub component can expose its public API by calling a callback at the proper
 timing, or by triggering an event.
 ### 30. `t-on` does not accept expressions, only functions
 In Owl 1, it was possible to define simple expressions inline, in a template:
 ```xml
 <button t-on-click="state.value = state.value + 1">blabla</button>
 <button t-on-click="someFunction(someVar)">blabla</button>
 ```
 This does not work anymore. Now, the `t-on` directive assumes that what it get is
 a function.
 Rationale: the fact that owl 1 had to support expressions meant that it was not
 possible to properly inject the event in general. With this restriction, Owl 2
 can support more general use cases. Also, the examples above can simply be
 wrapped in a lambda function. 
 Migration: use lambda functions. For example, the two examples above can be
 adapted like this:
 ```xml
 <button t-on-click="() => state.value = state.value + 1">blabla</button>
 <button t-on-click="() => this.someFunction(someVar)">blabla</button>
 ```
 ### 31. components can now have arbitrary content
 Before Owl 2, components had to limit themselves to one single htmlelement as
 root. Now, the content is arbitrary: it can be empty, or multiple html elements.
 So, the following template works for components:
 ```xml
  <div>1</div>
  <div>2</div>
  hello
 ```
 ### 32. `renderToString` on QWeb has been removed
 Rationale: the `renderToString` function was a qweb method, which made sense because
 the qweb instance knew all templates. But now, the closest analogy is the `App`
 class, but it is not as convenient, since the `app` instance is no longer visible
 to components (while before, `qweb` was in the environment).
 Also, this can easily be done in userspace, by mounting a component in a div.  For example:
 ```js
 export async function renderToString(template, context) {
  class C extends Component {
    static template = template;
  }
  const div = document.createElement('div');
  document.body.appendChild(div);
  const component = await mount(C, div);
  const result = div.innerHTML;
  app.destroy();
  div.remove();
  return result;
 }
@@ -0,0 +1,14 @@
 Most of the files are
  Copyright (c) 2004-2015 Odoo S.A.
 Many files also contain contributions from third
 parties. In this case the original copyright of
 the contributions can be traced through the
 history of the source version control system.
 When that is not the case, the files contain a prominent
 notice stating the original copyright and applicable
 license, or come with their own dedicated COPYRIGHT
 and/or LICENSE file.
@@ -1,102 +1,130 @@
-<h1 align="center">🦉 <a href="https://odoo.github.io/owl/">Odoo Web Library</a> 🦉</h1>
+<h1 align="center">🦉 <a href="https://odoo.github.io/owl/">Owl Framework</a> 🦉</h1>
-_A web framework for structured, dynamic and maintainable applications_
+ [![License: LGPL v3](https://img.shields.io/badge/License-LGPL%20v3-blue.svg)](https://www.gnu.org/licenses/lgpl-3.0)
 [![npm version](https://badge.fury.io/js/@odoo%2Fowl.svg)](https://badge.fury.io/js/@odoo%2Fowl)
 [![Downloads](https://img.shields.io/npm/dm/@odoo%2Fowl.svg)](https://www.npmjs.com/package/@odoo/owl)
 _Class based components with hooks, reactive state and concurrent mode_
 **Try it online!** you can experiment with the Owl framework in an online [playground](https://odoo.github.io/owl/playground).
 ## Project Overview
-The Odoo Web Library (OWL) is a small (~16kb gzipped) UI framework intended to be the basis for
+The Odoo Web Library (Owl) is a smallish (~<20kb gzipped) UI framework built by
-the [Odoo](https://www.odoo.com/) Web Client, and hopefully many other Odoo
+[Odoo](https://www.odoo.com/) for its products. Owl is a modern
-related projects. OWL's main features are:
+framework, written in Typescript, taking the best ideas from React and Vue in a
 simple and consistent way. Owl's main features are:
- a _declarative component system_, (template based, with asynchronous rendering and a virtual dom)
+- a declarative component system,
- a store implementation (for state management)
+- a reactivity system based on hooks,
- a small frontend router
+- concurrent mode by default,
-**Try it online!** An online playground is available at [https://odoo.github.io/owl/playground](https://odoo.github.io/owl/playground) to let you experiment with the OWL framework.
+Owl components are defined with ES6 classes and xml templates, uses an
 underlying virtual DOM, integrates beautifully with hooks, and the rendering is
 asynchronous.
-## OWL's Design Principles
+Quick links:
-OWL is designed to be used in highly dynamic applications where changing
+- [documentation](#documentation),
-requirements are common and code needs to be maintained by large teams.
+- [changelog](CHANGELOG.md) (from Owl 1.x to 2.x),
-
+- [playground](https://odoo.github.io/owl/playground)
 - **XML based**: templates are based on the XML format, which allows interesting
  applications. For example, they could be stored in a database and modified
  dynamically with `xpaths`.
 - **templates compilation in the browser**: this may not be a good fit for all
  applications, but if you need to generate dynamically user interfaces in the
  browser, this is very powerful. For example, a generic form view component
  could generate a specific form user interface for each various models, from a XML view.
 - **no toolchain required**: this is extremely useful for some applications, if,
  for various reasons (security/deployment/dynamic modules/specific assets tools),
  it is not ok to use standard web tools based on `npm`.
 Owl is not designed to be fast nor small (even though it is quite good on those
 two topics). It is a no nonsense framework to build applications.  There is only
 one way to define components (with classes).
 If you are interested in a comparison with React or Vue, you will
 find some more information [here](doc/comparison.md).
 ## Example
 Here is a short example to illustrate interactive components:
 ```xml
 <templates>
  <button t-name="Counter" t-on-click="increment">
    Click Me! [<t t-esc="state.value"/>]
  </button>
 </templates>
 ```
 ```javascript
-class Counter extends owl.Component {
+const { Component, useState, mount, xml } = owl;
  state = { value: 0 };
-  increment() {
+class Counter extends Component {
-    this.state.value++;
+  static template = xml`
-  }
+    <button t-on-click="() => state.value++">
      Click Me! [<t t-esc="state.value"/>]
    </button>`;
  state = useState({ value: 0 });
 }
-const qweb = new owl.QWeb(TEMPLATES);
+class App extends Component {
-const counter = new Counter({ qweb });
+  static template = xml`
-counter.mount(document.body);
+    <div>
      <span>Hello Owl</span>
      <Counter />
    </div>`;
  static components = { Counter };
 }
 mount(App, document.body);
 ```
-Note that we assume here that the xml templates are available in the `TEMPLATES`
+Note that the counter component is made reactive with the [`useState` hook](doc/reference/hooks.md#usestate).
-string. More interesting examples can be found on the
+Also, all examples here uses the [`xml` helper](doc/reference/tags.md#xml-tag) to define inline templates.
 But this is not mandatory, many applications will load templates separately.
 More interesting examples can be found on the
 [playground](https://odoo.github.io/owl/playground) application.
 ## Installing/Building
 If you want to use a simple `<script>` tag, the last release can be downloaded here:
 - [owl-0.19.0.js](https://github.com/odoo/owl/releases/download/v0.19.0/owl.js)
 - [owl-0.19.0.min.js](https://github.com/odoo/owl/releases/download/v0.19.0/owl.min.js)
 Some npm scripts are available:
 | Command               | Description                                                                  |
 | --------------------- | ---------------------------------------------------------------------------- |
 | `npm install`         | install every dependency required for this project                           |
 | `npm run build`       | build a bundle of _owl_ in the _/dist/_ folder                               |
 | `npm run minify`      | minify the prebuilt owl.js file                                              |
 | `npm run test`        | run all tests                                                                |
 | `npm run test:watch`  | run all tests, and keep a watcher                                            |
 | `npm run tools`       | build tools applications, start a static server (see [here](doc/tooling.md)) |
 | `npm run tools:watch` | same as `tools`, but with a watcher to rebuild owl                           |
 ## Documentation
-The complete documentation can be found [here](doc/readme.md). The most important sections are:
+### Learning Owl
- [Quick Start](doc/quick_start.md)
+Are you new to Owl? This is the place to start!
 - [Component](doc/component.md)
 - [QWeb](doc/qweb.md)
-Found an issue in the documentation? A broken link? Some outdated information?
+- [Tutorial: create a TodoList application](doc/learning/tutorial_todoapp.md)
-Submit a PR!
+- [How to start an Owl project](doc/learning/quick_start.md)
 - [How to test Components](doc/learning/how_to_test.md)
 - [How to write Single File Components](doc/learning/how_to_write_sfc.md)
-## License
+### Reference
 You will find here a complete reference of every feature, class or object
 provided by Owl.
 - [Animations](doc/reference/animations.md)
 - [Browser](doc/reference/browser.md)
 - [Component](doc/reference/component.md)
 - [Content](doc/reference/content.md)
 - [Concurrency Model](doc/reference/concurrency_model.md)
 - [Configuration](doc/reference/config.md)
 - [Context](doc/reference/context.md)
 - [Environment](doc/reference/environment.md)
 - [Event Bus](doc/reference/event_bus.md)
 - [Event Handling](doc/reference/event_handling.md)
 - [Error Handling](doc/reference/error_handling.md)
 - [Hooks](doc/reference/hooks.md)
 - [Mounting a component](doc/reference/mounting.md)
 - [Miscellaneous Components](doc/reference/misc.md)
 - [Observer](doc/reference/observer.md)
 - [Props](doc/reference/props.md)
 - [Props Validation](doc/reference/props_validation.md)
 - [QWeb Templating Language](doc/reference/qweb_templating_language.md)
 - [QWeb Engine](doc/reference/qweb_engine.md)
 - [Slots](doc/reference/slots.md)
 - [Tags](doc/reference/tags.md)
 - [Utils](doc/reference/utils.md)
 ### Other Topics
 This section provides miscellaneous document that explains some topics
 which cannot be considered either a tutorial, or reference documentation.
 - [Owl architecture: the Virtual DOM](doc/miscellaneous/vdom.md)
 - [Owl architecture: the rendering pipeline](doc/miscellaneous/rendering.md)
 - [Comparison with React/Vue](doc/miscellaneous/comparison.md)
 - [Why did Odoo built Owl?](doc/miscellaneous/why_owl.md)
 ## Installing Owl
 Owl is available on `npm` and can be installed with the following command:
 ```
 npm install @odoo/owl
 ```
 If you want to use a simple `<script>` tag, the last release can be downloaded here:
 - [owl-1.4.7](https://github.com/odoo/owl/releases/tag/v1.4.7)
 OWL is [GPL licensed](./LICENSE).
@@ -0,0 +1,95 @@
 # 🦉 How to test Components 🦉
 ## Content
 - [Overview](#overview)
 - [Unit Tests](#unit-tests)
 ## Overview
 It is a good practice to test applications and components to ensure that they
 behave as expected. There are many ways to test a user interface: manual
 testing, integration testing, unit testing, ...
 In this section, we will discuss how to write unit tests for components.
 ## Unit Tests
 Writing unit tests for Owl components really depends on the testing framework
 used in a project. But usually, it involves the following steps:
 - create a test file: for example `SomeComponent.test.js`,
 - in that file, import the code for `SomeComponent`,
 - add a test case:
  - create a real DOM element to use as test fixture,
  - create a test environment
  - create an instance of `SomeComponent`, mount it to the fixture
  - interact with the component and assert some properties.
 To help with this, it is useful to have a `helper.js` file that contains some
 common utility functions:
 ```js
 let lastFixture = null;
 export function makeTestFixture() {
  let fixture = document.createElement("div");
  document.body.appendChild(fixture);
  if (lastFixture) {
    lastFixture.remove();
  }
  lastFixture = fixture;
  return fixture;
 }
 export async function nextTick() {
  await new Promise((resolve) => setTimeout(resolve));
  await new Promise((resolve) => requestAnimationFrame(resolve));
 }
 ```
 With such a file, a typical test suite for Jest will look like this:
 ```js
 // in SomeComponent.test.js
 import { SomeComponent } from "../../src/ui/SomeComponent";
 import { nextTick, makeTestFixture } from '../helpers';
 //------------------------------------------------------------------------------
 // Setup
 //------------------------------------------------------------------------------
 let fixture: HTMLElement;
 let env: Env;
 beforeEach(() => {
  fixture = makeTestFixture();
 });
 afterEach(() => {
  fixture.remove();
 });
 //------------------------------------------------------------------------------
 // Tests
 //------------------------------------------------------------------------------
 describe("SomeComponent", () => {
  test("component behaves as expected", async () => {
    const props = {...}; // depends on the component
    const comp = await mount(SomeComponent, fixture, { props });
    // do some assertions
    expect(...).toBe(...);
    fixture.querySelector('button').click();
    await nextTick();
    // some other assertions
    expect(...).toBe(...);
  });
 });
 ```
 Note that Owl does wait for the next animation frame to actually update the DOM.
 This is why it is necessary to wait with the `nextTick` (or other methods) to
 make sure that the DOM is up-to-date.
@@ -0,0 +1,52 @@
 # 🦉 How to write Single File Components 🦉
 It is very useful to group code by feature instead of by type of file. It makes
 it easier to scale application to larger size.
 To do so, Owl has two small helpers that make it easy to define a
 template or a stylesheet inside a javascript (or typescript) file: the
 [`xml`](../reference/tags.md#xml-tag) and [`css`](../reference/tags.md#css-tag)
 helper.
 This means that the template, the style and the javascript code can be defined in
 the same file. For example:
 ```js
 const { Component } = owl;
 const { xml, css } = owl.tags;
 // -----------------------------------------------------------------------------
 // TEMPLATE
 // -----------------------------------------------------------------------------
 const TEMPLATE = xml/* xml */ `
 	<div class="main">
 		<Sidebar/>
 		<Content />
 	</div>`;
 // -----------------------------------------------------------------------------
 // STYLE
 // -----------------------------------------------------------------------------
 const STYLE = css/* css */ `
  .main {
    display: grid;
    grid-template-columns: 200px auto;
  }
 `;
 // -----------------------------------------------------------------------------
 // CODE
 // -----------------------------------------------------------------------------
 class Main extends Component {
  static template = TEMPLATE;
  static style = STYLE;
  static components = { Sidebar, Content };
  // rest of component...
 }
 ```
 Note that the above example has an inline xml comment, just after the `xml` call.
 This is useful for some editor plugins, such as the VS Code addon
 `Comment tagged template`, which, if installed, add syntax highlighting to the
 content of the template string.
@@ -0,0 +1,399 @@
 # 🦉 How to start an Owl project 🦉
 ## Content
 - [Overview](#overview)
 - [Simple html file](#simple-html-file)
 - [With a static server](#with-a-static-server)
 - [Standard Javascript project](#standard-javascript-project)
 ## Overview
 Each software project has its specific needs. Many of these needs can be solved
 with some tooling: `webpack`, `gulp`, css preprocessor, bundlers, transpilers, ...
 Because of that, it is usually not simple to just start a project. Some
 frameworks provide their own tooling to help with that. But then, you have to
 integrate and learn how these applications work.
 Owl is designed to be used with no tooling at all. Because of that, Owl can
 "easily" be integrated in a modern build toolchain. In this section, we will
 discuss a few different setups to start a project. Each of these setups has
 advantages and disadvantages in different situations.
 ## Simple html file
 The simplest possible setup is the following: a simple javascript file with your
 code. To do that, let us create the following file structure:
 ```
 hello_owl/
  index.html
  owl.js
  app.js
 ```
 The file `owl.js` can be downloaded from the last release published at
 [https://github.com/odoo/owl/releases](https://github.com/odoo/owl/releases). It
 is a single javascript file which export all Owl into the global `owl` object.
 Note that there are multiple files, and in this case, we need one of the two
 files suffixed with `.iife`: they are built to be directly used in a browser.
 Now, `index.html` should contain the following:
 ```html
 <!DOCTYPE html>
 <html lang="en">
  <head>
    <title>Hello Owl</title>
    <script src="owl.js"></script>
  </head>
  <body>
    <script src="app.js"></script>
  </body>
 </html>
 ```
 And `app.js` should look like this:
 ```js
 const { Component, mount, xml } = owl;
 // Owl Components
 class Root extends Component {
  static template = xml`<div>Hello Owl</div>`;
 }
 mount(Root, document.body);
 ```
 Now, simply loading this html file in a browser should display a welcome message.
 This setup is not fancy, but it is extremely simple. There are no tooling at
 all required. It can be slightly optimized by using the minified build of Owl.
 ## With a static server
 The previous setup has a big disadvantage: the application code is located in a
 single file. Obviously, we could split it in several files and add multiple
 `<script>` tags in the html page, but then we need to make sure the script are
 inserted in the proper order, we need to export each file content in global
 variables and we lose autocompletion across files.
 There is a low tech solution to this issue: using native javascript modules.
 This however has a requirement: for security reasons, browsers will not accept
 modules on content served through the `file` protocol. This means that we need
 to use a static server.
 Let us start a new project with the following file structure:
 ```
 hello_owl/
  src/
    index.html
    main.js
    owl.js
    root.js
 ```
 As previously, the file `owl.js` can be downloaded from the last release published at
 [https://github.com/odoo/owl/releases](https://github.com/odoo/owl/releases).
 Note that there are multiple files, and in this case, we need one of the two
 files suffixed with `.iife`: they are built to be directly used in a browser.
 Now, `index.html` should contain the following:
 ```html
 <!DOCTYPE html>
 <html lang="en">
  <head>
    <title>Hello Owl</title>
    <script src="owl.js"></script>
  </head>
  <body>
    <script src="main.js" type="module"></script>
  </body>
 </html>
 ```
 Not that the `main.js` script tag has the `type="module"` attribute. This means
 that the browser will parse the script as a module, and load all its dependencies.
 Here is the content of `root.js` and `main.js`:
 ```js
 // root.js ----------------------------------------------------------------------
 const { Component, mount, xml } = owl;
 export class Root extends Component {
  static template = xml`<div>Hello Owl</div>`;
 }
 // main.js ---------------------------------------------------------------------
 import { Root } from "./root.js";
 mount(Root, document.body);
 ```
 The `main.js` file imports the `root.js` file. Note that the import statement has
 a `.js` suffix, which is important. Most text editor can understand this syntax
 and will provide autocompletion.
 Now, to execute this code, we need to serve the `src` folder statically. A low
 tech way to do that is to use for example the python `SimpleHTTPServer` feature:
 ```
 $ cd src
 $ python -m SimpleHTTPServer 8022    # now content is available at localhost:8022
 ```
 Another more "javascripty" way to do it is to create a `npm` application. To do
 that, we can add the following `package.json` file at the root of the project:
 ```json
 {
  "name": "hello_owl",
  "version": "0.1.0",
  "description": "Starting Owl app",
  "main": "src/index.html",
  "scripts": {
    "serve": "serve src"
  },
  "author": "John",
  "license": "ISC",
  "devDependencies": {
    "serve": "^11.3.0"
  }
 }
 ```
 We can now install the `serve` tool with the command `npm install`, and then,
 start a static server with the simple `npm run serve` command.
 ## Standard Javascript project
 The previous setup works, and is certainly good for some usecases, including
 quick prototyping. However, it lacks some useful features, such as livereload,
 a test suite, or bundling the code in a single file.
 Each of these features, and many others, can be done in many different ways.
 Since it is really not trivial to configure such a project, we provide here an
 example that can be used as a starting point.
 Our standard Owl project has the following file structure:
 ```
 hello_owl/
  public/
    index.html
  src/
    components/
      Root.js
    main.js
  tests/
    components/
      Root.test.js
    helpers.js
  .gitignore
  package.json
  webpack.config.js
 ```
 This project as a `public` folder, meant to contain all static assets, such as
 images and styles. The `src` folder has the javascript source code, and finally,
 `tests` contains the test suite.
 Here is the content of `index.html`:
 ```html
 <!DOCTYPE html>
 <html lang="en">
  <head>
    <title>Hello Owl</title>
  </head>
  <body></body>
 </html>
 ```
 Note that there are no `<script>` tag here. They will be injected by webpack.
 Now, let's have a look at the javascript files:
 ```js
 // src/components/Root.js -------------------------------------------------------
 import { Component, xml, useState } from "@odoo/owl";
 export class Root extends Component {
  static template = xml`
    <div t-on-click="update">
      Hello <t t-esc="state.text"/>
    </div>`;
  state = useState({ text: "Owl" });
  update() {
    this.state.text = this.state.text === "Owl" ? "World" : "Owl";
  }
 }
 // src/main.js -----------------------------------------------------------------
 import { utils, mount } from "@odoo/owl";
 import { Root } from "./components/Root";
 mount(Root, document.body);
 // tests/components/Root.test.js ------------------------------------------------
 import { Root } from "../../src/components/Root";
 import { makeTestFixture, nextTick, click } from "../helpers";
 import { mount } from "@odoo/owl";
 let fixture;
 beforeEach(() => {
  fixture = makeTestFixture();
 });
 afterEach(() => {
  fixture.remove();
 });
 describe("Root", () => {
  test("Works as expected...", async () => {
    await mount(Root, fixture);
    expect(fixture.innerHTML).toBe("<div>Hello Owl</div>");
    click(fixture, "div");
    await nextTick();
    expect(fixture.innerHTML).toBe("<div>Hello World</div>");
  });
 });
 // tests/helpers.js ------------------------------------------------------------
 import { Component } from "@odoo/owl";
 import "regenerator-runtime/runtime";
 export async function nextTick() {
  await new Promise((resolve) => setTimeout(resolve));
  await new Promise((resolve) => requestAnimationFrame(resolve));
 }
 export function makeTestFixture() {
  let fixture = document.createElement("div");
  document.body.appendChild(fixture);
  return fixture;
 }
 export function click(elem, selector) {
  elem.querySelector(selector).dispatchEvent(new Event("click"));
 }
 ```
 Finally, here is the configuration files `.gitignore`, `package.json` and
 `webpack.config.js`:
 ```
 node_modules/
 package-lock.json
 dist/
 ```
 ```json
 {
  "name": "hello_owl",
  "version": "0.1.0",
  "description": "Demo app",
  "main": "src/index.html",
  "scripts": {
    "test": "jest",
    "build": "webpack --mode production",
    "dev": "webpack-dev-server --mode development"
  },
  "author": "Someone",
  "license": "ISC",
  "devDependencies": {
    "@babel/core": "^7.8.4",
    "@babel/plugin-proposal-class-properties": "^7.8.3",
    "babel-jest": "^25.1.0",
    "babel-loader": "^8.0.6",
    "babel-plugin-transform-es2015-modules-commonjs": "^6.26.2",
    "html-webpack-plugin": "^3.2.0",
    "jest": "^25.1.0",
    "regenerator-runtime": "^0.13.3",
    "serve": "^11.3.0",
    "webpack": "^4.41.5",
    "webpack-cli": "^3.3.10",
    "webpack-dev-server": "^3.10.2"
  },
  "dependencies": {
    "@odoo/owl": "^1.0.4"
  },
  "babel": {
    "plugins": ["@babel/plugin-proposal-class-properties"],
    "env": {
      "test": {
        "plugins": ["transform-es2015-modules-commonjs"]
      }
    }
  },
  "jest": {
    "verbose": false,
    "testRegex": "(/tests/.*(test|spec))\\.js?$",
    "moduleFileExtensions": ["js"],
    "transform": {
      "^.+\\.[t|j]sx?$": "babel-jest"
    }
  }
 }
 ```
 ```js
 const path = require("path");
 const HtmlWebpackPlugin = require("html-webpack-plugin");
 const host = process.env.HOST || "localhost";
 module.exports = function (env, argv) {
  const mode = argv.mode || "development";
  return {
    mode: mode,
    entry: "./src/main.js",
    output: {
      filename: "main.js",
      path: path.resolve(__dirname, "dist"),
    },
    module: {
      rules: [
        {
          test: /\.jsx?$/,
          loader: "babel-loader",
          exclude: /node_modules/,
        },
      ],
    },
    resolve: {
      extensions: [".js", ".jsx"],
    },
    devServer: {
      contentBase: path.resolve(__dirname, "public/index.html"),
      compress: true,
      hot: true,
      host,
      port: 3000,
      publicPath: "/",
    },
    plugins: [
      new HtmlWebpackPlugin({
        inject: true,
        template: path.resolve(__dirname, "public/index.html"),
      }),
    ],
  };
 };
 ```
 With this setup, we can now use the following script commands:
 ```
 npm run build # build the full application in prod mode in dist/
 npm run dev # start a dev server with livereload
 npm run test # run the jest test suite
 ```
@@ -0,0 +1,992 @@
 # 🦉 OWL Tutorial: TodoApp 🦉
 For this tutorial, we will build a very simple Todo list application. The app
 should satisfy the following requirements:
 - let the user create and remove tasks
 - tasks can be marked as completed
 - tasks can be filtered to display active/completed tasks
 This project will be an opportunity to discover and learn some important Owl
 concepts, such as components, store, and how to organize an application.
 ## Content
 1. [Setting up the project](#1-setting-up-the-project)
 2. [Adding a first component](#2-adding-a-first-component)
 3. [Displaying a list of tasks](#3-displaying-a-list-of-tasks)
 4. [Layout: some basic css](#4-layout-some-basic-css)
 5. [Extracting Task as a subcomponent](#5-extracting-task-as-a-subcomponent)
 6. [Adding tasks (part 1)](#6-adding-tasks-part-1)
 7. [Adding tasks (part 2)](#7-adding-tasks-part-2)
 8. [Toggling tasks](#8-toggling-tasks)
 9. [Deleting tasks](#9-deleting-tasks)
 10. [Using a store](#10-using-a-store)
 11. [Saving tasks in local storage](#11-saving-tasks-in-local-storage)
 12. [Filtering tasks](#12-filtering-tasks)
 13. [The Final Touch](#13-the-final-touch)
 14. [Final Code](#final-code)
 ## 1. Setting up the project
 For this tutorial, we will do a very simple project, with static files and
 no additional tooling. The first step is to create the following file structure:
 ```
 todoapp/
    index.html
    app.css
    app.js
    owl.js
 ```
 The entry point for this application is the file `index.html`, which should have
 the following content:
 ```html
 <!DOCTYPE html>
 <html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>OWL Todo App</title>
    <link rel="stylesheet" href="app.css" />
  </head>
  <body>
    <script src="owl.js"></script>
    <script src="app.js"></script>
  </body>
 </html>
 ```
 Then, `app.css` can be left empty for now. It will be useful later on to style
 our application. `app.js` is where we will write all our code. For now, let's
 just put the following code:
 ```js
 (function () {
  console.log("hello owl", owl.__info__.version);
 })();
 ```
 Note that we put everything inside an immediately executed function to avoid leaking
 anything to the global scope.
 Finally, `owl.js` should be the last version downloaded from the Owl repository (you can use `owl.min.js` if you prefer). Be aware that you should download the `owl.iife.js` or `owl.iife.min.js`, because these files
 are built to run directly on the browser, and rename it `owl.js` (other files such as `owl.cjs.js` are
 built to be bundled by other tools).
 Now, the project should be ready. Loading the `index.html` file into a browser
 should show an empty page, with the title `Owl Todo App`, and it should log a
 message such as `hello owl 2.x.y` in the console.
 ## 2. Adding a first component
 An Owl application is made out of [components](../reference/component.md), with
 a single root component. Let us start by defining a `Root` component. Replace the
 content of the function in `app.js` by the following code:
 ```js
 const { Component, mount, xml } = owl;
 // Owl Components
 class Root extends Component {
  static template = xml`<div>todo app</div>`;
 }
 mount(Root, document.body);
 ```
 Now, reloading the page in a browser should display a message.
 The code is pretty simple: we define a component with an inline template, then
 mount it in the document body.
 Note 1: in a larger project, we would split the code in multiple files, with
 components in a sub folder, and a main file that would initialize the application.
 However, this is a very small project, and we want to keep it as simple as possible.
 Note 2: this tutorial uses the static class field syntax. This is not yet
 supported by all browsers. Most real projects will transpile their code, so this
 is not a problem, but for this tutorial, if you need the code to work on every
 browser, you will need to translate each `static` keyword to an assignation to
 the class:
 ```js
 class App extends Component {}
 App.template = xml`<div>todo app</div>`;
 ```
 Note 3: writing inline templates with the [`xml` helper](../reference/tags.md#xml-tag)
 is nice, but there is no syntax highlighting, and this makes it very easy to
 have malformed xml. Some editors support syntax highlighting for this situation.
 For example, VS Code has an addon `Comment tagged template`, which, if installed,
 will properly display tagged templates:
 ```js
    static template = xml /* xml */`<div>todo app</div>`;
 ```
 Note 4: Large applications will probably want to be able to translate templates.
 Using inline templates makes it slightly harder, since we need additional tooling
 to extract the xml from the code, and to replace it with the translated values.
 ## 3. Displaying a list of tasks
 Now that the basics are done, it is time to start thinking about tasks. To
 accomplish what we need, we will keep track of the tasks as an array of objects
 with the following keys:
 - `id`: a number. It is extremely useful to have a way to uniquely identify
  tasks. Since the title is something created/edited by the user, it offers
  no guarantee that it is unique. So, we will generate a unique `id` number for
  each task.
 - `text`: a string, to explain what the task is about.
 - `isCompleted`: a boolean, to keep track of the status of the task
 Now that we decided on the internal format of the state, let us add some demo
 data and a template to the `App` component:
 ```js
 class Root extends Component {
  static template = xml/* xml */ `
    <div class="task-list">
        <t t-foreach="tasks" t-as="task" t-key="task.id">
            <div class="task">
                <input type="checkbox" t-att-checked="task.isCompleted"/>
                <span><t t-esc="task.text"/></span>
            </div>
        </t>
    </div>`;
  tasks = [
    {
      id: 1,
      text: "buy milk",
      isCompleted: true,
    },
    {
      id: 2,
      text: "clean house",
      isCompleted: false,
    },
  ];
 }
 ```
 The template contains a [`t-foreach`](../reference/qweb_templating_language.md#loops) loop to iterate
 through the tasks. It can find the `tasks` list from the component, since the
 component is the rendering context. Note that we use the `id` of each task as a
 `t-key`, which is very common. There are two css classes: `task-list` and `task`,
 that we will use in the next section.
 Finally, notice the use of the `t-att-checked` attribute:
 prefixing an attribute by [`t-att`](../reference/qweb_templating_language.md#dynamic-attributes) makes
 it dynamic. Owl will evaluate the expression and set it as the value of the
 attribute.
 ## 4. Layout: some basic css
 So far, our task list looks quite bad. Let us add the following to `app.css`:
 ```css
 .task-list {
  width: 300px;
  margin: 50px auto;
  background: aliceblue;
  padding: 10px;
 }
 .task {
  font-size: 18px;
  color: #111111;
 }
 ```
 This is better. Now, let us add an extra feature: completed tasks should be
 styled a little differently, to make it clearer that they are not as important.
 To do that, we will add a dynamic css class on each task:
 ```xml
    <div class="task" t-att-class="task.isCompleted ? 'done' : ''">
 ```
 ```css
 .task.done {
  opacity: 0.7;
 }
 ```
 Notice that we have here another use of a dynamic attribute.
 ## 5. Extracting Task as a subcomponent
 It is now clear that there should be a `Task` component to encapsulate the look
 and behavior of a task.
 This `Task` component will display a task, but it cannot _own_ the state of the
 task: a piece of data should only have one owner. Doing otherwise is asking for
 trouble. So, the `Task` component will get its data as a `prop`. This means that
 the data is still owned by the `App` component, but can be used by the `Task`
 component (without modifying it).
 Since we are moving code around, it is a good opportunity to refactor the code
 a little bit:
 ```js
 // -------------------------------------------------------------------------
 // Task Component
 // -------------------------------------------------------------------------
 class Task extends Component {
  static template = xml /* xml */`
    <div class="task" t-att-class="props.task.isCompleted ? 'done' : ''">
      <input type="checkbox" t-att-checked="props.task.isCompleted"/>
      <span><t t-esc="props.task.title"/></span>
    </div>`;
  static props = ["task"];
 }
 // -------------------------------------------------------------------------
 // Root Component
 // -------------------------------------------------------------------------
 class Root extends Component {
  static template = xml /* xml */`
    <div class="task-list">
      <t t-foreach="tasks" t-as="task" t-key="task.id">
        <Task task="task"/>
      </t>
    </div>`;
    static components = { Task };
    tasks = [
        ...
    ];
 }
 // -------------------------------------------------------------------------
 // Setup
 // -------------------------------------------------------------------------
 mount(Root, document.body, {dev: true});
 ```
 A lot of stuff happened here:
 - first, we have now a sub component `Task`, defined on top of the file,
 - whenever we define a sub component, it needs to be added to the static
  [`components`](../reference/component.md#static-properties)
  key of its parent, so Owl can get a reference to it,
 - the `Task` component has a `props` key: this is only useful for validation
  purpose. It says that each `Task` should be given exactly one prop, named
  `task`. If this is not the case, Owl will throw an
  [error](../reference/props_validation.md). This is extremely
  useful when refactoring components
 - finally, to activate the props validation, we need to set Owl's
  [mode](../reference/config.md#mode) to `dev`. This is done in the last argument
  of the `mount` function. Note that this should be removed when an app is used in a real
  production environment, since `dev` mode is slightly slower, due to extra
  checks and validations.
 ## 6. Adding tasks (part 1)
 We still use a list of hardcoded tasks. It's really time to give the user a way
 to add tasks himself. The first step is to add an input to the `Root` component.
 But this input will be outside of the task list, so we need to adapt `Root`
 template, js, and css:
 ```xml
 <div class="todo-app">
    <input placeholder="Enter a new task" t-on-keyup="addTask"/>
    <div class="task-list">
        <t t-foreach="tasks" t-as="task" t-key="task.id">
            <Task task="task"/>
        </t>
    </div>
 </div>
 ```
 ```js
 addTask(ev) {
    // 13 is keycode for ENTER
    if (ev.keyCode === 13) {
        const text = ev.target.value.trim();
        ev.target.value = "";
        console.log('adding task', text);
        // todo
    }
 }
 ```
 ```css
 .todo-app {
  width: 300px;
  margin: 50px auto;
  background: aliceblue;
  padding: 10px;
 }
 .todo-app > input {
  display: block;
  margin: auto;
 }
 .task-list {
  margin-top: 8px;
 }
 ```
 We now have a working input, which log to the console whenever the user adds a
 task. Notice that when you load the page, the input is not focused. But adding
 tasks is a core feature of a task list, so let us make it as fast as possible by
 focusing the input.
 We need to execute code when the `Root` component is ready (mounted). Let's do
 that using the `onMounted` hook. We will also need to get a reference to the
 input, by using the `t-ref` directive with the [`useRef`](../reference/hooks.md#useref) hook:
 ```xml
 <input placeholder="Enter a new task" t-on-keyup="addTask" t-ref="add-input"/>
 ```
 ```js
 // on top of file:
 const { Component, mount, xml, useRef, onMounted } = owl;
 ```
 ```js
 // in App
 setup() {
    const inputRef = useRef("add-input");
    onMounted(() => inputRef.el.focus());
 }
 ```
 This is a very common situation: whenever we need to perform some actions depending
 on the lifecycle of a component, we need to do it in the `setup` method, by using
 one of the lifecycle hook. Here, we first get a reference to the `inputRef`,
 then in the `onMounted` hook, we simply focus the html element.
 ## 7. Adding tasks (part 2)
 In the previous section, we did everything except implement the code that actually
 create tasks! So, let us do that now.
 We need a way to generate unique `id` numbers. To do that, we will simply add a
 `nextId` number in `App`. At the same time, let us remove the demo tasks in `App`:
 ```js
 nextId = 1;
 tasks = [];
 ```
 Now, the `addTask` method can be implemented:
 ```js
 addTask(ev) {
    // 13 is keycode for ENTER
    if (ev.keyCode === 13) {
        const text = ev.target.value.trim();
        ev.target.value = "";
        if (text) {
            const newTask = {
                id: this.nextId++,
                text: text,
                isCompleted: false,
            };
            this.tasks.push(newTask);
        }
    }
 }
 ```
 This almost works, but if you test it, you will notice that no new task is ever
 displayed when the user press `Enter`. But if you add a `debugger` or a
 `console.log` statement, you will see that the code is actually running as
 expected. The problem is that Owl has no way of knowing that it needs to rerender
 the user interface. We can fix the issue by making `tasks` reactive, with the
 [`useState`](../reference/hooks.md#usestate) hook:
 ```js
 // on top of the file
 const { Component, mount, xml, useRef, onMounted, useState } = owl;
 // replace the task definition in App with the following:
 tasks = useState([]);
 ```
 It now works as expected!
 ## 8. Toggling tasks
 If you tried to mark a task as completed, you may have noticed that the text
 did not change in opacity. This is because there is no code to modify the
 `isCompleted` flag.
 Now, this is an interesting situation: the task is displayed by the `Task`
 component, but it is not the owner of its state, so ideally, it should not modify it.
 However, for now, that's what we will do (this will be improved in a later step).
 In `Task`, change the `input` to:
 ```xml
 <input type="checkbox" t-att-checked="props.task.isCompleted" t-on-click="toggleTask"/>
 ```
 and add the `toggleTask` method:
 ```js
 toggleTask() {
  this.props.task.isCompleted = !this.props.task.isCompleted;
 }
 ```
 ## 9. Deleting tasks
 Let us now add the possibility do delete tasks. This is different from the previous
 feature: deleting task has to be done on the task itself, but the actual operation
 need to be done on the task list. So, we need to communicate the request to the
 `Root` component. This is usually done by providing a callback in a prop.
 First, let us update the `Task` template, css and js:
 ```xml
 <div class="task" t-att-class="props.task.isCompleted ? 'done' : ''">
    <input type="checkbox" t-att-checked="props.task.isCompleted" t-on-click="toggleTask"/>
    <span><t t-esc="props.task.text"/></span>
    <span class="delete" t-on-click="deleteTask">🗑</span>
 </div>
 ```
 ```css
 .task {
  font-size: 18px;
  color: #111111;
  display: grid;
  grid-template-columns: 30px auto 30px;
 }
 .task > input {
  margin: auto;
 }
 .delete {
  opacity: 0;
  cursor: pointer;
  text-align: center;
 }
 .task:hover .delete {
  opacity: 1;
 }
 ```
 ```js
 static props = ["task", "onDelete"];
 deleteTask() {
    this.props.onDelete(this.props.task);
 }
 ```
 And now, we need to provide the `onDelete` callback to each tasks in the `Root`
 component:
 ```xml
  <Task task="task" onDelete.bind="deleteTask"/>
 ```
 ```js
 deleteTask(task) {
    const index = this.tasks.findIndex(t => t.id === task.id);
    this.tasks.splice(index, 1);
 }
 ```
 Notice that the `onDelete` prop is defined with a `.bind` suffix: this is a special
 suffix that makes sure the function callback is bound to the component.
 ## 10. Using a store
 Looking at the code, it is apparent that all the code handling tasks is scattered
 all around the application. Also, it mixes UI code and business logic
 code. Owl does not provide any high level abstraction to manage business logic,
 but it is easy to do it with the basic reactivity primitives (`useState` and `reactive`).
 Let us use it in our application to implement a central store. This is a pretty
 large refactoring (for our application), since it involves extracting all task
 related code out of the components. Here is the new content of the `app.js` file:
 ```js
 const { Component, mount, xml, useRef, onMounted, useState, reactive, useEnv } = owl;
 // -------------------------------------------------------------------------
 // Store
 // -------------------------------------------------------------------------
 function useStore() {
  const env = useEnv();
  return useState(env.store);
 }
 // -------------------------------------------------------------------------
 // TaskList
 // -------------------------------------------------------------------------
 class TaskList {
  nextId = 1;
  tasks = [];
  addTask(text) {
    text = text.trim();
    if (text) {
      const task = {
        id: this.nextId++,
        text: text,
        isCompleted: false,
      };
      this.tasks.push(task);
    }
  }
  toggleTask(task) {
    task.isCompleted = !task.isCompleted;
  }
  deleteTask(task) {
    const index = this.tasks.findIndex((t) => t.id === task.id);
    this.tasks.splice(index, 1);
  }
 }
 function createTaskStore() {
  return reactive(new TaskList());
 }
 // -------------------------------------------------------------------------
 // Task Component
 // -------------------------------------------------------------------------
 class Task extends Component {
  static template = xml/* xml */ `
    <div class="task" t-att-class="props.task.isCompleted ? 'done' : ''">
      <input type="checkbox" t-att-checked="props.task.isCompleted" t-on-click="() => store.toggleTask(props.task)"/>
      <span><t t-esc="props.task.text"/></span>
      <span class="delete" t-on-click="() => store.deleteTask(props.task)">🗑</span>
    </div>`;
  static props = ["task"];
  setup() {
    this.store = useStore();
  }
 }
 // -------------------------------------------------------------------------
 // Root Component
 // -------------------------------------------------------------------------
 class Root extends Component {
  static template = xml/* xml */ `
    <div class="todo-app">
      <input placeholder="Enter a new task" t-on-keyup="addTask" t-ref="add-input"/>
      <div class="task-list">
        <t t-foreach="store.tasks" t-as="task" t-key="task.id">
          <Task task="task"/>
        </t>
      </div>
    </div>`;
  static components = { Task };
  setup() {
    const inputRef = useRef("add-input");
    onMounted(() => inputRef.el.focus());
    this.store = useStore();
  }
  addTask(ev) {
    // 13 is keycode for ENTER
    if (ev.keyCode === 13) {
      this.store.addTask(ev.target.value);
      ev.target.value = "";
    }
  }
 }
 // -------------------------------------------------------------------------
 // Setup
 // -------------------------------------------------------------------------
 const env = {
  store: createTaskStore(),
 };
 mount(Root, document.body, { dev: true, env });
 ```
 ## 11. Saving tasks in local storage
 Now, our TodoApp works great, except if the user closes or refresh the browser!
 It is really inconvenient to only keep the state of the application in memory.
 To fix this, we will save the tasks in the local storage. With our current
 codebase, it is a simple change: we need to save tasks to local storage and
 listen to any change.
 ```js
 class TaskList {
  constructor(tasks) {
    this.tasks = tasks || [];
    const taskIds = this.tasks.map((t) => t.id);
    this.nextId = taskIds.length ? Math.max(...taskIds) + 1 : 1;
  }
  // ...
 }
 function createTaskStore() {
  const saveTasks = () => localStorage.setItem("todoapp", JSON.stringify(taskStore.tasks));
  const initialTasks = JSON.parse(localStorage.getItem("todoapp") || "[]");
  const taskStore = reactive(new TaskList(initialTasks), saveTasks);
  saveTasks();
  return taskStore;
 }
 ```
 The key point is that the `reactive` function takes a callback that will be called
 every time an observed value is changed. Note that we need to call the `saveTasks`
 method initially to make sure we observe all current values.
 ## 12. Filtering tasks
 We are almost done, we can add/update/delete tasks. The only missing feature is
 the possibility to display the task according to their completed status. We will
 need to keep track of the state of the filter in `Root`, then filter the visible
 tasks according to its value.
 ```js
 class Root extends Component {
  static template = xml /* xml */`
    <div class="todo-app">
      <input placeholder="Enter a new task" t-on-keyup="addTask" t-ref="add-input"/>
      <div class="task-list">
        <t t-foreach="displayedTasks" t-as="task" t-key="task.id">
          <Task task="task"/>
        </t>
      </div>
      <div class="task-panel" t-if="store.tasks.length">
        <div class="task-counter">
          <t t-esc="displayedTasks.length"/>
          <t t-if="displayedTasks.length lt store.tasks.length">
              / <t t-esc="store.tasks.length"/>
          </t>
          task(s)
        </div>
        <div>
          <span t-foreach="['all', 'active', 'completed']"
            t-as="f" t-key="f"
            t-att-class="{active: filter.value===f}"
            t-on-click="() => this.setFilter(f)"
            t-esc="f"/>
        </div>
      </div>
    </div>`;
  setup() {
    ...
    this.filter = useState({ value: "all" });
  }
  get displayedTasks() {
    const tasks = this.store.tasks;
    switch (this.filter.value) {
      case "active": return tasks.filter(t => !t.isCompleted);
      case "completed": return tasks.filter(t => t.isCompleted);
      case "all": return tasks;
    }
  }
  setFilter(filter) {
    this.filter.value = filter;
  }
 }
 ```
 ```css
 .task-panel {
  color: #0088ff;
  margin-top: 8px;
  font-size: 14px;
  display: flex;
 }
 .task-panel .task-counter {
  flex-grow: 1;
 }
 .task-panel span {
  padding: 5px;
  cursor: pointer;
 }
 .task-panel span.active {
  font-weight: bold;
 }
 ```
 Notice here that we set dynamically the css class of the filter with the object
 syntax.
 ## 13. The Final Touch
 Our list is feature complete. We can still add a few extra details to improve
 the user experience.
 1. Add a visual feedback when the user mouse is over a task:
 ```css
 .task:hover {
  background-color: #def0ff;
 }
 ```
 2. Make the text of a task clickable, to toggle its checkbox:
 ```xml
 <input type="checkbox" t-att-checked="props.task.isCompleted"
    t-att-id="props.task.id"
    t-on-click="dispatch('toggleTask', props.task.id)"/>
 <label t-att-for="props.task.id"><t t-esc="props.task.text"/></label>
 ```
 3. Strike the text of completed task:
 ```css
 .task.done label {
  text-decoration: line-through;
 }
 ```
 ## Final code
 Our application is now complete. It works, the UI code is well separated from
 the business logic code, it is testable, all under 150 lines of code (template
 included!).
 For reference, here is the final code:
 ```html
 <!DOCTYPE html>
 <html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>OWL Todo App</title>
    <link rel="stylesheet" href="app.css" />
    <script src="owl.js"></script>
    <script src="app.js"></script>
  </head>
  <body></body>
 </html>
 ```
 ```js
 (function () {
  const { Component, mount, xml, useRef, onMounted, useState, reactive, useEnv } = owl;
  // -------------------------------------------------------------------------
  // Store
  // -------------------------------------------------------------------------
  function useStore() {
    const env = useEnv();
    return useState(env.store);
  }
  // -------------------------------------------------------------------------
  // TaskList
  // -------------------------------------------------------------------------
  class TaskList {
    constructor(tasks) {
      this.tasks = tasks || [];
      const taskIds = this.tasks.map((t) => t.id);
      this.nextId = taskIds.length ? Math.max(...taskIds) + 1 : 1;
    }
    addTask(text) {
      text = text.trim();
      if (text) {
        const task = {
          id: this.nextId++,
          text: text,
          isCompleted: false,
        };
        this.tasks.push(task);
      }
    }
    toggleTask(task) {
      task.isCompleted = !task.isCompleted;
    }
    deleteTask(task) {
      const index = this.tasks.findIndex((t) => t.id === task.id);
      this.tasks.splice(index, 1);
    }
  }
  function createTaskStore() {
    const saveTasks = () => localStorage.setItem("todoapp", JSON.stringify(taskStore.tasks));
    const initialTasks = JSON.parse(localStorage.getItem("todoapp") || "[]");
    const taskStore = reactive(new TaskList(initialTasks), saveTasks);
    saveTasks();
    return taskStore;
  }
  // -------------------------------------------------------------------------
  // Task Component
  // -------------------------------------------------------------------------
  class Task extends Component {
    static template = xml/* xml */ `
      <div class="task" t-att-class="props.task.isCompleted ? 'done' : ''">
        <input type="checkbox"
          t-att-id="props.task.id"
          t-att-checked="props.task.isCompleted"
          t-on-click="() => store.toggleTask(props.task)"/>
        <label t-att-for="props.task.id"><t t-esc="props.task.text"/></label>
        <span class="delete" t-on-click="() => store.deleteTask(props.task)">🗑</span>
      </div>`;
    static props = ["task"];
    setup() {
      this.store = useStore();
    }
  }
  // -------------------------------------------------------------------------
  // Root Component
  // -------------------------------------------------------------------------
  class Root extends Component {
    static template = xml/* xml */ `
      <div class="todo-app">
        <input placeholder="Enter a new task" t-on-keyup="addTask" t-ref="add-input"/>
        <div class="task-list">
          <t t-foreach="displayedTasks" t-as="task" t-key="task.id">
            <Task task="task"/>
          </t>
        </div>
        <div class="task-panel" t-if="store.tasks.length">
          <div class="task-counter">
            <t t-esc="displayedTasks.length"/>
            <t t-if="displayedTasks.length lt store.tasks.length">
                / <t t-esc="store.tasks.length"/>
            </t>
            task(s)
          </div>
          <div>
            <span t-foreach="['all', 'active', 'completed']"
              t-as="f" t-key="f"
              t-att-class="{active: filter.value===f}"
              t-on-click="() => this.setFilter(f)"
              t-esc="f"/>
          </div>
        </div>
      </div>`;
    static components = { Task };
    setup() {
      const inputRef = useRef("add-input");
      onMounted(() => inputRef.el.focus());
      this.store = useStore();
      this.filter = useState({ value: "all" });
    }
    addTask(ev) {
      // 13 is keycode for ENTER
      if (ev.keyCode === 13) {
        this.store.addTask(ev.target.value);
        ev.target.value = "";
      }
    }
    get displayedTasks() {
      const tasks = this.store.tasks;
      switch (this.filter.value) {
        case "active":
          return tasks.filter((t) => !t.isCompleted);
        case "completed":
          return tasks.filter((t) => t.isCompleted);
        case "all":
          return tasks;
      }
    }
    setFilter(filter) {
      this.filter.value = filter;
    }
  }
  // -------------------------------------------------------------------------
  // Setup
  // -------------------------------------------------------------------------
  const env = { store: createTaskStore() };
  mount(Root, document.body, { dev: true, env });
 })();
 ```
 ```css
 .todo-app {
  width: 300px;
  margin: 50px auto;
  background: aliceblue;
  padding: 10px;
 }
 .todo-app > input {
  display: block;
  margin: auto;
 }
 .task-list {
  margin-top: 8px;
 }
 .task {
  font-size: 18px;
  color: #111111;
  display: grid;
  grid-template-columns: 30px auto 30px;
 }
 .task:hover {
  background-color: #def0ff;
 }
 .task > input {
  margin: auto;
 }
 .delete {
  opacity: 0;
  cursor: pointer;
  text-align: center;
 }
 .task:hover .delete {
  opacity: 1;
 }
 .task.done {
  opacity: 0.7;
 }
 .task.done label {
  text-decoration: line-through;
 }
 .task-panel {
  color: #0088ff;
  margin-top: 8px;
  font-size: 14px;
  display: flex;
 }
 .task-panel .task-counter {
  flex-grow: 1;
 }
 .task-panel span {
  padding: 5px;
  cursor: pointer;
 }
 .task-panel span.active {
  font-weight: bold;
 }
 ```
@@ -3,8 +3,8 @@
 OWL, React and Vue have the same main feature: they allow developers to build
 declarative user interfaces. To do that, all these frameworks uses a virtual dom. However, there are still obviously many differences.
-In this page, we try to highlight some of these differences. Obviously, some
+In this page, we try to highlight some of these differences. Obviously, a lot of
-effort was done to be fair. However, if you disagree with some of the points
+effort was put to be fair. However, if you disagree with some of the points
 discussed, feel free to open an issue/submit a PR to correct this text.
 ## Content
@@ -14,8 +14,8 @@ discussed, feel free to open an issue/submit a PR to correct this text.
 - [Tooling/Build Step](#toolingbuild-step)
 - [Templating](#templating)
 - [Asynchronous rendering](#asynchronous-rendering)
- [Reactiveness](#reactiveness)
+- [Reactivity](#reactivity)
- [State Management](#state-management)
+- [Hooks](#hooks)
 ## Size
@@ -24,22 +24,38 @@ than React and Vue. Also, jQuery is not the same kind of framework, but it is in
 | Framework                | Size (minified, gzipped) |
 | ------------------------ | ------------------------ |
-| OWL                      | 16kb                     |
+| OWL                      | 18kb                     |
 | Vue + VueX               | 30kb                     |
 | Vue + VueX + Vue Router  | 39kb                     |
 | React + ReactDOM + Redux | 40kb                     |
 | jQuery                   | 30kb                     |
 Note that those comparisons are not entirely fair, because we do not compare
 the same exact set of features. For example, VueX and Vue Router support more
 advanced use cases.
 ## Class Based
-Both React and Vue moved away from defining components with classes.  They prefer
+Both React and Vue moved away from defining components with classes. They prefer
 a more functional approach, in particular, with the new `hooks` mechanisms.
-This has some advantages and disadvantages.  But the end result is that React
+This has some advantages and disadvantages. But the end result is that React
-and Vue both offers multiple different ways of defining new components.  In
+and Vue both offers multiple different ways of defining new components. In
 contrast, Owl has only one mechanism: class-based components. We believe that Owl
 components are fast enough for all our usecases, and making it as simple as
 possible for developers is more valuable (for us).
 Also, functions or class based components are more than just syntax. Functions
 come with a mindset of composition and class are about inheritance. Clearly,
 both of these are important mechanisms for reusing code. Also, one does not
 exclude the other.
 It certainly looks like the world of UI frameworks is moving toward composition,
 for many very good reasons. Owl is still good at composition (for example,
 Owl supports slots, which is the primary mechanism to make generic reusable
 components). But it can also use inheritance (and this is very important since
 templates can also be inherited with `xpaths` transformations).
 ## Tooling/Build step
 OWL is designed to be easy to use in a standalone way. For various reasons,
@@ -50,13 +66,23 @@ be used by simply adding a script tag to a page.
 <script src="owl.min.js" />
 ```
-In comparison, React encourages using JSX,
+In comparison, React encourages using JSX, which necessitate a build step, and
-which necessitate a build step, and most Vue applications uses single file
+most Vue applications uses single file components, which also necessitate a build step.
 components, which also necessitate a build step.
 On the flipside, external tooling may make it harder to use in some case, but it
 also brings a lot of benefits. And React/Vue have both a large ecosystem.
 Note that since Owl is not dependant on any external tool nor libraries, it is
 very easy to integrate into any build toolchain. Also, since we cannot rely on
 additional tools, we made a lot of effort to make the most of the web platform.
 For example, Owl uses the standard `xml` parser that comes with every browser.
 Because of that, Owl did not have to write its own template parser. Another
 example is the [`xml`](../reference/tags.md#xml-tag) tag helper function, which makes use of
 native template literals to allow in a natural way to write `xml` templates
 directly in the javascript code. This can be easily integrated with editor
 plugins to have autocompletion inside the template.
 ## Templating
 OWL uses its own QWeb engine, which compiles templates on the
@@ -79,7 +105,8 @@ into javascript functions. Note that Vue has a separate build which includes the
 template compiler.
 In contrast, most React applications do not use a templating language, but write
-some JSX code, which is precompiled into plain JavaScript by a build step.
+some JSX code, which is precompiled into plain JavaScript by a build step. This
 example is done with the (kind of outdated) React class system:
 ```jsx
 class Clock extends React.Component {
@@ -98,6 +125,20 @@ This has the advantage of having the full power of Javascript, but is less
 structured than a template language. Note that the tooling is quite impressive:
 there is a syntax highlighter for jsx here on github!
 By comparison, here is the equivalent Owl component, written with the
 [`xml`](../reference/tags.md#xml-tag) tag helper:
 ```js
 class Clock extends Component {
  static template = xml`
      <div>
        <h1>Hello, world!</h1>
        <h2>It is {props.date.toLocaleTimeString()}.</h2>
      </div>
    `;
 }
 ```
 ## Asynchronous Rendering
 This is actually a big difference between OWL and React/Vue: components in OWL
@@ -127,12 +168,14 @@ This may be dangerous (to stop the rendering waiting for the network), but it is
 extremely powerful as well, as demonstrated by the Odoo Web Client.
 Lazy loading static libraries can obviously be done with React/Vue, but it is
-more convoluted.
+more convoluted. For example, in Vue, you need to use a dynamic import keyword
 that needs to be transpiled at build time in order for the component to be loaded
 asynchronously (see [the documentation](https://vuejs.org/v2/guide/components-dynamic-async.html#Async-Components)).
-## Reactiveness
+## Reactivity
 React has a simple model: whenever the state changes, it is
-replaced with a new state (via the setState method). Then, the DOM is patched.
+replaced with a new state (via the `setState` method). Then, the DOM is patched.
 This is simple, efficient, and a little bit awkward to write.
 Vue is a little bit different: it replace magically the properties in the state
@@ -145,92 +188,68 @@ with a `Proxy`, which means that it is totally transparent to the developers.
 Adding new keys is supported. Once any part of the state has been changed, a
 rendering is scheduled in the next microtask tick (promise queue).
-## State Management
+## Hooks
-Managing the state of an application is a tricky issue. Many solutions have
+[Hooks](https://reactjs.org/docs/hooks-intro.html#motivation) recently took over
-been proposed these last few years. It also depends on the kind of application we
+the React world. They solve a lot of seemingly unconnected problems: attach
-are talking about. A small application may not need much more than a simple
+reusable behavior to a component, in a composable way, extract stateful logic
-object to contain its state.
+from a component or reuse stateful logic between component, without changing your
 component hierarchy.
-However, there are some common solutions for React and Vue: redux and vuex.
+Here is an example of the React `useState` hook:
 Both of them are a centralized store that own the state, and they dictate how
 the state can be mutated.
-**Redux**
+```js
 import React, { useState } from "react";
-In Redux, the state is mutated by reducers. Reducers are functions
+function Example() {
-that modify the state by returning a different object:
+  // Declare a new state variable, which we'll call "count"
  const [count, setCount] = useState(0);
-```javascript
+  return (
-  ...
+    <div>
-  switch (action.type) {
+      <p>You clicked {count} times</p>
-    case ADD_TODO: {
+      <button onClick={() => setCount(count + 1)}>Click me</button>
-      const { id, content } = action.payload;
+    </div>
-      return {
+  );
-        ...state,
+}
        allIds: [...state.allIds, id],
        byIds: {
          ...state.byIds,
          [id]: {
            content,
            completed: false
          }
        }
      };
    }
 ```
-This is a little bit awkward to write, but this allows the component system to
+Because of the way React designed the hooks API, they only work for functional
-check if a part of the state was changed. This is exactly what is done by the
+components. But in that case, they really are powerful. Every major React library
-`connect` function: it create a _connected_ component, which is subscribed to
+is in the process of redesigning their API with hooks (for example,
-the state and triggers a rerender if some part of the state was modified.
+[Redux](https://react-redux.js.org/next/api/hooks)).
-**VueX**
+Vue 2 does not have hooks, but the Vue project is working on its next version,
 which will feature its new [composition API](https://vue-composition-api-rfc.netlify.com/).
 This work is based on the new ideas introduced by React hooks.
-VueX is based on a different principle: the state is mutated through
+From the way React and Vue introduce their hooks, it may look like hooks are not
-some special functions (the mutations), which modify the state in place:
+compatible with class components. However, this is not the case, as shown by
 Owl [hooks](../reference/hooks.md). They are inspired by both React and Vue. For example,
 the `useState` hook is named after React, but its API is closer to the `reactive`
 Vue hook.
-```javascript
+Here is what the `Counter` example above look like in Owl:
    function ({state}, payload) {
        const { id, content } = payload;
        const message = {id, content, completed: false};
        state.messages.push(message)
    }
 ```
-This is simpler, but there is a little bit more happening behind the scene:
+```js
-each key from the state is silently replaced by getters and setters, and VueX
+import { Component, Owl } from "owl";
-keeps track of who get data, and retrigger a render when it was changed.
+import { xml } from "owl/tags";
-**Owl**
+class Example extends Component {
  static template = xml`
      <div>
        <p>You clicked {count.value} times</p>
        <button t-on-click="increment">Click me</button>
      </div>`;
-Owl store is a little bit like a mix of redux and vuex: it has actions (but not
+  count = useState({ value: 0 });
 mutations), and like VueX, it keeps track of the state changes. However, it does
 not notify a component when the state changes. Instead, components need to connect
 to the store like in redux, by inheriting the `ConnectedComponent` class.
 ```javascript
 const actions = {
  increment({ state }, val) {
    state.counter += val;
  }
 };
 const state = {
  counter: 0
 };
 const store = new owl.Store({ state, actions });
 class Counter extends owl.ConnectedComponent {
  static mapStoreToProps(state) {
    return {
      value: state.counter
    };
  }
  increment() {
-    this.env.store.dispatch("increment");
+    this.state.value++;
  }
 }
 ```
-const counter = new Counter({ store, qweb });
+Since the Owl framework had hooks from early in its life, its main APIs
-```
+are designed to be interacted with hooks from the start. For example, the
 `Context` abstraction.
@@ -0,0 +1,32 @@
 # 🦉 Rendering Pipeline 🦉
 We explain here how Owl is designed, from the perspective of its rendering
 pipeline.
 Warning: these notes are technical by nature, and intended for people working
 on Owl (or interested in understanding its design).
 ## Overview
 A rendering occurs in two phases:
 - virtual rendering: this generates the virtual dom in memory, asynchronously
 - patch: applies a virtual tree to the screen (synchronously)
 There are several classes involved in a rendering:
 - components
 - a scheduler
 - fibers: small objects containing some metadata, associated with a rendering of
  a specific component
 Components are organized in a dynamic component tree, visible in the user
 interface. Whenever a rendering is initiated in a component `C`:
 - a fiber is created on `C` with the rendering props information
 - the virtual rendering phase starts on C (will asynchronously render all the
  child components)
 - the fiber is added to the scheduler, which will poll continuously, every
  animation frame, if the fiber is done
 - once it is done, the scheduler will call the task callback, which will apply
  the patch (if it was not cancelled in the meantime).
@@ -0,0 +1,180 @@
 # 🦉 Why Owl ? 🦉
 The common wisdom is that one should not reinvent the wheel, because that would
 waste effort and resources. It is certainly true in many cases. A javascript
 framework is a considerable investment, so it is quite logical to ask the question:
 why did Odoo decide to make OWL instead of using a standard/well known framework,
 such as React or Vue?
 As you might expect, the answer to that question is not simple. But most of the
 reasons discussed in this page are a consequence from a single fact: Odoo is
 extremely modular.
 This means, for example, that the core parts of Odoo are not aware, before runtime,
 of what files will be loaded/executed, or what will be the state of the UI. Because
 of that, Odoo cannot rely on a standard build toolchain. Also, this implies that
 the core parts of Odoo need to be extremely generic. In other words, Odoo is not
 really an application with a user interface. It is an application which generates
 a dynamic user interface. And most frameworks are not up to the task.
 Betting on Owl was not an easy choice to make, because there certainly are a lot
 of conflicting needs that we want to carefully balance. Choosing anything other
 than a well known framework is bound to be controversial. This page will explain
 some of the reason why we still believe that building Owl is a worthwile
 endeavour.
 ## Strategy
 It is true that we want to keep control of our technology, in the sense that we
 do not want to depend on Facebook or Google, or any other large (or small)
 company. If they decide to change their license, or to go in a direction that
 will not work for us, this may be a problem. This is even more true because
 Odoo is not a conventional javascript application, and our needs are probably
 quite different as most other applications.
 ## Class components
 It is clear that the biggest frameworks are moving away from class components.
 There is an implicit assumption that class components are terrible, and that
 functional programming is the way to go. React even goes as far as to say that
 classes are confusing for developers.
 While there is some truth to that, and to the fact that composition is certainly
 a good mechanism for code reuse, we believe that classes and inheritance are
 important tools.
 Sharing code between generic components with inheritance is the way Odoo built
 its web client. And it is clear that inheritance is not the root of all evils.
 It is often a perfectly simple and appropriate solution. What matter most is
 the architectural decisions.
 Also, Odoo has another specific use out of class components: each method of a
 class provides an extension point for addons. This may not be a clean architecture
 pattern, but it is a pragmatic decision that served Odoo well: classes are
 sometimes monkey-patched to add behaviour from the outside. A little bit like
 mixins, but from the outside.
 Using React or Vue would make it significantly harder to monkey patch components,
 because a lot of the state is hidden in their internals.
 ## Tooling
 React or Vue have a huge community, and a lot of effort have been made into their
 tooling. This is wonderful, but at the same time, a pretty big issue for Odoo:
 since the assets are totally dynamic (and could change whenever the user installs
 or removes an addon), we need to have all that kind of tooling on the production
 servers. This is certainly not ideal.
 Also, this makes it very complicated to setup Vue or React tools: Odoo code is
 not a simple file that import other files. It changes all the time, assets
 are bundled differently in different contexts. This is the reason why Odoo has
 its own module system, which are resolved at runtime, by the browser. The
 dynamic nature of Odoo means that we often need to delay work as late as possible
 (in other word, we want a JIT user interface!)
 Our ideal framework has minimal (mandatory) tooling, which makes it easier to
 deploy. Using React without JSX, or Vue without vue file is not very appealing.
 At the same time, Owl is designed to solve this issue: it compiles templates
 by the browser, it doesn't need much code for that, since we use the XML parser
 built into each browser. Owl works with or without any additional tooling. It
 can use template strings to write single file components, and is easy to integrate
 in any html page, with a simple `<script>` tag.
 ## Template based
 Odoo stores templates as XML documents in a database. This is very powerful, since
 this allow the use of xpaths to customize other templates. This is a very
 important feature of odoo, and one of the key to Odoo modularity.
 Because of that, we still expect to write our templates in an XML document.
 Weirdly enough, no major framework uses XML to store templates, even though it
 is extremely convenient.
 So, using React or Vue means that we need to make a template compiler. For React,
 that would be a compiler that would take a QWeb template, and convert it to a
 React render function. For Vue, it would convert it to a Vue template. Then
 we need to bundle the vue template compiler as well.
 Not only this would be complex (compiling a templating language into another is
 not an easy task), but it would negatively impact the developer experience as
 well. Writing Vue or React components in a QWeb template would certainly be
 awkward, and very confusing.
 ## Developer Experience
 This brings us to the following point: developer experience. We see this choice
 as an investment for the future, and we want to make onboarding developers as
 easy as possible.
 While many javascript professionals clearly think that react/vue is not difficult
 (which is true to some extent), it is alsy true that many non js specialists are
 overwhelmed with the frontend world: functional components, hooks, and many other
 fancy words. Also, what is available in the compilation context may be difficult,
 there is a lot of black magic going on in pretty much every framework. Vue
 somehow join various namespaces into one, under the hood, and add various internal
 keys. Svelte transform the code. React require that state transformations are
 deep, and not shallow.
 Owl is trying very hard to have a simple and familiar API. It uses classes. Its
 reactivity system is explicit, not implicit. The scoping rules are obvious. In
 case of doubt, we err on the side of not implementing a feature.
 It is certainly different from React or Vue, but at the same time, kind of
 familiar for experienced developers.
 ## JIT compilation
 There is also a clear trend in the frontend world to compile code
 as much as possible ahead of time. Most frameworks will compile templates ahead
 of time. And now Svelte is trying to compile the JS code away, so it can remove
 itself from the bundle.
 This is certainly reasonable for many usecases. However, this is not what Odoo
 needs: Odoo will fetch templates from the database and need to compile them only
 at the last possible moment, so we can apply all necessary xpaths.
 Even more: Odoo needs to be able to generate (and compile) templates at runtime.
 Currently, Odoo form views interpret an xml description. But the form view code
 then needs to do a lot of complicated operations. With Owl, we will be able to
 transform a view description into a QWeb template, then compile that and use it
 immediately.
 ## Reactivity
 There are other design choices that we feel are not optimal in other frameworks.
 For example, the reactivity system. We like the way Vue did it, but it has a
 flaw: it is not really optional. There is actually a way to opt out of the reactivity
 system by freezing the state, but then, it is freezed.
 And there certainly are situations where we need a state, which is not read-only,
 and not observed. For example, imagine a spreadsheet component. It may have a
 very large internal state, and it knows exactly when it needs to be rendered
 (basically, whenever the user performs some action). Then, observing its state
 is a net performance loss, both for the CPU and the memory.
 ## Concurrency
 Many applications are happy to simply display a spinner whenever a new asynchronous
 action is performed, but Odoo wants a different user experience: most asynchronous
 state changes are not displayed until ready. This is sometimes called a concurrent
 mode: the UI is rendered in memory, and displayed only when it is ready (and
 only if it has not been cancelled by subsequent user actions).
 React has now an experimental concurrent mode, but it was not ready when Owl
 started. Vue has not really an equivalent API (suspense is not what we need).
 Also, React concurrent mode is complex to use. Concurrency was one of the rare
 strong point of the former Odoo js framework (widgets), and we feel that Owl has
 now a very strong concurrent mode, which is simple and powerful at the same time.
 ## Conclusion
 This lengthy discussion showed that there are many small and not so small reasons
 that current standard frameworks are not tailored to our needs. It is perfectly
 fine, because they each chose a different set of tradeoffs.
 However, we feel that there is still room in the framework world for something
 that is different. For a framework that makes choices compatible with Odoo.
 And that is why we built Owl 🦉.
@@ -1,50 +0,0 @@
 # 🦉 Observer 🦉
 Owl need to be able to react to state changes. For example, whenever the state
 of a component is changed, we need to rerender it. To help with that, we have
 an Observer class. Its job is to observe some object state, and react to any
 change. To do that, it recursively replace all keys of the observed state by
 getters and setters.
 For example, this code will display `update` in the console:
 ```javascript
 const observer = new owl.Observer();
 observer.notifyCB = () => console.log("update");
 observer.observe(obj);
 const obj = { a: { b: 1 } };
 obj.a.b = 2;
 ```
 ## Technical Limitations
 Since the observer uses getters and setters, it is actually unable to react to
 changes in three situations:
 - adding a key to an object
 - deleting a key from an object
 - modifying an array by setting a new value at a given index
 In those situations, we need a way to tell the observer that something happened.
 This can be done by using the `set` and `delete` (only for objects) static
 methods of the `Observer`.
 ```javascript
 const observer = new owl.Observer();
 const obj = { a: 1 };
 observer.observe(obj);
 obj.b = 2; // won't notify the change
 owl.Observer.set(obj, "b", 2); // will notify the change
 delete obj.b; // won't notify the change
 owl.Observer.delete(obj, "b"); // will notify the change
 ```
 ```javascript
 const observer = new owl.Observer();
 const arr = ["a"];
 observer.observe(arr);
 arr[0] = "b"; // won't notify the change
 owl.Observer.set(arr, 0, "b"); // will notify the change
 ```
@@ -1,101 +0,0 @@
 # 🦉 Quick Start 🦉
 ## Static Server
 Let us assume that we have a static server running somewhere. We could then
 simply add an html page with a few extra files.
 ### HTML and CSS
 In a file `index.html`:
 ```html
 <!DOCTYPE html>
 <html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>My OWL App</title>
    <link href="app.css" rel="stylesheet" />
    <script src="owl-X.Y.Z.js"></script>
  </head>
  <body>
    <div id="main"></div>
    <script src="app.js" type="module"></script>
  </body>
 </html>
 ```
 In `app.css`:
 ```css
 button {
  color: darkred;
  font-size: 30px;
  width: 220px;
 }
 ```
 Also, let's not forget to add a release of OWL (`owl-X.Y.Z.js`)
 ### XML
 In `templates.xml`:
 ```xml
 <templates>
   <button t-name="clickcounter" t-on-click="increment">
      Click Me! [<t t-esc="state.value"/>]
    </button>
 </templates>
 ```
 ### JS
 To build an application (or a sub-part of an application), we need two things:
 - an environment: it is the global context in which we are working. It needs to
  contain a QWeb instance (preloaded with templates), and anything else that we
  need. In practice, it could context some user session information, some
  configuration keys (for example, isMobile = true/false if we are in mobile mode).
 - a description of the user interface: there should be a root component, which can
  have sub components
 Here are a few steps that we may take to get started:
 - get the templates
 - create a qweb engine, with the templates
 - create an environment
 - create an instance of the root component
 - mount the root component to a DOM element
 Let us now add the javascript to make it work, in `app.js`:
 ```javascript
 class ClickCounter extends owl.Component {
  constructor() {
    super(...arguments);
    this.template = "clickcounter";
    this.state = { value: 0 };
  }
  increment() {
    this.state.value++;
  }
 }
 //------------------------------------------------------------------------------
 // Application initialization
 //------------------------------------------------------------------------------
 async function start() {
  const templates = await owl.utils.loadTemplates("templates.xml");
  const env = {
    qweb: new owl.QWeb(templates)
  };
  const counter = new ClickCounter(env);
  const target = document.getElementById("main");
  await counter.mount(target);
 }
 start();
 ```
@@ -1,49 +0,0 @@
 # 🦉 OWL Documentation 🦉
 ## Owl Content
 Owl is a javascript library that contains some core classes and function to help
 build applications.  Here is a complete representation of its content:
 ```
 owl
    Component
    QWeb
    core
        EventBus
        Observer
    router
        Link
        Router
    store
        Store
        ConnectedComponent
    utils
        debounce
        escape
        loadJS
        loadTemplates
        whenReady
 ```
 ## Reference
 - [Animations](animations.md)
 - [Component](component.md)
 - [Event Bus](event_bus.md)
 - [Observer](observer.md)
 - [QWeb](qweb.md)
 - [Router](router.md)
 - [Store](store.md)
 - [Utils](utils.md)
 - [Virtual DOM](vdom.md)
 ## Learning Resources
 - [Quick Start](quick_start.md)
 ## Miscellaneous
 - [Comparison with React/Vue](comparison.md)
 - [Tooling](tooling.md)
 - [Templates to start Owl applications (external link)](https://github.com/ged-odoo/owl-templates)
@@ -30,7 +30,7 @@ btn {
 }
 ```
-will produce a nice flash effect whenever the user click (or activate with the
+will produce a nice flash effect whenever the user clicks (or activates with the
 keyboard) the button.
 ## CSS Transitions
@@ -47,26 +47,25 @@ the lifetime of a node. Since this is not easy to do by hand, Owl `t-transition`
 directive is there to help.
 Whenever a node has a `t-transition` directive, with a `name` value, the following
-will happen:
+sequence of events will happen:
 At node insertion:
 - the css classes `name-enter` and `name-enter-active` will be added directly
-  when the node is inserted into the DOM,
+  when the node is inserted into the DOM.
 - on the next animation frame: the css class `name-enter` will be removed and the
  class `name-enter-to` will be added (so they can be used to trigger css
-  transition effects),
+  transition effects).
- the css class `name-enter-active` will be removed whenever a css transition
+- at the end of the transition, `name-enter-to` and `name-enter-active` will be removed.
  ends.
 At node destruction:
 - the css classes `name-leave` and `name-leave-active` will be added before the
-  node is removed to the DOM,
+  node is removed to the DOM.
- the css class `name-leave` will be removed on the next animation frame (so it
+- on the next animation frame: the css class `name-leave` will be removed and the
-  can be used to trigger css transition effects),
+  class `name-leave-to` will be added (so they can be used to trigger css
- the css class `name-leave-active` will be removed whenever a css transition
+  transition effects).
-  ends. Only then will the element be removed from the DOM.
+- at the end of the transition, `name-leave-to` and `name-leave-active` will be removed.
 For example, a simple fade in/out effect can be done with this:
@@ -91,6 +90,38 @@ The `t-transition` directive can be applied on a node element or on a component.
 Notes:
- more information on animations are available [here](animations.md).
+Owl does not support more than one transition on a single node, so the
- Owl does not support more than one transition on a single node, so the
+`t-transition` expression must be a single value (i.e. no space allowed).
-  `t-transition` expression must be a single value (i.e. no space allowed)
+
 ## SCSS Mixins
 If you use SCSS, you can use mixins to make generic animations. Here is an exemple with a fade in / fade out animation:
 ```scss
@mixin animation-fade($time, $name) {
  .#{$name}_fade-enter-active,
  .#{$name}_fade-active {
    transition: all $time;
  }
  .#{$name}_fade-enter {
    opacity: 0;
  }
  .#{$name}_fade-leave-to {
    opacity: 0;
  }
 }
 ```
 Usage:
 ```scss
@include animation-fade(0.5s, "o_notification");
 ```
 You can now have in your template:
 ```xml
 <SomeTag  t-transition="o_notification_fade"/>
 ```
@@ -0,0 +1,33 @@
 # 🦉 Browser 🦉
 ## Content
 - [Overview](#overview)
 - [Browser Content](#browser-content)
 ## Overview
 The browser object contains some browser native APIs, such as `setTimeout`, that
 are used by Owl and its utility functions. They are exposed with the intent of
 making them mockable if necessary.
 ```js
 owl.browser.setTimeout === window.setTimeout; // return true
 ```
 For now, this object contains some functions that are not used by Owl. They
 will eventually be removed in Owl 2.0.
 ## Browser Content
 More specifically, the `browser` object contains the following methods and objects:
 - `setTimeout`
 - `clearTimeout`
 - `setInterval`
 - `clearInterval`
 - `requestAnimationFrame`
 - `random`
 - `Date`
 - `fetch`
 - `localStorage`
@@ -0,0 +1,855 @@
 # 🦉 OWL Component 🦉
 ## Content
 - [Overview](#overview)
 - [Example](#example)
 - [Reference](#reference)
  - [Reactive System](#reactive-system)
  - [Properties](#properties)
  - [Static Properties](#static-properties)
  - [Methods](#methods)
  - [Lifecycle](#lifecycle)
    - [`constructor(parent, props)`](#constructorparent-props)
    - [`setup()`](#setup)
    - [`willStart()`](#willstart)
    - [`mounted()`](#mounted)
    - [`willUpdateProps(nextProps)`](#willupdatepropsnextprops)
    - [`willPatch()`](#willpatch)
    - [`patched(snapshot)`](#patchedsnapshot)
    - [`willUnmount()`](#willunmount)
    - [`catchError(error)`](#catcherrorerror)
  - [Root Component](#root-component)
  - [Composition](#composition)
  - [Form Input Bindings](#form-input-bindings)
  - [References](#references)
  - [Dynamic sub components](#dynamic-sub-components)
  - [Functional Components](#functional-components)
  - [SVG Components](#svg-components)
 ## Overview
 OWL components are the building blocks for user interface. They are designed to be:
 1. **declarative:** the user interface should be described in terms of the state
   of the application, not as a sequence of imperative steps.
 2. **composable:** each component can seamlessly be created in a parent component by
   a simple tag or directive in its template.
 3. **asynchronous rendering:** the framework will transparently wait for each
   sub components to be ready before applying the rendering. It uses native promises
   under the hood.
 4. **uses QWeb as a template system:** the templates are described in XML
   and follow the QWeb specification. This is a requirement for Odoo.
 OWL components are defined as a subclass of Component. The rendering is
 exclusively done by a [QWeb](qweb_templating_language.md) template (which needs to be preloaded in QWeb).
 Rendering a component generates a virtual dom representation
 of the component, which is then patched to the DOM, in order to apply the changes in an efficient way.
 ## Example
 Let us have a look at a simple component:
 ```javascript
 const { useState } = owl.hooks;
 class ClickCounter extends owl.Component {
  state = useState({ value: 0 });
  increment() {
    this.state.value++;
  }
 }
 ```
 ```xml
 <button t-name="ClickCounter" t-on-click="increment">
  Click Me! [<t t-esc="state.value"/>]
 </button>
 ```
 Note that this code is written in ESNext style, so it will only run on the
 latest browsers without a transpilation step.
 This example shows how a component should be defined: it simply subclasses the
 Component class. If no static `template` key is defined, then
 Owl will use the component's name as template name. Here,
 a state object is defined, by using the `useState` hook. It is not mandatory to use the state object, but it is certainly encouraged. The result of the `useState` call is
 [observed](observer.md), and any change to it will cause a rerendering.
 ## Reference
 An Owl component is a small class which represents a component or some UI element.
 It exists in the context of an [environment](environment.md) (`env`), which is propagated from a
 parent to its children. The environment needs to have a [QWeb](qweb_templating_language.md) instance, which
 will be used to render the component template.
 Be aware that the name of the component may be significant: if a component does
 not define a `template` key, then Owl will lookup in QWeb to
 find a template with the component name (or one of its ancestors).
 ### Reactive system
 OWL components are normal javascript classes. So, changing a component internal
 state does nothing more:
 ```js
 class Counter extends Component {
  static template = xml`<div t-on-click="increment"><t t-esc="state.value"/></div>`;
  state = { value: 0 };
  increment() {
    this.state.value++;
  }
 }
 ```
 Clicking on the `Counter` component defined above will call the `increment`
 method, but it will not rerender the component. To fix that, one could add an
 explicit call to `render` in `increment`:
 ```js
    increment() {
        this.state.value++;
        this.render();
    }
 ```
 However, it may be simple in this case, but it quickly become cumbersome, as a
 component get more complex, and its internal state is modified by more than one
 method.
 A better way is to use the reactive system: by using the `useState` hook (see the
 [hooks](hooks.md) section for more details), one can make Owl react to state
 changes. The `useState` hook generates a proxy version of an object
 (this is done by an [observer](observer.md)), which allows the component to
 react to any change. So, the `Counter` example above can be improved like this:
 ```js
 const { useState } = owl.hooks;
 class Counter extends Component {
  static template = xml`<div t-on-click="increment"><t t-esc="state.value"/></div>`;
  state = useState({ value: 0 });
  increment() {
    this.state.value++;
  }
 }
 ```
 Obviously, we can call the `useState` hook more than once:
 ```js
 const { useState } = owl.hooks;
 class Counter extends Component {
  static template = xml`
      <div>
        <span t-on-click="increment(counter1)"><t t-esc="counter1.value"/></span>
        <span t-on-click="increment(counter2)"><t t-esc="counter2.value"/></span>
      </div>`;
  counter1 = useState({ value: 0 });
  counter2 = useState({ value: 0 });
  increment(counter) {
    counter.value++;
  }
 }
 ```
 Note that hooks are subject to one important [rule](hooks.md#one-rule): they need
 to be called in the constructor.
 ### Properties
 - **`el`** (HTMLElement | null): reference to the DOM root node of the element. It is `null` when the
  component is not mounted.
 - **`env`** (Object): the component [environment](environment.md), which contains a QWeb instance.
 - **`props`** (Object): this is an object containing all the properties given by
  the parent to a child component. For example, in the following situation,
  the parent component gives a `user` and a `color` value to the `ChildComponent`.
  ```xml
    <div>
      <ChildComponent user="state.user" color="color">
    </div>
  ```
  Note that `props` are owned by the parent, not by the component.
  As such, it should not ever be modified by the component (otherwise you risk
  unintended effects, since the parent may not be aware of the change)!!
  The `props` can be modified dynamically by the parent. In that case, the
  component will go through the following lifecycle methods: `willUpdateProps`,
  `willPatch` and `patched`.
 ### Static Properties
 - **`template`** (string, optional): if given, this is the name of the QWeb template that will render the component. Note that there is a helper `xml` to
  make it easy to define an inline template.
 * **`components`** (Object, optional): if given, this is an object that contains
  the classes of any sub components needed by the template. This is the main way
  used by Owl to be able to create sub components.
  ```js
  class ParentComponent extends owl.Component {
    static components = { SubComponent };
  }
  ```
 * **`props`** (Object, optional): if given, this is an object that describes the
  type and shape of the (actual) props given to the component. If Owl mode is
  `dev`, this will be used to validate the props each time the component is
  created/updated. See [Props Validation](props_validation.md) for more information.
  ```js
  class Counter extends owl.Component {
    static props = {
      initialValue: Number,
      optional: true,
    };
  }
  ```
 - **`defaultProps`** (Object, optional): if given, this object define default
  values for (top-level) props. Whenever `props` are given to the object, they
  will be altered to add default value (if missing). Note that it does not
  change the initial object, a new object will be created instead.
  ```js
  class Counter extends owl.Component {
    static defaultProps = {
      initialValue: 0,
    };
  }
  ```
 - **`style`** (string, optional): it should be the return value of the [`css` tag](tags.md#css-tag),
  which is used to inject stylesheet whenever the component is visible on the
  screen.
 There is another static property defined on the `Component` class: `current`.
 This property is set to the currently being defined component (in the constructor).
 This is the way [hooks](hooks.md) are able to get a reference to the target
 component.
 ### Methods
 We explain here all the public methods of the `Component` class.
 - **`mount(target, options)`** (async): this is the main way a
  component is added to the DOM: the root component is mounted to a target
  HTMLElement (or document fragment). Obviously, this is asynchronous, since each children need to be
  created as well. Most applications will need to call `mount` exactly once, on
  the root component.
  The `options` argument is an optional object with a `position` key. The
  `position` key can have three possible values: `first-child`, `last-child`, `self`.
  - `first-child`: with this option, the component will be prepended inside the target,
  - `last-child` (default value): with this option, the component will be
    appended in the target element,
  - `self`: the target will be used as the root element for the component. This
    means that the target has to be an HTMLElement (and not a document fragment).
    In this situation, it is possible that the component cannot be unmounted. For
    example, if its target is `document.body`.
  Note that if a component is mounted, unmounted and remounted, it will be
  automatically re-rendered to ensure that changes in its state (or something
  in the environment) will be taken into account.
  If a component is mounted inside an element or a fragment which is not in the
  DOM, then it will be rendered fully, but not active: the `mounted` hooks will
  not be called. This is sometimes useful if we want to load an application in
  memory. In that case, we need to mount the root component again in an element
  which is in the DOM:
  ```js
  const app = new App();
  await app.mount(document.createDocumentFragment());
  // app is rendered in memory, but not active
  await app.mount(document.body);
  // app is now visible
  ```
  Note that the normal way of mounting an application is by using the `mount`
  method on a component class, not by creating the instance by hand. See the
  documentation on [mounting applications](mounting.md).
 * **`unmount()`**: in case a component needs to be detached/removed from the DOM, this
  method can be used. Most applications should not call `unmount`, this is more
  useful to the underlying component system.
 * **`render()`** (async): calling this method directly will cause a rerender. Note
  that this should be very rare to have to do it manually, the Owl framework is
  most of the time responsible for doing that at an appropriate moment.
  Note that the render method is asynchronous, so one cannot observe the updated
  DOM in the same stack frame.
 * **`shouldUpdate(nextProps)`**: this method is called each time a component's props
  are updated. It returns a boolean, which indicates if the component should
  ignore a props update. If it returns false, then `willUpdateProps` will not
  be called, and no rendering will occur. Its default implementation is to
  always return true. Note that this is an optimization, similar to React's `shouldComponentUpdate`. Most of the time, this should not be used, but it
  can be useful if we are handling large number of components. Since this is an
  optimization, Owl has the freedom to ignore the result of `shouldUpdate` in
  some cases (for example, if a component is remounted, or if we want to force
  a full rerender of the UI). However, if `shouldUpdate` returns true, then Owl
  provides the guarantee that the component will be rendered at some point in
  the future (except if the component is destroyed or if some part of the UI crashes).
 * **`destroy()`**. As its name suggests, this method will remove the component,
  and perform all necessary cleanup, such as unmounting the component, its children,
  removing the parent/children relationship. This method should almost never be
  called directly (except maybe on the root component), but should be done by the
  framework instead.
 Obviously, these methods are reserved for Owl, and should not be used by Owl
 users, unless they want to override them. Also, Owl reserves all method names
 starting with `__`, in order to prevent possible future conflicts with user code
 whenever Owl needs to change.
 ### Lifecycle
 A solid and robust component system needs useful hooks/methods to help
 developers write components. Here is a complete description of the lifecycle of
 a owl component:
 | Method                                           | Description                                                 |
 | ------------------------------------------------ | ----------------------------------------------------------- |
 | **[setup](#setup)**                              | setup                                                       |
 | **[willStart](#willstart)**                      | async, before first rendering                               |
 | **[mounted](#mounted)**                          | just after component is rendered and added to the DOM       |
 | **[willUpdateProps](#willupdatepropsnextprops)** | async, before props update                                  |
 | **[willPatch](#willpatch)**                      | just before the DOM is patched                              |
 | **[patched](#patchedsnapshot)**                  | just after the DOM is patched                               |
 | **[willUnmount](#willunmount)**                  | just before removing component from DOM                     |
 | **[catchError](#catcherrorerror)**               | catch errors (see [error handling page](error_handling.md)) |
 Notes:
 - hooks call order is precisely defined: `[willX]` hooks are called first on parent,
  then on children, and `[Xed]` are called in the reverse order: first children,
  then parent.
 - no hook method should ever be called manually. They are supposed to be
  called by the owl framework whenever it is required.
 #### `constructor(parent, props)`
 The constructor is not exactly a hook, it is the regular,
 normal, constructor of the component. Since it is not a hook, you need to make
 sure that `super` is called.
 This is usually where you would set the initial state and the template of the
 component.
 ```javascript
  constructor(parent, props) {
    super(parent, props);
    this.state = useState({someValue: true});
    this.template = 'mytemplate';
  }
 ```
 Note that with ESNext class fields, the constructor method does not need to be
 implemented in most cases:
 ```javascript
 class ClickCounter extends owl.Component {
  state = useState({ value: 0 });
  ...
 }
 ```
 Hook functions can be called in the constructor.
 #### `setup()`
 _setup_ is run just after the component is constructed. It is a lifecycle method,
 very similar to the _constructor_, except that it does not receive any argument.
 It is a valid method to call hook functions. Note that one of the main reason to
 have the `setup` hook in the component lifecycle is to make it possible to
 monkey patch it. It is a common need in the Odoo ecosystem.
 ```javascript
 setup() {
  useSetupAutofocus();
 }
 ```
 #### `willStart()`
 willStart is an asynchronous hook that can be implemented to
 perform some action before the initial rendering of a component.
 It will be called exactly once before the initial rendering. It is useful
 in some cases, for example, to load external assets (such as a JS library)
 before the component is rendered. Another use case is to load data from a server.
 ```javascript
  async willStart() {
    await owl.utils.loadJS("my-awesome-lib.js");
  }
 ```
 At this point, the component is not yet rendered. Note that a slow `willStart` method will slow down the rendering of the user
 interface. Therefore, some care should be made to make this method as
 fast as possible.
 #### `mounted()`
 `mounted` is called each time a component is attached to the
 DOM, after the initial rendering and possibly later if the component was unmounted
 and remounted. At this point, the component is considered _active_. This is a good place to add some listeners, or to interact with the
 DOM, if the component needs to perform some measure for example.
 It is the opposite of `willUnmount`. If a component has been mounted, it will
 always be unmounted at some point in the future.
 The mounted method will be called recursively on each of its children. First,
 the parent, then all its children.
 It is allowed (but not encouraged) to modify the state in the `mounted` hook.
 Doing so will cause a rerender, which will not be perceptible by the user, but
 will slightly slow down the component.
 #### `willUpdateProps(nextProps)`
 The willUpdateProps is an asynchronous hook, called just before new props
 are set. This is useful if the component needs to perform an asynchronous task,
 depending on the props (for example, assuming that the props are
 some record Id, fetching the record data).
 ```javascript
  willUpdateProps(nextProps) {
    return this.loadData({id: nextProps.id});
  }
 ```
 This hook is not called during the first render (but willStart is called
 and performs a similar job).
 #### `willPatch()`
 The willPatch hook is called just before the DOM patching process starts.
 It is not called on the initial render. This is useful to read
 information from the DOM. For example, the current position of the
 scrollbar.
 Note that modifying the state is not allowed here. This method is called just
 before an actual DOM patch, and is only intended to be used to save some local
 DOM state. Also, it will not be called if the component is not in the DOM.
 #### `patched(snapshot)`
 This hook is called whenever a component did actually update its DOM (most
 likely via a change in its state/props or environment).
 This method is not called on the initial render. It is useful to interact
 with the DOM (for example, through an external library) whenever the
 component was patched. Note that this hook will not be called if the component is
 not in the DOM.
 Updating the component state in this hook is possible, but not encouraged.
 One needs to be careful, because updates here will create an additional rendering, which in
 turn will cause other calls to the `patched` method. So, we need to be particularly
 careful at avoiding endless cycles.
 #### `willUnmount()`
 willUnmount is a hook that is called each time just before a component is unmounted from
 the DOM. This is a good place to remove listeners, for example.
 ```javascript
  mounted() {
    this.env.bus.on('someevent', this, this.doSomething);
  }
  willUnmount() {
    this.env.bus.off('someevent', this, this.doSomething);
  }
 ```
 This is the opposite method of `mounted`.
 #### `catchError(error)`
 The `catchError` method is useful when we need to intercept and properly react
 to (rendering) errors that occur in some sub components. See the page on
 [error handling](error_handling.md).
 ### Root Component
 Most of the time, an Owl component will be created automatically by a tag (or the `t-component`
 directive) in a template. There is however an obvious exception: the root component
 of an Owl application has to be created manually:
 ```js
 class App extends owl.Component { ... }
 const app = new App();
 app.mount(document.body);
 ```
 The root component does not have a parent nor `props` (see note below). It will be setup with an
 [environment](environment.md) (either the `env` defined on its class, or a
 default empty environment).
 Note: a root component can however be given a `props` object in its constructor,
 like this: `new App(null, {some: 'object'});`. It will not be a true `props`
 object, managed by Owl (so, for example, it will never be updated).
 ### Composition
 The example above shows a QWeb template with a sub component. In a template,
 components are declared with a tagname corresponding to the class name. It has
 to be capitalized.
 ```xml
 <div t-name="ParentComponent">
  <span>some text</span>
  <MyComponent info="13" />
 </div>
 ```
 ```js
 class ParentComponent extends owl.Component {
    static components = { MyComponent: MyComponent};
    ...
 }
 ```
 In this example, the `ParentComponent`'s template creates a component `MyComponent` just
 after the span. The `info` key will be added to the subcomponent's `props`. Each
 `props` is a string which represents a javascript (QWeb) expression, so it is
 dynamic. If it is necessary to give a string, this can be done by quoting it:
 `someString="'somevalue'"`.
 Note that the rendering context for the template is the component itself. This means
 that the template can access `state` (if it exists), `props`, `env`, or any
 methods defined in the component.
 ```xml
 <div t-name="ParentComponent">
    <ChildComponent count="state.val" />
 </div>
 ```
 ```js
 class ParentComponent {
  static components = { ChildComponent };
  state = useState({ val: 4 });
 }
 ```
 Whenever the template is rendered, it will automatically create the subcomponent
 `ChildComponent` at the correct place. It needs to find the reference to the
 actual component class in the special static `components` key, or the class registered in
 QWeb's global registry (see `register` function of QWeb). It first looks inside
 the static `components` key, then fallbacks on the global registry.
 _Props_: In this example, the child component will receive the object `{count: 4}` in its
 constructor. This will be assigned to the `props` variable, which can be accessed
 on the component (and also, in the template). Whenever the state is updated, then
 the sub component will also be updated automatically. See the [props section](props.md)
 for more information.
 **CSS and style:** Owl allows the parent to declare
 additional css classes or style for the sub component: css declared in `class`, `style`, `t-att-class` or `t-att-style` will be added to the
 root component element.
 ```xml
 <div t-name="ParentComponent">
  <MyComponent class="someClass" style="font-weight:bold;" info="13" />
 </div>
 ```
 Warning: there is a small caveat with dynamic class attributes: since Owl needs
 to be able to add/remove proper classes whenever necessary, it needs to be aware
 of the possible classes. Otherwise, it will not be able to make the difference
 between a valid css class added by the component, or other custom code, and a
 class that need to be removed. This is why we only support the explicit syntax
 with a class object:
 ```xml
 <MyComponent t-att-class="{a: state.flagA, b: state.flagB}" />
 ```
 ### Form Input Bindings
 It is very common to need to be able to read the value out of an html `input` (or
 `textarea`, or `select`) in order to use it (note: it does not need to be in a
 form!). A possible way to do this is to do it by hand:
 ```js
 class Form extends owl.Component {
  state = useState({ text: "" });
  _updateInputValue(event) {
    this.state.text = event.target.value;
  }
 }
 ```
 ```xml
 <div>
  <input t-on-input="_updateInputValue" />
  <span t-esc="state.text" />
 </div>
 ```
 This works. However, this requires a little bit of _plumbing_ code. Also, the
 plumbing code is slightly different if you need to interact with a checkbox,
 or with radio buttons, or with select tags.
 To help with this situation, Owl has a builtin directive `t-model`: its value
 should be an observed value in the component (usually `state.someValue`). With
 the `t-model` directive, we can write a shorter code, equivalent to the previous
 example:
 ```js
 class Form extends owl.Component {
  state = { text: "" };
 }
 ```
 ```xml
 <div>
  <input t-model="state.text" />
  <span t-esc="state.text" />
 </div>
 ```
 The `t-model` directive works with `<input>`, `<input type="checkbox">`,
 `<input type="radio">`, `<textarea>` and `<select>`:
 ```xml
 <div>
    <div>Text in an input: <input t-model="state.someVal"/></div>
    <div>Textarea: <textarea t-model="state.otherVal"/></div>
    <div>Boolean value: <input type="checkbox" t-model="state.someFlag"/></div>
    <div>Selection:
        <select t-model="state.color">
            <option value="">Select a color</option>
            <option value="red">Red</option>
            <option value="blue">Blue</option>
        </select>
    </div>
    <div>
        Selection with radio buttons:
        <span>
            <input type="radio" name="color" id="red" value="red" t-model="state.color"/>
            <label for="red">Red</label>
        </span>
        <span>
            <input type="radio" name="color" id="blue" value="blue" t-model="state.color" />
            <label for="blue">Blue</label>
        </span>
    </div>
 </div>
 ```
 Like event handling, the `t-model` directive accepts the following modifiers:
 | Modifier  | Description                                                          |
 | --------- | -------------------------------------------------------------------- |
 | `.lazy`   | update the value on the `change` event (default is on `input` event) |
 | `.number` | try to parse the value to a number (using `parseFloat`)              |
 | `.trim`   | trim the resulting value                                             |
 For example:
 ```xml
 <input t-model.lazy="state.someVal" />
 ```
 These modifiers can be combined. For instance, `t-model.lazy.number` will only
 update a number whenever the change is done.
 Note: the online playground has an example to show how it works.
 ### References
 The `useRef` hook is useful when we need a way to interact with some inside part
 of a component, rendered by Owl. It can work either on a DOM node, or on a component,
 tagged by the `t-ref` directive. See the [hooks section](hooks.md#useref) for
 more detail.
 As a short example, here is how we could set the focus on a given input:
 ```xml
 <div>
    <input t-ref="input"/>
    <button t-on-click="focusInput">Click</button>
 </div>
 ```
 ```js
 import { useRef } from "owl/hooks";
 class SomeComponent extends Component {
  inputRef = useRef("input");
  focusInput() {
    this.inputRef.el.focus();
  }
 }
 ```
 The `useRef` hook can also be used to get a reference to an instance of a sub
 component rendered by Owl. In that case, we need to access it with the `comp`
 property instead of `el`:
 ```xml
 <div>
    <SubComponent t-ref="sub"/>
    <button t-on-click="doSomething">Click</button>
 </div>
 ```
 ```js
 import { useRef } from "owl/hooks";
 class SomeComponent extends Component {
  static components = { SubComponent };
  subRef = useRef("sub");
  doSomething() {
    this.subRef.comp.doSomeThingElse();
  }
 }
 ```
 Note that these two examples uses the suffix `ref` to name the reference. This
 is not mandatory, but it is a useful convention, so we do not forget to access
 it with the `el` or `comp` suffix.
 ### Dynamic sub components
 It is not common, but sometimes we need a dynamic component name. In this case,
 the `t-component` directive can also be used to accept dynamic values with string interpolation (like the [`t-attf-`](qweb_templating_language.md#dynamic-attributes) directive):
 ```xml
 <div t-name="ParentComponent">
    <t t-component="ChildComponent{{id}}" />
 </div>
 ```
 ```js
 class ParentComponent {
  static components = { ChildComponent1, ChildComponent2 };
  state = { id: 1 };
 }
 ```
 There is an even more dynamic way to use `t-component`: its value can be an
 expression evaluating to an actual component class. In that case, this is the
 class that will be used to create the component:
 ```js
 class A extends Component<any, any, any> {
  static template = xml`<span>child a</span>`;
 }
 class B extends Component<any, any, any> {
  static template = xml`<span>child b</span>`;
 }
 class App extends Component<any, any, any> {
  static template = xml`<t t-component="myComponent" t-key="state.child"/>`;
  state = { child: "a" };
  get myComponent() {
    return this.state.child === "a" ? A : B;
  }
 }
 ```
 In this example, the component `App` selects dynamically the concrete sub
 component class.
 Note that the `t-component` directive can only be used on `<t>` nodes.
 ### Functional Components
 Owl does not exactly have functional components. However, there is an extremely
 close alternative: calling sub templates.
 A stateless functional component in react is usually some kind of function that
 maps props to a virtual dom (often with `jsx`). So, basically, almost like a
 template rendered with `props`. In Owl, this can be done by
 simply defining a template, that will access the `props` object:
 ```js
 const Welcome = xml`<h1>Hello, <t t-esc="props.name"/></h1>`;
 class MyComponent extends Component {
  static template = xml`
        <div>
            <t t-call=${Welcome}/>
            <div>something</div>
        </div>
    `;
 }
 ```
 The way this works is that sub templates are inlined, and have access to the
 ambient context. They can therefore access `props`, and any other part of the
 caller component.
 ### SVG Components
 Owl components can be used to generate dynamic SVG graphs:
 ```js
 class Node extends Component {
  static template = xml`
        <g>
            <circle t-att-cx="props.x" t-att-cy="props.y" r="4" fill="black"/>
            <text t-att-x="props.x - 5" t-att-y="props.y + 18"><t t-esc="props.node.label"/></text>
            <t t-set="childx" t-value="props.x + 100"/>
            <t t-set="height" t-value="props.height/(props.node.children || []).length"/>
            <t t-foreach="props.node.children || []" t-as="child">
                <t t-set="childy" t-value="props.y + child_index*height"/>
                <line t-att-x1="props.x" t-att-y1="props.y" t-att-x2="childx" t-att-y2="childy" stroke="black" />
                <Node x="childx" y="childy" node="child" height="height"/>
            </t>
        </g>
    `;
  static components = { Node };
 }
 class RootNode extends Component {
  static template = xml`
        <svg height="180">
            <Node node="graph" x="10" y="20" height="180"/>
        </svg>
    `;
  static components = { Node };
  graph = {
    label: "a",
    children: [
      { label: "b" },
      { label: "c", children: [{ label: "d" }, { label: "e" }] },
      { label: "f", children: [{ label: "g" }] },
    ],
  };
 }
 ```
 This `RootNode` component will then display a live SVG representation of the
 graph described by the `graph` property. Note that there is a recursive structure
 here: the `Node` component uses itself as a subcomponent.
 Note that since SVG needs to be handled in a specific way (its namespace needs
 to be properly set), there is a small constraint for Owl components: if an owl
 component is supposed to be a part of an svg graph, then its root node needs to
 be a `g` tag, so Owl can properly set the namespace.
@@ -0,0 +1,181 @@
 # 🦉 Concurrency Model 🦉
 ## Content
 - [Overview](#overview)
 - [Rendering Components](#rendering-components)
 - [Semantics](#semantics)
 - [Asynchronous Rendering](#asynchronous-rendering)
 ## Overview
 Owl was designed from the very beginning with asynchronous components. This comes
 from the `willStart` and the `willUpdateProps` lifecycle hooks. With these
 methods, it is possible to build complex highly concurrent applications.
 Owl concurrent mode has several benefits: it makes it possible to delay the
 rendering until some asynchronous operation is complete, it makes it possible
 to lazy load libraries, while keeping the previous screen completely functional.
 It is also good for performance reasons: Owl uses it to only apply the result of
 many different renderings only once in an animation frame. Owl can cancel
 a rendering that is no longer relevant, restart it, reuse it in some cases.
 But even though using concurrency is quite simple (and is the default behaviour),
 asynchrony is difficult, because it introduces an additional dimension that
 vastly increase the complexity of an application. This section will explain
 how Owl manages this complexity, how concurrent rendering works in a general way.
 ## Rendering Components
 The word _rendering_ is a little vague, so, let us explain more precisely the
 process by which Owl components are displayed on a screen.
 When a component is mounted or updated, a new rendering is started. It has
 two phases: _virtual rendering_ and _patching_.
 ### Virtual rendering
 This phase represent the process of rendering a template, in memory, which create a virtual representation of the desired component html). The output of this phase is a
 virtual DOM.
 It is asynchronous: each subcomponents needs to either be created (so, `willStart`
 will need to be called), or updated (which is done with the `willUpdateProps`
 method). This is completely a recursive process: a component is the root of a
 component tree, and each sub component needs to be (virtually) rendered.
 ### Patching
 Once a rendering is complete, it will be applied on the next animation frame.
 This is done synchronously: the whole component tree is patched to the real
 DOM.
 ## Semantics
 We give here an informal description of the way components are created/updated
 in an application. Here, ordered lists describe actions that are executed
 sequentially, bullet lists describe actions that are executed in parallel.
 **Scenario 1: initial rendering** Imagine we want to render the following component tree:
 ```
        A
       / \
      B   C
         / \
        D   E
 ```
 Here is what happen whenever we mount the root
 component (with some code like `app.mount(document.body)`).
 1. `willStart` is called on `A`
 2. when it is done, template `A` is rendered.
   - component `B` is created
     1. `willStart` is called on `B`
     2. template `B` is rendered
   - component `C` is created
     1. `willStart` is called on `C`
     2. template `C` is rendered
        - component `D` is created
          1. `willStart` is called on `D`
          2. template `D` is rendered
        - component `E` is created
          1. `willStart` is called on `E`
          2. template `E` is rendered
 3. each components are patched into a detached DOM element, in the following order:
   `E`, `D`, `C`, `B`, `A`. (so the actual full DOM tree is created
   in one pass)
 4. the component `A` root element is actually appended to `document.body`
 5. The method `mounted` is called recursively on all components in the following
   order: `E`, `D`, `C`, `B`, `A`.
 **Scenario 2: rerendering a component**. Now, let's assume that the user clicked on some
 button in `C`, and this results in a state update, which is supposed to:
 - update `D`,
 - remove `E`,
 - add new component `F`.
 So, the component tree should look like this:
 ```
        A
       / \
      B   C
         / \
        D   F
 ```
 Here is what Owl will do:
 1. because of a state change, the method `render` is called on `C`
 2. template `C` is rendered again
   - component `D` is updated:
     1. hook `willUpdateProps` is called on `D` (async)
     2. template `D` is rerendered
   - component `F` is created:
     1. hook `willStart` is called on `F` (async)
     2. template `F` is rendered
 3. `willPatch` hooks are called recursively on components `C`, `D` (not on `F`,
   because it is not mounted yet)
 4. components `F`, `D` are patched in that order
 5. component `C` is patched, which will cause recursively:
   1. `willUnmount` hook on `E`
   2. destruction of `E`,
 6. `mounted` hook is called on `F`, `patched` hooks are called on `D`, `C`
 Tags are very small helpers to make it easy to write inline templates. There is
 only one currently available tag: `xml`, but we plan to add other tags later,
 such as a `css` tag, which will be used to write [single file components](../learning/how_to_write_sfc.md).
 ### Asynchronous Rendering
 Working with asynchronous code always adds a lot of complexity to a system. Whenever
 different parts of a system are active at the same time, one needs to think
 carefully about all possible interactions. Clearly, this is also true for Owl
 components.
 There are two different common problems with Owl asynchronous rendering model:
 - any component can delay the rendering (initial and subsequent) of the whole
  application
 - for a given component, there are two independant situations that will trigger an
  asynchronous rerendering: a change in the state, or a change in the props.
  These changes may be done at different times, and Owl has no way of knowing
  how to reconcile the resulting renderings.
 Here are a few tips on how to work with asynchronous components:
 1. Minimize the use of asynchronous components!
 2. Lazy loading external libraries is a good use case for async rendering. This
   is mostly fine, because we can assume that it will only takes a fraction of a
   second, and only once (see [`owl.utils.loadJS`](utils.md#loadjs))
 3. For all the other cases, the [`AsyncRoot`](misc.md#asyncroot) component is there to help you. When
   this component is met, a new rendering
   sub tree is created, such that the rendering of that component (and its
   children) is not tied to the rendering of the rest of the interface. It can
   be used on an asynchronous component, to prevent it from delaying the
   rendering of the whole interface, or on a synchronous one, such that its
   rendering isn't delayed by other (asynchronous) components. Note that this
   directive has no effect on the first rendering, but only on subsequent ones
   (triggered by state or props changes).
   ```xml
   <div t-name="ParentComponent">
     <SyncChild />
     <AsyncRoot>
        <AsyncChild/>
     </AsyncRoot>
   </div>
   ```
@@ -0,0 +1,44 @@
 # 🦉 Config 🦉
 The Owl framework is designed to work in many situations. However, it is
 sometimes necessary to customize some behaviour. This is done by using the
 global `config` object. It provides two settings:
 - [`mode`](#mode) (default value: `prod`),
 - [`enableTransitions`](#enabletransitions) (default value: `true`).
 ## Mode
 By default, Owl is in _production_ mode, this means that it will try to do its
 job fast, and skip some expensive operations. However, it is sometimes necessary
 to have better information on what is going on, this is the purpose
 of the `dev` mode.
 Owl has a mode flag, in `owl.config.mode`. Its default value is `prod`, but
 it can be set to `dev`:
 ```js
 owl.config.mode = "dev";
 ```
 Note that templates compiled with the `prod` settings will not be recompiled.
 So, changing this setting is best done at startup.
 An important job done by the `dev` mode is to validate props for each component
 creation and update. Also, extra props will cause an error.
 ## `enableTransitions`
 Transitions are usually nice, but they can cause issues in some specific cases,
 such as automated tests. It is uncomfortable having to wait for a transition
 to end before moving to the next step.
 To solve this issue, Owl can be configured to ignore the `t-transition` directive.
 To do that, one only needs to set the `enableTransitions` flag to false:
 ```js
 owl.config.enableTransitions = false;
 ```
 Note that it suffers from the same drawback as the "dev" mode: all compiled
 templates, if any, will keep their current behaviours.
@@ -0,0 +1,36 @@
 # 🦉 Owl Content 🦉
 Here is a complete visual representation of everything exported by the `owl`
 global object.
 For example, `Component` is available at `owl.Component` and `EventBus` is
 exported as `owl.core.EventBus`.
 ```
 browser
 Component                               misc
 Context                                     AsyncRoot
 QWeb                                        Portal
 mount
 useState                                tags
 config                                      css
    mode                                    xml
 core                                    utils
    EventBus                                debounce
    Observer                                escape
 hooks                                       loadJS
    onWillStart                             loadFile
    onMounted                               shallowEqual
    onWillUpdateProps                       whenReady
    onWillPatch
    onPatched
    onWillUnmount
    useContext
    useState
    useRef
    useComponent
    useEnv
    useSubEnv
 ```
 Note that for convenience, the `useState` hook is also exported at the root of the `owl` object.
@@ -0,0 +1,105 @@
 # 🦉 Context 🦉
 ## Content
 - [Overview](#overview)
 - [Example](#example)
 - [Reference](#reference)
  - [`Context`](#context)
  - [`useContext`](#usecontext)
 ## Overview
 The `Context` object provides a way to share data between an arbitrary number
 of components. Usually, data is passed from a parent to its children component,
 but when we have to deal with some mostly global information, this can be
 annoying, since each component will need to pass the information to each children,
 even though some or most of them will not use the information.
 With a `Context` object, each component can subscribe (with the `useContext` hook)
 to its state, and will be updated whenever the context state is updated.
 ## Example
 Assume that we have an application with various components which needs to render
 differently depending on the size of the device. Here is how we could proceed
 to make sure that the information is properly shared. First, let us create a
 context, and add it to the environment:
 ```js
 const deviceContext = new Context({ isMobile: true });
 App.env.deviceContext = deviceContext;
 ```
 If we want to make it completely responsive, we need to update its value whenever
 the size of the screen is updated:
 ```js
 const isMobile = () => window.innerWidth <= 768;
 window.addEventListener(
  "resize",
  owl.utils.debounce(() => {
    const state = deviceContext.state;
    if (state.isMobile !== isMobile()) {
      state.isMobile = !state.isMobile;
    }
  }, 15)
 );
 ```
 Then, each component that want can subscribe and render differently depending on the
 fact that we are in a mobile or desktop mode.
 ```js
 class SomeComponent extends Component {
  static template = xml`
    <div>
      <t t-if=device.isMobile>
          some simplified user interface
      </t>
      <t t-else="">
          a more advanced user interface
      </t>
    </div>`;
  device = useContext(this.env.deviceContext);
 }
 ```
 ## Reference
 ### `Context`
 A `Context` object should be created with a state object:
 ```js
 const someContext = new Context({ some: "key" });
 ```
 Its state is now available in the `state` key:
 ```js
 someContext.state.some = "other key";
 ```
 This is the way some global code (such as the responsive code above) should
 read and update the context state. However, components should not ever read the
 context state directly from the context, they should instead use the `useContext`
 hook to properly register themselves to state changes.
 Note that the `Context` hook is different from the React version. For example,
 there is no concept of provider/consumer. So, the `Context` feature does not
 by itself allow the use of a different context state depending on the component
 place in the component tree. However, this functionality can be obtained, if
 necessary, with the use of sub environment.
 ### `useContext`
 The `useContext` hook is the normal way for a component to register themselve
 to context state changes. The `useContext` method returns the context state:
 ```js
 device = useContext(this.env.deviceContext);
 ```
 It is a simple observed state (with an owl `Observer`), which contains the shared
 information.
@@ -0,0 +1,136 @@
 # 🦉 Environment 🦉
 ## Content
 - [Overview](#overview)
 - [Setting an Environment](#setting-an-environment)
 - [Using a sub environment](#using-a-sub-environment)
 - [Content of an Environment](#content-of-an-environment)
 - [Special keys](#special-keys)
 ## Overview
 An environment is an object which contains a [`QWeb` instance](qweb_engine.md). Whenever
 a root component is created, it is assigned an environment (see
 [below](#setting-an-environment) for more info on this). This environment is
 then automatically given to each sub component (and accessible in the `this.env`
 property).
 ```
    Root
    /  \
   A    B
 ```
 This way, all components share the same `QWeb` instance. Owl internally requires
 that the environment has a `qweb` key which maps to a
 [`QWeb`](qweb_engine.md) instance. This is the QWeb instance that will be used to
 render each templates in this specific component tree. Note that if no `QWeb`
 instance is provided, Owl will simply generate it on the fly.
 The environment is mostly static. Each application is free to add anything to
 the environment, which is very useful, since this can be accessed by each sub
 component.
 ## Setting an environment
 An Owl application needs an [environment](environment.md) to be executed. The
 environment has an important key: the [QWeb](qweb_engine.md) instance, which will render
 all templates.
 Whenever a root component `App` is mounted, Owl will setup a valid environment by
 following the next steps:
 - take the `env` object defined on `App.env` (if no `env` was explicitly setup,
  this will return the empty `env` object defined on `Component`)
 - if `env.qweb` is not set, then Owl will create a `QWeb` instance.
 The correct way to customize an environment is to simply set it up on the root
 component class, before the first component is created:
 ```js
 const env = {
    _t: myTranslateFunction,
    user: {...},
    services: {
        ...
    },
 };
 mount(App, { target: document.body, env });
 ```
 It is also possible to simply share an environment between all root components,
 by simply doing this:
 ```js
 Component.env = myEnv; // will be the default env for all components
 ```
 Note that this environment is the global owl environment for an application. The
 next section explains how to extend an environment for a specific sub component
 and its children.
 ## Using a sub environment
 It is sometimes useful to add one (or more) specific keys to the environment,
 from the perspective of a specific component and its children. In that case, the
 solution presented above will not work, since it sets the global environment.
 There is a hook for this situation: [`useSubEnv`](hooks.md#usesubenv).
 ```js
 class FormComponent extends Component {
  constructor(parent, props) {
    super(parent, props);
    useSubEnv({ myKey: someValue });
  }
 }
 ```
 ## Content of an Environment
 Some good use cases for additional keys in the environment are:
 - some configuration keys,
 - session information,
 - generic services (such as doing rpcs).
 Doing it this way means that components are easily testable: we can simply
 create a test environment with mock services.
 For example:
 ```js
 async function myEnv() {
  const templates = await loadTemplates();
  const qweb = new QWeb({ templates });
  const session = getSession();
  return {
    _t: myTranslateFunction,
    session: session,
    qweb: qweb,
    services: {
      localStorage: localStorage,
      rpc: rpc,
    },
    debug: false,
    inMobileMode: true,
  };
 }
 async function start() {
  const env = await myEnv();
  mount(App, { target: document.body, env });
 }
 ```
 ## Special Keys
 There are two special key/value added by Owl if not provided in the environment:
 the `QWeb` instance and a `browser` object:
 - `qweb` will be set to an empty `QWeb` instance. This is absolutely necessary
  for Owl to be able to render anything
 - `browser`: this is an object that contains some common access points to the
  browser methods with a side effect. See [browser](browser.md) for more information. Note that the browser object will be removed from the environment in Owl 2.0.
@@ -0,0 +1,81 @@
 # 🦉 Error Handling 🦉
 ## Content
 - [Overview](#overview)
 - [Example](#example)
 - [Reference](#reference)
 ## Overview
 By default, whenever an error occurs in the rendering of an Owl application, we
 destroy the whole application. Otherwise, we cannot offer any guarantee on the
 state of the resulting component tree. It might be hopelessly corrupted, but
 without any user-visible state.
 Clearly, it sometimes is a little bit extreme to destroy the application. This
 is why we have a builtin mechanism to handle rendering errors (and errors coming
 from lifecycle hooks): the `catchError` hook.
 ## Example
 For example, here is how we could implement an `ErrorBoundary` component:
 ```xml
 <div t-name="ErrorBoundary">
    <t t-if="state.error">
        Error handled
    </t>
    <t t-else="">
        <t t-slot="default" />
    </t>
 </div>
 ```
 ```js
 class ErrorBoundary extends Component {
  state = useState({ error: false });
  catchError() {
    this.state.error = true;
  }
 }
 ```
 Using the `ErrorBoundary` is then extremely simple:
 ```xml
 <ErrorBoundary><SomeOtherComponent/></ErrorBoundary>
 ```
 Note that we need to be careful here: the fallback UI should not throw any
 error, otherwise we risk going into an infinite loop (also, see the page on
 [slots](slots.md) for more information on the `t-slot` directive).
 ## Reference
 Whenever the `catchError` lifecycle hook is implemented, all errors coming from
 sub components rendering and/or lifecycle method calls will be caught and given
 to the `catchError` method. This allows us to properly handle the error, and to
 not break the application.
 There are important things to know:
 - If an error that occured in the internal rendering cycle is not caught, then
  Owl will destroy the full application. This is done on purpose, because Owl
  cannot guarantee that the state is not corrupted from this point on.
 - errors coming from event handlers are NOT managed by `catchError` or any other
  owl mechanism. This is up to the application developer to properly recover
  from an error
 Also, it may be useful to know that whenever an error is caught, it is then
 broadcasted to the application by an event on the `qweb` instance. It may be
 useful, for example, to log the error somewhere.
 ```js
 env.qweb.on("error", null, function (error) {
  // do something
  // react to the error
 });
 ```
@@ -5,9 +5,9 @@ parts of the code. Owl has a very simple bus class, which manages subscriptions,
 triggering events, and callbacks.
 ```js
-const bus = new owl.EventBus();
+const bus = new owl.core.EventBus();
-bus.on("some-event", null, function(...args) {
+bus.on("some-event", null, function (...args) {
  console.log(...args);
 });
@@ -23,5 +23,3 @@ Its API is:
 | `off(eventType, owner)`          | remove all listeners for an owner |
 | `trigger(eventType, ...args)`    | trigger an event                  |
 | `clear`                          | remove all subscriptions          |
 Note that the [`Store`](store.md) is an example of an `EventBus`.
@@ -0,0 +1,151 @@
 # 🦉 Event Handling 🦉
 ## Content
 - [Event Handling](#event-handling)
 - [Business DOM Events](#business-dom-events)
 - [Inline Event Handlers](#inline-event-handlers)
 - [Modifiers](#modifiers)
 ## Event Handling
 In a component's template, it is useful to be able to register handlers on DOM
 elements to some specific events. This is what makes a template _alive_. There
 are four different use cases.
 1. Register an event handler on a DOM node (_pure_ DOM event)
 2. Register an event handler on a component (_pure_ DOM event)
 3. Register an event handler on a DOM node (_business_ DOM event)
 4. Register an event handler on a component (_business_ DOM event)
 A _pure_ DOM event is directly triggered by a user interaction (e.g. a `click`).
 ```xml
 <button t-on-click="someMethod">Do something</button>
 ```
 This will be roughly translated in javascript like this:
 ```js
 button.addEventListener("click", component.someMethod.bind(component));
 ```
 The suffix (`click` in this example) is simply the name of the actual DOM
 event.
 ## Business DOM Events
 A _business_ DOM event is triggered by a call to `trigger` on a component.
 ```xml
 <MyComponent t-on-menu-loaded="someMethod" />
 ```
 ```js
 class MyComponent {
     someWhere() {
         const payload = ...;
         this.trigger('menu-loaded', payload);
     }
 }
 ```
 The call to `trigger` generates an `OwlEvent`, a subclass of [_CustomEvent_](https://developer.mozilla.org/docs/Web/Guide/Events/Creating_and_triggering_events)
 with an additional attribute `originalComponent` (the component that triggered
 the event). The generated event is of type `menu-loaded` and dispatches it on
 the component's DOM element (`this.el`). The event bubbles and is cancelable.
 The parent component listening to event `menu-loaded` will receive the payload
 in its `someMethod` handler (in the `detail` property of the event), whenever
 the event is triggered.
 ```js
 class ParentComponent {
     someMethod(ev) {
         const payload = ev.detail;
         ...
     }
 }
 ```
 By convention, we use KebabCase for the name of _business_ events.
 The `t-on` directive allows to prebind its arguments. For example,
 ```xml
 <button t-on-click="someMethod(expr)">Do something</button>
 ```
 Here, `expr` is a valid Owl expression, so it could be `true` or some variable
 from the rendering context.
 ### Type Hinting
 Note that if you work with Typescript, the `trigger` method is generic on the type of the payload.
 You can then describe the type of the event, so you will see typing errors...
 ```typescript
 this.trigger<MyCustomPayload>("my-custom-event", payload);
 ```
 ```typescript
 myCustomEventHandler(ev: OwlEvent<MyCustomPayload>) { ... }
 ```
 ## Inline Event Handlers
 One can also directly specify inline statements. For example,
 ```xml
 <button t-on-click="state.counter++">Increment counter</button>
 ```
 Here, `state` must be defined in the rendering context (typically the component)
 as it will be translated to:
 ```js
 button.addEventListener("click", () => {
  context.state.counter++;
 });
 ```
 Warning: inline expressions are evaluated in the context of the template. This
 means that they can access the component methods and properties. But if they set
 a key, the inline statement will actually not modify the component, but a key in
 a sub scope.
 ```xml
 <button t-on-click="value = 1">Set value to 1 (does not work!!!)</button>
 <button t-on-click="state.value = 1">Set state.value to 1 (work as expected)</button>
 ```
 ## Modifiers
 In order to remove the DOM event details from the event handlers (like calls to
 `event.preventDefault`) and let them focus on data logic, _modifiers_ can be
 specified as additional suffixes of the `t-on` directive.
 | Modifier   | Description                                                                                                              |
 | ---------- | ------------------------------------------------------------------------------------------------------------------------ |
 | `.stop`    | calls `event.stopPropagation()` before calling the method                                                                |
 | `.prevent` | calls `event.preventDefault()` before calling the method                                                                 |
 | `.self`    | calls the method only if the `event.target` is the element itself                                                        |
 | `.capture` | bind the event handler in [capture](https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/addEventListener) mode. |
 ```xml
 <button t-on-click.stop="someMethod">Do something</button>
 ```
 Note that modifiers can be combined (ex: `t-on-click.stop.prevent`), and that
 the order may matter. For instance `t-on-click.prevent.self` will prevent all
 clicks while `t-on-click.self.prevent` will only prevent clicks on the element
 itself.
 Finally, empty handlers are tolerated as they could be defined only to apply
 modifiers. For example,
 ```xml
 <button t-on-click.stop="">Do something</button>
 ```
 This will simply stop the propagation of the event.
@@ -0,0 +1,446 @@
 # 🦉 Hooks 🦉
 ## Content
 - [Overview](#overview)
 - [Example: Mouse Position](#example-mouse-position)
 - [Example: Autofocus](#example-autofocus)
 - [Reference](#reference)
  - [One Rule](#one-rule)
  - [`useState`](#usestate)
  - [`onMounted`](#onmounted)
  - [`onWillUnmount`](#onwillunmount)
  - [`onWillPatch`](#onwillpatch)
  - [`onPatched`](#onpatched)
  - [`onWillStart`](#onwillstart)
  - [`onWillUpdateProps`](#onwillupdateprops)
  - [`useContext`](#usecontext)
  - [`useRef`](#useref)
  - [`useSubEnv`](#usesubenv)
  - [`useExternalListener`](#useexternallistener)
  - [`useComponent`](#usecomponent)
  - [`useEnv`](#useenv)
  - [Making customized hooks](#making-customized-hooks)
 ## Overview
 Hooks were popularised by React as a way to solve the following issues:
 - help reusing stateful logic between components
 - help organizing code by feature in complex components
 - use state in functional components, without writing a class.
 Owl hooks serve the same purpose, except that they work for class components
 (note: React hooks do not work on class components, and maybe because of that,
 there seems to be the misconception that hooks are in opposition to class. This
 is clearly not true, as shown by Owl hooks).
 Hooks work beautifully with Owl components: they solve the problems mentioned
 above, and in particular, they are the perfect way to make your component
 reactive.
 ## Example: mouse position
 Here is the classical example of a non trivial hook to track the mouse position.
 ```js
 const { useState, onMounted, onWillUnmount } = owl.hooks;
 // We define here a custom behaviour: this hook tracks the state of the mouse
 // position
 function useMouse() {
  const position = useState({ x: 0, y: 0 });
  function update(e) {
    position.x = e.clientX;
    position.y = e.clientY;
  }
  onMounted(() => {
    window.addEventListener("mousemove", update);
  });
  onWillUnmount(() => {
    window.removeEventListener("mousemove", update);
  });
  return position;
 }
 // Main root component
 class App extends owl.Component {
  static template = xml`
    <div t-name="App">
      <div>Mouse: <t t-esc="mouse.x"/>, <t t-esc="mouse.y"/></div>
    </div>`;
  // this hooks is bound to the 'mouse' property.
  mouse = useMouse();
 }
 ```
 Note that we use the prefix `use` for hooks, just like in React. This is just
 a convention.
 ## Example: autofocus
 Hooks can be combined to create the desired effect. For example, the following
 hook combines the `useRef` hook with the `onPatched` and `onMounted` functions
 to create an easy way to focus an input whenever it appears in the DOM:
 ```js
 function useAutofocus(name) {
  let ref = useRef(name);
  let isInDom = false;
  function updateFocus() {
    if (!isInDom && ref.el) {
      isInDom = true;
      ref.el.focus();
    } else if (isInDom && !ref.el) {
      isInDom = false;
    }
  }
  onPatched(updateFocus);
  onMounted(updateFocus);
 }
 ```
 This hook takes the name of a valid `t-ref` directive, which should be present
 in the template. It then checks whenever the component is mounted or patched if
 the reference is not valid, and in this case, it will focus the node element.
 This hook can be used like this:
 ```js
 class SomeComponent extends Component {
  static template = xml`
    <div>
        <input />
        <input t-ref="myinput"/>
    </div>`;
  constructor(...args) {
    super(...args);
    useAutofocus("myinput");
  }
 }
 ```
 ## Reference
 ### One rule
 There is only one rule: every hook for a component has to be called in the
 constructor, in the _setup_ method, or in class fields:
 ```js
 // ok
 class SomeComponent extends Component {
  state = useState({ value: 0 });
 }
 // also ok
 class SomeComponent extends Component {
  constructor(...args) {
    super(...args);
    this.state = useState({ value: 0 });
  }
 }
 // also ok
 class SomeComponent extends Component {
  setup() {
    this.state = useState({ value: 0 });
  }
 }
 // not ok: this is executed after the constructor is called
 class SomeComponent extends Component {
  async willStart() {
    this.state = useState({ value: 0 });
  }
 }
 ```
 As you can see, the `useState` hook does not need to be given a reference to
 the component. This is possible because there is a way to get a reference to the
 current component: the `Component.current` static property is the reference to the
 component instance that is currently being created.
 Hooks need to be called in the constructor to ensure that this reference is
 properly set. This is also a good thing for performance reasons (Owl can use
 this to optimize its implementation), and for a clean architecture (this makes
 it easier for developers to understand what is really happening in a component).
 ### `useState`
 The `useState` hook is certainly the most important hook for Owl components:
 this is what allows a component to be reactive, to react to state change.
 The `useState` hook has to be given an object or an array, and will return
 an observed version of it (using a `Proxy`).
 ```javascript
 const { useState } = owl.hooks;
 class Counter extends owl.Component {
  static template = xml`
    <button t-on-click="increment">
        Click Me! [<t t-esc="state.value"/>]
    </button>`;
  state = useState({ value: 0 });
  increment() {
    this.state.value++;
  }
 }
 ```
 It is important to remember that `useState` only works with objects or arrays. It
 is necessary, since Owl needs to react to a change in state.
 ### `onMounted`
 `onMounted` is not a user hook, but is a building block designed to help make useful
 abstractions. `onMounted` registers a callback, which will be called when the component
 is mounted (see example on top of this page).
 ### `onWillUnmount`
 `onWillUnmount` is not a user hook, but is a building block designed to help make useful
 abstractions. `onWillUnmount` registers a callback, which will be called when the component
 is unmounted (see example on top of this page).
 ### `onWillPatch`
 `onWillPatch` is not a user hook, but is a building block designed to help make useful
 abstractions. `onWillPatch` registers a callback, which will be called just
 before the component patched.
 ### `onPatched`
 `onPatched` is not a user hook, but is a building block designed to help make useful
 abstractions. `onPatched` registers a callback, which will be called just
 after the component patched.
 ### `onWillStart`
 `onWillStart` is an asynchronous hook. This means that the function registered
 in the hook will be run just before the component is first rendered and can return a
 promise, to express the fact that it is an asynchronous operation.
 Note that if there are more than one `onWillStart` registered callback, then they
 will all be run in parallel.
 It can be used to load some initial data. For example, the following hook will
 automatically load some data from the server, and return an object that will
 be ready whenever the component is rendered:
 ```js
 function useLoader() {
  const component = Component.current;
  const record = useState({});
  onWillStart(async () => {
    const recordId = component.props.id;
    Object.assign(record, await fetchSomeRecord(recordId));
  });
  return record;
 }
 ```
 Note that this example does not update the record value whenever props are
 updated. For that situation, we need to use the `onWillUpdateProps` hook.
 ### `onWillUpdateProps`
 Just like `onWillStart`, `onWillUpdateProps` is an asynchronous hook. It is
 designed to be run whenever the component props are updated. This could be
 useful to perform some asynchronous task such as fetching updated data.
 ```js
 function useLoader() {
  const component = Component.current;
  const record = useState({});
  async function updateRecord(id) {
    Object.assign(record, await fetchSomeRecord(id));
  }
  onWillStart(() => updateRecord(component.props.id));
  onWillUpdateProps((nextProps) => updateRecord(nextProps.id));
  return record;
 }
 ```
 Note that if there are more than one `onWillUpdateProps` registered callback,
 then they will all be run in parallel.
 ### `useContext`
 See [`useContext`](context.md#usecontext) for reference documentation.
 ### `useRef`
 The `useRef` hook is useful when we need a way to interact with some inside part
 of a component, rendered by Owl. It can work either on a DOM node, or on a component,
 tagged by the `t-ref` directive:
 ```xml
 <div>
    <div t-ref="someDiv"/>
    <SubComponent t-ref="someComponent"/>
 </div>
 ```
 In this example, the component will be able to access the `div` and the component
 `SubComponent` using the `useRef` hook:
 ```js
 class Parent extends Component {
  subRef = useRef("someComponent");
  divRef = useRef("someDiv");
  someMethod() {
    // here, if component is mounted, refs are active:
    // - this.divRef.el is the div HTMLElement
    // - this.subRef.comp is the instance of the sub component
    // - this.subRef.el is the root HTML node of the sub component (i.e. this.subRef.comp.el)
  }
 }
 ```
 As shown by the example above, html elements are accessed by using the `el`
 key, and components references are accessed with `comp`.
 Notes:
 - if used on a component, the reference will be set in the `refs`
  variable between `willPatch` and `patched`,
 - on a component, accessing `ref.el` will get the root node of the component.
 The `t-ref` directive also accepts dynamic values with string interpolation
 (like the [`t-attf-`](qweb_templating_language.md#dynamic-attributes) and
 `t-component` directives). For example,
 ```xml
 <div t-ref="component_{{someCondition ? '1' : '2'}}"/>
 ```
 Here, the references need to be set like this:
 ```js
 this.ref1 = useRef("component_1");
 this.ref2 = useRef("component_2");
 ```
 References are only guaranteed to be active while the parent component is mounted.
 If this is not the case, accessing `el` or `comp` on it will return `null`.
 ### `useSubEnv`
 The environment is sometimes useful to share some common information between
 all components. But sometimes, we want to _scope_ that knowledge to a subtree.
 For example, if we have a form view component, maybe we would like to make some
 `model` object available to all sub components, but not to the whole application.
 This is where the `useSubEnv` hook may be useful: it lets a component add some
 information to the environment in a way that only the component and its children
 can access it:
 ```js
 class FormComponent extends Component {
  constructor(...args) {
    super(...args);
    const model = makeModel();
    useSubEnv({ model });
  }
 }
 ```
 The `useSubEnv` takes one argument: an object which contains some key/value that
 will be added to the parent environment. Note that it will extend, not replace
 the parent environment. And of course, the parent environment will not be
 affected.
 ### `useExternalListener`
 The `useExternalListener` hook helps solve a very common problem: adding and removing
 a listener on some target whenever a component is mounted/unmounted. For example,
 a dropdown menu (or its parent) may need to listen to a `click` event on `window`
 to be closed:
 ```js
 useExternalListener(window, "click", this.closeMenu);
 ```
 ### `useComponent`
 The `useComponent` hook is useful as a building block for some customized hooks,
 that may need a reference to the component calling them.
 ### `useEnv`
 The `useEnv` hook is useful as a building block for some customized hooks,
 that may need a reference to the env of the component calling them.
 ### Making customized hooks
 Hooks are a wonderful way to organize the code of a complex component by feature
 instead of by lifecycle methods. They are like mixins, except that they can be
 easily composed together.
 But, like every good things in life, hooks should be used with moderation. They are
 not the solution to every problem.
 - they may be overkill: if your component needs to perform some action specific
  to itself (so, the specific code does not need to be shared), there is nothing
  wrong with a simple class method:
  ```js
  // maybe overkill
  class A extends Component {
    constructor(...args) {
      super(...args);
      useMySpecificHook();
    }
  }
  // ok
  class B extends Component {
    constructor(...args) {
      super(...args);
      this.performSpecificTask();
    }
  }
  ```
  Note that the second solution is easier to extend in sub components.
 - they may be harder to test: if a customized hook injects some external side
  effect dependency, then it is harder to test without doing some non obvious
  manipulation. For example, assume that we want to give a reference to a
  router in a `useRouter` hook. We could do this:
  ```js
  const router = new Router(...);
  function useRouter() {
      return router;
  }
  ```
  As you can see, this does not _hook_ into the internal of the component. It
  simply returns a global object, which is difficult to mock.
  A better way would be to do something like this: get the reference from the
  environment.
  ```js
  function useRouter() {
    const env = useEnv();
    return env.router;
  }
  ```
  This means that we give control to the application developer to create the
  router, which is good, so they can set it up, subclass it, ... And then, to
  test our components, we can just add a mock router in the environment.
@@ -0,0 +1,133 @@
 # 🦉 Miscellaneous 🦉
 ## Content
 - [Portal](#portal)
 - [AsyncRoot](#asyncroot)
 ## `Portal`
 ### Overview
 The component `Portal` is meant to be used as a transparent way to 'teleport' a piece
 of DOM to the node represented by its sole `target` props.
 This component aims at helping the implementation of the needed infrastructure
 for modals (as in `bootstrap-modal`).
 ### Usage
 The content it will teleport is defined within the `<Portal>` node and
 internally uses the `default` [Slot](slots.md).
 This slot must contain only **one** node, which in turn can have as many children as necessary.
 The element under which the content will be teleported is represented as a selector
 by the `target` props which only accepts a string as value.
 The `target` props only supports static selector, and is not meant to be passed to `Portal`
 as a variable. Namely, `<Portal target="'body'" />` is the intended use.
 By contrast, `<Portal target="state.target" />` is not supported.
 The component `Portal` has no particular state, rather it is meant to be a slave to its parent,
 and ultimately just a way for the parent to teleport a piece of its own DOM elsewhere.
 The `Portal`'s root node is always `<portal/>` and is placed where the teleported content
 _would have_ been. It is this element that the [teleported events](#expected-behaviors) are re-directed on.
 ### Example
 The canonic use-case is to implement a Dialog, where a Component may choose to break the natural
 workflow to help the user put in some data, which it could use later on.
 JavaScript:
 ```js
 const { Component, mount } = owl;
 const { Portal } = owl.misc;
 class TeleportedComponent extends Component {}
 class App extends Component {
  static components = { Portal, TeleportedComponent };
 }
 mount(App, { target: document.body });
 ```
 XML:
 ```xml
 <templates>
    <div t-name="TeleportedComponent">
        <span>I will move soon enough</span>
    </div>
    <div t-name="App">
        <span>I am like the rest of us</span>
        <Portal target="'body'">
            <TeleportedComponent />
        </Portal>
    </div>
 </templates>
 ```
 In this example, the `Portal` component will teleport the `TeleportedComponent`'s `div` as a child of the `body`.
 `TeleportedComponent` is acting as a Dialog here.
 The resulting DOM will look like:
 ```xml
 <body>
    <div>
        <span>I am like the rest of us</span>
        <portal></portal>
    </div>
    <div>
        <span>I will move soon enough</span>
    </div>
 </body>
 ```
 ### Expected Behaviors
 The teleported piece is updated as any other `Component`'s DOM and in the same sequence.
 Namely the teleported piece will be updated in function of its parents components, and patched as
 a normal child.
 The [_business_ events](event_handling.md#business-dom-events) triggered by a child component will be stopped
 to not bubble outside of the `target`. They will, on the other hand, be re-directed onto the
 `Portal`'s root node and bubble up the DOM as if it were triggered by a regular child component.
 Beware that those re-directed events are copies of the original event.
 They have:
 - The same payload.
 - The same `originalComponent` than their original counterpart,
  that is the actual Component that triggered it.
 - A **different** `target` property than their original counterpart.
  The `target` of a re-directed event is necessarily the `Portal`'s root node.
 Pure DOM events do not follow this pattern and are free to bubble their natural, unaltered way
 up to the `body`.
 ## `AsyncRoot`
 When this component is used, a new rendering sub tree is created, such that the
 rendering of that component (and its children) is not tied to the rendering of
 the rest of the interface. It can be used on an asynchronous component, to
 prevent it from delaying the rendering of the whole interface, or on a
 synchronous one, such that its rendering isn't delayed by other (asynchronous)
 components. Note that this directive has no effect on the first rendering, but
 only on subsequent ones (triggered by state or props changes).
 ```xml
 <div t-name="ParentComponent">
  <SyncChild />
  <AsyncRoot>
     <AsyncChild/>
  </AsyncRoot>
 </div>
 ```
 The `AsyncRoot` assumes that there is exactly one root node inside it. It can
 be a dom node or a component.
@@ -0,0 +1,60 @@
 # 🦉 Mounting an application 🦉
 ## Content
 - [Overview](#overview)
 - [API](#api)
 ## Overview
 Mounting an Owl application is done by using the `mount` method (available in
 `owl.mount` if you are using the iife build, or it can be directly imported
 from `owl` if you are using a module system):
 ```js
 const mount = { owl }; // if owl is available as an object
 const env = { ... };
 const app = await mount(MyComponent, { target: document.body, env });
 ```
 Another example:
 ```js
 const config = {
  env: ...,
  props: ...,
  target: document.body,
  position: "self",
 };
 const app = await mount(App, config);
 ```
 A common way to initialize an application is to first setup an environment,
 then to call the `mount` method.
 ## API
 Mount takes two parameters:
 - `C`, which should be a component class (NOT instance),
 - `params`, which is an object with the following keys:
  - `target (HTMLElement | DocumentFragment)`: the target of the mount operation
  - `env (optional, Env)` an environment
  - `position (optional, "first-child" | "last-child" | "self")` the position
    where it should be mounted (see below for more informations)
  - `props (optional, any)`: some initial values that are given as props. Useful
    when the root component is configurable, or when testing sub components
 Here are the various positions supported by Owl:
 - `first-child`: with this option, the component will be prepended inside the target,
 - `last-child` (default value): with this option, the component will be
  appended in the target element,
 - `self`: the target will be used as the root element for the component. This
  means that the target has to be an HTMLElement (and not a document fragment).
  In this situation, it is possible that the component cannot be unmounted. For
  example, if its target is `document.body`.
 The `mount` method returns a promise that resolves to the instance of the created
 component.
@@ -0,0 +1,52 @@
 # 🦉 Observer 🦉
 Owl needs to be able to react to state changes. For example, whenever the state
 of a component is changed, Owl needs to rerender it. To help with that, there is
 an Observer class. Its job is to observe the state of an object (or array), and
 to react to any change. The observer is implemented with the native `Proxy`
 object. Note that this means that it will not work on older browsers.
 Note that the `Observer` is used by the `useState` and `useContext` hooks. This
 is the way most Owl applications will create observers. For the majority of
 use cases, there is no need to directly instantiate an observer.
 ## Example
 For example, this code will display `update` in the console:
 ```javascript
 const observer = new owl.core.Observer();
 observer.notifyCB = () => console.log("update");
 const obj = observer.observe({ a: { b: 1 } });
 obj.a.b = 2;
 ```
 This example shows that an observer can observe nested properties.
 ## Reference
 **observe** An observer can observe multiple values with the `observe` method.
 This method takes an object or an array as its argument and will return a proxy
 (which is mapped to the initial object/array). With this proxy, the observer
 can detect whenever any internal value is changed.
 **Registering a callback** Whenever an observer sees a state change, it will
 call its `notifyCB` method. No additional information is given to the callback.
 **deepRevNumber** Each observed value has an internal revision number, which
 is incremented every time the value is observed. Sometimes, it can be useful
 to obtain that number:
 ```js
 const observer = new owl.core.Observer();
 const obj = observer.observe({ a: { b: 1 } });
 observer.revNumber(obj.a); // 1
 obj.a.b = 2;
 observer.revNumber(obj.a); // 2
 ```
 The `revNumber` can also return 0, which indicates that the value is not
 observed.
@@ -0,0 +1,97 @@
 # 🦉 Props 🦉
 ## Content
 - [Overview](#overview)
 - [Definition](#definition)
 - [Good Practices](#good-practices)
 - [Dynamic Props](#dynamic-props)
 ## Overview
 In Owl, `props` (short for _properties_) is an object which contains every piece
 of data given to a component by its parent.
 ```js
 class Child extends Component {
  static template = xml`<div><t t-esc="props.a"/><t t-esc="props.b"/></div>`;
 }
 class Parent extends Component {
  static template = xml`<div><Child a="state.a" b="'string'"/></div>`;
  static components = { Child };
  state = useState({ a: "fromparent" });
 }
 ```
 In this example, the `Child` component receives two props from its parent: `a`
 and `b`. They are collected into a `props` object by Owl, with each value being
 evaluated in the context of the parent. So, `props.a` is equal to `'fromparent'` and
 `props.b` is equal to `'string'`.
 Note that `props` is an object that only makes sense from the perspective of the
 child component.
 ## Definition
 The `props` object is made of every attributes defined on the template, with the
 following exceptions:
 - every attribute starting with `t-` are not props (they are QWeb directives),
 - `style` and `class` attributes are excluded as well (they are applied by Owl on
  the root element of the component).
 In the following example:
 ```xml
 <div>
    <ComponentA a="state.a" b="'string'"/>
    <ComponentB t-if="state.flag" model="model"/>
    <ComponentC style="color:red;" class="left-pane" />
 </div>
 ```
 the `props` object contains the following keys:
 - for `ComponentA`: `a` and `b`,
 - for `ComponentB`: `model`,
 - for `ComponentC`: empty object
 ## Good Practices
 A `props` object is a collection of values that come from the parent. As such,
 they are owned by the parent, and should never be modified by the child:
 ```js
 class MyComponent extends Component {
  constructor(parent, props) {
    super(parent, props);
    props.a.b = 43; // Never do that!!!
  }
 }
 ```
 Props should be considered readonly, from the perspective of the child component.
 If there is a need to modify them, then the request to update them should be
 sent to the parent (for example, with an event).
 Any value can go in a props. Strings, objects, classes, or even callbacks could
 be given to a child component (but then, in the case of callbacks, communicating
 with events seems more appropriate).
 ## Dynamic Props
 The `t-props` directive can be used to specify totally dynamic props:
 ```xml
 <div t-name="ParentComponent">
    <Child t-props="some.obj"/>
 </div>
 ```
 ```js
 class ParentComponent {
  static components = { Child };
  some = { obj: { a: 1, b: 2 } };
 }
 ```
@@ -0,0 +1,103 @@
 # 🦉 Props Validation 🦉
 As an application becomes complex, it may be quite unsafe to define props in an informal way. This leads to two issues:
 - hard to tell how a component should be used, by looking at its code.
 - unsafe, it is easy to send wrong props into a component, either by refactoring a component, or one of its parents.
 A props type system solves both issues, by describing the types and shapes
 of the props. Here is how it works in Owl:
 - `props` key is a static key (so, different from `this.props` in a component instance)
 - it is optional: it is ok for a component to not define a `props` key.
 - props are validated whenever a component is created/updated
 - props are only validated in `dev` mode (see [config page](config.md#mode))
 - if a key does not match the description, an error is thrown
 - it validates keys defined in (static) `props`. Additional keys given by the
  parent will cause an error.
 For example:
 ```js
 class ComponentA extends owl.Component {
    static props = ['id', 'url'];
    ...
 }
 class ComponentB extends owl.Component {
  static props = {
    count: {type: Number},
    messages: {
      type: Array,
      element: {type: Object, shape: {id: Boolean, text: String }
    },
   date: Date,
   combinedVal: [Number, Boolean]
  };
  ...
 }
 ```
 - it is an object or a list of strings
 - a list of strings is a simplified props definition, which only lists the name
  of the props. Also, if the name ends with `?`, it is considered optional.
 - all props are by default required, unless they are defined with `optional: true`
  (in that case, validation is only done if there is a value)
 - valid types are: `Number, String, Boolean, Object, Array, Date, Function`, and all
  constructor functions (so, if you have a `Person` class, it can be used as a type)
 - arrays are homogeneous (all elements have the same type/shape)
 For each key, a `prop` definition is either a boolean, a constructor, a list of constructors, or an object:
 - a boolean: indicate that the props exists, and is mandatory.
 - a constructor: this should describe the type, for example: `id: Number` describe
  the props `id` as a number
 - a list of constructors. In that case, this means that we allow more than one
  type. For example, `id: [Number, String]` means that `id` can be either a string
  or a number.
 - an object. This makes it possible to have more expressive definition. The following sub keys are then allowed (but not mandatory):
  - `type`: the main type of the prop being validated
  - `element`: if the type was `Array`, then the `element` key describes the type of each element in the array. If it is not set, then we only validate the array, not its elements,
  - `shape`: if the type was `Object`, then the `shape` key describes the interface of the object. If it is not set, then we only validate the object, not its elements,
  - `validate`: this is a function which should return a boolean to determine if
    the value is valid or not. Useful for custom validation logic.
 Examples:
 ```js
  // only the existence of those 3 keys is documented
  static props = ['message', 'id', 'date'];
 ```
 ```js
  // size is optional
  static props = ['message', 'size?'];
 ```
 ```js
  static props = {
    messageIds: {type: Array, element: Number},  // list of number
    otherArr: {type: Array},   // just array. no validation is made on sub elements
    otherArr2: Array,   // same as otherArr
    someObj: {type: Object},  // just an object, no internal validation
    someObj2: {
      type: Object,
      shape: {
        id: Number,
        name: {type: String, optional: true},
        url: String
      ]},    // object, with keys id (number), name (string, optional) and url (string)
    someFlag: Boolean,     // a boolean, mandatory (even if `false`)
    someVal: [Boolean, Date],   // either a boolean or a date
    otherValue: true,     // indicates that it is a prop
    kindofsmallnumber: {
      type: Number,
      validate: n => (0 <= n && n <= 10)
    },
    size: {
      validate:  e => ["small", "medium", "large"].includes(e)
    },
  };
 ```
@@ -0,0 +1,153 @@
 # 🦉 QWeb Engine 🦉
 ## Content
 - [Overview](#overview)
 - [Reference](#reference)
 ## Overview
 [QWeb](https://www.odoo.com/documentation/13.0/reference/qweb.html) is the primary
 templating engine used by Odoo. The QWeb class in the OWL project is an
 implementation of that specification with a few interesting points:
 - it compiles templates into functions that output a virtual DOM instead of a
  string. This is necessary for the component system.
 - it has a few extra directives: `t-component`, `t-on`, ...
 We present in this section the engine, not the templating language.
 ## Reference
 This section is about the javascript code that implements the `QWeb` specification.
 Owl exports a `QWeb` class in `owl.QWeb`. To use it, it just needs to be
 instantiated:
 ```js
 const qweb = new owl.QWeb();
 ```
 Its API is quite simple:
 - **`constructor(config)`**: constructor. Takes an optional configuration object
  with an optional `templates` string to add initial
  templates (see `addTemplates` for more information on format of the string)
  and an optional `translateFn` translate function (see the section on
  [translations](#translations)).
  ```js
  const qweb = new owl.QWeb({ templates: TEMPLATES, translateFn: _t });
  ```
 - **`addTemplate(name, xmlStr, allowDuplicate)`**: add a specific template.
  ```js
  qweb.addTemplate("mytemplate", "<div>hello</div>");
  ```
  If the optional `allowDuplicate` is set to `true`, then `QWeb` will simply
  ignore templates added for a second time. Otherwise, `QWeb` will crash.
 - **`addTemplates(xmlStr)`**: add a list of templates (identified by `t-name`
  attribute).
  ```js
  const TEMPLATES = `
    <templates>
      <div t-name="App" class="main">main</div>
      <div t-name="OtherComponent">other component</div>
    </templates>`;
  qweb.addTemplates(TEMPLATES);
  ```
 - **`render(name, context, extra)`**: renders a template. This returns a `vnode`,
  which is a virtual representation of the DOM (see [vdom doc](../miscellaneous/vdom.md)).
  ```js
  const vnode = qweb.render("App", component);
  ```
 - **`renderToString(name, context)`**: renders a template, but returns an html
  string.
  ```js
  const str = qweb.renderToString("someTemplate", somecontext);
  ```
 - **`registerTemplate(name, template)`**: static function to register a global
  QWeb template. This is useful for commonly used components accross the
  application, and for making a template available to an application without
  having a reference to the actual QWeb instance.
  ```js
  QWeb.registerTemplate("mytemplate", `<div>some template</div>`);
  ```
 - **`registerComponent(name, Component)`**: static function to register an OWL Component
  to QWeb's global registry. Globally registered Components can be used in
  templates (see the `t-component` directive). This is useful for commonly used
  components accross the application.
  ```js
  class Dialog extends owl.Component { ... }
  QWeb.registerComponent("Dialog", Dialog);
  ...
  class ParentComponent extends owl.Component { ... }
  qweb.addTemplate("ParentComponent", "<div><Dialog/></div>");
  ```
 In some way, a `QWeb` instance is the core of an Owl application. It is the only
 mandatory element of an [environment](environment.md). As such, it
 has an extra responsibility: it can act as an event bus for internal communication
 between Owl classes. This is the reason why `QWeb` actually extends [EventBus](event_bus.md).
 ### Translations
 take care of this and "cherry-pick" 8464a1b04e7469434f9dcb3d68a543f58cb61b8e
 If properly setup, Owl QWeb engine can translate all rendered templates. To do
 so, it needs a translate function, which takes a string and returns a string.
 For example:
 ```js
 const translations = {
  hello: "bonjour",
  yes: "oui",
  no: "non",
 };
 const translateFn = (str) => translations[str] || str;
 const qweb = new QWeb({ translateFn });
 ```
 Once setup, all rendered templates will be translated using `translateFn`:
 - each text node will be replaced with its translation,
 - each of the following attribute values will be translated as well: `title`,
  `placeholder`, `label` and `alt`,
 - translating text nodes can be disabled with the special attribute `t-translation`,
  if its value is `off`.
 So, with the above `translateFn`, the following templates:
 ```xml
 <div>hello</div>
 <div t-translation="off">hello</div>
 <div>Are you sure?</div>
 <input placeholder="hello" other="yes"/>
 ```
 will be rendered as:
 ```xml
 <div>bonjour</div>
 <div>hello</div>
 <div>Are you sure?</div>
 <input placeholder="bonjour" other="yes"/>
 ```
 Note that the translation is done during the compilation of the template, not
 when it is rendered.
@@ -1,10 +1,9 @@
-# 🦉 QWeb 🦉
+# 🦉 QWeb Templating Language🦉
 ## Content
 - [Overview](#overview)
 - [Directives](#directives)
 - [QWeb Engine](#qweb-engine)
 - [Reference](#reference)
  - [White Spaces](#white-spaces)
  - [Root Nodes](#root-nodes)
@@ -14,150 +13,78 @@
  - [Setting Variables](#setting-variables)
  - [Conditionals](#conditionals)
  - [Dynamic Attributes](#dynamic-attributes)
  - [Dynamic Class Attribute](#dynamic-class-attribute)
  - [Dynamic Tag Names](#dynamic-tag-names)
  - [Loops](#loops)
  - [Rendering Sub Templates](#rendering-sub-templates)
  - [Dynamic Sub Templates](#dynamic-sub-templates)
  - [Translations](#translations)
  - [Debugging](#debugging)
 ## Overview
-[QWeb](https://www.odoo.com/documentation/12.0/reference/qweb.html) is the primary templating engine used by Odoo. It is based on the XML format, and used
+[QWeb](https://www.odoo.com/documentation/13.0/reference/qweb.html) is the primary
 templating engine used by Odoo. It is based on the XML format, and used
 mostly to generate HTML. In OWL, QWeb templates are compiled into functions that
 generate a virtual dom representation of the HTML.
 Template directives are specified as XML attributes prefixed with `t-`, for instance `t-if` for conditionals, with elements and other attributes being rendered directly.
 To avoid element rendering, a placeholder element `<t>` is also available, which executes its directive but doesn’t generate any output in and of itself.
 ```xml
 <div>
    <span t-if="somecondition">Some string</span>
-    <ul t-else="1">
+    <ul t-else="">
        <li t-foreach="messages" t-as="message">
-            <t t-esc="message">
+            <t t-esc="message"/>
        </li>
    </ul>
 </div>
 ```
-The QWeb class in the OWL project is an implementation of that specification
+Template directives are specified as XML attributes prefixed with `t-`, for
-with a few interesting points:
+instance `t-if` for conditionals, with elements and other attributes being
 rendered directly.
- it compiles templates into functions that output a virtual DOM instead of a
+To avoid element rendering, a placeholder element `<t>` is also available, which
-  string. This is necessary for the component system.
+executes its directive but doesn’t generate any output in and of itself.
- it has a few extra directives: `t-component`, `t-on`, ...
+
 We present in this section the templating language, including its Owl specific
 extensions.
 ## Directives
-We present here a list of all standard QWeb directives:
+For reference, here is a list of all standard QWeb directives:
-| Name                           | Description                                                  |
+| Name                           | Description                                                    |
-| ------------------------------ | ------------------------------------------------------------ |
+| ------------------------------ | -------------------------------------------------------------- |
-| `t-esc`                        | [Outputting safely a value](#outputting-data)                |
+| `t-esc`                        | [Outputting safely a value](#outputting-data)                  |
-| `t-raw`                        | [Outputting value, without escaping](#outputting-data)       |
+| `t-raw`                        | [Outputting value, without escaping](#outputting-data)         |
-| `t-set`, `t-value`             | [Setting variables](#setting-variables)                      |
+| `t-set`, `t-value`             | [Setting variables](#setting-variables)                        |
-| `t-if`, `t-elif`, `t-else`,    | [conditionally rendering](#conditionals)                     |
+| `t-if`, `t-elif`, `t-else`,    | [conditionally rendering](#conditionals)                       |
-| `t-foreach`, `t-as`            | [Loops](#loops)                                              |
+| `t-foreach`, `t-as`            | [Loops](#loops)                                                |
-| `t-att`, `t-attf-*`, `t-att-*` | [Dynamic attributes](#dynamic-attributes)                    |
+| `t-att`, `t-attf-*`, `t-att-*` | [Dynamic attributes](#dynamic-attributes)                      |
-| `t-call`                       | [Rendering sub templates](#rendering-sub-templates)          |
+| `t-call`                       | [Rendering sub templates](#rendering-sub-templates)            |
-| `t-debug`, `t-log`             | [Debugging](#debugging)                                      |
+| `t-debug`, `t-log`             | [Debugging](#debugging)                                        |
-| `t-name`                       | [Defining a template (not really a directive)](#qweb-engine) |
+| `t-translation`                | [Disabling the translation of a node](#translations)           |
 | `t-name`                       | [Defining a template (not really a directive)](qweb_engine.md) |
 The component system in Owl requires additional directives, to express various
 needs. Here is a list of all Owl specific directives:
-| Name                                        | Description                                                                         |
+| Name                     | Description                                                                     |
-| ------------------------------------------- | ----------------------------------------------------------------------------------- |
+| ------------------------ | ------------------------------------------------------------------------------- |
-| `t-component`, `t-keepalive`, `t-asyncroot` | [Defining a sub component](component.md#composition)                                |
+| `t-component`, `t-props` | [Defining a sub component](component.md#composition)                            |
-| `t-ref`                                     | [Setting a reference to a dom node or a sub component](component.md#references)     |
+| `t-ref`                  | [Setting a reference to a dom node or a sub component](component.md#references) |
-| `t-key`                                     | [Defining a key (to help virtual dom reconciliation)](component.md#t-key-directive) |
+| `t-key`                  | [Defining a key (to help virtual dom reconciliation)](#loops)                   |
-| `t-on-*`                                    | [Event handling](component.md#event-handling)                                       |
+| `t-on-*`                 | [Event handling](event_handling.md)                                             |
-| `t-transition`                              | [Defining an animation](animations.md#css-transitions)                              |
+| `t-transition`           | [Defining an animation](animations.md#css-transitions)                          |
-| `t-mounted`                                 | [Callback when a node or component is mounted](component.md#t-mounted-directive)    |
+| `t-slot`                 | [Rendering a slot](slots.md)                                                    |
-| `t-slot`                                    | [Rendering a slot](component.md#slots)                                              |
+| `t-model`                | [Form input bindings](component.md#form-input-bindings)                         |
-| `t-model`                                   | [Form input bindings](component.md#form-input-bindings)                             |
+| `t-tag`                  | [Rendering nodes with dynamic tag name](#dynamic-tag-names)                     |
 ## QWeb Engine
 This section is about the javascript code that implements the `QWeb` specification.
 Owl exports a `QWeb` class in `owl.QWeb`. To use it, it just needs to be
 instantiated:
 ```js
 const qweb = new owl.QWeb();
 ```
 It's API is quite simple:
 - **`constructor(data)`**: constructor. Takes an optional string to add initial
  templates (see `addTemplates` for more information on format of the string).
  ```js
  const qweb = new owl.QWeb(TEMPLATES);
  ```
 - **`addTemplate(name, xmlStr, allowDuplicate)`**: add a specific template.
  ```js
  qweb.addTemplate("mytemplate", "<div>hello</div>");
  ```
  If the optional `allowDuplicate` is set to `true`, then `QWeb` will simply return whenever a template is added for a second time.  Otherwise, `QWeb` will crash.
 - **`addTemplates(xmlStr)`**: add a list of templates (identified by `t-name`
  attribute).
  ```js
  const TEMPLATES = `
    <templates>
      <div t-name="App" class="main">main</div>
      <div t-name="OtherComponent">other component</div>
    </templates>`;
  qweb.addTemplates(TEMPLATES);
  ```
 - **`render(name, context, extra)`**: renders a template. This returns a `vnode`,
  which is a virtual representation of the DOM (see [vdom doc](vdom.md)).
  ```js
  const vnode = qweb.render("App", component);
  ```
 - **`renderToString(name, context)`**: renders a template, but returns an html
  string.
  ```js
  const str = qweb.renderToString("someTemplate", somecontext);
  ```
 - **`register(name, Component)`**: static function to register an OWL Component
  to QWeb's global registry. Globally registered Components can be used in
  templates (see the `t-component` directive). This is useful for commonly used
  components accross the application.
  ```js
  class Dialog extends owl.Component { ... }
  QWeb.register("Dialog", Dialog);
  ...
  class ParentComponent extends owl.Component { ... }
  qweb.addTemplate("ParentComponent", "<div><Dialog/></div>");
  ```
 In some way, a `QWeb` instance is the core of an Owl application. It is the only
 mandatory element of an [environment](component.md#environment). As such, it
 has an extra responsability: it can act as an event bus for internal communication
 between Owl classes. This is the reason why `QWeb` actually extends [EventBus](event_bus.md).
 ## Reference
 We define in this section the specification of how `QWeb` templates should be
 rendered. Note that we only document here the standard QWeb specification. Owl
 specific extensions are documented in various other parts of the documentation.
 ### White Spaces
-White spaces in a templates are handled in a special way:
+White spaces in a template are handled in a special way:
 - consecutive whitespaces are always condensed to a single whitespace
 - if a whitespace-only text node contains a linebreak, it is ignored
@@ -178,7 +105,7 @@ precisely, the result of a template rendering should have a single root node:
 <!–– ok: result has one single root node ––>
 <t>
    <div t-if="someCondition">foo</div>
-    <span t-else="1">bar</span>
+    <span t-else="">bar</span>
 </t>
 ```
@@ -192,14 +119,14 @@ root nodes.
 ### Expression Evaluation
 QWeb expressions are strings that will be processed at compile time. Each variable in
-the javascript expression will be replaced by a lookup in the context (so, the
+the javascript expression will be replaced with a lookup in the context (so, the
 component). For example, `a + b.c(d)` will be converted into:
 ```js
 context["a"] + context["b"].c(context["d"]);
 ```
-It is useful to explain the various rules that applies on these expressions:
+It is useful to explain the various rules that apply on these expressions:
 1. it should be a simple expression which returns a value. It cannot be a statement.
@@ -225,14 +152,14 @@ It is useful to explain the various rules that applies on these expressions:
 3. it can use a few special operators to avoid using symbols such as `<`, `>`,
   `&` or `|`. This is useful to make sure that we still write valid XML.
-   | Word  | will be replaced by |
+   | Word  | replaced with |
-   | ----- | ------------------- |
+   | ----- | ------------- |
-   | `and` | `&&`                |
+   | `and` | `&&`          |
-   | `or`  | `\|\|`              |
+   | `or`  | `\|\|`        |
-   | `gt`  | `>`                 |
+   | `gt`  | `>`           |
-   | `gte` | `>=`                |
+   | `gte` | `>=`          |
-   | `lt`  | `<`                 |
+   | `lt`  | `<`           |
-   | `lte` | `<=`                |
+   | `lte` | `<=`          |
   So, one can write this:
@@ -277,6 +204,11 @@ rendered with the value `value` set to `<span>foo</span>` in the rendering conte
 <p><span>foo</span></p>
 ```
 Note that since the content of the expression is not known beforehand, the `t-raw`
 directive has to parse the html (and convert it to a virtual dom structure) for
 each rendering. So, it will be much slower than a regular template. It is
 therefore advised to limit the use of `t-raw` whenever possible.
 ### Setting Variables
 QWeb allows creating variables from within the template, to memoize a computation (to use it multiple times), give a piece of data a clearer name, ...
@@ -376,14 +308,59 @@ If an expression evaluates to a falsy value, it will not be set at all:
 <div t-att-foo="false"/>  <!-- result: <div></div> -->
 ```
-There is another way to format a string attribute: the `t-attf-` directive. With
+It is sometimes convenient to format an attribute with string interpolation. In
-it, you get string interpolation:
+that case, the `t-attf-` directive can be used. It is useful when we need to mix
 literal and dynamic elements, such as css classes.
 ```xml
 <div t-attf-foo="a {{value1}} is {{value2}} of {{value3}} ]"/>
 <!-- result if values are set to 1,2 and 3: <div foo="a 0 is 1 of 2 ]"></div> -->
 ```
 If we need completely dynamic attribute names, then there is an additional
 directive: `t-att`, which takes either an object (with keys mapping to their
 values) or a pair `[key, value]`. For example:
 ```xml
 <div t-att="{'a': 1, 'b': 2}"/> <!-- result: <div a="1" b="2"></div> -->
 <div t-att="['a', 'b']"/> <!-- <div a="b"></div> -->
 ```
 ### Dynamic class attribute
 For convenience, Owl supports a special case for the `t-att-class` case: one can
 use an object with keys describing the classes, and values boolean value denoting
 if the class is or is not present:
 ```xml
 <div t-att-class="{'a': true, 'b': true}"/> <!-- result: <div class="a b"></div> -->
 <div t-att-class="{'a b': true, 'c': true}"/> <!-- result: <div class="a b c"></div> -->
 ```
 Note that it can be combined with normal class attribute:
 ```xml
 <div class="a" t-att-class="{'b': true}"/> <!-- result: <div class="a b"></div> -->
 ```
 ### Dynamic tag names
 When writing generic components or templates, the specific concrete tag for an
 HTML element is not known yet. In those situations, the `t-tag` directive is
 useful. It simply evaluates dynamically an expression to use as a tag name. The
 template:
 ```xml
 <t t-tag="tag">
    <span>content</span>
 </t>
 ```
 will be rendered as `<div><span>content</span></div>` if the `tag` context key
 is set to `div`.
 ### Loops
 QWeb has an iteration directive `t-foreach` which take an expression returning the
@@ -418,7 +395,7 @@ is equivalent to the previous example.
 or an object (the current item will be the current key).
 In addition to the name passed via t-as, `t-foreach` provides a few other
-variables for various data points (note: `$as` will be replaced by the name
+variables for various data points (note: `$as` will be replaced with the name
 passed to `t-as`):
 - `$as_value`: the current iteration value, identical to `$as` for lists and
@@ -436,19 +413,94 @@ the context of the `t-foreach`, the value is copied at the end of the foreach
 into the global context.
 ```xml
-<t t-set="existing_variable" t-value="False"/>
+<t t-set="existing_variable" t-value="false"/>
 <!-- existing_variable now False -->
 <p t-foreach="Array(3)" t-as="i">
-    <t t-set="existing_variable" t-value="True"/>
+    <t t-set="existing_variable" t-value="true"/>
-    <t t-set="new_variable" t-value="True"/>
+    <t t-set="new_variable" t-value="true"/>
-    <!-- existing_variable and new_variable now True -->
+    <!-- existing_variable and new_variable now true -->
 </p>
-<!-- existing_variable always True -->
+<!-- existing_variable always true -->
 <!-- new_variable undefined -->
 ```
 Even though Owl tries to be as declarative as possible, the DOM does not fully
 expose its state declaratively in the DOM tree. For example, the scrolling state,
 the current user selection, the focused element or the state of an input are not
 set as attribute in the DOM tree. This is why we use a virtual dom
 algorithm to keep the actual DOM node as much as possible.
 However, in some situations, this is not enough, and we need to help Owl decide
 if an element is actually the same, or is a different element with the same
 properties.
 Consider the following situation: we have a list of two items `[{text: "a"}, {text: "b"}]`
 and we render them in this template:
 ```xml
 <p t-foreach="items" t-as="item"><t t-esc="item.text"/></p>
 ```
 The result will be two `<p>` tags with text `a` and `b`. Now, if we swap them,
 and rerender the template, Owl needs to know what the intent is:
 - should Owl actually swap the DOM nodes,
 - or should it keep the DOM nodes, but with an updated text content?
 This might look trivial, but it actually matters. These two possibilities lead
 to different results in some cases. For example, if the user selected the text
 of the first `p`, swapping them will keep the selection while updating the
 text content will not.
 There are many other cases where this is important: `input` tags with their
 value, css classes and animations, scroll position...
 So, the `t-key` directive is used to give an identity to an element. It allows
 Owl to understand if different elements of a list are actually different or not.
 The above example could be modified by adding an ID: `[{id: 1, text: "a"}, {id: 2, text: "b"}]`.
 Then, the template could look like this:
 ```xml
 <p t-foreach="items" t-as="item" t-key="item.id"><t t-esc="item.text"/></p>
 ```
 The `t-key` directive is useful for lists (`t-foreach`). A key should be
 a unique number or string (objects will not work: they will be cast to the
 `"[object Object]"` string, which is obviously not unique).
 Also, the key can be set on a `t` tag or on its children. The following variations
 are all equivalent:
 ```xml
 <p t-foreach="items" t-as="item" t-key="item.id">
  <t t-esc="item.text"/>
 </p>
 <t t-foreach="items" t-as="item" t-key="item.id">
  <p t-esc="item.text"/>
 </t>
 <t t-foreach="items" t-as="item">
  <p t-key="item.id" t-esc="item.text"/>
 </t>
 ```
 If there is no `t-key` directive, Owl will use the index as a default key.
 Note: the `t-foreach` directive only accepts arrays (lists) or objects. It does
 not work with other iterables, such as `Set`. However, it is only a matter of
 using the `...` javascript operator. For example:
 ```xml
 <t t-foreach="...items" t-as="item">...</t>
 ```
 The `...` operator will convert the `Set` (or any other iterables) into a list,
 which will work with Owl QWeb.
 ### Rendering Sub Templates
 QWeb templates can be used for top level rendering, but they can also be used
@@ -497,6 +549,46 @@ will result in :
 </div>
 ```
 This can be used to define variables scoped to a sub template:
 ```xml
 <t t-call="other-template">
    <t t-set="var" t-value="1"/>
 </t>
 <!-- "var" does not exist here -->
 ```
 ### Dynamic sub templates
 The `t-call` directive can also be used to dynamically call a sub template,
 using string interpolation. For example:
 ```xml
 <div t-name="main-template">
    <t t-call="{{template}}">
        <em>content</em>
    </t>
 </div>
 ```
 Here, the name of the template is obtained from the `template` value in the
 template rendering context.
 ### Translations
 By default, QWeb specify that templates should be translated. If this behaviour
 is not wanted, there is a `t-translation` directive which can turn off
 translations (if it is set to the `off` value), with the following rules:
 - each text node will be replaced with its translation,
 - each of the following attribute values will be translated as well: `title`,
  `placeholder`, `label` and `alt`,
 - translating text nodes can be disabled with the special attribute `t-translation`,
  if its value is `off`.
 See [here](qweb_engine.md#translations) for more information on how to setup a
 translate function in Owl QWeb.
 ### Debugging
 The javascript QWeb implementation provides two useful debugging directives:
@@ -505,7 +597,7 @@ The javascript QWeb implementation provides two useful debugging directives:
 ```xml
 <t t-if="a_test">
-    <t t-debug="">
+    <t t-debug=""/>
 </t>
 ```
@@ -518,4 +610,4 @@ will stop execution if the browser dev tools are open.
 <t t-log="foo"/>
 ```
-will print 42 to the console
+will print 42 to the console.
@@ -0,0 +1,111 @@
 # 🦉 Slots 🦉
 ## Content
 - [Overview](#overview)
 - [Example](#example)
 - [Reference](#reference)
 ## Overview
 Owl is a template based component system. There is therefore a need to be able
 to make generic components. For example, imagine a generic `Dialog`
 component, which is able to display some arbitrary content.
 Obviously, we want to use this component everywhere in our application, to
 display various different content. The `Dialog` component is technically the
 owner of its content, but is only a container. The user of the `Dialog` is
 the component that want to _inject_ something inside the `Dialog`. This is
 exactly what slots are for.
 ## Example
 To make generic components, it is useful to be able for a parent component to _inject_
 some sub template, but still be the owner. For example, a generic dialog component
 will need to render some content, some footer, but with the parent as the
 rendering context.
 Slots are inserted with the `t-slot` directive:
 ```xml
 <div t-name="Dialog" class="modal">
  <div class="modal-title"><t t-esc="props.title"/></div>
  <div class="modal-content">
    <t t-slot="content"/>
  </div>
  <div class="modal-footer">
    <t t-slot="footer"/>
  </div>
 </div>
 ```
 Slots are defined by the caller, with the `t-set-slot` directive:
 ```xml
 <div t-name="SomeComponent">
  <div>some component</div>
  <Dialog title="'Some Dialog'">
    <t t-set-slot="content">
      <div>hey</div>
    </t>
    <t t-set-slot="footer">
      <button t-on-click="doSomething">ok</button>
    </t>
  </Dialog>
 </div>
 ```
 In this example, the component `Dialog` will render the slots `content` and `footer`
 with its parent as rendering context. This means that clicking on the button
 will execute the `doSomething` method on the parent, not on the dialog.
 Note: Owl previously used the `t-set` directive to define the content of a slot.
 This is deprecated and should no longer be used in new code.
 ## Reference
 ### Default Slot
 The first element inside the component which is not a named slot will
 be considered the `default` slot. For example:
 ```xml
 <div t-name="Parent">
  <Child>
    <span>some content</span>
  </Child>
 </div>
 <div t-name="Child">
  <t t-slot="default"/>
 </div>
 ```
 ### Default content
 Slots can define a default content, in case the parent did not define them:
 ```xml
 <div t-name="Parent">
  <Child/>
 </div>
 <span t-name="Child">
  <t t-slot="default">default content</t>
 </span>
 <!-- will be rendered as: <div><span>default content</span></div> -->
 ```
 Rendering context: the content of the slots is actually rendered with the
 rendering context corresponding to where it was defined, not where it is
 positioned. This allows the user to define event handlers that will be bound
 to the correct component (usually, the grandparent of the slot content).
 ### Dynamic Slots
 The `t-slot` directive is actually able to use any expressions, using string
 interplolation:
 ```xml
 <t t-slot="{{current}}" />
 ```
@@ -0,0 +1,184 @@
 # 🦉 Tags 🦉
 ## Content
 - [Overview](#overview)
 - [`xml` tag](#xml-tag)
 - [`css` tag](#css-tag)
 ## Overview
 Tags are very small helpers intended to make it easy to write inline templates
 or styles. There are currently two tags: `css` and `xml`. With these functions,
 it is possible to write [single file components](../learning/how_to_write_sfc.md).
 ## XML tag
 The `xml` tag is certainly the most useful tag. It is used to define an inline
 QWeb template for a component. Without tags, creating a standalone component
 would look like this:
 ```js
 import { Component } from 'owl'
 const name = 'some-unique-name';
 const template = `
    <div>
        <span t-if="somecondition">text</span>
        <button t-on-click="someMethod">Click</button>
    </div>
 `;
 QWeb.registerTemplate(name, template);
 class MyComponent extends Component {
    static template = name;
    ...
 }
 ```
 With tags, this process is slightly simplified. The name is uniquely generated,
 and the template is automatically registered:
 ```js
 const { Component } = owl;
 const { xml } = owl.tags;
 class MyComponent extends Component {
    static template = xml`
        <div>
            <span t-if="somecondition">text</span>
            <button t-on-click="someMethod">Click</button>
        </div>
    `;
    ...
 }
 ```
 ## CSS tag
 The CSS tag is useful to define a css stylesheet in the javascript file:
 ```js
 class MyComponent extends Component {
  static template = xml`
        <div class="my-component">some template</div>
    `;
  static style = css`
    .my-component {
      color: red;
    }
  `;
 }
 ```
 The `css` tag registers internally the css information. Then, whenever the first
 instance of the component is created, will add a `<style>` tag to the document
 `<head>`.
 Note that to make it more useful, like other css preprocessors, the `css` tag
 accepts a small extension of the css specification: css scopes can be nested,
 and the rules will then be expanded by the `css` helper:
 ```scss
 .my-component {
  display: block;
  .sub-component h {
    color: red;
  }
 }
 ```
 will be formatted as:
 ```css
 .my-component {
  display: block;
 }
 .my-component .sub-component h {
  color: red;
 }
 ```
 This extension brings another useful feature: the `&` selector which refers to
 the parent selector. For example, we want our component to be red when hovered.
 We would like to write something like:
 ```scss
 .my-component {
  display: block;
  :hover {
    color: red;
  }
 }
 ```
 but it will be formatted as:
 ```css
 .my-component {
  display: block;
 }
 .my-component :hover {
  color: red;
 }
 ```
 The `&` selector can be used to solve this problem:
 ```scss
 .my-component {
  display: block;
  &:hover {
    color: red;
  }
 }
 ```
 will be formatted as:
 ```css
 .my-component {
  display: block;
 }
 .my-component:hover {
  color: red;
 }
 ```
 Now, there is no additional processing done by the `css` tag. However, since it
 is done in javascript at runtime, we actually have more power. For example:
 1. sharing values between javascript and css:
 ```js
 import { theme } from "./theme";
 class MyComponent extends Component {
  static template = xml`<div class="my-component">...</div>`;
  static style = css`
    .my-component {
      color: ${theme.MAIN_COLOR};
      background-color: ${theme.SECONDARY_color};
    }
  `;
 }
 ```
 2. scoping rules to the current component:
 ```js
 import { generateUUID } from "./utils";
 const uuid = generateUUID();
 class MyComponent extends Component {
  static template = xml`<div data-o-${uuid}="">...</div>`;
  static style = css`
    [data-o-${uuid}] {
      color: red;
    }
  `;
 }
 ```
@@ -0,0 +1,148 @@
 # 🦉 Utils 🦉
 Owl export a few useful utility functions, to help with common issues. Those
 functions are all available in the `owl.utils` namespace.
 ## Content
 - [`whenReady`](#whenready): executing code when DOM is ready
 - [`loadJS`](#loadjs): loading script files
 - [`loadFile`](#loadfile): loading a file (useful for templates)
 - [`escape`](#escape): sanitizing strings
 - [`debounce`](#debounce): limiting rate of function calls
 - [`shallowEqual`](#shallowequal): shallow object comparison
 ## `whenReady`
 The function `whenReady` returns a `Promise` resolved when the DOM is ready (if
 not ready yet, resolved directly otherwise). If called with a callback as
 argument, it executes it as soon as the DOM ready (or directly).
 ```js
 Promise.all([loadFile("templates.xml"), owl.utils.whenReady()]).then(function ([templates]) {
  const qweb = new owl.QWeb({ templates });
  const env = { qweb };
  await mount(App, { env, target: document.body });
 });
 ```
 or alternatively:
 ```js
 owl.utils.whenReady(function () {
  const qweb = new owl.QWeb();
  const env = { qweb };
  await mount(App, { env, target: document.body });
 });
 ```
 ## `loadJS`
 `loadJS` takes a url (string) for a javascript resource, and loads it (by adding
 a script tag in the document head). It returns a promise, so the caller can
 properly reacts when it is ready. Also, it is smart: it maintains a list of urls
 previously loaded (or currently being loaded), and prevent doing twice the work.
 For example, it is useful for lazy loading external libraries:
 ```js
 class MyComponent extends owl.Component {
  willStart() {
    return owl.utils.loadJS("/static/libs/someLib.js");
  }
 }
 ```
 ## `loadFile`
 `loadFile` is a helper function to fetch a file. It simply
 performs a `GET` request and returns the resulting string in a promise. The
 initial usecase for this function is to load a template file. For example:
 ```js
 async function makeEnv() {
  const templates = await owl.utils.loadFile("templates.xml");
  const qweb = new owl.QWeb({ templates });
  return { qweb };
 }
 ```
 Note that unlike `loadJS`, this function returns the content of the file as a
 string. It does not add a `script` tag or any other side effect.
 ## `escape`
 Sometimes, we need to display dynamic data (for example user-generated data) in
 the user interface. If this is done by a `QWeb` template, it is not an issue:
 ```xml
    <div><t t-esc="user.data"/></div>
 ```
 The `QWeb` engine will create a `div` node and add the content of the `user.data`
 string as a text node, so the web browser will not parse it as html. However,
 it may be a problem if this is done with some javascript code like this:
 ```js
 class BadComponent extends Component {
  // some template with a ref to a div
  // some code ...
  mounted() {
    this.divRef.el.innerHTML = this.state.value;
  }
 }
 ```
 In this case, the content of the `div` will be parsed as html, which may inject
 unwanted behaviour. To fix this, the `escape` function will simply transform a
 string into an escaped version of the same string, which will be properly displayed
 by the browser, but which will not be parsed as html (for example, `"<ok>"` is
 escaped to the string: `"&lt;ok&gt;"`). So, the bad example above can be fixed
 with the following change:
 ```js
 this.divRef.el.innerHTML = owl.utils.escape(this.state.value);
 ```
 ## `debounce`
 The `debounce` function is useful when we want to limit the number of times some
 function/action is perfomed. For example, this may be useful to prevent issue
 with people double clicking on a button.
 It takes three arguments:
 - `func` (function): this is the function that will be rate limited
 - `wait` (number): this is the number of milliseconds that we want to use to
  rate limit the function `func`
 - `immediate` (optional, boolean, default=false): if `immediate` is true, the
  function will be triggered immediately (leading edge of the interval). If false,
  the function will be triggered at the end (trailing edge).
 It returns a function. For example:
 ```js
 const debounce = owl.utils.debounce;
 window.addEventListener("mousemove", debounce(doSomething, 100));
 ```
 As this example shows, it is usualy useful for event handlers which are triggered
 very quickly, such as `scroll` or `mousemove` events.
 ## `shallowEqual`
 This function checks if two objects have the same values assigned to each keys:
 ```js
 shallowEqual({ a: 1, b: 2 }, { a: 1, b: 2 }); // true
 shallowEqual({ a: 1, b: 2 }, { a: 1, b: 3 }); // false
 ```
 However, for performance reasons, it assumes that the two objects have the same
 keys. If we are in a situation where this is not guaranteed, the following code
 will work:
 ```js
 const completeShallowEqual = (a, b) => shallowEqual(a, b) && shallowEqual(b, a);
 ```
@@ -1,172 +0,0 @@
 # 🦉 Router 🦉
 ## Content
 - [Overview](#overview)
 - [Example](#example)
 - [Reference](#reference)
  - [Route Definition](#route-definition)
  - [Router](#router)
  - [Navigation Guards](#navigation-guards)
  - [`t-routecomponent`](#t-routecomponent)
  - [Link](#link)
 ## Overview
 It is often useful to organize an application around urls. If the application is
 a single page application, then we need a way to manage those urls in the browser.
 This is why there are many different routers for different frameworks. A generic
 router can do the job just fine, but a specialized router for Owl can give a
 better developer experience.
 The Owl router support the following features:
 - `history` or `hash` mode
 - declarative routes
 - route redirection
 - navigation guards
 - parameterized routes
 - a `<Link>` component
 - a `t-routecomponent` directive
 Note that it is still in early stage of developments, and there are probably
 still some issues.
 ## Example
 To use the Owl router, there are some steps that needs to be done:
 - declare some routes
 - create a router
 - add it to the environment
 ```js
 async function protectRoute({ env, to }) {
  if (!env.session.authUser) {
    env.session.setNextRoute(to.name);
    return { to: "SIGN_IN" };
  }
  return true;
 }
 export const ROUTES = [
  { name: "LANDING", path: "/", component: Landing },
  { name: "TASK", path: "/tasks/{{id}}", component: Task },
  { name: "SIGN_UP", path: "/signup", component: SignUp },
  { name: "SIGN_IN", path: "/signin", component: SignIn },
  { name: "ADMIN", path: "/admin", component: Admin, beforeRouteEnter: protectRoute },
  { name: "ACCOUNT", path: "/account", component: Account, beforeRouteEnter: protectRoute },
  { name: "UNKNOWN", path: "*", redirect: { to: "LANDING" } }
 ];
 function makeEnvironment() {
    ...
    const env = { qweb };
    env.session = new Session(env);
    env.router = new owl.router.Router(env, ROUTES);
    await env.router.start();
    return env;
 }
 ```
 Notice that the router needs to be started. This is an asynchronous operation
 because it needs to apply the potential navigation guards on the current route
 (which may or may not mean that the application is redirected to another route).
 ## Reference
 ### Route definition
 A route need to be defined as an object with the following keys:
 - `name` (optional): a (unique) string useful to identify the current route. If not
  given, it will be assigned an automatic name,
 - `path`: a string describing the url. It can be static: `/admin` or dynamic: `/users/{{id}}`.
  It also can be `*`, to catch all remaining routes.
 - `component` (optional): an Owl component that will be used by the `t-routecomponent`
  directive if the route is active
 - `redirect` (optional): should be destination object (with optional keys `path`, `to` and `params`) if given, the application will be redirected to the destination whenever we match this route
 - `beforeRouteEnter`: defines a [navigation guard](#navigation-guards).
 ### `Router`
 The `Router` constructor takes three arguments:
 - `env`: a valid environment,
 - a list of routes,
 - an optional object (with the only key `mode` which can be `history` (default
  value) or `hash`).
 ```js
 const ROUTES = [...];
 const router = new owl.router.Router(env, ROUTES, {mode: 'history'});
 ```
 Note that the route are defined in a list, and the order matters: the router
 tries to find a match by going down the list.
 The router needs to be added to the environment in the `router` sub key.
 Once a router is created, it needs to be started. This is necessary to initialize
 its current state to the current URL (and also, to potentially apply any
 navigation guards and/or redirecting).
 ```js
 await router.start();
 ```
 Once started, the router will keep track of the current url and reflect its
 value in two keys:
 - `router.currentRoute`
 - `router.currentParams`
 The router also has a `navigate` method, useful to programmatically change the
 application to another state (and the url):
 ```js
 router.navigate({to: 'USER', params: {id: 51}});
 ```
 ### Navigation Guards
 Navigation guards are very useful to be able to execute some business logic/
 perform some actions or redirect to other routes whenever the application is
 entering a new route. For example, the following guard checks if there is an
 authenticated user, and if it is not the case, redirect to the sign in route.
 ```js
 async function protectRoute({ env, to }) {
  if (!env.session.authUser) {
    env.session.setNextRoute(to.name);
    return { to: "SIGN_IN" };
  }
  return true;
 }
 ```
 A navigation guard is a function that returns a promise, which either resolves
 to `true` (the navigation is accepted), or to another destination object.
 ### `t-routecomponent`
 The `t-routecomponent` directive directs Owl to render the component associated
 to the currently active route (if any):
 ```xml
 <div t-name="App">
    <NavBar />
    <t t-routecomponent="1"/>
 </div>
 ```
 ### `Link`
 The `Link` component is a Owl component which render as a `<a>` tag with any
 content. It will compute the proper href from its props, and allow Owl to
 properly navigate to a given url if clicked on it.
 ```xml
 <Link to="'HOME'">Home</Link>
 ```
@@ -1,289 +0,0 @@
 # 🦉 Store 🦉
 ## Content
 - [Overview](#overview)
 - [Example](#example)
 - [Reference](#reference)
  - [Store](#store)
  - [Actions](#actions)
  - [Getters](#getters)
  - [Connecting a Component](#connecting-a-component)
  - [Semantics](#semantics)
  - [Good Practices](#good-practices)
 ## Overview
 Managing the state in an application is not an easy task. In some cases, the
 state of an application can be part of the component tree, in a natural way.
 However, there are situations where some part of the state need to be displayed
 in various parts of the user interface, and then, it is not obvious which
 component should own which part of the state.
 Owl's solution to this issue is a centralized store. It is a class that owns
 some state, and let the developer update it in a structured way, with `actions`.
 Owl components can then connect to the store, and will be updated if necessary.
 Note: Owl store is inspired by React Redux and VueX.
 ## Example
 Here is what a simple store looks like:
 ```js
 const actions = {
  addTodo({ state }, message) {
    state.todos.push({
      id: state.nextId++,
      message,
      isCompleted: false
    });
  }
 };
 const state = {
  todos: [],
  nextId: 1
 };
 const store = new owl.Store({ state, actions });
 store.on("update", () => console.log(store.state));
 // updating the state
 store.dispatch("addTodo", "fix all bugs");
 ```
 This example shows how a store can be defined and used. Note that in most cases,
 actions will be dispatched by connected components.
 ## Reference
 ### `Store`
 The store is a simple [`owl.EventBus`](event_bus.md) that triggers `update` events
 whenever its state is changed. Note that these events are triggered only after a
 microtask tick, so only one event will be triggered for any number of state changes in a
 call stack.
 Also, it is important to mention that the state is observed (with an `owl.Observer`),
 which is the reason why it is able to know if it was changed. See the
 [Observer](observer.md)'s documentation for more details.
 The `Store` class is quite small. It has two public methods:
 - its constructor
 - `dispatch`
 The constructor takes a configuration object with four (optional) keys:
 - the initial state
 - the actions
 - the getters
 - the environment
 ```javascript
 const config = {
  state,
  actions,
  getters,
  env
 };
 const store = new Store(config);
 ```
 ### Actions
 Actions are used to coordinate state changes. It can be used for both synchronous
 and asynchronous logic.
 ```js
 const actions = {
  async login({ state }, info) {
    state.loginState = "pending";
    try {
      const loginInfo = await doSomeRPC("/login/", info);
      state.loginState = loginInfo;
    } catch {
      state.loginState = "error";
    }
  }
 };
 ```
 Actions are called with the `dispatch` method on the store, and can receive an
 arbitrary number of arguments.
 ```js
 store.dispatch("login", someInfo);
 ```
 Note that anything returned by an action will also be returned by the `dispatch`
 call.
 Also, it is important to be aware that we need to be careful with asynchronous
 logic. Each state change will potentially trigger a rerendering, so we need to
 make sure that we do not have a partial corrupted state. Here is an example that
 is likely not a good idea:
 ```javascript
 const actions = {
  async fetchSomeData({ state }, recordId) {
    state.recordId = recordId;
    const data = await doSomeRPC("/read/", recordId);
    state.recordData = data;
  }
 };
 ```
 In the previous example, there is a period of time in which the state has a
 `recordId` which does not correspond to the `recordData`. It is more likely that
 we want an atomic update: updating the `recordId` at the same time as the `recordData`
 values:
 ```javascript
 const actions = {
  async fetchSomeData({ state }, recordId) {
    const data = await doSomeRPC("/read/", recordId);
    state.recordId = recordId;
    state.recordData = data;
  }
 };
 ```
 ### Getters
 Usually, data contained in the store will be stored in a normalized way. For
 example,
 ```js
 {
    posts: [{id: 11, authorId: 4, content: 'Greetings'}],
    authors: [{id: 4, name: 'John'}]
 }
 ```
 However, the user interface will probably need some denormalized data like
 ```js
 {id: 11, author: {id: 4, name: 'John'}, content: 'Greetings'}
 ```
 This is what `getters` are for: they give a centralized way to process and
 transform the data contained in the store.
 ```js
 const getters = {
  getPost({ state }, id) {
    const post = state.posts.find(p => p.id === id);
    const author = state.authors.find(a => (a.id = post.id));
    return {
      id,
      author,
      content: post.content
    };
  }
 };
 // somewhere else
 const post = store.getters.getPost(id);
 ```
 Getters take _at most_ one argument.
 Note that getters are cached if they don't take any argument, or their argument
 is a string or a number.
 ### Connecting a Component
 At some point, we need a way to access the state in the store from a component.
 By default, an Owl `Component` is not connected to any store. To do that, we
 need to create a component inheriting from `OwlComponent`:
 ```javascript
 const actions = {
  increment({ state }, val) {
    state.counter += val;
  }
 };
 const state = {
  counter: 0
 };
 const store = new owl.Store({ state, actions });
 class Counter extends owl.ConnectedComponent {
  static mapStoreToProps(state) {
    return {
      value: state.counter
    };
  }
  increment() {
    this.env.store.dispatch("increment");
  }
 }
 const counter = new Counter({ store, qweb });
 ```
 ```xml
 <button t-name="Counter" t-on-click="increment">
  Click Me! [<t t-esc="props.value"/>]
 </button>
 ```
 The `ConnectedComponent` class can be configured with the following fields:
 - `mapStoreToProps`: a function that extracts the `props` of the Component
  from the `state` of the `Store` and returns them as a dict.
 - `getStore`: a function that takes the `env` in arguments and returns an
  instance of `Store` to connect to (if not given, connects to `env.store`)
 - `hashFunction`: the function to use to detect changes in the state (if not
  given, generates a function that uses revision numbers, incremented at
  each state change)
 - `deep` (boolean): [only useful if no hashFunction is given] if `false`, only watch
  for top level state changes (`true` by default)
 Note that the class `ConnectedComponent` has a `dispatch` method. This means
 that the previous example could be simplified like this:
 ```javascript
 class Counter extends owl.ConnectedComponent {
  static mapStoreToProps(state) {
    return {
      value: state.counter
    };
  }
 }
 ```
 ```xml
 <button t-name="Counter" t-on-click="dispatch('increment')">
  Click Me! [<t t-esc="props.value"/>]
 </button>
 ```
 ### Semantics
 The `Store` and the `ConnectedComponent` try to be smart and to optimize as much
 as possible the rendering and update process. What is important to know is:
 - components are always updated in the order of their creation (so, parent
  before children)
 - they are updated only if they are in the DOM
 - if a parent is asynchronous, the system will wait for it to complete its
  update before updating other components.
 - in general, updates are not coordinated. This is not a problem for synchronous
  components, but if there are many asynchronous components, this could lead to
  a situation where some part of the UI is updated and other parts of the UI is
  not updated.
 ### Good Practices
 - avoid asynchronous components as much as possible. Asynchronous components
  lead to situations where parts of the UI is not updated immediately.
 - do not be afraid to connect many components, parent or children if needed. For
  example, a `MessageList` component could get a list of ids in its `mapStoreToProps` and a `Message` component could get the data of its own
  message
 - since the `mapStoreToProps` function is called for each connected component,
  for each state update, it is important to make sure that these functions are
  as fast as possible.
@@ -1,58 +0,0 @@
 # 🦉 Tooling 🦉
 ## Content
 - [Overview](#overview)
 - [Development Mode](#development-mode)
 - [Playground](#playground)
 - [Benchmarks](#benchmarks)
 ## Overview
 To help work with/improve/learn OWL, there are a few extras tools/settings.
 - development mode: enable better error reporting for the developer
 - a playground application: a space to experiment and learn Owl.
 - a benchmarks application: allow comparison with a few common frameworks
 The two applications are available in the `tools/` folder, and can be accessed
 by using a static http server. A simple python
 server is available in `server.py`. There is also a npm script to start it:
 `npm run tools` (and its version with a watcher: `npm run tools:watch`).
 ## Development Mode
 By default, Owl is in _production_ mode, this means that it will try to do its
 job fast, and skip some expensive operations. However, in some cases, it is
 convenient to have better information on what is going on, this is the purpose
 of the dev mode.
 Owl has a mode flag, in `owl.__info__.mode`. Its default value is `prod`, but
 it can be set to `dev`:
 ```js
 owl.__info__.mode = "dev";
 ```
 Note that templates compiled with the `prod` settings will not be recompiled.
 So, changing this setting is best done at startup.
 An important job done by the `dev` mode is to validate props for each component
 creation and update.  Also, extra props will cause an error.
 ## Playground
 The playground is an important application designed to help learning and
 experimenting with Owl. The last published version of Owl can be tested [online](https://odoo.github.io/owl/playground/).
 It is an application similar to `jsFiddle`, but specialized for Owl: there are
 three tabs (`js`, `css` and `xml`), and a simple button `Run` to execute that
 code in an iframe.
 ## Benchmarks
 Note: This is more an internal tool, useful for people working on Owl.
 The benchmarks application is a very small application, implemented in different
 frameworks, and in different versions of Owl. This is a simple internal tool,
 useful to compare various performance metrics on some tasks.
@@ -1,65 +0,0 @@
 # 🦉 Utils 🦉
 Owl export a few useful utility functions, to help with common issues. Those
 functions are all available in the `owl.utils` namespace.
 ## Content
 - [`whenReady`](#whenready): executing code when DOM is ready
 - [`loadJS`](#loadjs): loading script files
 - [`loadTemplates`](#loadtemplates): loading xml files
 - [`escape`](#escape): sanitizing strings
 - [`debounce`](#debounce): limiting rate of function calls
 ## `whenReady`
 The function `whenReady` returns a `Promise` resolved when the DOM is ready (if
 not ready yet, resolved directly otherwise). If called with a callback as
 argument, it executes it as soon as the DOM ready (or directly).
 ```js
 Promise.all([loadTemplates(), owl.utils.whenReady()]).then(function([
  templates
 ]) {
  const qweb = new owl.QWeb(templates);
  const app = new App({ qweb });
  app.mount(document.body);
 });
 ```
 ```js
 owl.utils.whenReady(function() {
  const qweb = new owl.QWeb();
  const app = new App({ qweb });
  app.mount(document.body);
 });
 ```
 ## `loadJS`
 `loadJS` takes a url (string) for a javascript resource, and loads it. It returns
 a promise, so the caller can properly react when it is ready. Also, it is smart:
 it maintains a list of urls previously loaded (or currently being loaded), and
 prevent doing twice the work.
 ```js
 class MyComponent extends owl.Component {
  willStart() {
    return owl.utils.loadJS("/static/libs/someLib.js");
  }
 }
 ```
 ## `loadTemplates`
 ```js
 async function makeEnv() {
  const templates = await owl.utils.loadTemplates("templates.xml");
  const qweb = new owl.QWeb(templates);
  return { qweb };
 }
 ```
 ## `escape`
 ## `debounce`
@@ -1,53 +1,74 @@
 {
-  "name": "owl",
+  "name": "@odoo/owl",
-  "version": "0.19.0",
+  "version": "2.0.0-alpha1",
  "description": "Odoo Web Library (OWL)",
-  "main": "src/index.ts",
+  "main": "dist/owl.cjs.js",
  "browser": "dist/owl.iife.js",
  "module": "dist/owl.es.js",
  "types": "dist/types/index.d.ts",
  "files": [
    "dist"
  ],
  "engines": {
    "node": ">=12.18.3"
  },
  "scripts": {
    "build:js": "tsc --target esnext --module es6 --outDir dist/owl",
    "build:bundle": "rollup -c",
-    "build": "npm run build:js && npm run build:bundle",
+    "build": "npm run build:bundle",
    "buildcommonjs": "npm run build:js && npm run build:bundle -- -f cjs",
    "minify": "uglifyjs dist/owl.js -o dist/owl.min.js --compress --mangle",
    "test": "jest",
    "test:debug": "node --inspect-brk node_modules/.bin/jest --runInBand --watch --testTimeout=5000000",
    "test:watch": "jest --watch",
-    "tools:serve": "python3 tools/server.py || python tools/server.py",
+    "playground:serve": "python3 tools/server.py || python tools/server.py",
-    "tools": "npm run build && npm run tools:serve",
+    "playground": "npm run build && npm run playground:serve",
-    "pretools:watch": "npm run build",
+    "preplayground:watch": "npm run build",
-    "tools:watch": "npm-run-all  --parallel tools:serve \"build:* -- --watch\""
+    "playground:watch": "npm-run-all  --parallel playground:serve \"build:* -- --watch\"",
    "prettier": "prettier {src/*.ts,src/**/*.ts,tests/*.ts,tests/**/*.ts,doc/*.md,doc/**/*.md} --write",
    "check-formatting": "prettier {src/*.ts,src/**/*.ts,tests/*.ts,tests/**/*.ts,doc/*.md,doc/**/*.md} --check",
    "publish": "npm run build && npm publish",
    "release": "node tools/release.js"
  },
  "repository": {
    "type": "git",
    "url": "git+https://github.com/odoo/owl.git"
  },
  "author": "Odoo",
-  "license": "GPL-3.0-or-later",
+  "license": "LGPL-3.0-only",
  "bugs": {
    "url": "https://github.com/odoo/owl/issues"
  },
  "homepage": "https://github.com/odoo/owl#readme",
  "devDependencies": {
-    "@types/jest": "^23.3.12",
+    "@types/jest": "^27.0.1",
    "@types/node": "^14.11.8",
    "chalk": "^3.0.0",
    "cpx": "^1.5.0",
    "current-git-branch": "^1.1.0",
    "git-rev-sync": "^1.12.0",
-    "jest": "^23.6.0",
+    "github-api": "^3.3.0",
-    "jest-environment-jsdom": "^24.7.1",
+    "jest": "^27.1.0",
    "jest-diff": "^27.3.1",
    "jest-environment-jsdom": "^27.1.0",
    "live-server": "^1.2.1",
    "npm-run-all": "^4.1.5",
-    "rollup": "^1.6.0",
+    "prettier": "2.4.1",
-    "rollup-plugin-typescript2": "^0.20.1",
+    "rollup": "^2.56.3",
    "rollup-plugin-terser": "^7.0.2",
    "rollup-plugin-typescript2": "^0.31.1",
    "sass": "^1.16.1",
    "source-map-support": "^0.5.10",
-    "ts-jest": "^23.10.5",
+    "ts-jest": "^27.0.5",
-    "typescript": "^3.2.2",
+    "typescript": "4.5.2",
    "uglify-es": "^3.3.9"
  },
  "dependencies": {},
  "jest": {
    "testEnvironment": "jsdom",
    "roots": [
      "<rootDir>/src",
      "<rootDir>/tests"
    ],
    "setupFiles": [
      "./tests/mocks/mockEventTarget.js"
    ],
    "transform": {
      "^.+\\.ts?$": "ts-jest"
    },
@@ -63,6 +84,7 @@
    ]
  },
  "prettier": {
-    "printWidth": 100
+    "printWidth": 100,
    "endOfLine": "auto"
  }
 }
@@ -0,0 +1,28 @@
 # 🦉 OWL Roadmap 🦉
 - Current version: 1.4.7
 - Status: stable
 This roadmap is only an attempt at predicting Owl's future.  Everything may
 change!
 ### 1.x
 - add chrome and firefox devtools,
 - fix every bugs,
 - improve documentation,
 - small backward compatible improvements.
 ### 2.x (2020? 2021? 2022?)
 - stop support for `t-set` directive to define the content of a slot
 Maybe:
 - reimplement vdom to use *block* system, like Vue 3, which should make Owl
  much faster
 - refactor `QWeb` to use an intermediate representation (some kind of AST) to
  allow additional optimisations.
@@ -1,14 +1,71 @@
-import { version } from "./package.json";
+import pkg from "./package.json";
 import git from "git-rev-sync";
 import typescript from 'rollup-plugin-typescript2';
 import { terser } from "rollup-plugin-terser";
 const name = "owl";
 const extend = true;
 /**
 * Meta data to be added on the __info__ object.
 * Used to let external tools know the current owl version.
 */
 const outro = `
 __info__.version = '${pkg.version}';
 __info__.date = '${new Date().toISOString()}';
 __info__.hash = '${git.short()}';
 __info__.url = 'https://github.com/odoo/owl';
 `;
 /**
 * Generate from a string depicting a path a new path for the minified version.
 * @param {string} pkgFileName file name
 */
 function generateMinifiedNameFromPkgName(pkgFileName) {
  const parts = pkgFileName.split('.');
  parts.splice(parts.length - 1, 0, "min");
  return parts.join('.');
 }
 /**
 * Get the rollup config based on the arguments
 * @param {string} format format of the bundle
 * @param {string} generatedFileName generated file name
 * @param {boolean} minified should it be minified
 */
 function getConfigForFormat(format, generatedFileName, minified = false) {
  return {
    file: minified ? generateMinifiedNameFromPkgName(generatedFileName) : generatedFileName,
    format: format,
    name: name,
    extend: extend,
    outro: outro,
    freeze: false,
    plugins: minified ? [terser()] : [],
    indent: '    ', // indent with 4 spaces
  };
 }
 // rollup.config.js
 export default {
-  input: "dist/owl/index.js",
+  input: "src/index.ts",
-  output: {
+  output: [
-    file: "dist/owl.js",
+
-    format: "iife",
+    /**
-    name: "owl",
+     * Read about module formats:
-    extend: true,
+     *  https://auth0.com/blog/javascript-module-systems-showdown/
-    outro: `exports.__info__.version = '${version}';\nexports.__info__.date = '${new Date().toISOString()}';\nexports.__info__.hash = '${git.short()}';\nexports.__info__.url = 'https://github.com/odoo/owl';`
+     *  https://medium.com/@kelin2025/so-you-wanna-use-es6-modules-714f48b3a953
-  }
+     */
    getConfigForFormat('esm', pkg.module),
    getConfigForFormat('esm', pkg.module, true),
    getConfigForFormat('cjs', pkg.main),
    getConfigForFormat('cjs', pkg.main, true),
    getConfigForFormat('iife', pkg.browser),
    getConfigForFormat('iife', pkg.browser, true),
  ],
  plugins: [
    typescript({
      useTsconfigDeclarationDir: true
    }),
  ]
 };
@@ -0,0 +1,105 @@
 import { Component } from "../component/component";
 import { ComponentNode } from "../component/component_node";
 import { MountOptions } from "../component/fibers";
 import { Scheduler } from "../component/scheduler";
 import { TemplateSet, TemplateSetConfig } from "./template_set";
 import { nodeErrorHandlers } from "../component/error_handling";
 // reimplement dev mode stuff see last change in 0f7a8289a6fb8387c3c1af41c6664b2a8448758f
 export interface Env {
  [key: string]: any;
 }
 export interface AppConfig extends TemplateSetConfig {
  env?: Env;
  props?: any;
 }
 export const DEV_MSG = `Owl is running in 'dev' mode.
 This is not suitable for production use.
 See https://github.com/odoo/owl/blob/master/doc/reference/config.md#mode for more information.`;
 export class App<T extends typeof Component = any> extends TemplateSet {
  Root: T;
  props: any;
  env: Env;
  scheduler = new Scheduler(window.requestAnimationFrame.bind(window));
  root: ComponentNode | null = null;
  constructor(Root: T, config: AppConfig = {}) {
    super(config);
    this.Root = Root;
    if (config.dev) {
      console.info(DEV_MSG);
    }
    const descrs = Object.getOwnPropertyDescriptors(config.env || {});
    this.env = Object.freeze(Object.defineProperties({}, descrs));
    this.props = config.props || {};
  }
  mount(target: HTMLElement, options?: MountOptions): Promise<InstanceType<T>> {
    this.checkTarget(target);
    const node = this.makeNode(this.Root, this.props);
    const prom = this.mountNode(node, target, options);
    this.root = node;
    return prom;
  }
  checkTarget(target: HTMLElement) {
    if (!(target instanceof HTMLElement)) {
      throw new Error("Cannot mount component: the target is not a valid DOM element");
    }
    if (!document.body.contains(target)) {
      throw new Error("Cannot mount a component on a detached dom node");
    }
  }
  makeNode(Component: T, props: any): ComponentNode {
    return new ComponentNode(Component, props, this);
  }
  mountNode(node: ComponentNode, target: HTMLElement, options?: MountOptions) {
    const promise: any = new Promise((resolve, reject) => {
      let isResolved = false;
      // manually set a onMounted callback.
      // that way, we are independant from the current node.
      node.mounted.push(() => {
        resolve(node.component);
        isResolved = true;
      });
      // Manually add the last resort error handler on the node
      let handlers = nodeErrorHandlers.get(node);
      if (!handlers) {
        handlers = [];
        nodeErrorHandlers.set(node, handlers);
      }
      handlers.unshift((e) => {
        if (isResolved) {
          console.error(e);
        } else {
          reject(e);
        }
        throw e;
      });
    });
    node.mountComponent(target, options);
    return promise;
  }
  destroy() {
    if (this.root) {
      this.root.destroy();
    }
  }
 }
 export async function mount<T extends typeof Component>(
  C: T,
  target: HTMLElement,
  config: AppConfig & MountOptions = {}
 ): Promise<InstanceType<T>> {
  return new App(C, config).mount(target, config);
 }
@@ -0,0 +1,213 @@
 import { BDom, multi, text, toggler } from "../blockdom";
 import { validateProps } from "../component/props_validation";
 import { Markup } from "../utils";
 import { html } from "../blockdom/index";
 import { VPortal } from "../portal";
 /**
 * This file contains utility functions that will be injected in each template,
 * to perform various useful tasks in the compiled code.
 */
 function withDefault(value: any, defaultValue: any): any {
  return value === undefined || value === null || value === false ? defaultValue : value;
 }
 function callPortal(
  ctx: any,
  parent: any,
  key: string,
  target: string,
  content: (ctx: any, node: any, key: string) => BDom
 ): BDom {
  const portal = new VPortal(target, content(ctx, parent, key), ctx.__owl__) as any;
  return portal;
 }
 function callSlot(
  ctx: any,
  parent: any,
  key: string,
  name: string,
  dynamic: boolean,
  extra: any,
  defaultContent?: (ctx: any, node: any, key: string) => BDom
 ): BDom {
  const slots = (ctx.props && ctx.props.slots) || {};
  const { __render, __ctx, __scope } = slots[name] || {};
  const slotScope = Object.create(__ctx || {});
  if (__scope) {
    slotScope[__scope] = extra || {};
  }
  const slotBDom = __render ? __render.call(__ctx.__owl__.component, slotScope, parent, key) : null;
  if (defaultContent) {
    let child1: BDom | undefined = undefined;
    let child2: BDom | undefined = undefined;
    if (slotBDom) {
      child1 = dynamic ? toggler(name, slotBDom) : slotBDom;
    } else {
      child2 = defaultContent.call(ctx.__owl__.component, ctx, parent, key);
    }
    return multi([child1, child2]);
  }
  return slotBDom || text("");
 }
 function capture(ctx: any): any {
  const component = ctx.__owl__.component;
  const result = Object.create(component);
  for (let k in ctx) {
    result[k] = ctx[k];
  }
  return result;
 }
 function withKey(elem: any, k: string) {
  elem.key = k;
  return elem;
 }
 function prepareList(collection: any): [any[], any[], number, any[]] {
  let keys: any[];
  let values: any[];
  if (Array.isArray(collection)) {
    keys = collection;
    values = collection;
  } else if (collection) {
    values = Object.keys(collection);
    keys = Object.values(collection);
  } else {
    throw new Error("Invalid loop expression");
  }
  const n = values.length;
  return [keys, values, n, new Array(n)];
 }
 const isBoundary = Symbol("isBoundary");
 function setContextValue(ctx: { [key: string]: any }, key: string, value: any): void {
  const ctx0 = ctx;
  while (!ctx.hasOwnProperty(key) && !ctx.hasOwnProperty(isBoundary)) {
    const newCtx = ctx.__proto__;
    if (!newCtx) {
      ctx = ctx0;
      break;
    }
    ctx = newCtx;
  }
  ctx[key] = value;
 }
 function toNumber(val: string): number | string {
  const n = parseFloat(val);
  return isNaN(n) ? val : n;
 }
 function shallowEqual(l1: any[], l2: any[]): boolean {
  for (let i = 0, l = l1.length; i < l; i++) {
    if (l1[i] !== l2[i]) {
      return false;
    }
  }
  return true;
 }
 class LazyValue {
  fn: any;
  ctx: any;
  node: any;
  constructor(fn: any, ctx: any, node: any) {
    this.fn = fn;
    this.ctx = capture(ctx);
    this.node = node;
  }
  evaluate(): any {
    return this.fn(this.ctx, this.node);
  }
  toString() {
    return this.evaluate().toString();
  }
 }
 /*
 * Safely outputs `value` as a block depending on the nature of `value`
 */
 export function safeOutput(value: any): ReturnType<typeof toggler> {
  if (!value) {
    return value;
  }
  let safeKey;
  let block;
  if (value instanceof Markup) {
    safeKey = `string_safe`;
    block = html(value as string);
  } else if (value instanceof LazyValue) {
    safeKey = `lazy_value`;
    block = value.evaluate();
  } else if (typeof value === "string") {
    safeKey = "string_unsafe";
    block = text(value);
  } else {
    // Assuming it is a block
    safeKey = "block_safe";
    block = value;
  }
  return toggler(safeKey, block);
 }
 let boundFunctions = new WeakMap();
 function bind(ctx: any, fn: Function): Function {
  let component = ctx.__owl__.component;
  let boundFnMap = boundFunctions.get(component);
  if (!boundFnMap) {
    boundFnMap = new WeakMap();
    boundFunctions.set(component, boundFnMap);
  }
  let boundFn = boundFnMap.get(fn);
  if (!boundFn) {
    boundFn = fn.bind(component);
    boundFnMap.set(fn, boundFn);
  }
  return boundFn;
 }
 type RefMap = { [key: string]: HTMLElement | null };
 type RefSetter = (el: HTMLElement | null) => void;
 function multiRefSetter(refs: RefMap, name: string): RefSetter {
  let count = 0;
  return (el) => {
    if (el) {
      count++;
      if (count > 1) {
        throw new Error("Cannot have 2 elements with same ref name at the same time");
      }
    }
    if (count === 0 || el) {
      refs[name] = el;
    }
  };
 }
 export const UTILS = {
  withDefault,
  zero: Symbol("zero"),
  isBoundary,
  callSlot,
  callPortal,
  capture,
  withKey,
  prepareList,
  setContextValue,
  multiRefSetter,
  shallowEqual,
  toNumber,
  validateProps,
  LazyValue,
  safeOutput,
  bind,
 };
@@ -0,0 +1,126 @@
 import { createBlock, html, list, multi, text, toggler, comment } from "../blockdom";
 import { compile, Template } from "../compiler";
 import { component } from "../component/component_node";
 import { UTILS } from "./template_helpers";
 const bdom = { text, createBlock, list, multi, html, toggler, component, comment };
 export const globalTemplates: { [key: string]: string | Node } = {};
 function parseXML(xml: string): Document {
  const parser = new DOMParser();
  const doc = parser.parseFromString(xml, "text/xml");
  if (doc.getElementsByTagName("parsererror").length) {
    let msg = "Invalid XML in template.";
    const parsererrorText = doc.getElementsByTagName("parsererror")[0].textContent;
    if (parsererrorText) {
      msg += "\nThe parser has produced the following error message:\n" + parsererrorText;
      const re = /\d+/g;
      const firstMatch = re.exec(parsererrorText);
      if (firstMatch) {
        const lineNumber = Number(firstMatch[0]);
        const line = xml.split("\n")[lineNumber - 1];
        const secondMatch = re.exec(parsererrorText);
        if (line && secondMatch) {
          const columnIndex = Number(secondMatch[0]) - 1;
          if (line[columnIndex]) {
            msg +=
              `\nThe error might be located at xml line ${lineNumber} column ${columnIndex}\n` +
              `${line}\n${"-".repeat(columnIndex - 1)}^`;
          }
        }
      }
    }
    throw new Error(msg);
  }
  return doc;
 }
 export interface TemplateSetConfig {
  dev?: boolean;
  translatableAttributes?: string[];
  translateFn?: (s: string) => string;
  templates?: string | Document;
 }
 export class TemplateSet {
  dev: boolean;
  rawTemplates: typeof globalTemplates = Object.create(globalTemplates);
  templates: { [name: string]: Template } = {};
  translateFn?: (s: string) => string;
  translatableAttributes?: string[];
  utils: typeof UTILS = Object.assign({}, UTILS, {
    call: (owner: any, subTemplate: string, ctx: any, parent: any, key: any) => {
      const template = this.getTemplate(subTemplate);
      return toggler(subTemplate, template.call(owner, ctx, parent, key));
    },
    getTemplate: (name: string) => this.getTemplate(name),
  });
  constructor(config: TemplateSetConfig = {}) {
    this.dev = config.dev || false;
    this.translateFn = config.translateFn;
    this.translatableAttributes = config.translatableAttributes;
    if (config.templates) {
      this.addTemplates(config.templates);
    }
  }
  addTemplate(name: string, template: string | Node, options: { allowDuplicate?: boolean } = {}) {
    if (name in this.rawTemplates && !options.allowDuplicate) {
      throw new Error(`Template ${name} already defined`);
    }
    this.rawTemplates[name] = template;
  }
  addTemplates(xml: string | Document, options: { allowDuplicate?: boolean } = {}) {
    if (!xml) {
      // empty string
      return;
    }
    xml = xml instanceof Document ? xml : parseXML(xml);
    for (const template of xml.querySelectorAll("[t-name]")) {
      const name = template.getAttribute("t-name")!;
      template.removeAttribute("t-name");
      this.addTemplate(name, template, options);
    }
  }
  getTemplate(name: string): Template {
    if (!(name in this.templates)) {
      const rawTemplate = this.rawTemplates[name];
      if (rawTemplate === undefined) {
        throw new Error(`Missing template: "${name}"`);
      }
      const templateFn = this._compileTemplate(name, rawTemplate);
      // first add a function to lazily get the template, in case there is a
      // recursive call to the template name
      this.templates[name] = (context, parent) => this.templates[name](context, parent);
      const template = templateFn(bdom, this.utils);
      this.templates[name] = template;
    }
    return this.templates[name];
  }
  _compileTemplate(name: string, template: string | Node) {
    return compile(template, {
      name,
      dev: this.dev,
      translateFn: this.translateFn,
      translatableAttributes: this.translatableAttributes,
    });
  }
 }
 // -----------------------------------------------------------------------------
 //  xml tag helper
 // -----------------------------------------------------------------------------
 export function xml(...args: Parameters<typeof String.raw>) {
  const name = `__template__${xml.nextId++}`;
  const value = String.raw(...args);
  globalTemplates[name] = value;
  return name;
 }
 xml.nextId = 1;
@@ -0,0 +1,167 @@
 import type { Setter } from "./block_compiler";
 const { setAttribute: elemSetAttribute, removeAttribute } = Element.prototype;
 const tokenList = DOMTokenList.prototype;
 const tokenListAdd = tokenList.add;
 const tokenListRemove = tokenList.remove;
 const isArray = Array.isArray;
 const { split, trim } = String.prototype;
 const wordRegexp = /\s+/;
 /**
 * We regroup here all code related to updating attributes in a very loose sense:
 * attributes, properties and classs are all managed by the functions in this
 * file.
 */
 function setAttribute(this: HTMLElement, key: string, value: any) {
  switch (value) {
    case false:
    case undefined:
      removeAttribute.call(this, key);
      break;
    case true:
      elemSetAttribute.call(this, key, "");
      break;
    default:
      elemSetAttribute.call(this, key, value);
  }
 }
 export function createAttrUpdater(attr: string): Setter<HTMLElement> {
  return function (this: HTMLElement, value: any) {
    setAttribute.call(this, attr, value);
  };
 }
 export function attrsSetter(this: HTMLElement, attrs: any) {
  if (isArray(attrs)) {
    setAttribute.call(this, attrs[0], attrs[1]);
  } else {
    for (let k in attrs) {
      setAttribute.call(this, k, attrs[k]);
    }
  }
 }
 export function attrsUpdater(this: HTMLElement, attrs: any, oldAttrs: any) {
  if (isArray(attrs)) {
    const name = attrs[0];
    const val = attrs[1];
    if (name === oldAttrs[0]) {
      if (val === oldAttrs[1]) {
        return;
      }
      setAttribute.call(this, name, val);
    } else {
      removeAttribute.call(this, oldAttrs[0]);
      setAttribute.call(this, name, val);
    }
  } else {
    for (let k in oldAttrs) {
      if (!(k in attrs)) {
        removeAttribute.call(this, k);
      }
    }
    for (let k in attrs) {
      const val = attrs[k];
      if (val !== oldAttrs[k]) {
        setAttribute.call(this, k, val);
      }
    }
  }
 }
 function toClassObj(expr: string | number | { [c: string]: any }) {
  const result: { [c: string]: any } = {};
  switch (typeof expr) {
    case "string":
      // we transform here a list of classes into an object:
      //  'hey you' becomes {hey: true, you: true}
      const str = trim.call(expr);
      if (!str) {
        return {};
      }
      let words = split.call(str, wordRegexp);
      for (let i = 0, l = words.length; i < l; i++) {
        result[words[i]] = true;
      }
      return result;
    case "object":
      // this is already an object but we may need to split keys:
      // {'a': true, 'b c': true} should become {a: true, b: true, c: true}
      for (let key in expr as any) {
        const value = (expr as any)[key];
        if (value) {
          const words = split.call(key, wordRegexp);
          for (let word of words) {
            result[word] = value;
          }
        }
      }
      return result;
    case "undefined":
      return {};
    case "number":
      return { [expr as number]: true };
    default:
      return { [expr as any]: true };
  }
 }
 export function setClass(this: HTMLElement, val: any) {
  val = val === "" ? {} : toClassObj(val);
  // add classes
  const cl = this.classList;
  for (let c in val) {
    tokenListAdd.call(cl, c);
  }
 }
 export function updateClass(this: HTMLElement, val: any, oldVal: any) {
  oldVal = oldVal === "" ? {} : toClassObj(oldVal);
  val = val === "" ? {} : toClassObj(val);
  const cl = this.classList;
  // remove classes
  for (let c in oldVal) {
    if (!(c in val)) {
      tokenListRemove.call(cl, c);
    }
  }
  // add classes
  for (let c in val) {
    if (!(c in oldVal)) {
      tokenListAdd.call(cl, c);
    }
  }
 }
 export function makePropSetter(name: string): Setter<HTMLElement> {
  return function setProp(this: HTMLElement, value: any) {
    (this as any)[name] = value;
  };
 }
 export function isProp(tag: string, key: string): boolean {
  switch (tag) {
    case "input":
      return (
        key === "checked" ||
        key === "indeterminate" ||
        key === "value" ||
        key === "readonly" ||
        key === "disabled"
      );
    case "option":
      return key === "selected" || key === "disabled";
    case "textarea":
      return key === "value" || key === "readonly" || key === "disabled";
    case "select":
      return key === "value" || key === "disabled";
    case "button":
    case "optgroup":
      return key === "disabled";
  }
  return false;
 }
@@ -0,0 +1,613 @@
 import {
  attrsSetter,
  attrsUpdater,
  createAttrUpdater,
  isProp,
  makePropSetter,
  setClass,
  updateClass,
 } from "./attributes";
 import { config } from "./config";
 import { createEventHandler } from "./events";
 import type { VNode } from "./index";
 import { VMulti } from "./multi";
 import { toText } from "./text";
 const getDescriptor = (o: any, p: any) => Object.getOwnPropertyDescriptor(o, p)!;
 const nodeProto = Node.prototype;
 const elementProto = Element.prototype;
 const characterDataProto = CharacterData.prototype;
 const characterDataSetData = getDescriptor(characterDataProto, "data").set!;
 const nodeGetFirstChild = getDescriptor(nodeProto, "firstChild").get!;
 const nodeGetNextSibling = getDescriptor(nodeProto, "nextSibling").get!;
 const NO_OP = () => {};
 // -----------------------------------------------------------------------------
 // Main compiler code
 // -----------------------------------------------------------------------------
 type BlockType = (data?: any[], children?: VNode[]) => VNode;
 const cache: { [key: string]: BlockType } = {};
 /**
 * Compiling blocks is a multi-step process:
 *
 * 1. build an IntermediateTree from the HTML element. This intermediate tree
 *    is a binary tree structure that encode dynamic info sub nodes, and the
 *    path required to reach them
 * 2. process the tree to build a block context, which is an object that aggregate
 *    all dynamic info in a list, and also, all ref indexes.
 * 3. process the context to build appropriate builder/setter functions
 * 4. make a dynamic block class, which will efficiently collect references and
 *    create/update dynamic locations/children
 *
 * @param str
 * @returns a new block type, that can build concrete blocks
 */
 export function createBlock(str: string, deepRemove: boolean = false): BlockType {
  if (str in cache) {
    return cache[str];
  }
  // step 0: prepare html base element
  const doc = new DOMParser().parseFromString(`<t>${str}</t>`, "text/xml");
  const node = doc.firstChild!.firstChild!;
  if (config.shouldNormalizeDom) {
    normalizeNode(node as any);
  }
  // step 1: prepare intermediate tree
  const tree = buildTree(node);
  // step 2: prepare block context
  const context = buildContext(tree);
  // step 3: build the final block class
  const template = tree.el as HTMLElement;
  const Block = buildBlock(template, context, deepRemove);
  cache[str] = Block;
  return Block;
 }
 // -----------------------------------------------------------------------------
 // Helper
 // -----------------------------------------------------------------------------
 function normalizeNode(node: HTMLElement | Text) {
  if (node.nodeType === Node.TEXT_NODE) {
    if (!/\S/.test((node as Text).textContent!)) {
      (node as Text).remove();
      return;
    }
  }
  if (node.nodeType === Node.ELEMENT_NODE) {
    if ((node as HTMLElement).tagName === "pre") {
      return;
    }
  }
  for (let i = node.childNodes.length - 1; i >= 0; --i) {
    normalizeNode(node.childNodes.item(i) as any);
  }
 }
 // -----------------------------------------------------------------------------
 // building a intermediate tree
 // -----------------------------------------------------------------------------
 interface DynamicInfo {
  idx: number;
  refIdx?: number;
  type: "text" | "child" | "handler" | "attribute" | "attributes" | "ref";
  isOnlyChild?: boolean;
  name?: string;
  tag?: string;
  event?: string;
 }
 interface IntermediateTree {
  parent: IntermediateTree | null;
  firstChild: IntermediateTree | null;
  nextSibling: IntermediateTree | null;
  el: Node;
  info: DynamicInfo[];
  isRef?: boolean;
  refIdx?: number;
  refN: number;
  currentNS: string | null;
 }
 function buildTree(
  node: Node,
  parent: IntermediateTree | null = null,
  domParentTree: IntermediateTree | null = null
 ): IntermediateTree {
  switch (node.nodeType) {
    case Node.ELEMENT_NODE: {
      // HTMLElement
      let currentNS = domParentTree && domParentTree.currentNS;
      const tagName = (node as Element).tagName;
      let el: Node | undefined = undefined;
      const info: DynamicInfo[] = [];
      if (tagName.startsWith("block-text-")) {
        const index = parseInt(tagName.slice(11), 10);
        info.push({ type: "text", idx: index });
        el = document.createTextNode("");
      }
      if (tagName.startsWith("block-child-")) {
        if (!domParentTree!.isRef) {
          addRef(domParentTree!);
        }
        const index = parseInt(tagName.slice(12), 10);
        info.push({ type: "child", idx: index });
        el = document.createTextNode("");
      }
      const attrs = (node as Element).attributes;
      const ns = attrs.getNamedItem("block-ns");
      if (ns) {
        attrs.removeNamedItem("block-ns");
        currentNS = ns.value;
      }
      if (!el) {
        el = currentNS
          ? document.createElementNS(currentNS, tagName)
          : document.createElement(tagName);
      }
      if (el instanceof Element) {
        for (let i = 0; i < attrs.length; i++) {
          const attrName = attrs[i].name;
          const attrValue = attrs[i].value;
          if (attrName.startsWith("block-handler-")) {
            const idx = parseInt(attrName.slice(14), 10);
            info.push({
              type: "handler",
              idx,
              event: attrValue,
            });
          } else if (attrName.startsWith("block-attribute-")) {
            const idx = parseInt(attrName.slice(16), 10);
            info.push({
              type: "attribute",
              idx,
              name: attrValue,
              tag: tagName,
            });
          } else if (attrName === "block-attributes") {
            info.push({
              type: "attributes",
              idx: parseInt(attrValue, 10),
            });
          } else if (attrName === "block-ref") {
            info.push({
              type: "ref",
              idx: parseInt(attrValue, 10),
            });
          } else {
            el.setAttribute(attrs[i].name, attrValue);
          }
        }
      }
      const tree: IntermediateTree = {
        parent,
        firstChild: null,
        nextSibling: null,
        el,
        info,
        refN: 0,
        currentNS,
      };
      if (node.firstChild) {
        const childNode = node.childNodes[0];
        if (
          node.childNodes.length === 1 &&
          childNode.nodeType === Node.ELEMENT_NODE &&
          (childNode as Element).tagName.startsWith("block-child-")
        ) {
          const tagName = (childNode as Element).tagName;
          const index = parseInt(tagName.slice(12), 10);
          info.push({ idx: index, type: "child", isOnlyChild: true });
        } else {
          tree.firstChild = buildTree(node.firstChild, tree, tree);
          el.appendChild(tree.firstChild.el);
          let curNode: Node | null = node.firstChild;
          let curTree: IntermediateTree | null = tree.firstChild;
          while ((curNode = curNode.nextSibling)) {
            curTree.nextSibling = buildTree(curNode, curTree, tree);
            el.appendChild(curTree.nextSibling.el);
            curTree = curTree.nextSibling;
          }
        }
      }
      if (tree.info.length) {
        addRef(tree);
      }
      return tree;
    }
    case Node.TEXT_NODE:
    case Node.COMMENT_NODE: {
      // text node or comment node
      const el =
        node.nodeType === Node.TEXT_NODE
          ? document.createTextNode(node.textContent!)
          : document.createComment(node.textContent!);
      return {
        parent: parent,
        firstChild: null,
        nextSibling: null,
        el,
        info: [],
        refN: 0,
        currentNS: null,
      };
    }
  }
  throw new Error("boom");
 }
 function addRef(tree: IntermediateTree) {
  tree.isRef = true;
  do {
    tree.refN++;
  } while ((tree = tree.parent as any));
 }
 function parentTree(tree: IntermediateTree): IntermediateTree | null {
  let parent = tree.parent;
  while (parent && parent.nextSibling === tree) {
    tree = parent;
    parent = parent.parent;
  }
  return parent;
 }
 // -----------------------------------------------------------------------------
 // Building a block context
 // -----------------------------------------------------------------------------
 interface RefCollector {
  idx: number;
  prevIdx: number;
  getVal: Function;
 }
 export type Setter<T = any> = (this: T, value: any) => void;
 export type Updater<T = any> = (this: T, value: any, oldVal: any) => void;
 interface Location {
  refIdx: number;
  setData: Setter;
  updateData: Updater;
 }
 interface IndexedLocation extends Location {
  idx: number;
 }
 interface Child {
  parentRefIdx: number;
  afterRefIdx?: number;
  isOnlyChild?: boolean;
 }
 interface BlockCtx {
  refN: number;
  collectors: RefCollector[];
  locations: IndexedLocation[];
  children: Child[];
  cbRefs: number[];
 }
 function buildContext(tree: IntermediateTree, ctx?: BlockCtx, fromIdx?: number): BlockCtx {
  if (!ctx) {
    const children = new Array(tree.info.filter((v) => v.type === "child").length);
    ctx = { collectors: [], locations: [], children, cbRefs: [], refN: tree.refN };
    fromIdx = 0;
  }
  if (tree.refN) {
    const initialIdx = fromIdx!;
    const isRef = tree.isRef;
    const firstChild = tree.firstChild ? tree.firstChild.refN : 0;
    const nextSibling = tree.nextSibling ? tree.nextSibling.refN : 0;
    //node
    if (isRef) {
      for (let info of tree.info) {
        info.refIdx = initialIdx!;
      }
      tree.refIdx = initialIdx!;
      updateCtx(ctx, tree);
      fromIdx!++;
    }
    // right
    if (nextSibling) {
      const idx = fromIdx! + firstChild;
      ctx.collectors.push({ idx, prevIdx: initialIdx, getVal: nodeGetNextSibling });
      buildContext(tree.nextSibling!, ctx, idx);
    }
    // left
    if (firstChild) {
      ctx.collectors.push({ idx: fromIdx!, prevIdx: initialIdx, getVal: nodeGetFirstChild });
      buildContext(tree.firstChild!, ctx, fromIdx!);
    }
  }
  return ctx;
 }
 function updateCtx(ctx: BlockCtx, tree: IntermediateTree) {
  for (let info of tree.info) {
    switch (info.type) {
      case "text":
        ctx.locations.push({
          idx: info.idx,
          refIdx: info.refIdx!,
          setData: setText,
          updateData: setText,
        });
        break;
      case "child":
        if (info.isOnlyChild) {
          // tree is the parentnode here
          ctx.children[info.idx] = {
            parentRefIdx: info.refIdx!,
            isOnlyChild: true,
          };
        } else {
          // tree is the anchor text node
          ctx.children[info.idx] = {
            parentRefIdx: parentTree(tree)!.refIdx!,
            afterRefIdx: info.refIdx!,
          };
        }
        break;
      case "attribute": {
        const refIdx = info.refIdx!;
        let updater: any;
        let setter: any;
        if (isProp(info.tag!, info.name!)) {
          const setProp = makePropSetter(info.name!);
          setter = setProp;
          updater = setProp;
        } else if (info.name === "class") {
          setter = setClass;
          updater = updateClass;
        } else {
          setter = createAttrUpdater(info.name!);
          updater = setter;
        }
        ctx.locations.push({
          idx: info.idx,
          refIdx,
          setData: setter,
          updateData: updater,
        });
        break;
      }
      case "attributes":
        ctx.locations.push({
          idx: info.idx,
          refIdx: info.refIdx!,
          setData: attrsSetter,
          updateData: attrsUpdater,
        });
        break;
      case "handler": {
        const { setup, update } = createEventHandler(info.event!);
        ctx.locations.push({
          idx: info.idx,
          refIdx: info.refIdx!,
          setData: setup,
          updateData: update,
        });
        break;
      }
      case "ref":
        ctx.cbRefs.push(info.idx);
        ctx.locations.push({
          idx: info.idx,
          refIdx: info.refIdx!,
          setData: setRef,
          updateData: NO_OP,
        });
    }
  }
 }
 // -----------------------------------------------------------------------------
 // building the concrete block class
 // -----------------------------------------------------------------------------
 function buildBlock(template: HTMLElement, ctx: BlockCtx, deepRemove: boolean): BlockType {
  let B = createBlockClass(template, ctx);
  if (ctx.cbRefs.length) {
    const refs = ctx.cbRefs;
    B = class extends B {
      remove() {
        super.remove();
        for (let ref of refs) {
          let fn = (this as any).data[ref];
          fn(null);
        }
      }
    };
  }
  if (ctx.children.length) {
    B = class extends B {
      children: (VNode | undefined)[] | undefined;
      constructor(data?: any[], children?: VNode[]) {
        super(data);
        this.children = children;
      }
    };
    B.prototype.beforeRemove = VMulti.prototype.beforeRemove;
    if (deepRemove) {
      const blockRemove = B.prototype.remove;
      const vMultiRemove = VMulti.prototype.remove;
      B.prototype.remove = function () {
        blockRemove.call(this);
        vMultiRemove.call(this);
      };
    }
    return (data?: any[], children: (VNode | undefined)[] = []) => new B(data, children);
  }
  return (data?: any[]) => new B(data);
 }
 type Constructor<T> = new (...args: any[]) => T;
 type BlockClass = Constructor<VNode<any>>;
 function createBlockClass(template: HTMLElement, ctx: BlockCtx): BlockClass {
  const { refN, collectors, children } = ctx;
  const colN = collectors.length;
  ctx.locations.sort((a, b) => a.idx - b.idx);
  const locations: Location[] = ctx.locations.map((loc) => ({
    refIdx: loc.refIdx,
    setData: loc.setData,
    updateData: loc.updateData,
  }));
  const locN = locations.length;
  const childN = children.length;
  const childrenLocs = children;
  const isDynamic = refN > 0;
  // these values are defined here to make them faster to lookup in the class
  // block scope
  const nodeCloneNode = nodeProto.cloneNode;
  const nodeInsertBefore = nodeProto.insertBefore;
  const elementRemove = elementProto.remove;
  return class Block {
    el: HTMLElement | undefined;
    refs: Node[] | undefined;
    data: any[] | undefined;
    parentEl?: HTMLElement | undefined;
    children?: (VNode | undefined)[];
    constructor(data?: any[]) {
      this.data = data;
    }
    beforeRemove() {}
    remove() {
      console.log('ddd')
      elementRemove.call(this.el);
    }
    firstNode(): Node {
      return this.el!;
    }
    moveBefore(other: Block | null, afterNode: Node | null) {
      const target = other ? other.el! : afterNode;
      nodeInsertBefore.call(this.parentEl, this.el!, target);
    }
    mount(parent: HTMLElement, afterNode: Node | null) {
      const el = nodeCloneNode.call(template, true);
      nodeInsertBefore.call(parent, el, afterNode);
      if (isDynamic) {
        // collecting references
        const refs: Node[] = new Array(refN);
        this.refs = refs;
        refs[0] = el;
        for (let i = 0; i < colN; i++) {
          const w = collectors[i];
          refs[w.idx] = w.getVal.call(refs[w.prevIdx]);
        }
        // applying data to all update points
        if (locN) {
          const data = this.data!;
          for (let i = 0; i < locN; i++) {
            const loc = locations[i];
            loc.setData.call(refs[loc.refIdx], data[i]);
          }
        }
        // preparing all children
        if (childN) {
          const children = this.children;
          for (let i = 0; i < childN; i++) {
            const child = children![i];
            if (child) {
              const loc = childrenLocs[i];
              const afterNode = loc.afterRefIdx ? refs[loc.afterRefIdx] : null;
              child.isOnlyChild = loc.isOnlyChild;
              child.mount(refs[loc.parentRefIdx] as any, afterNode);
            }
          }
        }
      }
      this.el = el as HTMLElement;
      this.parentEl = parent;
    }
    patch(other: Block, withBeforeRemove: boolean) {
      if (this === other) {
        return;
      }
      const refs = this.refs!;
      // update texts/attributes/
      if (locN) {
        const data1 = this.data!;
        const data2 = other.data!;
        for (let i = 0; i < locN; i++) {
          const val1 = data1[i];
          const val2 = data2[i];
          if (val1 !== val2) {
            const loc = locations[i];
            loc.updateData.call(refs[loc.refIdx], val2, val1);
          }
        }
        this.data = data2;
      }
      // update children
      if (childN) {
        let children1 = this.children;
        const children2 = other.children;
        for (let i = 0; i < childN; i++) {
          const child1 = children1![i];
          const child2 = children2![i];
          if (child1) {
            if (child2) {
              child1.patch(child2, withBeforeRemove);
            } else {
              if (withBeforeRemove) {
                child1.beforeRemove();
              }
              child1.remove();
              children1![i] = undefined;
            }
          } else if (child2) {
            const loc = childrenLocs[i];
            const afterNode = loc.afterRefIdx ? refs[loc.afterRefIdx] : null;
            child2.mount(refs[loc.parentRefIdx] as any, afterNode);
            children1![i] = child2;
          }
        }
      }
    }
    toString() {
      const div = document.createElement("div");
      this.mount(div, null);
      return div.innerHTML;
    }
  };
 }
 function setText(this: Text, value: any) {
  characterDataSetData.call(this, toText(value));
 }
 function setRef(this: HTMLElement, fn: any) {
  fn(this);
 }
@@ -0,0 +1,28 @@
 export function filterOutModifiersFromData(dataList: any[]): { modifiers: string[]; data: any[] } {
  dataList = dataList.slice();
  const modifiers = [];
  let elm;
  while ((elm = dataList[0]) && typeof elm === "string") {
    modifiers.push(dataList.shift());
  }
  return { modifiers, data: dataList };
 }
 export const config = {
  // whether or not blockdom should normalize DOM whenever a block is created.
  // Normalizing dom mean removing empty text nodes (or containing only spaces)
  shouldNormalizeDom: true,
  // this is the main event handler. Every event handler registered with blockdom
  // will go through this function, giving it the data registered in the block
  // and the event
  mainEventHandler: (data: any, ev: Event, currentTarget?: EventTarget | null): boolean => {
    if (typeof data === "function") {
      data(ev);
    } else if (Array.isArray(data)) {
      data = filterOutModifiersFromData(data).data;
      data[0](data[1], ev);
    }
    return false;
  },
 };
@@ -0,0 +1,90 @@
 import { config } from "./config";
 type EventHandlerSetter = (this: HTMLElement, data: any) => void;
 interface EventHandlerCreator {
  setup: EventHandlerSetter;
  update: EventHandlerSetter;
 }
 export function createEventHandler(rawEvent: string): EventHandlerCreator {
  const eventName = rawEvent.split(".")[0];
  const capture = rawEvent.includes(".capture");
  if (rawEvent.includes(".synthetic")) {
    return createSyntheticHandler(eventName, capture);
  } else {
    return createElementHandler(eventName, capture);
  }
 }
 // Native listener
 let nextNativeEventId = 1;
 function createElementHandler(evName: string, capture: boolean = false): EventHandlerCreator {
  let eventKey = `__event__${evName}_${nextNativeEventId++}`;
  if (capture) {
    eventKey = `${eventKey}_capture`;
  }
  function listener(ev: Event) {
    const currentTarget = ev.currentTarget;
    if (!currentTarget || !document.contains(currentTarget as HTMLElement)) return;
    const data = (currentTarget as any)[eventKey];
    if (!data) return;
    config.mainEventHandler(data, ev, currentTarget);
  }
  function setup(this: HTMLElement, data: any) {
    (this as any)[eventKey] = data;
    this.addEventListener(evName, listener, { capture });
  }
  function update(this: HTMLElement, data: any) {
    (this as any)[eventKey] = data;
  }
  return { setup, update };
 }
 // Synthetic handler: a form of event delegation that allows placing only one
 // listener per event type.
 let nextSyntheticEventId = 1;
 function createSyntheticHandler(evName: string, capture: boolean = false): EventHandlerCreator {
  let eventKey = `__event__synthetic_${evName}`;
  if (capture) {
    eventKey = `${eventKey}_capture`;
  }
  setupSyntheticEvent(evName, eventKey, capture);
  const currentId = nextSyntheticEventId++;
  function setup(this: HTMLElement, data: any) {
    const _data = (this as any)[eventKey] || {};
    _data[currentId] = data;
    (this as any)[eventKey] = _data;
  }
  return { setup, update: setup };
 }
 function nativeToSyntheticEvent(eventKey: string, event: Event) {
  let dom = event.target;
  while (dom !== null) {
    const _data = (dom as any)[eventKey];
    if (_data) {
      for (const data of Object.values(_data)) {
        const stopped = config.mainEventHandler(data, event, dom);
        if (stopped) return;
      }
    }
    dom = (dom as any).parentNode;
  }
 }
 const CONFIGURED_SYNTHETIC_EVENTS: { [event: string]: boolean } = {};
 function setupSyntheticEvent(evName: string, eventKey: string, capture: boolean = false) {
  if (CONFIGURED_SYNTHETIC_EVENTS[eventKey]) {
    return;
  }
  document.addEventListener(evName, (event) => nativeToSyntheticEvent(eventKey, event), {
    capture,
  });
  CONFIGURED_SYNTHETIC_EVENTS[eventKey] = true;
 }
@@ -0,0 +1,87 @@
 import type { VNode } from "./index";
 const nodeProto = Node.prototype;
 const nodeInsertBefore = nodeProto.insertBefore;
 const nodeRemoveChild = nodeProto.removeChild;
 class VHtml {
  html: string;
  parentEl?: HTMLElement | undefined;
  content: ChildNode[] = [];
  constructor(html: string) {
    this.html = html;
  }
  mount(parent: HTMLElement, afterNode: Node | null) {
    this.parentEl = parent;
    const template = document.createElement("template");
    template.innerHTML = this.html;
    this.content = [...(template.content.childNodes as any)];
    for (let elem of this.content) {
      nodeInsertBefore.call(parent, elem, afterNode);
    }
    if (!this.content.length) {
      const textNode = document.createTextNode("");
      this.content.push(textNode);
      nodeInsertBefore.call(parent, textNode, afterNode);
    }
  }
  moveBefore(other: VHtml | null, afterNode: Node | null) {
    const target = other ? other.content[0] : afterNode;
    const parent = this.parentEl;
    for (let elem of this.content) {
      nodeInsertBefore.call(parent, elem, target);
    }
  }
  patch(other: VHtml) {
    if (this === other) {
      return;
    }
    const html2 = other.html;
    if (this.html !== html2) {
      const parent = this.parentEl;
      // insert new html in front of current
      const afterNode = this.content[0];
      const template = document.createElement("template");
      template.innerHTML = html2;
      const content = [...(template.content.childNodes as any)];
      for (let elem of content) {
        nodeInsertBefore.call(parent, elem, afterNode);
      }
      if (!content.length) {
        const textNode = document.createTextNode("");
        content.push(textNode);
        nodeInsertBefore.call(parent, textNode, afterNode);
      }
      // remove current content
      this.remove();
      this.content = content;
    }
  }
  beforeRemove() {}
  remove() {
    const parent = this.parentEl;
    for (let elem of this.content) {
      nodeRemoveChild.call(parent, elem);
    }
  }
  firstNode(): Node {
    return this.content[0]!;
  }
  toString() {
    return this.html;
  }
 }
 export function html(str: string): VNode<VHtml> {
  return new VHtml(str);
 }
@@ -0,0 +1,44 @@
 export { config } from "./config";
 export { toggler } from "./toggler";
 export { createBlock } from "./block_compiler";
 export { list } from "./list";
 export { multi } from "./multi";
 export { text, comment } from "./text";
 export { html } from "./html";
 export interface VNode<T = any> {
  mount(parent: HTMLElement, afterNode: Node | null): void;
  moveBefore(other: T | null, afterNode: Node | null): void;
  patch(other: T, withBeforeRemove: boolean): void;
  beforeRemove(): void;
  remove(): void;
  firstNode(): Node | undefined;
  el?: undefined | HTMLElement | Text;
  parentEl?: undefined | HTMLElement;
  isOnlyChild?: boolean | undefined;
  key?: any;
 }
 export type BDom = VNode<any>;
 export function mount(vnode: VNode, fixture: HTMLElement, afterNode: Node | null = null) {
  vnode.mount(fixture, afterNode);
 }
 export function patch(vnode1: VNode, vnode2: VNode, withBeforeRemove: boolean = false) {
  vnode1.patch(vnode2, withBeforeRemove);
 }
 export function remove(vnode: VNode, withBeforeRemove: boolean = false) {
  if (withBeforeRemove) {
    vnode.beforeRemove();
  }
  vnode.remove();
 }
 export function withKey(vnode: VNode, key: any) {
  vnode.key = key;
  return vnode;
 }
@@ -0,0 +1,241 @@
 import type { VNode } from "./index";
 const getDescriptor = (o: any, p: any) => Object.getOwnPropertyDescriptor(o, p)!;
 const nodeProto = Node.prototype;
 const nodeInsertBefore = nodeProto.insertBefore;
 const nodeAppendChild = nodeProto.appendChild;
 const nodeRemoveChild = nodeProto.removeChild;
 const nodeSetTextContent = getDescriptor(nodeProto, "textContent").set!;
 // -----------------------------------------------------------------------------
 // List Node
 // -----------------------------------------------------------------------------
 class VList {
  children: VNode[];
  anchor: Node | undefined;
  parentEl?: HTMLElement | undefined;
  isOnlyChild?: boolean | undefined;
  deepRemove: boolean;
  constructor(children: VNode[], deepRemove: boolean) {
    this.children = children;
    this.deepRemove = deepRemove;
  }
  mount(parent: HTMLElement, afterNode: Node | null) {
    const children = this.children;
    const _anchor = document.createTextNode("");
    this.anchor = _anchor;
    nodeInsertBefore.call(parent, _anchor, afterNode);
    const l = children.length;
    if (l) {
      const mount = children[0].mount;
      for (let i = 0; i < l; i++) {
        mount.call(children[i], parent, _anchor);
      }
    }
    this.parentEl = parent;
  }
  moveBefore(other: VList | null, afterNode: Node | null) {
    if (other) {
      const next = other!.children[0];
      afterNode = (next ? next.firstNode() : other!.anchor) || null;
    }
    const children = this.children;
    for (let i = 0, l = children.length; i < l; i++) {
      children[i].moveBefore(null, afterNode);
    }
    this.parentEl!.insertBefore(this.anchor!, afterNode);
  }
  patch(other: VList, withBeforeRemove: boolean) {
    if (this === other) {
      return;
    }
    const ch1 = this.children;
    const ch2: VNode[] = other.children;
    if (ch2.length === 0 && ch1.length === 0) {
      return;
    }
    this.children = ch2;
    const proto = ch2[0] || ch1[0];
    const {
      mount: cMount,
      patch: cPatch,
      remove: cRemove,
      beforeRemove,
      moveBefore: cMoveBefore,
      firstNode: cFirstNode,
    } = proto;
    const _anchor = this.anchor!;
    const isOnlyChild = this.isOnlyChild;
    const parent = this.parentEl!;
    // fast path: no new child => only remove
    if (ch2.length === 0 && isOnlyChild && !this.deepRemove) {
      if (withBeforeRemove) {
        for (let i = 0, l = ch1.length; i < l; i++) {
          beforeRemove.call(ch1[i]);
        }
      }
      nodeSetTextContent.call(parent, "");
      nodeAppendChild.call(parent, _anchor);
      return;
    }
    let startIdx1 = 0;
    let startIdx2 = 0;
    let startVn1 = ch1[0];
    let startVn2 = ch2[0];
    let endIdx1 = ch1.length - 1;
    let endIdx2 = ch2.length - 1;
    let endVn1 = ch1[endIdx1];
    let endVn2 = ch2[endIdx2];
    let mapping: any = undefined;
    while (startIdx1 <= endIdx1 && startIdx2 <= endIdx2) {
      // -------------------------------------------------------------------
      if (startVn1 === null) {
        startVn1 = ch1[++startIdx1];
        continue;
      }
      // -------------------------------------------------------------------
      if (endVn1 === null) {
        endVn1 = ch1[--endIdx1];
        continue;
      }
      // -------------------------------------------------------------------
      let startKey1 = startVn1.key;
      let startKey2 = startVn2.key;
      if (startKey1 === startKey2) {
        cPatch.call(startVn1, startVn2, withBeforeRemove);
        ch2[startIdx2] = startVn1;
        startVn1 = ch1[++startIdx1];
        startVn2 = ch2[++startIdx2];
        continue;
      }
      // -------------------------------------------------------------------
      let endKey1 = endVn1.key;
      let endKey2 = endVn2.key;
      if (endKey1 === endKey2) {
        cPatch.call(endVn1, endVn2, withBeforeRemove);
        ch2[endIdx2] = endVn1;
        endVn1 = ch1[--endIdx1];
        endVn2 = ch2[--endIdx2];
        continue;
      }
      // -------------------------------------------------------------------
      if (startKey1 === endKey2) {
        // bnode moved right
        cPatch.call(startVn1, endVn2, withBeforeRemove);
        ch2[endIdx2] = startVn1;
        const nextChild = ch2[endIdx2 + 1];
        cMoveBefore.call(startVn1, nextChild, _anchor);
        startVn1 = ch1[++startIdx1];
        endVn2 = ch2[--endIdx2];
        continue;
      }
      // -------------------------------------------------------------------
      if (endKey1 === startKey2) {
        // bnode moved left
        cPatch.call(endVn1, startVn2, withBeforeRemove);
        ch2[startIdx2] = endVn1;
        const nextChild = ch1[startIdx1];
        cMoveBefore.call(endVn1, nextChild, _anchor);
        endVn1 = ch1[--endIdx1];
        startVn2 = ch2[++startIdx2];
        continue;
      }
      // -------------------------------------------------------------------
      mapping = mapping || createMapping(ch1, startIdx1, endIdx1);
      let idxInOld = mapping[startKey2];
      if (idxInOld === undefined) {
        cMount.call(startVn2, parent, cFirstNode.call(startVn1) || null);
      } else {
        const elmToMove = ch1[idxInOld];
        cMoveBefore.call(elmToMove, startVn1, null);
        cPatch.call(elmToMove, startVn2, withBeforeRemove);
        ch2[startIdx2] = elmToMove;
        ch1[idxInOld] = null as any;
      }
      startVn2 = ch2[++startIdx2];
    }
    // ---------------------------------------------------------------------
    if (startIdx1 <= endIdx1 || startIdx2 <= endIdx2) {
      if (startIdx1 > endIdx1) {
        const nextChild = ch2[endIdx2 + 1];
        const anchor = nextChild ? cFirstNode.call(nextChild) || null : _anchor;
        for (let i = startIdx2; i <= endIdx2; i++) {
          cMount.call(ch2[i], parent, anchor);
        }
      } else {
        for (let i = startIdx1; i <= endIdx1; i++) {
          let ch = ch1[i];
          if (ch) {
            if (withBeforeRemove) {
              beforeRemove.call(ch);
            }
            cRemove.call(ch);
          }
        }
      }
    }
  }
  beforeRemove() {
    const children = this.children;
    const l = children.length;
    if (l) {
      const beforeRemove = children[0].beforeRemove;
      for (let i = 0; i < l; i++) {
        beforeRemove.call(children[i]);
      }
    }
  }
  remove() {
    const { parentEl, anchor } = this;
    if (this.isOnlyChild && !this.deepRemove) {
      nodeSetTextContent.call(parentEl, "");
    } else {
      const children = this.children;
      const l = children.length;
      if (l) {
        const remove = children[0].remove;
        for (let i = 0; i < l; i++) {
          remove.call(children[i]);
        }
      }
      nodeRemoveChild.call(parentEl, anchor!);
    }
  }
  firstNode(): Node | undefined {
    const child = this.children[0];
    return child ? child.firstNode() : undefined;
  }
  toString(): string {
    return this.children.map((c) => c!.toString()).join("");
  }
 }
 export function list(children: VNode[], deepRemove = false): VNode<VList> {
  return new VList(children, deepRemove);
 }
 function createMapping(ch1: any[], startIdx1: number, endIdx2: number): { [key: string]: any } {
  let mapping: any = {};
  for (let i = startIdx1; i <= endIdx2; i++) {
    mapping[ch1[i].key] = i;
  }
  return mapping;
 }
@@ -0,0 +1,136 @@
 import type { VNode } from "./index";
 const getDescriptor = (o: any, p: any) => Object.getOwnPropertyDescriptor(o, p)!;
 const nodeProto = Node.prototype;
 const nodeInsertBefore = nodeProto.insertBefore;
 const nodeSetTextContent = getDescriptor(nodeProto, "textContent").set!;
 const nodeRemoveChild = nodeProto.removeChild;
 // -----------------------------------------------------------------------------
 // Multi NODE
 // -----------------------------------------------------------------------------
 export class VMulti {
  children: (VNode | undefined)[];
  anchors?: Node[] | undefined;
  parentEl?: HTMLElement | undefined;
  isOnlyChild?: boolean | undefined;
  deepRemove: boolean;
  constructor(children: (VNode | undefined)[], deepRemove: boolean) {
    this.children = children;
    this.deepRemove = deepRemove;
  }
  mount(parent: HTMLElement, afterNode: Node | null) {
    const children = this.children;
    const l = children.length;
    const anchors = new Array(l);
    for (let i = 0; i < l; i++) {
      let child = children[i];
      if (child) {
        child.mount(parent, afterNode);
      } else {
        const childAnchor = document.createTextNode("");
        anchors[i] = childAnchor;
        nodeInsertBefore.call(parent, childAnchor, afterNode);
      }
    }
    this.anchors = anchors;
    this.parentEl = parent;
  }
  moveBefore(other: VMulti | null, afterNode: Node | null) {
    if (other) {
      const next = other!.children[0];
      afterNode = (next ? next.firstNode() : other!.anchors![0]) || null;
    }
    const children = this.children;
    const parent = this.parentEl;
    const anchors = this.anchors;
    for (let i = 0, l = children.length; i < l; i++) {
      let child = children[i];
      if (child) {
        child.moveBefore(null, afterNode);
      } else {
        const anchor = anchors![i];
        nodeInsertBefore.call(parent, anchor, afterNode);
      }
    }
  }
  patch(other: VMulti, withBeforeRemove: boolean) {
    if (this === other) {
      return;
    }
    const children1 = this.children;
    const children2 = other.children;
    const anchors = this.anchors!;
    const parentEl = this.parentEl!;
    for (let i = 0, l = children1.length; i < l; i++) {
      const vn1 = children1[i];
      const vn2 = children2[i];
      if (vn1) {
        if (vn2) {
          vn1.patch(vn2, withBeforeRemove);
        } else {
          const afterNode = vn1.firstNode()!;
          const anchor = document.createTextNode("");
          anchors[i] = anchor;
          nodeInsertBefore.call(parentEl, anchor, afterNode);
          if (withBeforeRemove) {
            vn1.beforeRemove();
          }
          vn1.remove();
          children1[i] = undefined;
        }
      } else if (vn2) {
        children1[i] = vn2;
        const anchor = anchors[i];
        vn2.mount(parentEl, anchor);
        nodeRemoveChild.call(parentEl, anchor);
      }
    }
  }
  beforeRemove() {
    const children = this.children;
    for (let i = 0, l = children.length; i < l; i++) {
      const child = children[i];
      if (child) {
        child.beforeRemove();
      }
    }
  }
  remove() {
    const parentEl = this.parentEl;
    if (this.isOnlyChild && !this.deepRemove) {
      nodeSetTextContent.call(parentEl, "");
    } else {
      const children = this.children;
      const anchors = this.anchors;
      for (let i = 0, l = children.length; i < l; i++) {
        const child = children[i];
        if (child) {
          child.remove();
        } else {
          nodeRemoveChild.call(parentEl, anchors![i]);
        }
      }
    }
  }
  firstNode(): Node | undefined {
    const child = this.children[0];
    return child ? child.firstNode() : this.anchors![0];
  }
  toString(): string {
    return this.children.map((c) => c!.toString()).join("");
  }
 }
 export function multi(children: (VNode | undefined)[], deepRemove = false): VNode<VMulti> {
  return new VMulti(children, deepRemove);
 }
@@ -0,0 +1,87 @@
 import type { VNode } from "./index";
 const getDescriptor = (o: any, p: any) => Object.getOwnPropertyDescriptor(o, p)!;
 const nodeProto = Node.prototype;
 const characterDataProto = CharacterData.prototype;
 const nodeInsertBefore = nodeProto.insertBefore;
 const characterDataSetData = getDescriptor(characterDataProto, "data").set!;
 const nodeRemoveChild = nodeProto.removeChild;
 abstract class VSimpleNode {
  text: string;
  parentEl?: HTMLElement | undefined;
  el?: any;
  constructor(text: string) {
    this.text = text;
  }
  mountNode(node: Node, parent: HTMLElement, afterNode: Node | null) {
    this.parentEl = parent;
    nodeInsertBefore.call(parent, node, afterNode);
    this.el = node;
  }
  moveBefore(other: VText | null, afterNode: Node | null) {
    const target = other ? other.el! : afterNode;
    nodeInsertBefore.call(this.parentEl, this.el!, target);
  }
  beforeRemove() {}
  remove() {
    nodeRemoveChild.call(this.parentEl, this.el!);
  }
  firstNode(): Node {
    return this.el!;
  }
  toString() {
    return this.text;
  }
 }
 class VText extends VSimpleNode {
  mount(parent: HTMLElement, afterNode: Node | null) {
    this.mountNode(document.createTextNode(toText(this.text)), parent, afterNode);
  }
  patch(other: VText) {
    const text2 = other.text;
    if (this.text !== text2) {
      characterDataSetData.call(this.el!, toText(text2));
      this.text = text2;
    }
  }
 }
 class VComment extends VSimpleNode {
  mount(parent: HTMLElement, afterNode: Node | null) {
    this.mountNode(document.createComment(toText(this.text)), parent, afterNode);
  }
  patch() {}
 }
 export function text(str: string): VNode<VText> {
  return new VText(str);
 }
 export function comment(str: string): VNode<VComment> {
  return new VComment(str);
 }
 export function toText(value: any): string {
  switch (typeof value) {
    case "string":
      return value;
    case "number":
      return String(value);
    case "boolean":
      return value ? "true" : "false";
    default:
      return value || "";
  }
 }
@@ -0,0 +1,65 @@
 import type { VNode } from "./index";
 // -----------------------------------------------------------------------------
 // Toggler node
 // -----------------------------------------------------------------------------
 class VToggler {
  key: string;
  child: VNode;
  parentEl?: HTMLElement | undefined;
  constructor(key: string, child: VNode) {
    this.key = key;
    this.child = child;
  }
  mount(parent: HTMLElement, afterNode: Node | null) {
    this.parentEl = parent;
    this.child.mount(parent, afterNode);
  }
  moveBefore(other: VToggler | null, afterNode: Node | null) {
    this.child.moveBefore(other ? other.child : null, afterNode);
  }
  patch(other: VToggler, withBeforeRemove: boolean) {
    if (this === other) {
      return;
    }
    let child1 = this.child;
    let child2 = other.child;
    if (this.key === other.key) {
      child1.patch(child2, withBeforeRemove);
    } else {
      child2.mount(this.parentEl!, child1.firstNode()!);
      if (withBeforeRemove) {
        child1.beforeRemove();
      }
      child1.remove();
      this.child = child2;
      this.key = other.key;
    }
  }
  beforeRemove() {
    this.child.beforeRemove();
  }
  remove() {
    this.child.remove();
  }
  firstNode(): Node | undefined {
    return this.child.firstNode();
  }
  toString(): string {
    return this.child.toString();
  }
 }
 export function toggler(key: string, child: VNode): VNode<VToggler> {
  return new VToggler(key, child);
 }
@@ -0,0 +1,27 @@
 import type { BDom } from "../blockdom";
 import { CodeGenerator, Config } from "./code_generator";
 import { parse } from "./parser";
 export type Template = (context: any, vnode: any, key?: string) => BDom;
 export type TemplateFunction = (blocks: any, utils: any) => Template;
 interface CompileOptions extends Config {
  name?: string;
 }
 export function compile(template: string | Node, options: CompileOptions = {}): TemplateFunction {
  // parsing
  const ast = parse(template);
  // some work
  const hasSafeContext =
    template instanceof Node
      ? !(template instanceof Element) || template.querySelector("[t-set], [t-call]") === null
      : !template.includes("t-set") && !template.includes("t-call");
  // code generation
  const codeGenerator = new CodeGenerator(ast, { ...options, hasSafeContext });
  const code = codeGenerator.generateCode();
  // template function
  return new Function("bdom, helpers", code) as TemplateFunction;
 }
@@ -25,30 +25,27 @@
 // Misc types, constants and helpers
 //------------------------------------------------------------------------------
-const RESERVED_WORDS = "true,false,NaN,null,undefined,debugger,console,window,in,instanceof,new,function,return,this,typeof,eval,void,Math,RegExp,Array,Object,Date".split(
+const RESERVED_WORDS =
-  ","
+  "true,false,NaN,null,undefined,debugger,console,window,in,instanceof,new,function,return,this,eval,void,Math,RegExp,Array,Object,Date".split(
-);
+    ","
  );
-const WORD_REPLACEMENT = {
+const WORD_REPLACEMENT: { [key: string]: string } = Object.assign(Object.create(null), {
  and: "&&",
  or: "||",
  gt: ">",
  gte: ">=",
  lt: "<",
-  lte: "<="
+  lte: "<=",
-};
+});
-export interface QWebExprVar {
+export interface QWebVar {
-  id: string;
+  id: string; // foo
-  expr: string;
+  expr: string; // scope.foo (local variables => only foo)
  value?: string; // 1 + 3
  hasBody?: boolean;
 }
 export interface QWebXMLVar {
  xml: NodeList;
 }
 export type QWebVar = QWebExprVar | QWebXMLVar;
 //------------------------------------------------------------------------------
 // Tokenizer
 //------------------------------------------------------------------------------
@@ -61,6 +58,7 @@ type TKind =
  | "RIGHT_PAREN"
  | "COMMA"
  | "VALUE"
  | "TEMPLATE_STRING"
  | "SYMBOL"
  | "OPERATOR"
  | "COLON";
@@ -68,10 +66,14 @@ type TKind =
 interface Token {
  type: TKind;
  value: string;
  originalValue?: string;
  size?: number;
  varName?: string;
  replace?: Function;
  isLocal?: boolean;
 }
-const STATIC_TOKEN_MAP: { [key: string]: TKind } = {
+const STATIC_TOKEN_MAP: { [key: string]: TKind } = Object.assign(Object.create(null), {
  "{": "LEFT_BRACE",
  "}": "RIGHT_BRACE",
  "[": "LEFT_BRACKET",
@@ -79,17 +81,19 @@ const STATIC_TOKEN_MAP: { [key: string]: TKind } = {
  ":": "COLON",
  ",": "COMMA",
  "(": "LEFT_PAREN",
-  ")": "RIGHT_PAREN"
+  ")": "RIGHT_PAREN",
-};
+});
-const OPERATORS = ".,===,==,+,!==,!=,!,||,&&,>=,>,<=,<,?,-,*,/,%".split(",");
+// note that the space after typeof is relevant. It makes sure that the formatted
 // expression has a space after typeof
 const OPERATORS = "...,.,===,==,+,!==,!=,!,||,&&,>=,>,<=,<,?,-,*,/,%,typeof ,=>,=,;,in ".split(",");
 type Tokenizer = (expr: string) => Token | false;
-let tokenizeString: Tokenizer = function(expr) {
+let tokenizeString: Tokenizer = function (expr) {
  let s = expr[0];
  let start = s;
-  if (s !== "'" && s !== '"') {
+  if (s !== "'" && s !== '"' && s !== "`") {
    return false;
  }
  let i = 1;
@@ -111,10 +115,21 @@ let tokenizeString: Tokenizer = function(expr) {
    throw new Error("Invalid expression");
  }
  s += start;
  if (start === "`") {
    return {
      type: "TEMPLATE_STRING",
      value: s,
      replace(replacer: any) {
        return s.replace(/\$\{(.*?)\}/g, (match, group) => {
          return "${" + replacer(group) + "}";
        });
      },
    };
  }
  return { type: "VALUE", value: s };
 };
-let tokenizeNumber: Tokenizer = function(expr) {
+let tokenizeNumber: Tokenizer = function (expr) {
  let s = expr[0];
  if (s && s.match(/[0-9]/)) {
    let i = 1;
@@ -128,7 +143,7 @@ let tokenizeNumber: Tokenizer = function(expr) {
  }
 };
-let tokenizeSymbol: Tokenizer = function(expr) {
+let tokenizeSymbol: Tokenizer = function (expr) {
  let s = expr[0];
  if (s && s.match(/[a-zA-Z_\$]/)) {
    let i = 1;
@@ -145,7 +160,7 @@ let tokenizeSymbol: Tokenizer = function(expr) {
  }
 };
-const tokenizeStatic: Tokenizer = function(expr) {
+const tokenizeStatic: Tokenizer = function (expr) {
  const char = expr[0];
  if (char && char in STATIC_TOKEN_MAP) {
    return { type: STATIC_TOKEN_MAP[char], value: char };
@@ -153,7 +168,7 @@ const tokenizeStatic: Tokenizer = function(expr) {
  return false;
 };
-const tokenizeOperator: Tokenizer = function(expr) {
+const tokenizeOperator: Tokenizer = function (expr) {
  for (let op of OPERATORS) {
    if (expr.startsWith(op)) {
      return { type: "OPERATOR", value: op };
@@ -165,9 +180,9 @@ const tokenizeOperator: Tokenizer = function(expr) {
 const TOKENIZERS = [
  tokenizeString,
  tokenizeNumber,
  tokenizeOperator,
  tokenizeSymbol,
  tokenizeStatic,
  tokenizeOperator
 ];
 /**
@@ -210,6 +225,11 @@ export function tokenize(expr: string): Token[] {
 // Expression "evaluator"
 //------------------------------------------------------------------------------
 const isLeftSeparator = (token: Token) =>
  token && (token.type === "LEFT_BRACE" || token.type === "COMMA");
 const isRightSeparator = (token: Token) =>
  token && (token.type === "RIGHT_BRACE" || token.type === "COMMA");
 /**
 * This is the main function exported by this file. This is the code that will
 * process an expression (given as a string) and returns another expression with
@@ -230,35 +250,107 @@ export function tokenize(expr: string): Token[] {
 * - unless the previous token is a dot (in that case, this is a property: `a.b`)
 * - or if the previous token is a left brace or a comma, and the next token is
 *   a colon (in that case, this is an object key: `{a: b}`)
 *
 * Some specific code is also required to support arrow functions. If we detect
 * the arrow operator, then we add the current (or some previous tokens) token to
 * the list of variables so it does not get replaced by a lookup in the context
 */
-export function compileExpr(expr: string, vars: { [key: string]: QWebVar }): string {
+export function compileExprToArray(expr: string): Token[] {
  const localVars = new Set<string>();
  const tokens = tokenize(expr);
-  let result = "";
+  let i = 0;
-  for (let i = 0; i < tokens.length; i++) {
+  let stack = []; // to track last opening [ or {
  while (i < tokens.length) {
    let token = tokens[i];
    let prevToken = tokens[i - 1];
    let nextToken = tokens[i + 1];
    let groupType = stack[stack.length - 1];
    switch (token.type) {
      case "LEFT_BRACE":
      case "LEFT_BRACKET":
        stack.push(token.type);
        break;
      case "RIGHT_BRACE":
      case "RIGHT_BRACKET":
        stack.pop();
    }
    let isVar = token.type === "SYMBOL" && !RESERVED_WORDS.includes(token.value);
    if (token.type === "SYMBOL" && !RESERVED_WORDS.includes(token.value)) {
      // we need to find if it is a variable
      let isVar = true;
      let prevToken = tokens[i - 1];
      if (prevToken) {
        // normalize missing tokens: {a} should be equivalent to {a:a}
        if (
          groupType === "LEFT_BRACE" &&
          isLeftSeparator(prevToken) &&
          isRightSeparator(nextToken)
        ) {
          tokens.splice(i + 1, 0, { type: "COLON", value: ":" }, { ...token });
          nextToken = tokens[i + 1];
        }
        if (prevToken.type === "OPERATOR" && prevToken.value === ".") {
          isVar = false;
        } else if (prevToken.type === "LEFT_BRACE" || prevToken.type === "COMMA") {
          let nextToken = tokens[i + 1];
          if (nextToken && nextToken.type === "COLON") {
            isVar = false;
          }
        }
      }
-      if (isVar) {
+    }
-        if (token.value in vars && "id" in vars[token.value]) {
+    if (token.type === "TEMPLATE_STRING") {
-          token.value = (<QWebExprVar>vars[token.value]).id;
+      token.value = token.replace!((expr: any) => compileExpr(expr));
-        } else {
+    }
-          token.value = `context['${token.value}']`;
+    if (nextToken && nextToken.type === "OPERATOR" && nextToken.value === "=>") {
      if (token.type === "RIGHT_PAREN") {
        let j = i - 1;
        while (j > 0 && tokens[j].type !== "LEFT_PAREN") {
          if (tokens[j].type === "SYMBOL" && tokens[j].originalValue) {
            tokens[j].value = tokens[j].originalValue!;
            localVars.add(tokens[j].value); //] = { id: tokens[j].value, expr: tokens[j].value };
          }
          j--;
        }
      } else {
        localVars.add(token.value); //] = { id: token.value, expr: token.value };
      }
    }
-    result += token.value;
+
    if (isVar) {
      token.varName = token.value;
      if (!localVars.has(token.value)) {
        token.originalValue = token.value;
        token.value = `ctx['${token.value}']`;
      }
    }
    i++;
  }
-  return result;
+  // Mark all variables that have been used locally.
  // This assumes the expression has only one scope (incorrect but "good enough for now")
  for (const token of tokens) {
    if (token.type === "SYMBOL" && localVars.has(token.value)) {
      token.isLocal = true;
    }
  }
  return tokens;
 }
 export function compileExpr(expr: string): string {
  return compileExprToArray(expr)
    .map((t) => t.value)
    .join("");
 }
 export const INTERP_REGEXP = /\{\{.*?\}\}/g;
 const INTERP_GROUP_REGEXP = /\{\{.*?\}\}/g;
 export function interpolate(s: string): string {
  let matches = s.match(INTERP_REGEXP);
  if (matches && matches[0].length === s.length) {
    return `(${compileExpr(s.slice(2, -2))})`;
  }
  let r = s.replace(INTERP_GROUP_REGEXP, (s) => "${" + compileExpr(s.slice(2, -2)) + "}");
  return "`" + r + "`";
 }
@@ -0,0 +1,997 @@
 // -----------------------------------------------------------------------------
 // AST Type definition
 // -----------------------------------------------------------------------------
 export const enum ASTType {
  Text,
  Comment,
  DomNode,
  Multi,
  TEsc,
  TIf,
  TSet,
  TCall,
  TOut,
  TForEach,
  TKey,
  TComponent,
  TDebug,
  TLog,
  TSlot,
  TCallBlock,
  TTranslation,
  TPortal,
 }
 export interface ASTText {
  type: ASTType.Text;
  value: string;
 }
 export interface ASTComment {
  type: ASTType.Comment;
  value: string;
 }
 export interface ASTDomNode {
  type: ASTType.DomNode;
  tag: string;
  dynamicTag: string | null;
  attrs: { [key: string]: string };
  content: AST[];
  ref: string | null;
  on: { [key: string]: string };
  model: {
    baseExpr: string;
    expr: string;
    targetAttr: string;
    specialInitTargetAttr: string | null;
    eventType: "change" | "click" | "input";
    shouldTrim: boolean;
    shouldNumberize: boolean;
  } | null;
  ns: string | null;
 }
 export interface ASTMulti {
  type: ASTType.Multi;
  content: AST[];
  deepRemove: boolean;
 }
 export interface ASTTEsc {
  type: ASTType.TEsc;
  expr: string;
  defaultValue: string;
 }
 export interface ASTTOut {
  type: ASTType.TOut;
  expr: string;
  body: AST[] | null;
 }
 export interface ASTTif {
  type: ASTType.TIf;
  condition: string;
  content: AST;
  tElif: { condition: string; content: AST }[] | null;
  tElse: AST | null;
  deepRemove: boolean;
 }
 export interface ASTTSet {
  type: ASTType.TSet;
  name: string;
  value: string | null; // value defined in attribute
  defaultValue: string | null; // value defined in body, if text
  body: AST[] | null; // content of body if not text
 }
 export interface ASTTForEach {
  type: ASTType.TForEach;
  collection: string;
  elem: string;
  key: string | null;
  body: AST;
  memo: string;
  deepRemove: boolean;
  hasNoFirst: boolean;
  hasNoLast: boolean;
  hasNoIndex: boolean;
  hasNoValue: boolean;
 }
 export interface ASTTKey {
  type: ASTType.TKey;
  expr: string;
  content: AST;
 }
 export interface ASTTCall {
  type: ASTType.TCall;
  name: string;
  body: AST[] | null;
 }
 export interface ASTComponent {
  type: ASTType.TComponent;
  name: string;
  isDynamic: boolean;
  dynamicProps: string | null;
  props: { [name: string]: string };
  slots: { [name: string]: { content: AST; attrs?: { [key: string]: string }; scope?: string } };
 }
 export interface ASTSlot {
  type: ASTType.TSlot;
  name: string;
  attrs: { [key: string]: string };
  defaultContent: AST | null;
 }
 export interface ASTTCallBlock {
  type: ASTType.TCallBlock;
  name: string;
 }
 export interface ASTDebug {
  type: ASTType.TDebug;
  content: AST | null;
 }
 export interface ASTLog {
  type: ASTType.TLog;
  expr: string;
  content: AST | null;
 }
 export interface ASTTranslation {
  type: ASTType.TTranslation;
  content: AST | null;
 }
 export interface ASTTPortal {
  type: ASTType.TPortal;
  target: string;
  content: AST;
 }
 export type AST =
  | ASTText
  | ASTComment
  | ASTDomNode
  | ASTMulti
  | ASTTEsc
  | ASTTif
  | ASTTSet
  | ASTTCall
  | ASTTOut
  | ASTTForEach
  | ASTTKey
  | ASTComponent
  | ASTSlot
  | ASTTCallBlock
  | ASTLog
  | ASTDebug
  | ASTTranslation
  | ASTTPortal;
 // -----------------------------------------------------------------------------
 // Parser
 // -----------------------------------------------------------------------------
 interface ParsingContext {
  inPreTag: boolean;
  inSVG: boolean;
 }
 export function parse(xml: string | Node): AST {
  const node = xml instanceof Element ? xml : (parseXML(`<t>${xml}</t>`).firstChild! as Element);
  normalizeXML(node);
  const ctx = { inPreTag: false, inSVG: false };
  const ast = parseNode(node, ctx);
  if (!ast) {
    return { type: ASTType.Text, value: "" };
  }
  return ast;
 }
 function parseNode(node: ChildNode, ctx: ParsingContext): AST | null {
  if (!(node instanceof Element)) {
    return parseTextCommentNode(node, ctx);
  }
  return (
    parseTDebugLog(node, ctx) ||
    parseTForEach(node, ctx) ||
    parseTIf(node, ctx) ||
    parseTPortal(node, ctx) ||
    parseTCall(node, ctx) ||
    parseTCallBlock(node, ctx) ||
    parseTEscNode(node, ctx) ||
    parseTKey(node, ctx) ||
    parseTTranslation(node, ctx) ||
    parseTSlot(node, ctx) ||
    parseTOutNode(node, ctx) ||
    parseComponent(node, ctx) ||
    parseDOMNode(node, ctx) ||
    parseTSetNode(node, ctx) ||
    parseTNode(node, ctx)
  );
 }
 // -----------------------------------------------------------------------------
 // <t /> tag
 // -----------------------------------------------------------------------------
 function parseTNode(node: Element, ctx: ParsingContext): AST | null {
  if (node.tagName !== "t") {
    return null;
  }
  return parseChildNodes(node, ctx);
 }
 // -----------------------------------------------------------------------------
 // Text and Comment Nodes
 // -----------------------------------------------------------------------------
 const lineBreakRE = /[\r\n]/;
 const whitespaceRE = /\s+/g;
 function parseTextCommentNode(node: ChildNode, ctx: ParsingContext): AST | null {
  if (node.nodeType === Node.TEXT_NODE) {
    let value = node.textContent || "";
    if (!ctx.inPreTag) {
      if (lineBreakRE.test(value) && !value.trim()) {
        return null;
      }
      value = value.replace(whitespaceRE, " ");
    }
    return { type: ASTType.Text, value };
  } else if (node.nodeType === Node.COMMENT_NODE) {
    return { type: ASTType.Comment, value: node.textContent || "" };
  }
  return null;
 }
 // -----------------------------------------------------------------------------
 // debugging
 // -----------------------------------------------------------------------------
 function parseTDebugLog(node: Element, ctx: ParsingContext): AST | null {
  if (node.hasAttribute("t-debug")) {
    node.removeAttribute("t-debug");
    return {
      type: ASTType.TDebug,
      content: parseNode(node, ctx),
    };
  }
  if (node.hasAttribute("t-log")) {
    const expr = node.getAttribute("t-log")!;
    node.removeAttribute("t-log");
    return {
      type: ASTType.TLog,
      expr,
      content: parseNode(node, ctx),
    };
  }
  return null;
 }
 // -----------------------------------------------------------------------------
 // Regular dom node
 // -----------------------------------------------------------------------------
 const hasDotAtTheEnd = /\.[\w_]+\s*$/;
 const hasBracketsAtTheEnd = /\[[^\[]+\]\s*$/;
 function parseDOMNode(node: Element, ctx: ParsingContext): AST | null {
  const { tagName } = node;
  const dynamicTag = node.getAttribute("t-tag");
  node.removeAttribute("t-tag");
  if (tagName === "t" && !dynamicTag) {
    return null;
  }
  ctx = Object.assign({}, ctx);
  if (tagName === "pre") {
    ctx.inPreTag = true;
  }
  const shouldAddSVGNS = tagName === "svg" || (tagName === "g" && !ctx.inSVG);
  ctx.inSVG = ctx.inSVG || shouldAddSVGNS;
  const ns = shouldAddSVGNS ? "http://www.w3.org/2000/svg" : null;
  const ref = node.getAttribute("t-ref");
  node.removeAttribute("t-ref");
  const children = parseChildren(node, ctx);
  const nodeAttrsNames = node.getAttributeNames();
  const attrs: ASTDomNode["attrs"] = {};
  const on: ASTDomNode["on"] = {};
  let model: ASTDomNode["model"] = null;
  for (let attr of nodeAttrsNames) {
    const value = node.getAttribute(attr)!;
    if (attr.startsWith("t-on")) {
      if (attr === "t-on") {
        throw new Error("Missing event name with t-on directive");
      }
      on[attr.slice(5)] = value;
    } else if (attr.startsWith("t-model")) {
      if (!["input", "select", "textarea"].includes(tagName)) {
        throw new Error("The t-model directive only works with <input>, <textarea> and <select>");
      }
      let baseExpr, expr;
      if (hasDotAtTheEnd.test(value)) {
        const index = value.lastIndexOf(".");
        baseExpr = value.slice(0, index);
        expr = `'${value.slice(index + 1)}'`;
      } else if (hasBracketsAtTheEnd.test(value)) {
        const index = value.lastIndexOf("[");
        baseExpr = value.slice(0, index);
        expr = value.slice(index + 1, -1);
      } else {
        throw new Error(`Invalid t-model expression: "${value}" (it should be assignable)`);
      }
      const typeAttr = node.getAttribute("type");
      const isInput = tagName === "input";
      const isSelect = tagName === "select";
      const isTextarea = tagName === "textarea";
      const isCheckboxInput = isInput && typeAttr === "checkbox";
      const isRadioInput = isInput && typeAttr === "radio";
      const isOtherInput = isInput && !isCheckboxInput && !isRadioInput;
      const hasLazyMod = attr.includes(".lazy");
      const hasNumberMod = attr.includes(".number");
      const hasTrimMod = attr.includes(".trim");
      const eventType = isRadioInput ? "click" : isSelect || hasLazyMod ? "change" : "input";
      model = {
        baseExpr,
        expr,
        targetAttr: isCheckboxInput ? "checked" : "value",
        specialInitTargetAttr: isRadioInput ? "checked" : null,
        eventType,
        shouldTrim: hasTrimMod && (isOtherInput || isTextarea),
        shouldNumberize: hasNumberMod && (isOtherInput || isTextarea),
      };
    } else {
      if (attr.startsWith("t-") && !attr.startsWith("t-att")) {
        throw new Error(`Unknown QWeb directive: '${attr}'`);
      }
      attrs[attr] = value;
    }
  }
  return {
    type: ASTType.DomNode,
    tag: tagName,
    dynamicTag,
    attrs,
    on,
    ref,
    content: children,
    model,
    ns,
  };
 }
 // -----------------------------------------------------------------------------
 // t-esc
 // -----------------------------------------------------------------------------
 function parseTEscNode(node: Element, ctx: ParsingContext): AST | null {
  if (!node.hasAttribute("t-esc")) {
    return null;
  }
  const escValue = node.getAttribute("t-esc")!;
  node.removeAttribute("t-esc");
  const tesc: AST = {
    type: ASTType.TEsc,
    expr: escValue,
    defaultValue: node.textContent || "",
  };
  let ref = node.getAttribute("t-ref");
  node.removeAttribute("t-ref");
  const ast = parseNode(node, ctx);
  if (!ast) {
    return tesc;
  }
  if (ast.type === ASTType.DomNode) {
    return {
      ...ast,
      ref,
      content: [tesc],
    };
  }
  if (ast.type === ASTType.TComponent) {
    throw new Error("t-esc is not supported on Component nodes");
  }
  return tesc;
 }
 // -----------------------------------------------------------------------------
 // t-out
 // -----------------------------------------------------------------------------
 function parseTOutNode(node: Element, ctx: ParsingContext): AST | null {
  if (!node.hasAttribute("t-out") && !node.hasAttribute("t-raw")) {
    return null;
  }
  if (node.hasAttribute("t-raw")) {
    console.warn(
      `t-raw has been deprecated in favor of t-out. If the value to render is not wrapped by the "markup" function, it will be escaped`
    );
  }
  const expr = (node.getAttribute("t-out") || node.getAttribute("t-raw"))!;
  node.removeAttribute("t-out");
  node.removeAttribute("t-raw");
  const tOut: AST = { type: ASTType.TOut, expr, body: null };
  const ref = node.getAttribute("t-ref");
  node.removeAttribute("t-ref");
  const ast = parseNode(node, ctx);
  if (!ast) {
    return tOut;
  }
  if (ast.type === ASTType.DomNode) {
    tOut.body = ast.content.length ? ast.content : null;
    return {
      ...ast,
      ref,
      content: [tOut],
    };
  }
  return tOut;
 }
 // -----------------------------------------------------------------------------
 // t-foreach and t-key
 // -----------------------------------------------------------------------------
 function parseTForEach(node: Element, ctx: ParsingContext): AST | null {
  if (!node.hasAttribute("t-foreach")) {
    return null;
  }
  const html = node.outerHTML;
  const collection = node.getAttribute("t-foreach")!;
  node.removeAttribute("t-foreach");
  const elem = node.getAttribute("t-as") || "";
  node.removeAttribute("t-as");
  const key = node.getAttribute("t-key");
  if (!key) {
    throw new Error(
      `"Directive t-foreach should always be used with a t-key!" (expression: t-foreach="${collection}" t-as="${elem}")`
    );
  }
  node.removeAttribute("t-key");
  const memo = node.getAttribute("t-memo") || "";
  node.removeAttribute("t-memo");
  const body = parseNode(node, ctx);
  if (!body) {
    return null;
  }
  const hasNoTCall = !html.includes("t-call");
  const hasNoFirst = hasNoTCall && !html.includes(`${elem}_first`);
  const hasNoLast = hasNoTCall && !html.includes(`${elem}_last`);
  const hasNoIndex = hasNoTCall && !html.includes(`${elem}_index`);
  const hasNoValue = hasNoTCall && !html.includes(`${elem}_value`);
  return {
    type: ASTType.TForEach,
    collection,
    elem,
    body,
    memo,
    deepRemove: needDeepRemove(body),
    key,
    hasNoFirst,
    hasNoLast,
    hasNoIndex,
    hasNoValue,
  };
 }
 /**
 * @returns true if we are sure that a deep remove (without optimisation) is needed, for exemple
 * if there is a portal.
 */
 function needDeepRemove(ast: AST): boolean {
  switch (ast.type) {
    case ASTType.Multi:
    case ASTType.TForEach:
    case ASTType.TIf:
      return ast.deepRemove;
    case ASTType.TPortal:
      return true;
    case ASTType.TComponent:
    case ASTType.TOut:
    case ASTType.TCall:
    case ASTType.TCallBlock:
    case ASTType.TSlot:
    case ASTType.Text:
    case ASTType.Comment:
    case ASTType.TEsc:
      return false;
    case ASTType.TKey:
      return needDeepRemove(ast.content);
    case ASTType.TDebug:
    case ASTType.TLog:
    case ASTType.TTranslation:
      return ast.content ? needDeepRemove(ast.content) : false;
    case ASTType.TSet:
      return ast.body ? ast.body.some((ast) => needDeepRemove(ast)) : false;
    case ASTType.DomNode:
      return ast.content.some((ast) => needDeepRemove(ast));
  }
 }
 function parseTKey(node: Element, ctx: ParsingContext): AST | null {
  if (!node.hasAttribute("t-key")) {
    return null;
  }
  const key = node.getAttribute("t-key")!;
  node.removeAttribute("t-key");
  const body = parseNode(node, ctx);
  if (!body) {
    return null;
  }
  return { type: ASTType.TKey, expr: key, content: body };
 }
 // -----------------------------------------------------------------------------
 // t-call
 // -----------------------------------------------------------------------------
 function parseTCall(node: Element, ctx: ParsingContext): AST | null {
  if (!node.hasAttribute("t-call")) {
    return null;
  }
  const subTemplate = node.getAttribute("t-call")!;
  node.removeAttribute("t-call");
  if (node.tagName !== "t") {
    const ast = parseNode(node, ctx);
    const tcall: AST = { type: ASTType.TCall, name: subTemplate, body: null };
    if (ast && ast.type === ASTType.DomNode) {
      ast.content = [tcall];
      return ast;
    }
    if (ast && ast.type === ASTType.TComponent) {
      return {
        ...ast,
        slots: { default: { content: tcall } },
      };
    }
  }
  const body = parseChildren(node, ctx);
  return {
    type: ASTType.TCall,
    name: subTemplate,
    body: body.length ? body : null,
  };
 }
 // -----------------------------------------------------------------------------
 // t-call-block
 // -----------------------------------------------------------------------------
 function parseTCallBlock(node: Element, ctx: ParsingContext): AST | null {
  if (!node.hasAttribute("t-call-block")) {
    return null;
  }
  const name = node.getAttribute("t-call-block")!;
  return {
    type: ASTType.TCallBlock,
    name,
  };
 }
 // -----------------------------------------------------------------------------
 // t-if
 // -----------------------------------------------------------------------------
 function parseTIf(node: Element, ctx: ParsingContext): AST | null {
  if (!node.hasAttribute("t-if")) {
    return null;
  }
  const condition = node.getAttribute("t-if")!;
  node.removeAttribute("t-if");
  const content = parseNode(node, ctx) || { type: ASTType.Text, value: "" };
  let nextElement = node.nextElementSibling;
  // t-elifs
  const tElifs: any[] = [];
  while (nextElement && nextElement.hasAttribute("t-elif")) {
    const condition = nextElement.getAttribute("t-elif");
    nextElement.removeAttribute("t-elif");
    const tElif = parseNode(nextElement, ctx);
    const next = nextElement.nextElementSibling;
    nextElement.remove();
    nextElement = next;
    if (tElif) {
      tElifs.push({ condition, content: tElif });
    }
  }
  // t-else
  let tElse: AST | null = null;
  if (nextElement && nextElement.hasAttribute("t-else")) {
    nextElement.removeAttribute("t-else");
    tElse = parseNode(nextElement, ctx);
    nextElement.remove();
  }
  let deepRemove = needDeepRemove(content);
  if (tElifs) {
    deepRemove = deepRemove || tElifs.some((ast) => needDeepRemove(ast));
  }
  if (tElse) {
    deepRemove = deepRemove || needDeepRemove(tElse);
  }
  return {
    type: ASTType.TIf,
    condition,
    content,
    tElif: tElifs.length ? tElifs : null,
    tElse,
    deepRemove,
  };
 }
 // -----------------------------------------------------------------------------
 // t-set directive
 // -----------------------------------------------------------------------------
 function parseTSetNode(node: Element, ctx: ParsingContext): AST | null {
  if (!node.hasAttribute("t-set")) {
    return null;
  }
  const name = node.getAttribute("t-set")!;
  const value = node.getAttribute("t-value") || null;
  const defaultValue = node.innerHTML === node.textContent ? node.textContent || null : null;
  let body: AST[] | null = null;
  if (node.textContent !== node.innerHTML) {
    body = parseChildren(node, ctx);
  }
  return { type: ASTType.TSet, name, value, defaultValue, body };
 }
 // -----------------------------------------------------------------------------
 // Components
 // -----------------------------------------------------------------------------
 // Error messages when trying to use an unsupported directive on a component
 const directiveErrorMap = new Map([
  ["t-on", "t-on is no longer supported on components. Consider passing a callback in props."],
  [
    "t-ref",
    "t-ref is no longer supported on components. Consider exposing only the public part of the component's API through a callback prop.",
  ],
  ["t-att", "t-att makes no sense on component: props are already treated as expressions"],
  [
    "t-attf",
    "t-attf is not supported on components: use template strings for string interpolation in props",
  ],
 ]);
 function parseComponent(node: Element, ctx: ParsingContext): AST | null {
  let name = node.tagName;
  const firstLetter = name[0];
  let isDynamic = node.hasAttribute("t-component");
  if (isDynamic && name !== "t") {
    throw new Error(`Directive 't-component' can only be used on <t> nodes (used on a <${name}>)`);
  }
  if (!(firstLetter === firstLetter.toUpperCase() || isDynamic)) {
    return null;
  }
  if (isDynamic) {
    name = node.getAttribute("t-component")!;
    node.removeAttribute("t-component");
  }
  const dynamicProps = node.getAttribute("t-props");
  node.removeAttribute("t-props");
  const props: ASTComponent["props"] = {};
  for (let name of node.getAttributeNames()) {
    const value = node.getAttribute(name)!;
    if (name.startsWith("t-")) {
      const message = directiveErrorMap.get(name.split("-").slice(0, 2).join("-"));
      throw new Error(message || `unsupported directive on Component: ${name}`);
    } else {
      props[name] = value;
    }
  }
  const slots: ASTComponent["slots"] = {};
  if (node.hasChildNodes()) {
    const clone = <Element>node.cloneNode(true);
    // named slots
    const slotNodes = Array.from(clone.querySelectorAll("[t-set-slot]"));
    for (let slotNode of slotNodes) {
      if (slotNode.tagName !== "t") {
        throw new Error(
          `Directive 't-set-slot' can only be used on <t> nodes (used on a <${slotNode.tagName}>)`
        );
      }
      const name = slotNode.getAttribute("t-set-slot")!;
      // check if this is defined in a sub component (in which case it should
      // be ignored)
      let el = slotNode.parentElement!;
      let isInSubComponent = false;
      while (el !== clone) {
        if (el!.hasAttribute("t-component") || el!.tagName[0] === el!.tagName[0].toUpperCase()) {
          isInSubComponent = true;
          break;
        }
        el = el.parentElement!;
      }
      if (isInSubComponent) {
        continue;
      }
      slotNode.removeAttribute("t-set-slot");
      slotNode.remove();
      const slotAst = parseNode(slotNode, ctx);
      if (slotAst) {
        const slotInfo: any = { content: slotAst };
        const attrs: { [key: string]: string } = {};
        for (let attributeName of slotNode.getAttributeNames()) {
          const value = slotNode.getAttribute(attributeName)!;
          if (attributeName === "t-slot-scope") {
            slotInfo.scope = value;
            continue;
          }
          attrs[attributeName] = value;
        }
        if (Object.keys(attrs).length) {
          slotInfo.attrs = attrs;
        }
        slots[name] = slotInfo;
      }
    }
    // default slot
    const defaultContent = parseChildNodes(clone, ctx);
    if (defaultContent) {
      slots.default = { content: defaultContent };
    }
  }
  return { type: ASTType.TComponent, name, isDynamic, dynamicProps, props, slots };
 }
 // -----------------------------------------------------------------------------
 // Slots
 // -----------------------------------------------------------------------------
 function parseTSlot(node: Element, ctx: ParsingContext): AST | null {
  if (!node.hasAttribute("t-slot")) {
    return null;
  }
  const name = node.getAttribute("t-slot")!;
  node.removeAttribute("t-slot");
  const attrs: { [key: string]: string } = {};
  for (let attributeName of node.getAttributeNames()) {
    const value = node.getAttribute(attributeName)!;
    attrs[attributeName] = value;
  }
  return {
    type: ASTType.TSlot,
    name,
    attrs,
    defaultContent: parseChildNodes(node, ctx),
  };
 }
 function parseTTranslation(node: Element, ctx: ParsingContext): AST | null {
  if (node.getAttribute("t-translation") !== "off") {
    return null;
  }
  node.removeAttribute("t-translation");
  return {
    type: ASTType.TTranslation,
    content: parseNode(node, ctx),
  };
 }
 // -----------------------------------------------------------------------------
 // Portal
 // -----------------------------------------------------------------------------
 function parseTPortal(node: Element, ctx: ParsingContext): AST | null {
  if (!node.hasAttribute("t-portal")) {
    return null;
  }
  if (node.tagName !== "t") {
    throw new Error(
      `Directive 't-portal' can only be used on <t> nodes (used on a <${node.tagName}>)`
    );
  }
  const target = node.getAttribute("t-portal")!;
  node.removeAttribute("t-portal");
  const content = parseNode(node, ctx);
  if (!content) {
    return {
      type: ASTType.Text,
      value: "",
    };
  }
  return {
    type: ASTType.TPortal,
    target,
    content,
  };
 }
 // -----------------------------------------------------------------------------
 // helpers
 // -----------------------------------------------------------------------------
 /**
 * Parse all the child nodes of a given node and return a list of ast elements
 */
 function parseChildren(node: Node, ctx: ParsingContext): AST[] {
  const children: AST[] = [];
  for (let child of node.childNodes) {
    const childAst = parseNode(child, ctx);
    if (childAst) {
      if (childAst.type === ASTType.Multi) {
        children.push(...childAst.content);
      } else {
        children.push(childAst);
      }
    }
  }
  return children;
 }
 /**
 * Parse all the child nodes of a given node and return an ast if possible.
 * In the case there are multiple children, they are wrapped in a astmulti.
 */
 function parseChildNodes(node: Node, ctx: ParsingContext): AST | null {
  const children = parseChildren(node, ctx);
  switch (children.length) {
    case 0:
      return null;
    case 1:
      return children[0];
    default:
      return {
        type: ASTType.Multi,
        content: children,
        deepRemove: children.some((ast) => needDeepRemove(ast)),
      };
  }
 }
 /**
 * Normalizes the content of an Element so that t-if/t-elif/t-else directives
 * immediately follow one another (by removing empty text nodes or comments).
 * Throws an error when a conditional branching statement is malformed. This
 * function modifies the Element in place.
 *
 * @param el the element containing the tree that should be normalized
 */
 function normalizeTIf(el: Element) {
  let tbranch = el.querySelectorAll("[t-elif], [t-else]");
  for (let i = 0, ilen = tbranch.length; i < ilen; i++) {
    let node = tbranch[i];
    let prevElem = node.previousElementSibling!;
    let pattr = (name: string) => prevElem.getAttribute(name);
    let nattr = (name: string) => +!!node.getAttribute(name);
    if (prevElem && (pattr("t-if") || pattr("t-elif"))) {
      if (pattr("t-foreach")) {
        throw new Error(
          "t-if cannot stay at the same level as t-foreach when using t-elif or t-else"
        );
      }
      if (
        ["t-if", "t-elif", "t-else"].map(nattr).reduce(function (a, b) {
          return a + b;
        }) > 1
      ) {
        throw new Error("Only one conditional branching directive is allowed per node");
      }
      // All text (with only spaces) and comment nodes (nodeType 8) between
      // branch nodes are removed
      let textNode;
      while ((textNode = node.previousSibling) !== prevElem) {
        if (textNode!.nodeValue!.trim().length && textNode!.nodeType !== 8) {
          throw new Error("text is not allowed between branching directives");
        }
        textNode!.remove();
      }
    } else {
      throw new Error(
        "t-elif and t-else directives must be preceded by a t-if or t-elif directive"
      );
    }
  }
 }
 /**
 * Normalizes the content of an Element so that t-esc directives on components
 * are removed and instead places a <t t-esc=""> as the default slot of the
 * component. Also throws if the component already has content. This function
 * modifies the Element in place.
 *
 * @param el the element containing the tree that should be normalized
 */
 function normalizeTEsc(el: Element) {
  const elements = [...el.querySelectorAll("[t-esc]")].filter(
    (el) => el.tagName[0] === el.tagName[0].toUpperCase() || el.hasAttribute("t-component")
  );
  for (const el of elements) {
    if (el.childNodes.length) {
      throw new Error("Cannot have t-esc on a component that already has content");
    }
    const value = el.getAttribute("t-esc");
    el.removeAttribute("t-esc");
    const t = el.ownerDocument.createElement("t");
    if (value != null) {
      t.setAttribute("t-esc", value);
    }
    el.appendChild(t);
  }
 }
 /**
 * Normalizes the tree inside a given element and do some preliminary validation
 * on it. This function modifies the Element in place.
 *
 * @param el the element containing the tree that should be normalized
 */
 function normalizeXML(el: Element) {
  normalizeTIf(el);
  normalizeTEsc(el);
 }
 /**
 * Parses an XML string into an XML document, throwing errors on parser errors
 * instead of returning an XML document containing the parseerror.
 *
 * @param xml the string to parse
 * @returns an XML document corresponding to the content of the string
 */
 function parseXML(xml: string): XMLDocument {
  const parser = new DOMParser();
  const doc = parser.parseFromString(xml, "text/xml");
  if (doc.getElementsByTagName("parsererror").length) {
    let msg = "Invalid XML in template.";
    const parsererrorText = doc.getElementsByTagName("parsererror")[0].textContent;
    if (parsererrorText) {
      msg += "\nThe parser has produced the following error message:\n" + parsererrorText;
      const re = /\d+/g;
      const firstMatch = re.exec(parsererrorText);
      if (firstMatch) {
        const lineNumber = Number(firstMatch[0]);
        const line = xml.split("\n")[lineNumber - 1];
        const secondMatch = re.exec(parsererrorText);
        if (line && secondMatch) {
          const columnIndex = Number(secondMatch[0]) - 1;
          if (line[columnIndex]) {
            msg +=
              `\nThe error might be located at xml line ${lineNumber} column ${columnIndex}\n` +
              `${line}\n${"-".repeat(columnIndex - 1)}^`;
          }
        }
      }
    }
    throw new Error(msg);
  }
  return doc;
 }
@@ -1,725 +1,27 @@
-import { Observer } from "../core/observer";
+import type { Env } from "../app/app";
-import { CompiledTemplate, QWeb } from "../qweb/index";
+import type { ComponentNode } from "./component_node";
 import { h, patch, VNode } from "../vdom/index";
 import "./directive";
 import "./props_validation";
-/**
+// -----------------------------------------------------------------------------
- * Owl Component System
+//  Component Class
- *
+// -----------------------------------------------------------------------------
 * This file introduces a declarative and composable component system. It
 * contains:
 *
 * - the Env interface (generic type for the environment)
 * - the Meta interface (the owl specific metadata attached to a component)
 * - the Component class
 */
-//------------------------------------------------------------------------------
+export class Component {
-// Types/helpers
+  static template: string = "";
 //------------------------------------------------------------------------------
 /**
 * An Env (environment) is an object that will be (mostly) shared between all
 * components of an Owl application.  It is the location which should contain
 * the qweb instance necessary to render all components.
 *
 * Note that it is totally fine to extend the environment with application
 * specific keys/objects/whatever.  For example, a key `isMobile` (to declare
 * if we are in "mobile" mode), or a shared bus could be useful.
 */
 export interface Env {
  qweb: QWeb;
  [key: string]: any;
 }
 /**
 * This is mostly an internal detail of implementation. The Meta interface is
 * useful to typecheck and describe the internal keys used by Owl to manage the
 * component tree.
 */
 interface Internal<T extends Env, Props> {
  // each component has a unique id, useful mostly to handle parent/child
  // relationships
  readonly id: number;
  vnode: VNode | null;
  isMounted: boolean;
  isDestroyed: boolean;
  // parent and children keys are obviously useful to setup the parent-children
  // relationship.
  parent: Component<T, any, any> | null;
  children: { [key: number]: Component<T, any, any> };
  // children mapping: from templateID to componentID. templateID identifies a
  // place in a template. The t-component directive needs it to be able to get
  // the component instance back whenever the template is rerendered.
  cmap: { [key: number]: number };
  renderId: number;
  // the renderProps and renderPromise keys are only useful for the "prepare"
  // step of the lifecycle of a component.  Once a component has been rendered
  // and patched, it is no longer useful.
  renderProps: Props | null;
  renderPromise: Promise<VNode> | null;
  boundHandlers: { [key: number]: any };
  observer: Observer | null;
  render: CompiledTemplate | null;
  mountedHandlers: { [key: number]: Function };
  classObj: { [key: string]: boolean } | null;
 }
 // If a component does not define explicitely a template
 // key, it needs to find a template with its name (or a parent's).  This is
 // qweb dependant, so we need a place to store this information indexed by
 // qweb instances.
 const TEMPLATE_MAP: { [key: number]: { [name: string]: string } } = {};
 //------------------------------------------------------------------------------
 // Component
 //------------------------------------------------------------------------------
 let nextId = 1;
 export class Component<T extends Env, Props extends {}, State extends {}> {
  readonly __owl__: Internal<Env, Props>;
  template?: string;
  /**
   * The `el` is the root element of the component.  Note that it could be null:
   * this is the case if the component is not mounted yet, or is destroyed.
   */
  get el(): HTMLElement | null {
    return this.__owl__.vnode ? (<any>this).__owl__.vnode.elm : null;
  }
  env: T;
  state?: State;
  props: Props;
  // type of props is not easily representable in typescript...
  static props?: any;
  static defaultProps?: any;
-  refs: {
+  props: any;
-    [key: string]: Component<T, any, any> | HTMLElement | undefined;
+  env: Env;
-  } = {};
+  __owl__: ComponentNode;
-  //--------------------------------------------------------------------------
+  constructor(props: any, env: Env, node: ComponentNode) {
-  // Lifecycle
+    this.props = props;
-  //--------------------------------------------------------------------------
+    this.env = env;
-
+    this.__owl__ = node;
  /**
   * Creates an instance of Component.
   *
   * The root component of a component tree needs an environment:
   *
   * ```javascript
   *   const root = new RootComponent(env, props);
   * ```
   *
   * Every other component simply needs a reference to its parent:
   *
   * ```javascript
   *   const child = new SomeComponent(parent, props);
   * ```
   *
   * Note that most of the time, only the root component needs to be created by
   * hand.  Other components should be created automatically by the framework (with
   * the t-component directive in a template)
   */
  constructor(parent: Component<T, any, any> | T, props?: Props) {
    const defaultProps = (<any>this.constructor).defaultProps;
    if (defaultProps) {
      props = this.__applyDefaultProps(props, defaultProps);
    }
    // is this a good idea?
    //   Pro: if props is empty, we can create easily a component
    //   Con: this is not really safe
    //   Pro: but creating component (by a template) is always unsafe anyway
    this.props = <Props>props || <Props>{};
    let id: number = nextId++;
    let p: Component<T, any, any> | null = null;
    if (parent instanceof Component) {
      p = parent;
      this.env = parent.env;
      parent.__owl__.children[id] = this;
    } else {
      this.env = parent;
      if (QWeb.dev) {
        // we only validate props for root widgets here.  "Regular" widget
        // props are validated by the t-component directive
        QWeb.utils.validateProps(this.constructor, this.props);
      }
      this.env.qweb.on("update", this, () => {
        if (this.__owl__.isMounted) {
          this.render(true);
        }
        if (this.__owl__.isDestroyed) {
          // this is unlikely to happen, but if a root widget is destroyed,
          // we want to remove our subscription.  The usual way to do that
          // would be to perform some check in the destroy method, but since
          // it is very performance sensitive, and since this is a rare event,
          // we simply do it lazily
          this.env.qweb.off("update", this);
        }
      });
    }
    this.__owl__ = {
      id: id,
      vnode: null,
      isMounted: false,
      isDestroyed: false,
      parent: p,
      children: {},
      cmap: {},
      renderId: 1,
      renderPromise: null,
      renderProps: props || null,
      boundHandlers: {},
      mountedHandlers: {},
      observer: null,
      render: null,
      classObj: null
    };
  }
-  /**
+  setup() {}
   * willStart is an asynchronous hook that can be implemented to perform some
   * action before the initial rendering of a component.
   *
   * It will be called exactly once before the initial rendering. It is useful
   * in some cases, for example, to load external assets (such as a JS library)
   * before the component is rendered.
   *
   * Note that a slow willStart method will slow down the rendering of the user
   * interface.  Therefore, some effort should be made to make this method as
   * fast as possible.
   *
   * Note: this method should not be called manually.
   */
  async willStart() {}
-  /**
+  render() {
-   * mounted is a hook that is called each time a component is attached to the
+    this.__owl__.render();
   * DOM. This is a good place to add some listeners, or to interact with the
   * DOM, if the component needs to perform some measure for example.
   *
   * Note: this method should not be called manually.
   *
   * @see willUnmount
   */
  mounted() {}
  /**
   * The willUpdateProps is an asynchronous hook, called just before new props
   * are set. This is useful if the component needs some asynchronous task
   * performed, depending on the props (for example, assuming that the props are
   * some record Id, fetching the record data).
   *
   * This hook is not called during the first render (but willStart is called
   * and performs a similar job).
   */
  async willUpdateProps(nextProps: Props) {}
  /**
   * The willPatch hook is called just before the DOM patching process starts.
   * It is not called on the initial render.  This is useful to get some
   * information which are in the DOM.  For example, the current position of the
   * scrollbar
   *
   * The return value of willPatch will be given to the patched function.
   */
  willPatch(): any {}
  /**
   * This hook is called whenever a component did actually update its props,
   * state or env.
   *
   * This method is not called on the initial render. It is useful to interact
   * with the DOM (for example, through an external library) whenever the
   * component was updated.
   *
   * Updating the component state in this hook is possible, but not encouraged.
   * One need to be careful, because updates here will cause rerender, which in
   * turn will cause other calls to updated. So, we need to be particularly
   * careful at avoiding endless cycles.
   *
   * The snapshot parameter is the result of the call to willPatch.
   */
  patched(snapshot: any) {}
  /**
   * willUnmount is a hook that is called each time just before a component is
   * unmounted from the DOM. This is a good place to remove some listeners, for
   * example.
   *
   * Note: this method should not be called manually.
   *
   * @see mounted
   */
  willUnmount() {}
  /**
   * catchError is a method called whenever some error happens in the rendering or
   * lifecycle hooks of a child.
   */
  catchError(error: Error): void {}
  //--------------------------------------------------------------------------
  // Public
  //--------------------------------------------------------------------------
  /**
   * Mount the component to a target element.
   *
   * This should only be done if the component was created manually. Components
   * created declaratively in templates are managed by the Owl system.
   *
   * Note that a component can be mounted an unmounted several times
   */
  async mount(target: HTMLElement, renderBeforeRemount: boolean = false): Promise<void> {
    const __owl__ = this.__owl__;
    if (__owl__.isMounted) {
      return;
    }
    if (!__owl__.vnode) {
      const vnode = await this.__prepare();
      if (__owl__.isDestroyed) {
        // component was destroyed before we get here...
        return;
      }
      this.__patch(vnode);
    } else if (renderBeforeRemount) {
      const patchQueue = [];
      await this.__render(false, patchQueue, undefined, undefined);
      this.__applyPatchQueue(<any[]>patchQueue);
    }
    target.appendChild(this.el!);
    if (document.body.contains(target)) {
      this.__callMounted();
    }
  }
  /**
   * The unmount method is the opposite of the mount method.  It is useful
   * to call willUnmount calls and remove the component from the DOM.
   */
  unmount() {
    if (this.__owl__.isMounted) {
      this.__callWillUnmount();
      this.el!.remove();
    }
  }
  /**
   * The render method is the main entry point to render a component (once it
   * is ready. This method is not initially called when the component is
   * rendered the first time).
   *
   * This method will cause all its sub components to potentially rerender
   * themselves.  Note that `render` is not called if a component is updated via
   * its props.
   */
  async render(force: boolean = false): Promise<void> {
    const __owl__ = this.__owl__;
    if (!__owl__.isMounted) {
      return;
    }
    const patchQueue = [];
    const renderId = ++__owl__.renderId;
    await this.__render(force, patchQueue, undefined, undefined);
    if (__owl__.isMounted && renderId === __owl__.renderId) {
      // we only update the vnode and the actual DOM if no other rendering
      // occurred between now and when the render method was initially called.
      this.__applyPatchQueue(<any[]>patchQueue);
    }
  }
  /**
   * Destroy the component.  This operation is quite complex:
   *  - it recursively destroy all children
   *  - call the willUnmount hooks if necessary
   *  - remove the dom node from the dom
   *
   * This should only be called manually if you created the component.  Most
   * components will be automatically destroyed.
   */
  destroy() {
    const __owl__ = this.__owl__;
    if (!__owl__.isDestroyed) {
      const el = this.el;
      this.__destroy(__owl__.parent);
      if (el) {
        el.remove();
      }
    }
  }
  /**
   * This method is called by the component system whenever its props are
   * updated. If it returns true, then the component will be rendered.
   * Otherwise, it will skip the rendering (also, its props will not be updated)
   */
  shouldUpdate(nextProps: Props): boolean {
    return true;
  }
  /**
   * This method is the correct way to update the environment of a component. Doing
   * this will cause a full rerender of the component and its children, so this is
   * an operation that should not be done frequently.
   *
   * A good usecase for updating the environment would be to update some mostly
   * static config keys, such as a boolean to determine if we are in mobile
   * mode or not.
   */
  async updateEnv(nextEnv: Partial<T>): Promise<void> {
    const __owl__ = this.__owl__;
    if (__owl__.parent && __owl__.parent.env === this.env) {
      this.env = Object.create(this.env);
    }
    Object.assign(this.env, nextEnv);
    if (__owl__.isMounted) {
      await this.render(true);
    }
  }
  /**
   * Emit a custom event of type 'eventType' with the given 'payload' on the
   * component's el, if it exists. However, note that the event will only bubble
   * up to the parent DOM nodes. Thus, it must be called between mounted() and
   * willUnmount().
   */
  trigger(eventType: string, payload?: any) {
    if (this.el) {
      const ev = new CustomEvent(eventType, {
        bubbles: true,
        cancelable: true,
        detail: payload
      });
      this.el.dispatchEvent(ev);
    }
  }
  //--------------------------------------------------------------------------
  // Private
  //--------------------------------------------------------------------------
  /**
   * Private helper to perform a full destroy, from the point of view of an Owl
   * component. It does not remove the el (this is done only once on the top
   * level destroyed component, for performance reasons).
   *
   * The job of this method is mostly to call willUnmount hooks, and to perform
   * all necessary internal cleanup.
   *
   * Note that it does not call the __callWillUnmount method to avoid visiting
   * all children many times.
   */
  __destroy(parent: Component<any, any, any> | null) {
    const __owl__ = this.__owl__;
    const isMounted = __owl__.isMounted;
    if (isMounted) {
      this.willUnmount();
      __owl__.isMounted = false;
    }
    const children = __owl__.children;
    for (let key in children) {
      children[key].__destroy(this);
    }
    if (parent) {
      let id = __owl__.id;
      delete parent.__owl__.children[id];
      __owl__.parent = null;
    }
    __owl__.isDestroyed = true;
    delete __owl__.vnode;
  }
  __callMounted() {
    const __owl__ = this.__owl__;
    const children = __owl__.children;
    for (let id in children) {
      const comp = children[id];
      if (!comp.__owl__.isMounted && this.el!.contains(comp.el)) {
        comp.__callMounted();
      }
    }
    __owl__.isMounted = true;
    const handlers = __owl__.mountedHandlers;
    for (let key in handlers) {
      handlers[key]();
    }
    try {
      this.mounted();
    } catch (e) {
      errorHandler(e, this);
    }
  }
  __callWillUnmount() {
    this.willUnmount();
    const __owl__ = this.__owl__;
    __owl__.isMounted = false;
    const children = __owl__.children;
    for (let id in children) {
      const comp = children[id];
      if (comp.__owl__.isMounted) {
        comp.__callWillUnmount();
      }
    }
  }
  /**
   * The __updateProps method is called by the t-component directive whenever
   * it updates a component (so, when the parent template is rerendered).
   */
  async __updateProps(
    nextProps: Props,
    forceUpdate: boolean = false,
    patchQueue?: any[],
    scope?: any,
    vars?: any
  ): Promise<void> {
    const shouldUpdate = forceUpdate || this.shouldUpdate(nextProps);
    if (shouldUpdate) {
      const defaultProps = (<any>this.constructor).defaultProps;
      if (defaultProps) {
        nextProps = this.__applyDefaultProps(nextProps, defaultProps);
      }
      await this.willUpdateProps(nextProps);
      this.props = nextProps;
      await this.__render(forceUpdate, patchQueue, scope, vars);
    }
  }
  /**
   * Main patching method. We call the virtual dom patch method here to convert
   * a virtual dom vnode into some actual dom.
   */
  __patch(vnode) {
    const __owl__ = this.__owl__;
    const target = __owl__.vnode || document.createElement(vnode.sel!);
    __owl__.vnode = patch(target, vnode);
  }
  __prepare(scope?: Object, vars?: any): Promise<VNode> {
    const __owl__ = this.__owl__;
    __owl__.renderProps = this.props;
    __owl__.renderPromise = this.__prepareAndRender(scope, vars);
    return __owl__.renderPromise;
  }
  async __prepareAndRender(scope?: Object, vars?: any): Promise<VNode> {
    try {
      await this.willStart();
    } catch (e) {
      errorHandler(e, this);
      return Promise.resolve(h("div"));
    }
    const __owl__ = this.__owl__;
    if (__owl__.isDestroyed) {
      return Promise.resolve(h("div"));
    }
    const qweb = this.env.qweb;
    if (!this.template) {
      let tmap = TEMPLATE_MAP[qweb.id];
      if (!tmap) {
        tmap = {};
        TEMPLATE_MAP[qweb.id] = tmap;
      }
      let p = (<any>this).constructor;
      let name: string = p.name;
      let template = tmap[name];
      if (template) {
        this.template = template;
      } else {
        while ((template = p.name) && !(template in qweb.templates) && p !== Component) {
          p = p.__proto__;
        }
        if (p === Component) {
          throw new Error(`Could not find template for component "${this.constructor.name}"`);
        } else {
          tmap[name] = template;
          this.template = template;
        }
      }
    }
    __owl__.render = qweb.render.bind(qweb, this.template);
    this.__observeState();
    return this.__render(false, [], scope, vars);
  }
  __render(
    force: boolean = false,
    patchQueue: any[] = [],
    scope?: Object,
    vars?: any
  ): Promise<VNode> {
    const __owl__ = this.__owl__;
    const promises: Promise<void>[] = [];
    const patch: any[] = [this];
    patchQueue.push(patch);
    if (__owl__.observer) {
      __owl__.observer.allowMutations = false;
    }
    let vnode;
    try {
      vnode = __owl__.render!(this, {
        promises,
        handlers: __owl__.boundHandlers,
        mountedHandlers: __owl__.mountedHandlers,
        forceUpdate: force,
        patchQueue,
        scope,
        vars
      });
    } catch (e) {
      vnode = __owl__.vnode || h("div");
      errorHandler(e, this);
    }
    patch.push(vnode);
    if (__owl__.observer) {
      __owl__.observer.allowMutations = true;
    }
    // this part is critical for the patching process to be done correctly. The
    // tricky part is that a child component can be rerendered on its own, which
    // will update its own vnode representation without the knowledge of the
    // parent component.  With this, we make sure that the parent component will be
    // able to patch itself properly after
    vnode.key = __owl__.id;
    // we applly here the class information described on the component by the
    // template (so, something like <MyComponent class="..."/>) to the actual
    // root vnode
    if (__owl__.classObj) {
      vnode.data.class = Object.assign(vnode.data.class || {}, __owl__.classObj);
    }
    return Promise.all(promises).then(() => vnode);
  }
  /**
   * Only called by qweb t-component directive
   */
  __mount(vnode: VNode, elm: HTMLElement): VNode {
    const __owl__ = this.__owl__;
    if (__owl__.classObj) {
      (<any>vnode).data.class = Object.assign((<any>vnode).data.class || {}, __owl__.classObj);
    }
    __owl__.vnode = patch(elm, vnode);
    if (__owl__.parent!.__owl__.isMounted && !__owl__.isMounted) {
      this.__callMounted();
    }
    return __owl__.vnode;
  }
  /**
   * Only called by qweb t-component directive (when t-keepalive is set)
   */
  __remount() {
    const __owl__ = this.__owl__;
    if (!__owl__.isMounted) {
      __owl__.isMounted = true;
      this.mounted();
    }
  }
  /**
   * Enable the observe feature on the state.  We only create an observer if
   * there is some state to be observed.
   */
  __observeState() {
    if (this.state) {
      const __owl__ = this.__owl__;
      __owl__.observer = new Observer();
      this.state = __owl__.observer.observe(this.state);
      __owl__.observer.notifyCB = this.render.bind(this);
    }
  }
  /**
   * Apply default props (only top level).
   *
   * Note that this method does not modify in place the props, it returns a new
   * prop object
   */
  __applyDefaultProps(props: Object | undefined, defaultProps: Object): Props {
    props = props ? Object.assign({}, props) : {};
    for (let propName in defaultProps) {
      if (props![propName] === undefined) {
        props![propName] = defaultProps[propName];
      }
    }
    return <Props>props;
  }
  /**
   * Apply the given patch queue. A patch is a pair [c, vn], where c is a
   * Component instance and vn a VNode.
   *   1) Call 'willPatch' on the component of each patch
   *   2) Call '__patch' on the component of each patch
   *   3) Call 'patched' on the component of each patch, in inverse order
   */
  __applyPatchQueue(patchQueue: any[]) {
    let component = this;
    try {
      const patchLen = patchQueue.length;
      for (let i = 0; i < patchLen; i++) {
        const patch = patchQueue[i];
        component = patch[0];
        patch.push(patch[0].willPatch());
      }
      for (let i = 0; i < patchLen; i++) {
        const patch = patchQueue[i];
        patch[0].__patch(patch[1]);
      }
      for (let i = patchLen - 1; i >= 0; i--) {
        const patch = patchQueue[i];
        component = patch[0];
        patch[0].patched(patch[2]);
      }
    } catch (e) {
      errorHandler(e, component);
    }
  }
 }
 //------------------------------------------------------------------------------
 // Error handling
 //------------------------------------------------------------------------------
 /**
 * This is the global error handler for errors occurring in Owl main lifecycle
 * methods.  Caught errors are triggered on the QWeb instance, and are
 * potentially given to some parent component which implements `catchError`.
 *
 * If there are no such component, we destroy everything. This is better than
 * being in a corrupted state.
 */
 function errorHandler(error: Error, component: Component<any, any, any>) {
  let canCatch = false;
  let qweb = component.env.qweb;
  let root = component;
  while (component && !(canCatch = component.catchError !== Component.prototype.catchError)) {
    root = component;
    component = component.__owl__.parent!;
  }
  console.error(error);
  // we trigger error on QWeb so it can be logged/handled
  qweb.trigger("error", error);
  if (canCatch) {
    setTimeout(() => {
      component.catchError(error);
    });
  } else {
    root.destroy();
  }
 }
@@ -0,0 +1,310 @@
 import type { App, Env } from "../app/app";
 import { BDom, VNode } from "../blockdom";
 import { Component } from "./component";
 import {
  Fiber,
  makeChildFiber,
  makeRootFiber,
  MountFiber,
  MountOptions,
  RootFiber,
 } from "./fibers";
 import { handleError, fibersInError } from "./error_handling";
 import { applyDefaultProps } from "./props_validation";
 import { STATUS } from "./status";
 let currentNode: ComponentNode | null = null;
 export function getCurrent(): ComponentNode | null {
  return currentNode;
 }
 export function useComponent(): Component {
  return currentNode!.component;
 }
 export function component(
  name: string | typeof Component,
  props: any,
  key: string,
  ctx: ComponentNode,
  parent: any
 ): ComponentNode {
  let node: any = ctx.children[key];
  let isDynamic = typeof name !== "string";
  if (node) {
    if (node.status < STATUS.MOUNTED) {
      node.destroy();
      node = undefined;
    } else if (node.status === STATUS.DESTROYED) {
      node = undefined;
    }
  }
  if (isDynamic && node && node.component.constructor !== name) {
    node = undefined;
  }
  const parentFiber = ctx.fiber!;
  if (node) {
    node.updateAndRender(props, parentFiber);
  } else {
    // new component
    let C;
    if (isDynamic) {
      C = name;
    } else {
      C = parent.constructor.components[name as any];
      if (!C) {
        throw new Error(`Cannot find the definition of component "${name}"`);
      }
    }
    node = new ComponentNode(C, props, ctx.app, ctx);
    ctx.children[key] = node;
    const fiber = makeChildFiber(node, parentFiber);
    node.initiateRender(fiber);
  }
  return node;
 }
 // -----------------------------------------------------------------------------
 //  Component VNode
 // -----------------------------------------------------------------------------
 type LifecycleHook = Function;
 export class ComponentNode<T extends typeof Component = typeof Component>
  implements VNode<ComponentNode>
 {
  el?: HTMLElement | Text | undefined;
  app: App;
  fiber: Fiber | null = null;
  component: InstanceType<T>;
  bdom: BDom | null = null;
  status: STATUS = STATUS.NEW;
  renderFn: Function;
  parent: ComponentNode | null;
  level: number;
  childEnv: Env;
  children: { [key: string]: ComponentNode } = Object.create(null);
  refs: any = {};
  willStart: LifecycleHook[] = [];
  willUpdateProps: LifecycleHook[] = [];
  willUnmount: LifecycleHook[] = [];
  mounted: LifecycleHook[] = [];
  willPatch: LifecycleHook[] = [];
  patched: LifecycleHook[] = [];
  willDestroy: LifecycleHook[] = [];
  constructor(C: T, props: any, app: App, parent?: ComponentNode) {
    currentNode = this;
    this.app = app;
    this.parent = parent || null;
    this.level = parent ? parent.level + 1 : 0;
    applyDefaultProps(props, C);
    const env = (parent && parent.childEnv) || app.env;
    this.childEnv = env;
    this.component = new C(props, env, this) as any;
    this.renderFn = app.getTemplate(C.template).bind(this.component, this.component, this);
    this.component.setup();
  }
  mountComponent(target: any, options?: MountOptions) {
    const fiber = new MountFiber(this, target, options);
    this.app.scheduler.addFiber(fiber);
    this.initiateRender(fiber);
  }
  async initiateRender(fiber: Fiber | MountFiber) {
    this.fiber = fiber;
    if (this.mounted.length) {
      fiber.root.mounted.push(fiber);
    }
    const component = this.component;
    try {
      await Promise.all(this.willStart.map((f) => f.call(component)));
    } catch (e) {
      handleError({ node: this, error: e });
      return;
    }
    if (this.status === STATUS.NEW && this.fiber === fiber) {
      this._render(fiber);
    }
  }
  async render() {
    let current = this.fiber;
    if (current && current.root.locked) {
      await Promise.resolve();
      // situation may have changed after the microtask tick
      current = this.fiber;
    }
    if (current && !current.bdom && !fibersInError.has(current)) {
      return;
    }
    if (!this.bdom && !current) {
      return;
    }
    const fiber = makeRootFiber(this);
    this.fiber = fiber;
    this.app.scheduler.addFiber(fiber);
    await Promise.resolve();
    if (this.status === STATUS.DESTROYED) {
      return;
    }
    // We only want to actually render the component if the following two
    // conditions are true:
    // * this.fiber: it could be null, in which case the render has been cancelled
    // * (current || !fiber.parent): if current is not null, this means that the
    //   render function was called when a render was already occurring. In this
    //   case, the pending rendering was cancelled, and the fiber needs to be
    //   rendered to complete the work.  If current is null, we check that the
    //   fiber has no parent.  If that is the case, the fiber was downgraded from
    //   a root fiber to a child fiber in the previous microtick, because it was
    //   embedded in a rendering coming from above, so the fiber will be rendered
    //   in the next microtick anyway, so we should not render it again.
    if (this.fiber && (current || !fiber.parent)) {
      this._render(fiber);
    }
  }
  _render(fiber: Fiber | RootFiber) {
    try {
      fiber.bdom = this.renderFn();
      fiber.root.counter--;
    } catch (e) {
      handleError({ node: this, error: e });
    }
  }
  destroy() {
    let shouldRemove = this.status === STATUS.MOUNTED;
    this._destroy();
    if (shouldRemove) {
      this.bdom!.remove();
    }
  }
  _destroy() {
    const component = this.component;
    if (this.status === STATUS.MOUNTED) {
      for (let cb of this.willUnmount) {
        cb.call(component);
      }
    }
    for (let child of Object.values(this.children)) {
      child._destroy();
    }
    for (let cb of this.willDestroy) {
      cb.call(component);
    }
    this.status = STATUS.DESTROYED;
  }
  async updateAndRender(props: any, parentFiber: Fiber) {
    // update
    const fiber = makeChildFiber(this, parentFiber);
    this.fiber = fiber;
    const component = this.component;
    applyDefaultProps(props, component.constructor as any);
    const prom = Promise.all(this.willUpdateProps.map((f) => f.call(component, props)));
    await prom;
    if (fiber !== this.fiber) {
      return;
    }
    component.props = props;
    this._render(fiber);
    const parentRoot = parentFiber.root;
    if (this.willPatch.length) {
      parentRoot.willPatch.push(fiber);
    }
    if (this.patched.length) {
      parentRoot.patched.push(fiber);
    }
  }
  /**
   * Finds a child that has dom that is not yet updated, and update it. This
   * method is meant to be used only in the context of repatching the dom after
   * a mounted hook failed and was handled.
   */
  updateDom() {
    if (!this.fiber) {
      return;
    }
    if (this.bdom === this.fiber!.bdom) {
      // If the error was handled by some child component, we need to find it to
      // apply its change
      for (let k in this.children) {
        const child = this.children[k];
        child.updateDom();
      }
    } else {
      // if we get here, this is the component that handled the error and rerendered
      // itself, so we can simply patch the dom
      this.bdom!.patch(this.fiber!.bdom, false);
      this.fiber!.appliedToDom = true;
      this.fiber = null;
    }
  }
  // ---------------------------------------------------------------------------
  // Block DOM methods
  // ---------------------------------------------------------------------------
  firstNode(): Node | undefined {
    const bdom = this.bdom;
    return bdom ? bdom.firstNode() : undefined;
  }
  mount(parent: HTMLElement, anchor: ChildNode) {
    const bdom = this.fiber!.bdom!;
    this.bdom = bdom;
    bdom.mount(parent, anchor);
    this.status = STATUS.MOUNTED;
    this.fiber!.appliedToDom = true;
    this.fiber = null;
  }
  moveBefore(other: ComponentNode | null, afterNode: Node | null) {
    this.bdom!.moveBefore(other ? other.bdom : null, afterNode);
  }
  patch() {
    this.bdom!.patch(this!.fiber!.bdom!, false);
    this.cleanOutdatedChildren();
    this.fiber!.appliedToDom = true;
    this.fiber = null;
  }
  beforeRemove() {
    console.log('ddddddd')
    this._destroy();
  }
  remove() {
    console.log('coucou')
    this.bdom!.remove();
  }
  cleanOutdatedChildren() {
    const childrenEntries = Object.entries(this.children);
    if (!childrenEntries.length) {
      return;
    }
    const children = this.children;
    for (const [key, node] of childrenEntries) {
      const status = node.status;
      if (status !== STATUS.MOUNTED) {
        delete children[key];
        if (status !== STATUS.DESTROYED) {
          node.destroy();
        }
      }
    }
  }
 }
@@ -1,501 +0,0 @@
 import { QWeb } from "../qweb/index";
 import { MODS_CODE } from "../qweb/extensions";
 //------------------------------------------------------------------------------
 // t-component
 //------------------------------------------------------------------------------
 const T_COMPONENT_MODS_CODE = Object.assign({}, MODS_CODE, {
  self: "if (e.target !== vn.elm) {return}"
 });
 QWeb.utils.defineProxy = function defineProxy(target, source) {
  for (let k in source) {
    Object.defineProperty(target, k, {
      get() {
        return source[k];
      },
      set(val) {
        source[k] = val;
      }
    });
  }
 };
 /**
 * The t-component directive is certainly a complicated and hard to maintain piece
 * of code.  To help you, fellow developer, if you have to maintain it, I offer
 * you this advice: Good luck...
 *
 * Since it is not 'direct' code, but rather code that generates other code, it
 * is not easy to understand.  To help you, here  is a detailed and commented
 * explanation of the code generated by the t-component directive for the following
 * situation:
 * ```xml
 *   <Child
 *      t-key="'somestring'"
 *      flag="state.flag"
 *      t-transition="fade"/>
 * ```
 *
 * ```js
 * // we assign utils on top of the function because it will be useful for
 * // each components
 * let utils = this.utils;
 *
 * // this is the virtual node representing the parent div
 * let c1 = [], p1 = { key: 1 };
 * var vn1 = h("div", p1, c1);
 *
 * // t-component directive: we start by evaluating the expression given by t-key:
 * let key5 = "somestring";
 *
 * // def3 is the promise that will contain later either the new component
 * // creation, or the props update...
 * let def3;
 *
 * // this is kind of tricky: we need here to find if the component was already
 * // created by a previous rendering.  This is done by checking the internal
 * // `cmap` (children map) of the parent component: it maps keys to component ids,
 * // and, then, if there is an id, we look into the children list to get the
 * // instance
 * let w4 =
 *   key5 in context.__owl__.cmap
 *   ? context.__owl__.children[context.__owl__.cmap[key5]]
 *   : false;
 *
 * // We keep the index of the position of the component in the closure.  We push
 * // null to reserve the slot, and will replace it later by the component vnode,
 * // when it will be ready (do not forget that preparing/rendering a component is
 * // asynchronous)
 * let _2_index = c1.length;
 * c1.push(null);
 *
 * // we evaluate here the props given to the component. It is done here to be
 * // able to easily reference it later, and also, it might be an expensive
 * // computation, so it is certainly better to do it only once
 * let props4 = { flag: context["state"].flag };
 *
 * // If we have a component, currently rendering, but not ready yet, we do not want
 * // to wait for it to be ready if we can avoid it
 * if (w4 && w4.__owl__.renderPromise && !w4.__owl__.vnode) {
 *   // we check if the props are the same.  In that case, we can simply reuse
 *   // the previous rendering and skip all useless work
 *   if (utils.shallowEqual(props4, w4.__owl__.renderProps)) {
 *     def3 = w4.__owl__.renderPromise;
 *   } else {
 *     // if the props are not the same, we destroy the component and starts anew.
 *     // this will be faster than waiting for its rendering, then updating it
 *     w4.destroy();
 *     w4 = false;
 *   }
 * }
 *
 * if (!w4) {
 *   // in this situation, we need to create a new component.  First step is
 *   // to get a reference to the class, then create an instance with
 *   // current context as parent, and the props.
 *   let W4 = context.component && context.components[componentKey4] || QWeb.component[componentKey4];
 *   if (!W4) {
 *     throw new Error("Cannot find the definition of component 'child'");
 *   }
 *   w4 = new W4(owner, props4);
 *
 *   // Whenever we rerender the parent component, we need to be sure that we
 *   // are able to find the component instance. To do that, we register it to
 *   // the parent cmap (children map).  Note that the 'template' key is
 *   // used here, since this is what identify the component from the template
 *   // perspective.
 *   context.__owl__.cmap[key5] = w4.__owl__.id;
 *
 *   // __prepare is called, to basically call willStart, then render the
 *   // component
 *   def3 = w4.__prepare();
 *
 *   def3 = def3.then(vnode => {
 *     // we create here a virtual node for the parent (NOT the component). This
 *     // means that the vdom of the parent will be stopped here, and from
 *     // the parent's perspective, it simply is a vnode with no children.
 *     // However, it shares the same dom element with the component root
 *     // vnode.
 *     let pvnode = h(vnode.sel, { key: key5 });
 *
 *     // we add hooks to the parent vnode so we can interact with the new
 *     // component at the proper time
 *     pvnode.data.hook = {
 *       insert(vn) {
 *         // the __mount method will patch the component vdom into the elm vn.elm,
 *         // then call the mounted hooks. However, suprisingly, the snabbdom
 *         // patch method actually replace the elm by a new elm, so we need
 *         // to synchronise the pvnode elm with the resulting elm
 *         let nvn = w4.__mount(vnode, vn.elm);
 *         pvnode.elm = nvn.elm;
 *         // what follows is only present if there are animations on the component
 *         utils.transitionInsert(vn, "fade");
 *       },
 *       remove() {
 *         // override with empty function to prevent from removing the node
 *         // directly. It will be removed when destroy is called anyway, which
 *         // delays the removal if there are animations.
 *       },
 *       destroy() {
 *         // if there are animations, we delay the call to destroy on the
 *         // component, if not, we call it directly.
 *         let finalize = () => {
 *           w4.destroy();
 *         };
 *         utils.transitionRemove(vn, "fade", finalize);
 *       }
 *     };
 *     // the pvnode is inserted at the correct position in the div's children
 *     c1[_2_index] = pvnode;
 *
 *     // we keep here a reference to the parent vnode (representing the
 *     // component, so we can reuse it later whenever we update the component
 *     w4.__owl__.pvnode = pvnode;
 *   });
 * } else {
 *   // this is the 'update' path of the directive.
 *   // the call to __updateProps is the actual component update
 *   // Note that we only update the props if we cannot reuse the previous
 *   // rendering work (in the case it was rendered with the same props)
 *   def3 = def3 || w4.__updateProps(props4, extra.forceUpdate, extra.patchQueue);
 *   def3 = def3.then(() => {
 *     // if component was destroyed in the meantime, we do nothing (so, this
 *     // means that the parent's element children list will have a null in
 *     // the component's position, which will cause the pvnode to be removed
 *     // when it is patched.
 *     if (w4.__owl__.isDestroyed) {
 *       return;
 *     }
 *     // like above, we register the pvnode to the children list, so it
 *     // will not be patched out of the dom.
 *     let pvnode = w4.__owl__.pvnode;
 *     c1[_2_index] = pvnode;
 *   });
 * }
 *
 * // we register the deferred here so the parent can coordinate its patch operation
 * // with all the children.
 * extra.promises.push(def3);
 * return vn1;
 * ```
 */
 QWeb.addDirective({
  name: "component",
  extraNames: ["props", "keepalive", "asyncroot"],
  priority: 100,
  atNodeEncounter({ ctx, value, node, qweb }): boolean {
    ctx.addLine("//COMPONENT");
    ctx.rootContext.shouldDefineOwner = true;
    ctx.rootContext.shouldDefineQWeb = true;
    ctx.rootContext.shouldDefineParent = true;
    ctx.rootContext.shouldDefineUtils = true;
    let keepAlive = node.getAttribute("t-keepalive") ? true : false;
    let async = node.getAttribute("t-asyncroot") ? true : false;
    // t-on- events and t-transition
    const events: [string, string[], string, string][] = [];
    let transition: string = "";
    const attributes = (<Element>node).attributes;
    const props: { [key: string]: string } = {};
    for (let i = 0; i < attributes.length; i++) {
      const name = attributes[i].name;
      const value = attributes[i].textContent!;
      if (name.startsWith("t-on-")) {
        const [eventName, ...mods] = name.slice(5).split(".");
        let extraArgs;
        let handlerName = value.replace(/\(.*\)/, function(args) {
          extraArgs = args.slice(1, -1);
          return "";
        });
        events.push([eventName, mods, handlerName, extraArgs]);
      } else if (name === "t-transition") {
        transition = value;
      } else if (!name.startsWith("t-")) {
        if (name !== "class" && name !== "style") {
          // this is a prop!
          props[name] = ctx.formatExpression(value);
        }
      }
    }
    let key = node.getAttribute("t-key");
    if (key) {
      key = ctx.formatExpression(key);
    }
    // computing the props string representing the props object
    let propStr = Object.keys(props)
      .map(k => k + ":" + props[k])
      .join(",");
    let dummyID = ctx.generateID();
    let defID = ctx.generateID();
    let componentID = ctx.generateID();
    let keyID = key && ctx.generateID();
    if (key) {
      // we bind a variable to the key (could be a complex expression, so we
      // want to evaluate it only once)
      ctx.addLine(`let key${keyID} = ${key};`);
    }
    ctx.addLine(`let def${defID};`);
    let templateID = key
      ? `key${keyID}`
      : ctx.inLoop
      ? `String(-${componentID} - i)`
      : String(componentID);
    if (ctx.allowMultipleRoots) {
      // necessary to prevent collisions
      if (!key && ctx.inLoop) {
        let id = ctx.generateID();
        ctx.addLine(`let template${id} = "_slot_" + String(-${componentID} - i)`);
        templateID = `template${id}`;
      } else {
        templateID = `"_slot_${templateID}"`;
      }
    }
    let ref = node.getAttribute("t-ref");
    let refExpr = "";
    let refKey: string = "";
    if (ref) {
      refKey = `ref${ctx.generateID()}`;
      ctx.addLine(`const ${refKey} = ${ctx.interpolate(ref)};`);
      refExpr = `context.refs[${refKey}] = w${componentID};`;
    }
    let transitionsInsertCode = "";
    if (transition) {
      transitionsInsertCode = `utils.transitionInsert(vn, '${transition}');`;
    }
    let finalizeComponentCode = `w${componentID}.${keepAlive ? "unmount" : "destroy"}();`;
    if (ref && !keepAlive) {
      finalizeComponentCode += `delete context.refs[${refKey}];`;
    }
    if (transition) {
      finalizeComponentCode = `let finalize = () => {
          ${finalizeComponentCode}
        };
        utils.transitionRemove(vn, '${transition}', finalize);`;
    }
    let createHook = "";
    let classAttr = node.getAttribute("class");
    let tattClass = node.getAttribute("t-att-class");
    let styleAttr = node.getAttribute("style");
    let tattStyle = node.getAttribute("t-att-style");
    if (tattStyle) {
      const attVar = `_${ctx.generateID()}`;
      ctx.addLine(`const ${attVar} = ${ctx.formatExpression(tattStyle)};`);
      tattStyle = attVar;
    }
    let classObj = "";
    if (classAttr || tattClass || styleAttr || tattStyle || events.length) {
      if (classAttr) {
        let classDef = classAttr
          .trim()
          .split(/\s+/)
          .map(a => `'${a}':true`)
          .join(",");
        classObj = `_${ctx.generateID()}`;
        ctx.addLine(`let ${classObj} = {${classDef}};`);
      }
      if (tattClass) {
        let tattExpr = ctx.formatExpression(tattClass);
        if (tattExpr[0] !== "{" || tattExpr[tattExpr.length - 1] !== "}") {
          tattExpr = `utils.toObj(${tattExpr})`;
        }
        if (classAttr) {
          ctx.addLine(`Object.assign(${classObj}, ${tattExpr})`);
        } else {
          classObj = `_${ctx.generateID()}`;
          ctx.addLine(`let ${classObj} = ${tattExpr};`);
        }
      }
      let eventsCode = events
        .map(function([eventName, mods, handlerName, extraArgs]) {
          let params = "owner";
          if (extraArgs) {
            if (ctx.inLoop) {
              let argId = ctx.generateID();
              // we need to evaluate the arguments now, because the handler will
              // be set asynchronously later when the widget is ready, and the
              // context might be different.
              ctx.addLine(`let arg${argId} = ${ctx.formatExpression(extraArgs)};`);
              params = `owner, arg${argId}`;
            } else {
              params = `owner, ${ctx.formatExpression(extraArgs)}`;
            }
          }
          let handler;
          if (mods.length > 0) {
            handler = `function (e) {`;
            handler += mods
              .map(function(mod) {
                return T_COMPONENT_MODS_CODE[mod];
              })
              .join("");
            handler += `owner['${handlerName}'].call(${params}, e);}`;
          } else {
            handler = `owner['${handlerName}'].bind(${params})`;
          }
          return `vn.elm.addEventListener('${eventName}', ${handler});`;
        })
        .join("");
      const styleExpr = tattStyle || (styleAttr ? `'${styleAttr}'` : false);
      const styleCode = styleExpr ? `vn.elm.style = ${styleExpr};` : "";
      createHook = `vnode.data.hook = {create(_, vn){${styleCode}${eventsCode}}};`;
    }
    ctx.addLine(
      `let w${componentID} = ${templateID} in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap[${templateID}]] : false;`
    );
    if (ctx.parentNode) {
      ctx.addLine(`let _${dummyID}_index = c${ctx.parentNode}.length;`);
    }
    let shouldProxy = false;
    if (async) {
      ctx.addLine(`const patchQueue${componentID} = [];`);
      ctx.addLine(
        `c${ctx.parentNode}.push(w${componentID} && w${componentID}.__owl__.pvnode || null);`
      );
    } else {
      if (ctx.parentNode) {
        ctx.addLine(`c${ctx.parentNode}.push(null);`);
      } else {
        let id = ctx.generateID();
        ctx.rootContext.rootNode = id;
        shouldProxy = true;
        ctx.rootContext.shouldDefineResult = true;
        ctx.addLine(`let vn${id} = {};`);
        ctx.addLine(`result = vn${id};`);
      }
    }
    ctx.addLine(`let props${componentID} = {${propStr}};`);
    ctx.addIf(
      `w${componentID} && w${componentID}.__owl__.renderPromise && !w${componentID}.__owl__.vnode`
    );
    ctx.addIf(`utils.shallowEqual(props${componentID}, w${componentID}.__owl__.renderProps)`);
    ctx.addLine(`def${defID} = w${componentID}.__owl__.renderPromise;`);
    ctx.addElse();
    ctx.addLine(`w${componentID}.destroy();`);
    ctx.addLine(`w${componentID} = false;`);
    ctx.closeIf();
    ctx.closeIf();
    ctx.addIf(`!w${componentID}`);
    // new component
    ctx.addLine(`let componentKey${componentID} = ${ctx.interpolate(value)};`);
    ctx.addLine(
      `let W${componentID} = context.components && context.components[componentKey${componentID}] || QWeb.components[componentKey${componentID}];`
    );
    // maybe only do this in dev mode...
    ctx.addLine(
      `if (!W${componentID}) {throw new Error('Cannot find the definition of component "' + componentKey${componentID} + '"')}`
    );
    if (QWeb.dev) {
      ctx.addLine(`utils.validateProps(W${componentID}, props${componentID})`);
    }
    ctx.addLine(`w${componentID} = new W${componentID}(parent, props${componentID});`);
    ctx.addLine(`parent.__owl__.cmap[${templateID}] = w${componentID}.__owl__.id;`);
    // SLOTS
    const varDefs: string[] = [];
    const hasSlots = node.childNodes.length;
    if (hasSlots) {
      ctx.rootContext.shouldTrackScope = true;
      for (let v of Object.values(ctx.variables)) {
        if (v["id"]) {
          varDefs.push(v["id"]);
        }
      }
      const clone = <Element>node.cloneNode(true);
      const slotNodes = clone.querySelectorAll("[t-set]");
      const slotId = qweb.nextSlotId++;
      ctx.addLine(`w${componentID}.__owl__.slotId = ${slotId};`);
      if (slotNodes.length) {
        for (let i = 0, length = slotNodes.length; i < length; i++) {
          const slotNode = slotNodes[i];
          slotNode.parentElement!.removeChild(slotNode);
          const key = slotNode.getAttribute("t-set")!;
          slotNode.removeAttribute("t-set");
          const slotFn = qweb._compile(`slot_${key}_template`, slotNode, ctx);
          qweb.slots[`${slotId}_${key}`] = slotFn.bind(qweb);
        }
      }
      if (clone.childNodes.length) {
        const t = clone.ownerDocument!.createElement("t");
        for (let child of Object.values(clone.childNodes)) {
          t.appendChild(child);
        }
        const slotFn = qweb._compile(`slot_default_template`, t, ctx);
        qweb.slots[`${slotId}_default`] = slotFn.bind(qweb);
      }
    }
    let scopeVars = "";
    if (hasSlots) {
      scopeVars += ctx.scopeVars.length ? `Object.assign({}, scope)` : varDefs.length ? `{}` : "";
      if (varDefs.length) {
        scopeVars += `, {${varDefs.join(",")}}`;
      }
    }
    ctx.addLine(`def${defID} = w${componentID}.__prepare(${scopeVars});`);
    // hack: specify empty remove hook to prevent the node from being removed from the DOM
    let registerCode = `c${ctx.parentNode}[_${dummyID}_index]=pvnode;`;
    if (shouldProxy) {
      registerCode = `utils.defineProxy(vn${ctx.rootNode}, pvnode);`;
    }
    ctx.addLine(
      `def${defID} = def${defID}.then(vnode=>{${createHook}let pvnode=h(vnode.sel, {key: ${templateID}, hook: {insert(vn) {let nvn=w${componentID}.__mount(vnode, pvnode.elm);pvnode.elm=nvn.elm;${refExpr}${transitionsInsertCode}},remove() {},destroy(vn) {${finalizeComponentCode}}}});${registerCode}w${componentID}.__owl__.pvnode = pvnode;});`
    );
    ctx.addElse();
    // need to update component
    let patchQueueCode = async ? `patchQueue${componentID}` : "extra.patchQueue";
    if (keepAlive) {
        // if we have t-keepalive="1", the component could be unmounted, but then
        // we __updateProps is called.  This is ok, but we do not want to call
        // the willPatch/patched hooks of the component in this case, so we
        // disable the patch queue
        patchQueueCode = `w${componentID}.__owl__.isMounted ? ${patchQueueCode} : []`;
    }
    if (QWeb.dev) {
      ctx.addLine(`utils.validateProps(w${componentID}.constructor, props${componentID})`);
    }
    ctx.addLine(
      `def${defID} = def${defID} || w${componentID}.__updateProps(props${componentID}, extra.forceUpdate, ${patchQueueCode}${scopeVars &&
        ", " + scopeVars});`
    );
    let keepAliveCode = "";
    if (keepAlive) {
      keepAliveCode = `pvnode.data.hook.insert = vn => {vn.elm.parentNode.replaceChild(w${componentID}.el,vn.elm);vn.elm=w${componentID}.el;w${componentID}.__remount();};`;
    }
    ctx.addLine(
      `def${defID} = def${defID}.then(()=>{if (w${componentID}.__owl__.isDestroyed) {return};${
        tattStyle ? `w${componentID}.el.style=${tattStyle};` : ""
      }let pvnode=w${componentID}.__owl__.pvnode;${keepAliveCode}${registerCode}});`
    );
    ctx.closeIf();
    if (classObj) {
      ctx.addLine(`w${componentID}.__owl__.classObj=${classObj};`);
    }
    if (async) {
      ctx.addLine(
        `def${defID}.then(w${componentID}.__applyPatchQueue.bind(w${componentID}, patchQueue${componentID}));`
      );
    } else {
      ctx.addLine(`extra.promises.push(def${defID});`);
    }
    if (node.hasAttribute("t-if") || node.hasAttribute("t-else") || node.hasAttribute("t-elif")) {
      ctx.closeIf();
    }
    return true;
  }
 });
@@ -0,0 +1,66 @@
 import type { ComponentNode } from "./component_node";
 import type { Fiber } from "./fibers";
 // Maps fibers to thrown errors
 export const fibersInError: WeakMap<Fiber, any> = new WeakMap();
 export const nodeErrorHandlers: WeakMap<ComponentNode, ((error: any) => void)[]> = new WeakMap();
 function _handleError(node: ComponentNode | null, error: any, isFirstRound = false): boolean {
  if (!node) {
    return false;
  }
  const fiber = node.fiber;
  if (fiber) {
    fibersInError.set(fiber, error);
  }
  const errorHandlers = nodeErrorHandlers.get(node);
  if (errorHandlers) {
    let stopped = false;
    // execute in the opposite order
    for (let i = errorHandlers.length - 1; i >= 0; i--) {
      try {
        errorHandlers[i](error);
        stopped = true;
        break;
      } catch (e) {
        error = e;
      }
    }
    if (stopped) {
      if (isFirstRound && fiber) {
        fiber.root.counter--;
      }
      return true;
    }
  }
  return _handleError(node.parent, error);
 }
 type ErrorParams = { error: any } & ({ node: ComponentNode } | { fiber: Fiber });
 export function handleError(params: ErrorParams) {
  const error = params.error;
  const node = "node" in params ? params.node : params.fiber.node;
  const fiber = "fiber" in params ? params.fiber : node.fiber!;
  // resets the fibers on components if possible. This is important so that
  // new renderings can be properly included in the initial one, if any.
  let current: Fiber | null = fiber;
  do {
    current.node.fiber = current;
    current = current.parent;
  } while (current);
  fibersInError.set(fiber.root, error);
  const handled = _handleError(node, error, true);
  if (!handled) {
    console.warn(`[Owl] Unhandled error. Destroying the root component`);
    try {
      node.app.destroy();
    } catch (e) {
      console.error(e);
    }
  }
 }
@@ -0,0 +1,236 @@
 import { BDom, mount } from "../blockdom";
 import type { ComponentNode } from "./component_node";
 import { fibersInError, handleError } from "./error_handling";
 import { STATUS } from "./status";
 /**
 * Cleans on the root fiber the patch and willPatch fiber lists
 * It is typically needed when the same root fiber needs to recycle on
 * of its children or grandchildren's fiber.
 */
 function cleanPatchableFiber(child: Fiber, root: RootFiber) {
  const { willPatch, patched } = root;
  let i = willPatch.indexOf(child);
  if (i > -1) {
    willPatch.splice(i, 1);
  }
  i = patched.indexOf(child);
  if (i > -1) {
    patched.splice(i, 1);
  }
 }
 export function makeChildFiber(node: ComponentNode, parent: Fiber): Fiber {
  let current = node.fiber;
  if (current) {
    // current is necessarily a rootfiber here
    let root = parent.root;
    const isSameRoot = current.root === root;
    cancelFibers(root, current.children);
    current.children = [];
    current.parent = parent;
    // only increment our rendering if we were not
    // already accounted for, or that we have been rendered
    // already (in which case our fiber was removed from the root rendering)
    if (!isSameRoot || current.bdom) {
      root.counter++;
    }
    if (isSameRoot) {
      cleanPatchableFiber(current, root);
    }
    current.bdom = null;
    current.root = root;
    return current;
  }
  return new Fiber(node, parent);
 }
 export function makeRootFiber(node: ComponentNode): Fiber {
  let current = node.fiber;
  if (current) {
    let root = current.root;
    root.counter -= cancelFibers(root, current.children);
    current.children = [];
    root.counter++;
    current.bdom = null;
    if (fibersInError.has(current)) {
      fibersInError.delete(current);
      fibersInError.delete(root);
      current.appliedToDom = false;
    }
    return current;
  }
  const fiber = new RootFiber(node, null);
  if (node.willPatch.length) {
    fiber.willPatch.push(fiber);
  }
  if (node.patched.length) {
    fiber.patched.push(fiber);
  }
  return fiber;
 }
 /**
 * @returns number of not-yet rendered fibers cancelled
 */
 function cancelFibers(root: any, fibers: Fiber[]): number {
  let result = 0;
  for (let fiber of fibers) {
    fiber.node.fiber = null;
    fiber.root = root;
    if (!fiber.bdom) {
      result++;
    }
    result += cancelFibers(root, fiber.children);
  }
  return result;
 }
 export class Fiber {
  node: ComponentNode;
  bdom: BDom | null = null;
  root: RootFiber;
  parent: Fiber | null;
  children: Fiber[] = [];
  appliedToDom = false;
  constructor(node: ComponentNode, parent: Fiber | null) {
    this.node = node;
    this.parent = parent;
    if (parent) {
      const root = parent.root;
      root.counter++;
      this.root = root;
      parent.children.push(this);
    } else {
      this.root = this as any;
    }
  }
 }
 export class RootFiber extends Fiber {
  counter: number = 1;
  // only add stuff in this if they have registered some hooks
  willPatch: Fiber[] = [];
  patched: Fiber[] = [];
  mounted: Fiber[] = [];
  // A fiber is typically locked when it is completing and the patch has not, or is being applied.
  // i.e.: render triggered in onWillUnmount or in willPatch will be delayed
  locked: boolean = false;
  complete() {
    const node = this.node;
    this.locked = true;
    let current: Fiber | undefined = undefined;
    try {
      // Step 1: calling all willPatch lifecycle hooks
      for (current of this.willPatch) {
        // because of the asynchronous nature of the rendering, some parts of the
        // UI may have been rendered, then deleted in a followup rendering, and we
        // do not want to call onWillPatch in that case.
        let node = current.node;
        if (node.fiber === current) {
          const component = node.component;
          for (let cb of node.willPatch) {
            cb.call(component);
          }
        }
      }
      current = undefined;
      // Step 2: patching the dom
      node.bdom!.patch(this.bdom!, Object.keys(node.children).length > 0);
      node.cleanOutdatedChildren();
      this.appliedToDom = true;
      this.locked = false;
      // unregistering the fiber before mounted since it can do another render
      // and that the current rendering is obviously completed
      node.fiber = null;
      // Step 4: calling all mounted lifecycle hooks
      let mountedFibers = this.mounted;
      while ((current = mountedFibers.pop())) {
        current = current;
        if (current.appliedToDom) {
          for (let cb of current.node.mounted) {
            cb();
          }
        }
      }
      // Step 5: calling all patched hooks
      let patchedFibers = this.patched;
      while ((current = patchedFibers.pop())) {
        current = current;
        if (current.appliedToDom) {
          for (let cb of current.node.patched) {
            cb();
          }
        }
      }
    } catch (e) {
      this.locked = false;
      handleError({ fiber: current || this, error: e });
    }
  }
 }
 type Position = "first-child" | "last-child";
 export interface MountOptions {
  position?: Position;
 }
 export class MountFiber extends RootFiber {
  target: HTMLElement;
  position: Position;
  constructor(node: ComponentNode, target: HTMLElement, options: MountOptions = {}) {
    super(node, null);
    this.target = target;
    this.position = options.position || "last-child";
  }
  complete() {
    let current: Fiber | undefined = this;
    try {
      const node = this.node;
      if (node.bdom) {
        // this is a complicated situation: if we mount a fiber with an existing
        // bdom, this means that this same fiber was already completed, mounted,
        // but a crash occurred in some mounted hook. Then, it was handled and
        // the new rendering is being applied.
        node.updateDom();
      } else {
        node.bdom = this.bdom;
        if (this.position === "last-child" || this.target.childNodes.length === 0) {
          mount(node.bdom!, this.target);
        } else {
          const firstChild = this.target.childNodes[0];
          mount(node.bdom!, this.target, firstChild);
        }
      }
      // unregistering the fiber before mounted since it can do another render
      // and that the current rendering is obviously completed
      node.fiber = null;
      node.status = STATUS.MOUNTED;
      this.appliedToDom = true;
      let mountedFibers = this.mounted;
      while ((current = mountedFibers.pop())) {
        if (current.appliedToDom) {
          for (let cb of current.node.mounted) {
            cb();
          }
        }
      }
    } catch (e) {
      handleError({ fiber: current as Fiber, error: e });
    }
  }
 }
@@ -0,0 +1,36 @@
 import { filterOutModifiersFromData } from "../blockdom/config";
 export const mainEventHandler = (data: any, ev: Event, currentTarget?: EventTarget | null) => {
  const { data: _data, modifiers } = filterOutModifiersFromData(data);
  data = _data;
  let stopped = false;
  if (modifiers.length) {
    let selfMode = false;
    const isSelf = ev.target === currentTarget;
    for (const mod of modifiers) {
      switch (mod) {
        case "self":
          selfMode = true;
          if (isSelf) {
            continue;
          } else {
            return stopped;
          }
        case "prevent":
          if ((selfMode && isSelf) || !selfMode) ev.preventDefault();
          continue;
        case "stop":
          if ((selfMode && isSelf) || !selfMode) ev.stopPropagation();
          stopped = true;
          continue;
      }
    }
  }
  // If handler is empty, the array slot 0 will also be empty, and data will not have the property 0
  // We check this rather than data[0] being truthy (or typeof function) so that it crashes
  // as expected when there is a handler expression that evaluates to a falsy value
  if (Object.hasOwnProperty.call(data, 0)) {
    data[0].call(data[1] ? data[1].__owl__.component : null, ev);
  }
  return stopped;
 };
@@ -0,0 +1,71 @@
 import { getCurrent } from "./component_node";
 import { nodeErrorHandlers } from "./error_handling";
 // -----------------------------------------------------------------------------
 //  hooks
 // -----------------------------------------------------------------------------
 export function onWillStart(fn: () => Promise<void> | void | any) {
  const node = getCurrent()!;
  node.willStart.push(fn);
 }
 export function onWillUpdateProps(fn: (nextProps: any) => Promise<void> | void | any) {
  const node = getCurrent()!;
  node.willUpdateProps.push(fn);
 }
 export function onMounted(fn: () => void | any) {
  const node = getCurrent()!;
  node.mounted.push(fn);
 }
 export function onWillPatch(fn: () => Promise<void> | any | void) {
  const node = getCurrent()!;
  node.willPatch.unshift(fn);
 }
 export function onPatched(fn: () => void | any) {
  const node = getCurrent()!;
  node.patched.push(fn);
 }
 export function onWillUnmount(fn: () => Promise<void> | void | any) {
  const node = getCurrent()!;
  node.willUnmount.unshift(fn);
 }
 export function onWillDestroy(fn: () => Promise<void> | void | any) {
  const node = getCurrent()!;
  node.willDestroy.push(fn);
 }
 export function onWillRender(fn: () => void | any) {
  const node = getCurrent()!;
  const renderFn = node.renderFn;
  node.renderFn = () => {
    fn();
    return renderFn();
  };
 }
 export function onRendered(fn: () => void | any) {
  const node = getCurrent()!;
  const renderFn = node.renderFn;
  node.renderFn = () => {
    const result = renderFn();
    fn();
    return result;
  };
 }
 type OnErrorCallback = (error: any) => void | any;
 export function onError(callback: OnErrorCallback) {
  const node = getCurrent()!;
  let handlers = nodeErrorHandlers.get(node);
  if (!handlers) {
    handlers = [];
    nodeErrorHandlers.set(node, handlers);
  }
  handlers.push(callback);
 }
@@ -1,8 +1,32 @@
-import { QWeb } from "../qweb/index";
+import { Component } from "./component";
 /**
 * Apply default props (only top level).
 *
 * Note that this method does modify in place the props
 */
 export function applyDefaultProps(props: { [key: string]: any }, ComponentClass: typeof Component) {
  const defaultProps = (ComponentClass as any).defaultProps;
  if (defaultProps) {
    for (let propName in defaultProps) {
      if (props![propName] === undefined) {
        props![propName] = defaultProps[propName];
      }
    }
  }
 }
 //------------------------------------------------------------------------------
 // Prop validation helper
 //------------------------------------------------------------------------------
 function getPropDescription(staticProps: any) {
  if (staticProps instanceof Array) {
    return Object.fromEntries(
      staticProps.map((p) => (p.endsWith("?") ? [p.slice(0, -1), false] : [p, true]))
    );
  }
  return staticProps || { "*": true };
 }
 /**
 * Validate the component props (or next props) against the (static) props
@@ -10,44 +34,44 @@ import { QWeb } from "../qweb/index";
 * visit recursively the props and all the children to check if they are valid.
 * This is why it is only done in 'dev' mode.
 */
 export const validateProps = function (name: string | typeof Component, props: any, parent?: any) {
  const ComponentClass = (
    typeof name !== "string" ? name : parent.constructor.components[name]
  ) as typeof Component;
-QWeb.utils.validateProps = function(Widget, props: Object) {
+  applyDefaultProps(props, ComponentClass);
-  const propsDef = (<any>Widget).props;
+
-  if (propsDef instanceof Array) {
+  let propsDef = getPropDescription(ComponentClass.props);
-    // list of strings (prop names)
+  const allowAdditionalProps = "*" in propsDef;
-    for (let i = 0, l = propsDef.length; i < l; i++) {
+
-      const propName = propsDef[i];
+  for (let propName in propsDef) {
-      if (propName[propName.length - 1] === "?") {
+    if (propName === "*") {
-        // optional prop
+      continue;
-        break;
+    }
-      }
+    if (props[propName] === undefined) {
-      if (!props[propName]) {
+      if (propsDef[propName] && !propsDef[propName].optional) {
-        throw new Error(`Missing props '${propsDef[i]}' (component '${Widget.name}')`);
+        throw new Error(`Missing props '${propName}' (component '${ComponentClass.name}')`);
      } else {
        continue;
      }
    }
-    for (let key in props) {
+    let isValid;
-      if (!propsDef.includes(key) && !propsDef.includes(key + "?")) {
+    try {
-        throw new Error(`Unknown prop '${key}' given to component '${Widget.name}'`);
+      isValid = isValidProp(props[propName], propsDef[propName]);
-      }
+    } catch (e) {
      (e as Error).message = `Invalid prop '${propName}' in component ${ComponentClass.name} (${
        (e as Error).message
      })`;
      throw e;
    }
-  } else if (propsDef) {
+    if (!isValid) {
-    // propsDef is an object now
+      throw new Error(`Invalid Prop '${propName}' in component '${ComponentClass.name}'`);
    for (let propName in propsDef) {
      if (props[propName] === undefined) {
        if (propsDef[propName] && !propsDef[propName].optional) {
          throw new Error(`Missing props '${propName}' (component '${Widget.name}')`);
        } else {
          break;
        }
      }
      let isValid = isValidProp(props[propName], propsDef[propName]);
      if (!isValid) {
        throw new Error(`Props '${propName}' of invalid type in component '${Widget.name}'`);
      }
    }
  }
  if (!allowAdditionalProps) {
    for (let propName in props) {
      if (!(propName in propsDef)) {
-        throw new Error(`Unknown prop '${propName}' given to component '${Widget.name}'`);
+        throw new Error(`Unknown prop '${propName}' given to component '${ComponentClass.name}'`);
      }
    }
  }
@@ -56,7 +80,7 @@ QWeb.utils.validateProps = function(Widget, props: Object) {
 /**
 * Check if an invidual prop value matches its (static) prop definition
 */
-function isValidProp(prop, propDef): boolean {
+function isValidProp(prop: any, propDef: any): boolean {
  if (propDef === true) {
    return true;
  }
@@ -80,17 +104,30 @@ function isValidProp(prop, propDef): boolean {
    return result;
  }
  // propsDef is an object
-  let result = isValidProp(prop, propDef.type);
+  if (propDef.optional && prop === undefined) {
-  if (propDef.type === Array) {
+    return true;
  }
  let result = propDef.type ? isValidProp(prop, propDef.type) : true;
  if (propDef.validate) {
    result = result && propDef.validate(prop);
  }
  if (propDef.type === Array && propDef.element) {
    for (let i = 0, iLen = prop.length; i < iLen; i++) {
      result = result && isValidProp(prop[i], propDef.element);
    }
  }
-  if (propDef.type === Object) {
+  if (propDef.type === Object && propDef.shape) {
    const shape = propDef.shape;
    for (let key in shape) {
      result = result && isValidProp(prop[key], shape[key]);
    }
    if (result) {
      for (let propName in prop) {
        if (!(propName in shape)) {
          throw new Error(`unknown prop '${propName}'`);
        }
      }
    }
  }
  return result;
 }
@@ -0,0 +1,74 @@
 import { fibersInError } from "./error_handling";
 import { Fiber, RootFiber } from "./fibers";
 import { STATUS } from "./status";
 // -----------------------------------------------------------------------------
 //  Scheduler
 // -----------------------------------------------------------------------------
 export class Scheduler {
  tasks: Set<RootFiber> = new Set();
  isRunning: boolean = false;
  requestAnimationFrame: Window["requestAnimationFrame"];
  constructor(requestAnimationFrame: Window["requestAnimationFrame"]) {
    this.requestAnimationFrame = requestAnimationFrame;
  }
  start() {
    this.isRunning = true;
    this.scheduleTasks();
  }
  stop() {
    this.isRunning = false;
  }
  addFiber(fiber: Fiber) {
    this.tasks.add(fiber.root);
    if (!this.isRunning) {
      this.start();
    }
  }
  /**
   * Process all current tasks. This only applies to the fibers that are ready.
   * Other tasks are left unchanged.
   */
  flush() {
    this.tasks.forEach((fiber) => {
      if (fiber.root !== fiber) {
        this.tasks.delete(fiber);
        return;
      }
      const hasError = fibersInError.has(fiber);
      if (hasError && fiber.counter !== 0) {
        this.tasks.delete(fiber);
        return;
      }
      if (fiber.node.status === STATUS.DESTROYED) {
        this.tasks.delete(fiber);
        return;
      }
      if (fiber.counter === 0) {
        if (!hasError) {
          fiber.complete();
        }
        this.tasks.delete(fiber);
      }
    });
    if (this.tasks.size === 0) {
      this.stop();
    }
  }
  scheduleTasks() {
    this.requestAnimationFrame(() => {
      this.flush();
      if (this.isRunning) {
        this.scheduleTasks();
      }
    });
  }
 }
@@ -0,0 +1,24 @@
 import type { Component } from "./component";
 // -----------------------------------------------------------------------------
 //  Status
 // -----------------------------------------------------------------------------
 export const enum STATUS {
  NEW,
  MOUNTED, // is ready, and in DOM. It has a valid el
  DESTROYED,
 }
 type STATUS_DESCR = "new" | "mounted" | "destroyed";
 export function status(component: Component): STATUS_DESCR {
  switch (component.__owl__.status) {
    case STATUS.NEW:
      return "new";
    case STATUS.MOUNTED:
      return "mounted";
    case STATUS.DESTROYED:
      return "destroyed";
  }
 }
@@ -1,79 +0,0 @@
 /**
 * We define here a simple event bus: it can
 * - emit events
 * - add/remove listeners.
 *
 * This is a useful pattern of communication in many cases.  For OWL, each
 * components and stores are event buses.
 */
 //------------------------------------------------------------------------------
 // Types
 //------------------------------------------------------------------------------
 export type Callback = (...args: any[]) => void;
 export interface Subscription {
  owner: any;
  callback: Callback;
 }
 //------------------------------------------------------------------------------
 // EventBus
 //------------------------------------------------------------------------------
 export class EventBus {
  subscriptions: { [eventType: string]: Subscription[] } = {};
  /**
   * Add a listener for the 'eventType' events.
   *
   * Note that the 'owner' of this event can be anything, but will more likely
   * be a component or a class. The idea is that the callback will be called with
   * the proper owner bound.
   *
   * Also, the owner should be kind of unique. This will be used to remove the
   * listener.
   */
  on(eventType: string, owner: any, callback: Callback) {
    if (!callback) {
      throw new Error("Missing callback");
    }
    if (!this.subscriptions[eventType]) {
      this.subscriptions[eventType] = [];
    }
    this.subscriptions[eventType].push({
      owner,
      callback
    });
  }
  /**
   * Remove a listener
   */
  off(eventType: string, owner: any) {
    const subs = this.subscriptions[eventType];
    if (subs) {
      this.subscriptions[eventType] = subs.filter(s => s.owner !== owner);
    }
  }
  /**
   * Emit an event of type 'eventType'.  Any extra arguments will be passed to
   * the listeners callback.
   */
  trigger(eventType: string, ...args: any[]) {
    const subs = this.subscriptions[eventType] || [];
    for (let i = 0, iLen = subs.length; i < iLen; i++) {
      const sub = subs[i];
      sub.callback.call(sub.owner, ...args);
    }
  }
  /**
   * Remove all subscriptions.
   */
  clear() {
    this.subscriptions = {};
  }
 }
@@ -1,110 +0,0 @@
 /**
 * Owl Observer
 *
 * This code contains the logic that allows Owl to observe and react to state
 * changes.
 *
 * This is a Observer class that can observe any JS values.  The way it works
 * can be summarized thusly:
 * - primitive values are not observed at all
 * - Objects and arrays are observed by replacing them with a Proxy
 * - each object/array metadata are tracked in a weakmap, and keep a revision
 *   number
 *
 * Note that this code is loosely inspired by Vue.
 */
 //------------------------------------------------------------------------------
 // Observer
 //------------------------------------------------------------------------------
 export class Observer {
  rev: number = 1;
  allowMutations: boolean = true;
  dirty: boolean = false;
  weakMap: WeakMap<any, any> = new WeakMap();
  notifyCB() {}
  async notifyChange() {
    this.dirty = true;
    await Promise.resolve();
    if (this.dirty) {
      this.dirty = false;
      this.notifyCB();
    }
  }
  observe(value: any, parent?: any): any {
    if (value === null || typeof value !== "object" || value instanceof Date) {
      // fun fact: typeof null === 'object'
      return value;
    }
    let metadata = this.weakMap.get(value) || this._observe(value, parent);
    return metadata.proxy;
  }
  revNumber(value): number {
    const metadata = this.weakMap.get(value);
    return metadata ? metadata.rev : 0;
  }
  deepRevNumber(value): number {
    const metadata = this.weakMap.get(value);
    return metadata ? metadata.deepRev : 0;
  }
  _observe(value, parent) {
    var self = this;
    const proxy = new Proxy(value, {
      get(target, k) {
        const targetValue = target[k];
        return self.observe(targetValue, value);
      },
      set(target, key: string, newVal): boolean {
        const value = target[key];
        if (newVal !== value) {
          if (!self.allowMutations) {
            throw new Error(
              `Observed state cannot be changed here! (key: "${key}", val: "${newVal}")`
            );
          }
          self._updateRevNumber(target);
          target[key] = newVal;
          self.notifyChange();
        }
        return true;
      },
      deleteProperty(target, key) {
        if (key in target) {
          delete target[key];
          self._updateRevNumber(target);
          self.notifyChange();
        }
        return true;
      }
    });
    const metadata = {
      value,
      proxy,
      rev: this.rev,
      deepRev: this.rev,
      parent
    };
    this.weakMap.set(value, metadata);
    this.weakMap.set(metadata.proxy, metadata);
    return metadata;
  }
  _updateRevNumber(target: any) {
    this.rev++;
    let metadata = this.weakMap.get(target);
    metadata.rev!++;
    let parent = target;
    do {
      metadata = this.weakMap.get(parent);
      metadata.deepRev++;
    } while ((parent = metadata.parent) && parent !== target);
  }
 }
@@ -0,0 +1,119 @@
 import type { Env } from "./app/app";
 import { getCurrent } from "./component/component_node";
 import { onMounted, onPatched, onWillUnmount } from "./component/lifecycle_hooks";
 // -----------------------------------------------------------------------------
 // useRef
 // -----------------------------------------------------------------------------
 /**
 * The purpose of this hook is to allow components to get a reference to a sub
 * html node or component.
 */
 export function useRef<T extends HTMLElement = HTMLElement>(name: string): { el: T | null } {
  const node = getCurrent()!;
  const refs = node.refs;
  return {
    get el(): T | null {
      return refs[name] || null;
    },
  };
 }
 // -----------------------------------------------------------------------------
 // useEnv and useSubEnv
 // -----------------------------------------------------------------------------
 /**
 * This hook is useful as a building block for some customized hooks, that may
 * need a reference to the env of the component calling them.
 */
 export function useEnv<E extends Env>(): E {
  return getCurrent()!.component.env as any;
 }
 /**
 * This hook is a simple way to let components use a sub environment.  Note that
 * like for all hooks, it is important that this is only called in the
 * constructor method.
 */
 export function useSubEnv(envExtension: Env) {
  const node = getCurrent()!;
  const env = Object.create(node.childEnv);
  const descrs = Object.getOwnPropertyDescriptors(envExtension);
  node.childEnv = Object.freeze(Object.defineProperties(env, descrs));
 }
 // -----------------------------------------------------------------------------
 // useEffect
 // -----------------------------------------------------------------------------
 const NO_OP = () => {};
 /**
 * @param {...any} dependencies the dependencies computed by computeDependencies
 * @returns {void|(()=>void)} a cleanup function that reverses the side
 *      effects of the effect callback.
 */
 type Effect = (...dependencies: any[]) => void | (() => void);
 /**
 * This hook will run a callback when a component is mounted and patched, and
 * will run a cleanup function before patching and before unmounting the
 * the component.
 *
 * @param {Effect} effect the effect to run on component mount and/or patch
 * @param {()=>any[]} [computeDependencies=()=>[NaN]] a callback to compute
 *      dependencies that will decide if the effect needs to be cleaned up and
 *      run again. If the dependencies did not change, the effect will not run
 *      again. The default value returns an array containing only NaN because
 *      NaN !== NaN, which will cause the effect to rerun on every patch.
 */
 export function useEffect(effect: Effect, computeDependencies: () => any[] = () => [NaN]) {
  let cleanup: () => void;
  let dependencies: any[];
  onMounted(() => {
    dependencies = computeDependencies();
    cleanup = effect(...dependencies) || NO_OP;
  });
  onPatched(() => {
    const newDeps = computeDependencies();
    const shouldReapply = newDeps.some((val, i) => val !== dependencies[i]);
    if (shouldReapply) {
      dependencies = newDeps;
      cleanup();
      cleanup = effect(...dependencies) || NO_OP;
    }
  });
  onWillUnmount(() => cleanup());
 }
 // -----------------------------------------------------------------------------
 // useExternalListener
 // -----------------------------------------------------------------------------
 /**
 * When a component needs to listen to DOM Events on element(s) that are not
 * part of his hierarchy, we can use the `useExternalListener` hook.
 * It will correctly add and remove the event listener, whenever the
 * component is mounted and unmounted.
 *
 * Example:
 *  a menu needs to listen to the click on window to be closed automatically
 *
 * Usage:
 *  in the constructor of the OWL component that needs to be notified,
 *  `useExternalListener(window, 'click', this._doSomething);`
 * */
 export function useExternalListener(
  target: HTMLElement | typeof window,
  eventName: string,
  handler: EventListener,
  eventParams?: AddEventListenerOptions
 ) {
  const node = getCurrent()!;
  const boundHandler = handler.bind(node.component);
  onMounted(() => target.addEventListener(eventName, boundHandler, eventParams));
  onWillUnmount(() => target.removeEventListener(eventName, boundHandler, eventParams));
 }
@@ -1,40 +1,57 @@
-/**
+import {
- * This file is the main file packaged by rollup (see rollup.config.js).  From
+  config,
- * this file, we export all public owl elements.
+  createBlock,
- *
+  html,
- * Note that dynamic values, such as a date or a commit hash are added by rollup
+  list,
- */
+  mount as blockMount,
-import { EventBus } from "./core/event_bus";
+  multi,
-import { Observer } from "./core/observer";
+  patch,
-import { QWeb } from "./qweb/index";
+  remove,
-import { ConnectedComponent } from "./store/connected_component";
+  text,
-import { Store } from "./store/store";
+  toggler,
-import * as _utils from "./utils";
+  comment,
-import { Link } from "./router/Link";
+} from "./blockdom";
-import { Router } from "./router/Router";
+import { mainEventHandler } from "./component/handler";
 config.shouldNormalizeDom = false;
 config.mainEventHandler = mainEventHandler;
 export const blockDom = {
  config,
  // bdom entry points
  mount: blockMount,
  patch,
  remove,
  // bdom block types
  list,
  multi,
  text,
  toggler,
  createBlock,
  html,
  comment,
 };
 export { App, mount } from "./app/app";
 export { Component } from "./component/component";
-export { QWeb };
+export { useComponent } from "./component/component_node";
-export const core = { EventBus, Observer };
+export { status } from "./component/status";
-export const router = { Router, Link };
+export { Memo } from "./memo";
-export const store = { Store, ConnectedComponent };
+export { xml } from "./app/template_set";
-export const utils = _utils;
+export { useState, reactive } from "./reactivity";
 export { useEffect, useEnv, useExternalListener, useRef, useSubEnv } from "./hooks";
 export { EventBus, whenReady, loadFile, markup } from "./utils";
 export {
  onWillStart,
  onMounted,
  onWillUnmount,
  onWillUpdateProps,
  onWillPatch,
  onPatched,
  onWillRender,
  onRendered,
  onWillDestroy,
  onError,
 } from "./component/lifecycle_hooks";
 export const __info__ = {};
 Object.defineProperty(__info__, "mode", {
  get() {
    return QWeb.dev ? "dev" : "prod";
  },
  set(mode: string) {
    QWeb.dev = mode === "dev";
    if (QWeb.dev) {
      const url = `https://github.com/odoo/owl/blob/master/doc/tooling.md#development-mode`;
      console.warn(
        `Owl is running in 'dev' mode.  This is not suitable for production use. See ${url} for more information.`
      );
    } else {
      console.log(`Owl is now running in 'prod' mode.`);
    }
  }
 });
@@ -0,0 +1,47 @@
 import { Component } from "./component/component";
 import type { ComponentNode } from "./component/component_node";
 import { xml } from "./app/template_set";
 import { Fiber } from "./component/fibers";
 export class Memo extends Component {
  static template = xml`<t t-slot="default"/>`;
  constructor(props: any, env: any, node: ComponentNode) {
    super(props, env, node);
    // prevent patching process conditionally
    let applyPatch = false;
    const patchFn = node.patch;
    node.patch = () => {
      if (applyPatch) {
        patchFn.call(node);
        applyPatch = false;
      }
    };
    // check props change, and render/apply patch if it changed
    let prevProps = props;
    const updateAndRender = node.updateAndRender;
    node.updateAndRender = function (props: any, parentFiber: Fiber) {
      const shouldUpdate = !shallowEqual(prevProps, props);
      if (shouldUpdate) {
        prevProps = props;
        updateAndRender.call(node, props, parentFiber);
        applyPatch = true;
      }
      return Promise.resolve();
    };
  }
 }
 /**
 * we assume that each object have the same set of keys
 */
 function shallowEqual(p1: any, p2: any): boolean {
  for (let k in p1) {
    if (k !== "slots" && p1[k] !== p2[k]) {
      return false;
    }
  }
  return true;
 }
@@ -0,0 +1,51 @@
 import { BDom, text, VNode } from "./blockdom";
 const VText: any = text("").constructor;
 export class VPortal extends VText implements Partial<VNode<VPortal>> {
  //   selector: string;
  realBDom: BDom | null;
  target: HTMLElement | null = null;
  constructor(selector: string, realBDom: BDom, ownerComponent: ComponentNode) {
    super("");
    this.ownerComponent = ownerComponent;
    this.selector = selector;
    this.realBDom = realBDom;
  }
  mount(parent: HTMLElement, anchor: ChildNode) {
    super.mount(parent, anchor);
    this.ownerComponent.willDestroy.push(() => this.cleanup());
    this.target = document.querySelector(this.selector) as any;
    if (!this.target) {
      let el: any = this.el;
      while (el && el.parentElement instanceof HTMLElement) {
        el = el.parentElement;
      }
      this.target = el && el.querySelector(this.selector);
      if (!this.target) {
        throw new Error("invalid portal target");
      }
    }
    this.realBDom!.mount(this.target!, null);
  }
  beforeRemove() {
    this.realBDom!.beforeRemove();
  }
  remove() {
    super.remove();
    this.realBDom!.remove();
    this.realBDom = null;
  }
  patch(other: VPortal) {
    super.patch(other);
    if (this.realBDom) {
      this.realBDom.patch(other.realBDom!, true);
    } else {
      this.realBDom = other.realBDom;
      this.realBDom!.mount(this.target!, null);
    }
  }
 }
@@ -1,320 +0,0 @@
 import { Context } from "./context";
 import { QWebExprVar } from "./expression_parser";
 import { QWeb } from "./qweb";
 /**
 * Owl QWeb Directives
 *
 * This file contains the implementation of most standard QWeb directives:
 * - t-esc
 * - t-raw
 * - t-set/t-value
 * - t-if/t-elif/t-else
 * - t-call
 * - t-foreach/t-as
 * - t-debug
 * - t-log
 */
 //------------------------------------------------------------------------------
 // t-esc and t-raw
 //------------------------------------------------------------------------------
 QWeb.utils.getFragment = function(str: string): DocumentFragment {
  const temp = document.createElement("template");
  temp.innerHTML = str;
  return temp.content;
 };
 function compileValueNode(value: any, node: Element, qweb: QWeb, ctx: Context) {
  if (value === "0" && ctx.caller) {
    qweb._compileNode(ctx.caller, ctx);
    return;
  }
  if (value.xml instanceof NodeList) {
    for (let node of Array.from(value.xml)) {
      qweb._compileNode(<ChildNode>node, ctx);
    }
    return;
  }
  let exprID: string;
  if (typeof value === "string") {
    exprID = `_${ctx.generateID()}`;
    ctx.addLine(`var ${exprID} = ${ctx.formatExpression(value)};`);
  } else {
    exprID = value.id;
  }
  ctx.addIf(`${exprID} || ${exprID} === 0`);
  if (ctx.escaping) {
    if (ctx.parentTextNode) {
      ctx.addLine(`vn${ctx.parentTextNode}.text += ${exprID};`);
    } else if (ctx.parentNode) {
      ctx.addLine(`c${ctx.parentNode}.push({text: ${exprID}});`);
    } else {
      let nodeID = ctx.generateID();
      ctx.rootContext.rootNode = nodeID;
      ctx.rootContext.parentTextNode = nodeID;
      ctx.addLine(`var vn${nodeID} = {text: ${exprID}};`);
    }
  } else {
    let fragID = ctx.generateID();
    ctx.rootContext.shouldDefineUtils = true;
    ctx.addLine(`var frag${fragID} = utils.getFragment(${exprID})`);
    let tempNodeID = ctx.generateID();
    ctx.addLine(`var p${tempNodeID} = {hook: {`);
    ctx.addLine(`  insert: n => n.elm.parentNode.replaceChild(frag${fragID}, n.elm),`);
    ctx.addLine(`}};`);
    ctx.addLine(`var vn${tempNodeID} = h('div', p${tempNodeID})`);
    ctx.addLine(`c${ctx.parentNode}.push(vn${tempNodeID});`);
  }
  if (node.childNodes.length) {
    ctx.addElse();
    qweb._compileChildren(node, ctx);
  }
  ctx.closeIf();
 }
 QWeb.addDirective({
  name: "esc",
  priority: 70,
  atNodeEncounter({ node, qweb, ctx }): boolean {
    if (node.nodeName !== "t") {
      let nodeID = qweb._compileGenericNode(node, ctx);
      ctx = ctx.withParent(nodeID);
    }
    let value = ctx.getValue(node.getAttribute("t-esc")!);
    compileValueNode(value, node, qweb, ctx.subContext("escaping", true));
    return true;
  }
 });
 QWeb.addDirective({
  name: "raw",
  priority: 80,
  atNodeEncounter({ node, qweb, ctx }): boolean {
    if (node.nodeName !== "t") {
      let nodeID = qweb._compileGenericNode(node, ctx);
      ctx = ctx.withParent(nodeID);
    }
    let value = ctx.getValue(node.getAttribute("t-raw")!);
    compileValueNode(value, node, qweb, ctx);
    return true;
  }
 });
 //------------------------------------------------------------------------------
 // t-set
 //------------------------------------------------------------------------------
 QWeb.addDirective({
  name: "set",
  extraNames: ["value"],
  priority: 60,
  atNodeEncounter({ node, ctx }): boolean {
    const variable = node.getAttribute("t-set")!;
    let value = node.getAttribute("t-value")!;
    if (value) {
      const formattedValue = ctx.formatExpression(value);
      if (ctx.variables.hasOwnProperty(variable)) {
        ctx.addLine(`${(<QWebExprVar>ctx.variables[variable]).id} = ${formattedValue}`);
      } else {
        const varName = `_${ctx.generateID()}`;
        ctx.addLine(`var ${varName} = ${formattedValue};`);
        ctx.variables[variable] = {
          id: varName,
          expr: formattedValue
        };
      }
    } else {
      ctx.variables[variable] = {
        xml: node.childNodes
      };
    }
    return true;
  }
 });
 //------------------------------------------------------------------------------
 // t-if, t-elif, t-else
 //------------------------------------------------------------------------------
 QWeb.addDirective({
  name: "if",
  priority: 20,
  atNodeEncounter({ node, ctx }): boolean {
    let cond = ctx.getValue(node.getAttribute("t-if")!);
    ctx.addIf(`${ctx.formatExpression(cond)}`);
    return false;
  },
  finalize({ ctx }) {
    ctx.closeIf();
  }
 });
 QWeb.addDirective({
  name: "elif",
  priority: 30,
  atNodeEncounter({ node, ctx }): boolean {
    let cond = ctx.getValue(node.getAttribute("t-elif")!);
    ctx.addLine(`else if (${ctx.formatExpression(cond)}) {`);
    ctx.indent();
    return false;
  },
  finalize({ ctx }) {
    ctx.closeIf();
  }
 });
 QWeb.addDirective({
  name: "else",
  priority: 40,
  atNodeEncounter({ ctx }): boolean {
    ctx.addLine(`else {`);
    ctx.indent();
    return false;
  },
  finalize({ ctx }) {
    ctx.closeIf();
  }
 });
 //------------------------------------------------------------------------------
 // t-call
 //------------------------------------------------------------------------------
 QWeb.addDirective({
  name: "call",
  priority: 50,
  atNodeEncounter({ node, qweb, ctx }): boolean {
    if (node.nodeName !== "t") {
      throw new Error("Invalid tag for t-call directive (should be 't')");
    }
    const subTemplate = node.getAttribute("t-call")!;
    const nodeTemplate = qweb.templates[subTemplate];
    if (!nodeTemplate) {
      throw new Error(`Cannot find template "${subTemplate}" (t-call)`);
    }
    const nodeCopy = node.cloneNode(true) as Element;
    nodeCopy.removeAttribute("t-call");
    // extract variables from nodecopy
    const tempCtx = new Context();
    tempCtx.nextID = ctx.rootContext.nextID;
    qweb._compileNode(nodeCopy, tempCtx);
    const vars = Object.assign({}, ctx.variables, tempCtx.variables);
    ctx.rootContext.nextID = tempCtx.nextID;
    // open new scope, if necessary
    const hasNewVariables = Object.keys(tempCtx.variables).length > 0;
    if (hasNewVariables) {
      ctx.addLine("{");
      ctx.indent();
      // add new variables, if any
      for (let key in tempCtx.variables) {
        const v = tempCtx.variables[key];
        if ((<QWebExprVar>v).expr) {
          ctx.addLine(`let ${(<QWebExprVar>v).id} = ${(<QWebExprVar>v).expr};`);
        }
        // todo: handle XML variables...
      }
    }
    // compile sub template
    const subCtx = ctx.subContext("caller", nodeCopy).subContext("variables", Object.create(vars));
    qweb._compileNode(nodeTemplate.elem, subCtx);
    // close new scope
    if (hasNewVariables) {
      ctx.dedent();
      ctx.addLine("}");
    }
    if (node.hasAttribute("t-if") || node.hasAttribute("t-else") || node.hasAttribute("t-elif")) {
      ctx.closeIf();
    }
    return true;
  }
 });
 //------------------------------------------------------------------------------
 // t-foreach
 //------------------------------------------------------------------------------
 QWeb.addDirective({
  name: "foreach",
  extraNames: ["as"],
  priority: 10,
  atNodeEncounter({ node, qweb, ctx }): boolean {
    ctx.rootContext.shouldProtectContext = true;
    ctx = ctx.subContext("inLoop", true);
    const elems = node.getAttribute("t-foreach")!;
    const name = node.getAttribute("t-as")!;
    let arrayID = ctx.generateID();
    ctx.addLine(`var _${arrayID} = ${ctx.formatExpression(elems)};`);
    ctx.addLine(`if (!_${arrayID}) { throw new Error('QWeb error: Invalid loop expression')}`);
    let keysID = ctx.generateID();
    let valuesID = ctx.generateID();
    ctx.addLine(`var _${keysID} = _${valuesID} = _${arrayID};`);
    ctx.addIf(`!(_${arrayID} instanceof Array)`);
    ctx.addLine(`_${keysID} = Object.keys(_${arrayID});`);
    ctx.addLine(`_${valuesID} = Object.values(_${arrayID});`);
    ctx.closeIf();
    ctx.addLine(`var _length${keysID} = _${keysID}.length;`);
    ctx.addLine(`for (let i = 0; i < _length${keysID}; i++) {`);
    ctx.indent();
    ctx.addToScope(name + "_first", "i === 0");
    ctx.addToScope(name + "_last", `i === _length${keysID} - 1`);
    ctx.addToScope(name + "_index", "i");
    ctx.addToScope(name, `_${keysID}[i]`);
    ctx.addToScope(name + "_value", `_${valuesID}[i]`);
    const nodeCopy = <Element>node.cloneNode(true);
    let shouldWarn = nodeCopy.tagName !== "t" && !nodeCopy.hasAttribute("t-key");
    if (!shouldWarn && node.tagName === "t") {
      if (node.hasAttribute("t-component") && !node.hasAttribute("t-key")) {
        shouldWarn = true;
      }
      if (
        !shouldWarn &&
        node.children.length === 1 &&
        node.children[0].tagName !== "t" &&
        !node.children[0].hasAttribute("t-key")
      ) {
        shouldWarn = true;
      }
    }
    if (shouldWarn) {
      console.warn(
        `Directive t-foreach should always be used with a t-key! (in template: '${
          ctx.templateName
        }')`
      );
    }
    nodeCopy.removeAttribute("t-foreach");
    qweb._compileNode(nodeCopy, ctx);
    ctx.dedent();
    ctx.addLine("}");
    return true;
  }
 });
 //------------------------------------------------------------------------------
 // t-debug
 //------------------------------------------------------------------------------
 QWeb.addDirective({
  name: "debug",
  priority: 1,
  atNodeEncounter({ ctx }) {
    ctx.addLine("debugger;");
  }
 });
 //------------------------------------------------------------------------------
 // t-log
 //------------------------------------------------------------------------------
 QWeb.addDirective({
  name: "log",
  priority: 1,
  atNodeEncounter({ ctx, value }) {
    const expr = ctx.formatExpression(value);
    ctx.addLine(`console.log(${expr})`);
  }
 });
@@ -1,167 +0,0 @@
 import { compileExpr, QWebVar } from "./expression_parser";
 //------------------------------------------------------------------------------
 // Compilation Context
 //------------------------------------------------------------------------------
 export class Context {
  nextID: number = 1;
  code: string[] = [];
  variables: { [key: string]: QWebVar } = {};
  escaping: boolean = false;
  parentNode: number | null = null;
  parentTextNode: number | null = null;
  rootNode: number | null = null;
  indentLevel: number = 0;
  rootContext: Context;
  caller: Element | undefined;
  shouldDefineOwner: boolean = false;
  shouldDefineParent: boolean = false;
  shouldDefineQWeb: boolean = false;
  shouldDefineUtils: boolean = false;
  shouldDefineResult: boolean = false;
  shouldProtectContext: boolean = false;
  shouldTrackScope: boolean = false;
  inLoop: boolean = false;
  inPreTag: boolean = false;
  templateName: string;
  allowMultipleRoots: boolean = false;
  hasParentWidget: boolean = false;
  scopeVars: any[] = [];
  constructor(name?: string) {
    this.rootContext = this;
    this.templateName = name || "noname";
    this.addLine("var h = this.h;");
  }
  generateID(): number {
    const id = this.rootContext.nextID++;
    return id;
  }
  generateCode(): string[] {
    const shouldTrackScope = this.shouldTrackScope && this.scopeVars.length;
    if (shouldTrackScope) {
      // add some vars to scope if needed
      for (let scopeVar of this.scopeVars.reverse()) {
        let { index, key, indent } = scopeVar;
        const prefix = new Array(indent + 2).join("    ");
        this.code.splice(index + 1, 0, prefix + `scope.${key} = context.${key};`);
      }
      this.code.unshift("    const scope = Object.create(null);");
    }
    if (this.shouldProtectContext) {
      this.code.unshift("    context = Object.create(context);");
    }
    if (this.shouldDefineResult) {
      this.code.unshift("    let result;");
    }
    if (this.shouldDefineOwner) {
      // this is necessary to prevent some directives (t-forach for ex) to
      // pollute the rendering context by adding some keys in it.
      this.code.unshift("    let owner = context;");
    }
    if (this.shouldDefineParent) {
      if (this.hasParentWidget) {
        this.code.unshift("    let parent = extra.parent;");
      } else {
        this.code.unshift("    let parent = context;");
      }
    }
    if (this.shouldDefineQWeb) {
      this.code.unshift("    let QWeb = this.constructor;");
    }
    if (this.shouldDefineUtils) {
      this.code.unshift("    let utils = this.constructor.utils;");
    }
    return this.code;
  }
  withParent(node: number): Context {
    if (
      !this.allowMultipleRoots &&
      this === this.rootContext &&
      (this.parentNode || this.parentTextNode)
    ) {
      throw new Error("A template should not have more than one root node");
    }
    if (!this.rootContext.rootNode) {
      this.rootContext.rootNode = node;
    }
    return this.subContext("parentNode", node);
  }
  subContext(key: keyof Context, value: any): Context {
    const newContext = Object.create(this);
    newContext[key] = value;
    return newContext;
  }
  indent() {
    this.indentLevel++;
  }
  dedent() {
    this.indentLevel--;
  }
  addLine(line: string): number {
    const prefix = new Array(this.indentLevel + 2).join("    ");
    this.code.push(prefix + line);
    return this.code.length - 1;
  }
  addToScope(key: string, expr: string) {
    const index = this.addLine(`context.${key} = ${expr};`);
    this.rootContext.scopeVars.push({ index, key, indent: this.indentLevel });
  }
  addIf(condition: string) {
    this.addLine(`if (${condition}) {`);
    this.indent();
  }
  addElse() {
    this.dedent();
    this.addLine("} else {");
    this.indent();
  }
  closeIf() {
    this.dedent();
    this.addLine("}");
  }
  getValue(val: any): any {
    return val in this.variables ? this.getValue(this.variables[val]) : val;
  }
  /**
   * Prepare an expression for being consumed at render time.  Its main job
   * is to
   * - replace unknown variables by a lookup in the context
   * - replace already defined variables by their internal name
   */
  formatExpression(expr: string): string {
    return compileExpr(expr, this.variables);
  }
  /**
   * Perform string interpolation on the given string. Note that if the whole
   * string is an expression, it simply returns it (formatted and enclosed in
   * parentheses).
   * For instance:
   *   'Hello {{x}}!' -> `Hello ${x}`
   *   '{{x ? 'a': 'b'}}' -> (x ? 'a' : 'b')
   */
  interpolate(s: string): string {
    let matches = s.match(/\{\{.*?\}\}/g);
    if (matches && matches[0].length === s.length) {
      return `(${this.formatExpression(s.slice(2, -2))})`;
    }
    let r = s.replace(/\{\{.*?\}\}/g, s => "${" + this.formatExpression(s.slice(2, -2)) + "}");
    return "`" + r + "`";
  }
 }
@@ -1,284 +0,0 @@
 import { VNode } from "../vdom/index";
 import { QWeb } from "./qweb";
 /**
 * Owl QWeb Extensions
 *
 * This file contains the implementation of non standard QWeb directives, added
 * by Owl and that will only work on Owl projects:
 *
 * - t-on
 * - t-ref
 * - t-transition
 * - t-mounted
 * - t-slot
 * - t-model
 */
 //------------------------------------------------------------------------------
 // t-on
 //------------------------------------------------------------------------------
 // these are pieces of code that will be injected into the event handler if
 // modifiers are specified
 export const MODS_CODE = {
  prevent: "e.preventDefault();",
  self: "if (e.target !== this.elm) {return}",
  stop: "e.stopPropagation();"
 };
 QWeb.addDirective({
  name: "on",
  priority: 90,
  atNodeCreation({ ctx, fullName, value, nodeID }) {
    ctx.rootContext.shouldDefineOwner = true;
    const [eventName, ...mods] = fullName.slice(5).split(".");
    if (!eventName) {
      throw new Error("Missing event name with t-on directive");
    }
    let extraArgs;
    let handlerName = value.replace(/\(.*\)/, function(args) {
      extraArgs = args.slice(1, -1);
      return "";
    });
    ctx.addIf(`!context['${handlerName}']`);
    ctx.addLine(
      `throw new Error('Missing handler \\'' + '${handlerName}' + \`\\' when evaluating template '${ctx.templateName.replace(
        /`/g,
        "'"
      )}'\`)`
    );
    ctx.closeIf();
    let params = extraArgs ? `owner, ${ctx.formatExpression(extraArgs)}` : "owner";
    let handler;
    if (mods.length > 0) {
      handler = `function (e) {`;
      handler += mods
        .map(function(mod) {
          return MODS_CODE[mod];
        })
        .join("");
      handler += `context['${handlerName}'].call(${params}, e);}`;
    } else {
      handler = `context['${handlerName}'].bind(${params})`;
    }
    if (extraArgs) {
      ctx.addLine(`p${nodeID}.on['${eventName}'] = ${handler};`);
    } else {
      ctx.addLine(
        `extra.handlers['${eventName}' + ${nodeID}] = extra.handlers['${eventName}' + ${nodeID}] || ${handler};`
      );
      ctx.addLine(`p${nodeID}.on['${eventName}'] = extra.handlers['${eventName}' + ${nodeID}];`);
    }
  }
 });
 //------------------------------------------------------------------------------
 // t-ref
 //------------------------------------------------------------------------------
 QWeb.addDirective({
  name: "ref",
  priority: 95,
  atNodeCreation({ ctx, value, addNodeHook }) {
    const refKey = `ref${ctx.generateID()}`;
    ctx.addLine(`const ${refKey} = ${ctx.interpolate(value)};`);
    addNodeHook("create", `context.refs[${refKey}] = n.elm;`);
  }
 });
 //------------------------------------------------------------------------------
 // t-transition
 //------------------------------------------------------------------------------
 QWeb.utils.nextFrame = function(cb: () => void) {
  requestAnimationFrame(() => requestAnimationFrame(cb));
 };
 QWeb.utils.transitionInsert = function(vn: VNode, name: string) {
  const elm = <HTMLElement>vn.elm;
  // remove potential duplicated vnode that is currently being removed, to
  // prevent from having twice the same node in the DOM during an animation
  const dup = elm.parentElement && elm.parentElement!.querySelector(`*[data-owl-key='${vn.key}']`);
  if (dup) {
    dup.remove();
  }
  elm.classList.add(name + "-enter");
  elm.classList.add(name + "-enter-active");
  const finalize = () => {
    elm.classList.remove(name + "-enter-active");
    elm.classList.remove(name + "-enter-to");
  };
  this.nextFrame(() => {
    elm.classList.remove(name + "-enter");
    elm.classList.add(name + "-enter-to");
    whenTransitionEnd(elm, finalize);
  });
 };
 QWeb.utils.transitionRemove = function(vn: VNode, name: string, rm: () => void) {
  const elm = <HTMLElement>vn.elm;
  elm.setAttribute("data-owl-key", vn.key!);
  elm.classList.add(name + "-leave");
  elm.classList.add(name + "-leave-active");
  const finalize = () => {
    elm.classList.remove(name + "-leave-active");
    elm.classList.remove(name + "-leave-to");
    rm();
  };
  this.nextFrame(() => {
    elm.classList.remove(name + "-leave");
    elm.classList.add(name + "-leave-to");
    whenTransitionEnd(elm, finalize);
  });
 };
 function getTimeout(delays: Array<string>, durations: Array<string>): number {
  /* istanbul ignore next */
  while (delays.length < durations.length) {
    delays = delays.concat(delays);
  }
  return Math.max.apply(
    null,
    durations.map((d, i) => {
      return toMs(d) + toMs(delays[i]);
    })
  );
 }
 // Old versions of Chromium (below 61.0.3163.100) formats floating pointer numbers
 // in a locale-dependent way, using a comma instead of a dot.
 // If comma is not replaced with a dot, the input will be rounded down (i.e. acting
 // as a floor function) causing unexpected behaviors
 function toMs(s: string): number {
  return Number(s.slice(0, -1).replace(",", ".")) * 1000;
 }
 function whenTransitionEnd(elm: HTMLElement, cb) {
  const styles = window.getComputedStyle(elm);
  const delays: Array<string> = (styles.transitionDelay || "").split(", ");
  const durations: Array<string> = (styles.transitionDuration || "").split(", ");
  const timeout: number = getTimeout(delays, durations);
  if (timeout > 0) {
    elm.addEventListener("transitionend", cb, { once: true });
  } else {
    cb();
  }
 }
 QWeb.addDirective({
  name: "transition",
  priority: 96,
  atNodeCreation({ ctx, value, addNodeHook }) {
    ctx.rootContext.shouldDefineUtils = true;
    let name = value;
    const hooks = {
      insert: `utils.transitionInsert(vn, '${name}');`,
      remove: `utils.transitionRemove(vn, '${name}', rm);`
    };
    for (let hookName in hooks) {
      addNodeHook(hookName, hooks[hookName]);
    }
  }
 });
 //------------------------------------------------------------------------------
 // t-mounted
 //------------------------------------------------------------------------------
 QWeb.addDirective({
  name: "mounted",
  priority: 97,
  atNodeCreation({ ctx, fullName, value, nodeID, addNodeHook }) {
    ctx.rootContext.shouldDefineOwner = true;
    const eventName = fullName.slice(5);
    if (!eventName) {
      throw new Error("Missing event name with t-on directive");
    }
    let extraArgs;
    let handler = value.replace(/\(.*\)/, function(args) {
      extraArgs = args.slice(1, -1);
      return "";
    });
    let error = `(function () {throw new Error('Missing handler \\'' + '${handler}' + \`\\' when evaluating template '${ctx.templateName.replace(
      /`/g,
      "'"
    )}'\`)})()`;
    if (extraArgs) {
      ctx.addLine(
        `extra.mountedHandlers[${nodeID}] = (context['${handler}'] || ${error}).bind(owner, ${ctx.formatExpression(
          extraArgs
        )});`
      );
    } else {
      ctx.addLine(
        `extra.mountedHandlers[${nodeID}] = extra.mountedHandlers[${nodeID}] || (context['${handler}'] || ${error}).bind(owner);`
      );
    }
    addNodeHook("insert", `if (context.__owl__.isMounted) { extra.mountedHandlers[${nodeID}](); }`);
  }
 });
 //------------------------------------------------------------------------------
 // t-slot
 //------------------------------------------------------------------------------
 QWeb.addDirective({
  name: "slot",
  priority: 80,
  atNodeEncounter({ ctx, value }): boolean {
    const slotKey = ctx.generateID();
    ctx.rootContext.shouldDefineOwner = true;
    ctx.addLine(`const slot${slotKey} = this.slots[context.__owl__.slotId + '_' + '${value}'];`);
    ctx.addIf(`slot${slotKey}`);
    ctx.addLine(
      `slot${slotKey}(context.__owl__.parent, Object.assign({}, extra, {parentNode: c${
        ctx.parentNode
      }, vars: extra.vars, parent: owner}));`
    );
    ctx.closeIf();
    return true;
  }
 });
 //------------------------------------------------------------------------------
 // t-model
 //------------------------------------------------------------------------------
 QWeb.utils.toNumber = function(val: string): number | string {
  const n = parseFloat(val);
  return isNaN(n) ? val : n;
 };
 QWeb.addDirective({
  name: "model",
  priority: 42,
  atNodeCreation({ ctx, nodeID, value, node, fullName }) {
    const type = node.getAttribute("type");
    let handler;
    let event = fullName.includes(".lazy") ? "change" : "input";
    if (node.tagName === "select") {
      ctx.addLine(`p${nodeID}.props = {value: context.state['${value}']};`);
      event = "change";
      handler = `(ev) => {context.state['${value}'] = ev.target.value}`;
    } else if (type === "checkbox") {
      ctx.addLine(`p${nodeID}.props = {checked: context.state['${value}']};`);
      handler = `(ev) => {context.state['${value}'] = ev.target.checked}`;
    } else if (type === "radio") {
      const nodeValue = node.getAttribute("value")!;
      ctx.addLine(`p${nodeID}.props = {checked:context.state['${value}'] === '${nodeValue}'};`);
      handler = `(ev) => {context.state['${value}'] = ev.target.value}`;
      event = "click";
    } else {
      ctx.addLine(`p${nodeID}.props = {value: context.state['${value}']};`);
      const trimCode = fullName.includes(".trim") ? ".trim()" : "";
      let valueCode = `ev.target.value${trimCode}`;
      if (fullName.includes(".number")) {
        ctx.rootContext.shouldDefineUtils = true;
        valueCode = `utils.toNumber(${valueCode})`;
      }
      handler = `(ev) => {context.state['${value}'] = ${valueCode}}`;
    }
    ctx.addLine(
      `extra.handlers['${event}' + ${nodeID}] = extra.handlers['${event}' + ${nodeID}] || (${handler});`
    );
    ctx.addLine(`p${nodeID}.on['${event}'] = extra.handlers['${event}' + ${nodeID}];`);
  }
 });
@@ -1,4 +0,0 @@
 import "./base_directives";
 import "./extensions";
 export { CompiledTemplate, QWeb } from "./qweb";
@@ -1,695 +0,0 @@
 import { EventBus } from "../core/event_bus";
 import { h, patch, VNode } from "../vdom/index";
 import { Context } from "./context";
 /**
 * Owl QWeb Engine
 *
 * In this file, you will find a QWeb engine/template compiler.  It is the core
 * of how Owl component works.
 *
 * Briefly, Owl QWeb compiles XML templates into functions that output a virtual
 * DOM representation.
 *
 * We have here:
 * - a CompilationContext class, which is an internal object that contains all
 *   compilation specific information, while a template is being compiled.
 * - a QWeb class: this is the code of the QWeb compiler.
 *
 * Note that this file does not contain the implementation of the QWeb
 * directives (see qweb_directives.ts and qweb_extensions.ts).
 */
 //------------------------------------------------------------------------------
 // Types
 //------------------------------------------------------------------------------
 export type EvalContext = { [key: string]: any };
 export type CompiledTemplate = (context: EvalContext, extra: any) => VNode;
 interface Template {
  elem: Element;
  fn: CompiledTemplate;
 }
 interface CompilationInfo {
  node: Element;
  qweb: QWeb;
  ctx: Context;
  fullName: string;
  value: string;
 }
 interface NodeCreationCompilationInfo extends CompilationInfo {
  nodeID: number;
  addNodeHook: Function;
 }
 export interface Directive {
  name: string;
  extraNames?: string[];
  priority: number;
  // if return true, then directive is fully applied and there is no need to
  // keep processing node. Otherwise, we keep going.
  atNodeEncounter?(info: CompilationInfo): boolean | void;
  atNodeCreation?(info: NodeCreationCompilationInfo): void;
  finalize?(info: CompilationInfo): void;
 }
 //------------------------------------------------------------------------------
 // Const/global stuff/helpers
 //------------------------------------------------------------------------------
 const DISABLED_TAGS = ["input", "textarea", "button", "select", "option", "optgroup"];
 const lineBreakRE = /[\r\n]/;
 const whitespaceRE = /\s+/g;
 const NODE_HOOKS_PARAMS = {
  create: "(_, n)",
  insert: "vn",
  remove: "(vn, rm)"
 };
 interface Utils {
  toObj(expr: any): Object;
  shallowEqual(p1: Object, p2: Object): boolean;
  [key: string]: any;
 }
 const UTILS: Utils = {
  toObj(expr) {
    if (typeof expr === "string") {
      expr = expr.trim();
      if (!expr) {
        return {};
      }
      let words = expr.split(/\s+/);
      let result = {};
      for (let i = 0; i < words.length; i++) {
        result[words[i]] = true;
      }
      return result;
    }
    return expr;
  },
  shallowEqual(p1, p2) {
    for (let k in p1) {
      if (p1[k] !== p2[k]) {
        return false;
      }
    }
    return true;
  }
 };
 function parseXML(xml: string): Document {
  const parser = new DOMParser();
  const doc = parser.parseFromString(xml, "text/xml");
  if (doc.getElementsByTagName("parsererror").length) {
    let msg = "Invalid XML in template.";
    const parsererrorText = doc.getElementsByTagName("parsererror")[0].textContent;
    if (parsererrorText) {
      msg += "\nThe parser has produced the following error message:\n" + parsererrorText;
      const re = /\d+/g;
      const firstMatch = re.exec(parsererrorText);
      if (firstMatch) {
        const lineNumber = Number(firstMatch[0]);
        const line = xml.split("\n")[lineNumber - 1];
        const secondMatch = re.exec(parsererrorText);
        if (line && secondMatch) {
          const columnIndex = Number(secondMatch[0]) - 1;
          if (line[columnIndex]) {
            msg +=
              `\nThe error might be located at xml line ${lineNumber} column ${columnIndex}\n` +
              `${line}\n${"-".repeat(columnIndex - 1)}^`;
          }
        }
      }
    }
    throw new Error(msg);
  }
  return doc;
 }
 let nextID = 1;
 //------------------------------------------------------------------------------
 // QWeb rendering engine
 //------------------------------------------------------------------------------
 export class QWeb extends EventBus {
  templates: { [name: string]: Template } = {};
  static utils = UTILS;
  static components = Object.create(null);
  static DIRECTIVE_NAMES: { [key: string]: 1 } = {
    name: 1,
    att: 1,
    attf: 1,
    key: 1
  };
  static DIRECTIVES: Directive[] = [];
  h = h;
  // dev mode enables better error messages or more costly validations
  static dev: boolean = false;
  // the id field is useful to be able to hash qweb instances.  The current
  // use case is that component's templates are qweb dependant, and need to be
  // able to map a qweb instance to a template name.
  id = nextID++;
  // slots contains sub templates defined with t-set inside t-component nodes, and
  // are meant to be used by the t-slot directive.
  slots = {};
  nextSlotId = 1;
  isUpdating: boolean = false;
  constructor(data?: string) {
    super();
    if (data) {
      this.addTemplates(data);
    }
  }
  static addDirective(directive: Directive) {
    if (directive.name in QWeb.DIRECTIVE_NAMES) {
      throw new Error(`Directive "${directive.name} already registered`);
    }
    QWeb.DIRECTIVES.push(directive);
    QWeb.DIRECTIVE_NAMES[directive.name] = 1;
    QWeb.DIRECTIVES.sort((d1, d2) => d1.priority - d2.priority);
    if (directive.extraNames) {
      directive.extraNames.forEach(n => (QWeb.DIRECTIVE_NAMES[n] = 1));
    }
  }
  static register(name: string, Component: any) {
    if (QWeb.components[name]) {
      throw new Error(`Component '${name}' has already been registered`);
    }
    QWeb.components[name] = Component;
  }
  /**
   * Add a template to the internal template map.  Note that it is not
   * immediately compiled.
   */
  addTemplate(name: string, xmlString: string, allowDuplicate?: boolean) {
    if (allowDuplicate && name in this.templates) {
      return;
    }
    const doc = parseXML(xmlString);
    if (!doc.firstChild) {
      throw new Error("Invalid template (should not be empty)");
    }
    this._addTemplate(name, <Element>doc.firstChild);
  }
  /**
   * Load templates from a xml (as a string or xml document).  This will look up
   * for the first <templates> tag, and will consider each child of this as a
   * template, with the name given by the t-name attribute.
   */
  addTemplates(xmlstr: string | Document) {
    const doc = typeof xmlstr === 'string' ? parseXML(xmlstr) : xmlstr;
    const templates = doc.getElementsByTagName("templates")[0];
    if (!templates) {
      return;
    }
    for (let elem of <any>templates.children) {
      const name = elem.getAttribute("t-name");
      this._addTemplate(name, elem);
    }
  }
  _addTemplate(name: string, elem: Element) {
    if (name in this.templates) {
      throw new Error(`Template ${name} already defined`);
    }
    this._processTemplate(elem);
    const template = {
      elem,
      fn: (context, extra) => {
        const compiledFunction = this._compile(name, elem);
        template.fn = compiledFunction;
        return compiledFunction.call(this, context, extra);
      }
    };
    this.templates[name] = template;
  }
  _processTemplate(elem: Element) {
    let tbranch = elem.querySelectorAll("[t-elif], [t-else]");
    for (let i = 0, ilen = tbranch.length; i < ilen; i++) {
      let node = tbranch[i];
      let prevElem = node.previousElementSibling!;
      let pattr = function(name) {
        return prevElem.getAttribute(name);
      };
      let nattr = function(name) {
        return +!!node.getAttribute(name);
      };
      if (prevElem && (pattr("t-if") || pattr("t-elif"))) {
        if (pattr("t-foreach")) {
          throw new Error(
            "t-if cannot stay at the same level as t-foreach when using t-elif or t-else"
          );
        }
        if (
          ["t-if", "t-elif", "t-else"].map(nattr).reduce(function(a, b) {
            return a + b;
          }) > 1
        ) {
          throw new Error("Only one conditional branching directive is allowed per node");
        }
        // All text nodes between branch nodes are removed
        let textNode;
        while ((textNode = node.previousSibling) !== prevElem) {
          if (textNode.nodeValue.trim().length) {
            throw new Error("text is not allowed between branching directives");
          }
          textNode.remove();
        }
      } else {
        throw new Error(
          "t-elif and t-else directives must be preceded by a t-if or t-elif directive"
        );
      }
    }
  }
  /**
   * Render a template
   *
   * @param {string} name the template should already have been added
   */
  render(name: string, context: EvalContext = {}, extra: any = null): VNode {
    const template = this.templates[name];
    if (!template) {
      throw new Error(`Template ${name} does not exist`);
    }
    return template.fn.call(this, context, extra);
  }
  /**
   * Render a template to a html string.
   *
   * Note that this is more limited than the `render` method: it is not suitable
   * to render a full component tree, since this is an asynchronous operation.
   * This method can only render templates without components.
   */
  renderToString(name: string, context: EvalContext = {}): string {
    const vnode = this.render(name, context);
    if (vnode.sel === undefined) {
      return vnode.text!;
    }
    const node = document.createElement(vnode.sel);
    const result = patch(node, vnode);
    return (<HTMLElement>result.elm).outerHTML;
  }
  /**
   * Force all widgets connected to this QWeb instance to rerender themselves.
   *
   * This method is mostly useful for external code that want to modify the
   * application in some cases.  For example, a router plugin.
   */
  forceUpdate() {
    this.isUpdating = true;
    Promise.resolve().then(() => {
      if (this.isUpdating) {
        this.isUpdating = false;
        this.trigger("update");
      }
    });
  }
  _compile(name: string, elem: Element, parentContext?: Context): CompiledTemplate {
    const isDebug = elem.attributes.hasOwnProperty("t-debug");
    const ctx = new Context(name);
    if (parentContext) {
      ctx.variables = Object.create(parentContext.variables);
      ctx.nextID = parentContext.parentNode! + 1;
      ctx.parentNode = parentContext.parentNode!;
      ctx.allowMultipleRoots = true;
      ctx.hasParentWidget = true;
      ctx.addLine(`let c${ctx.parentNode} = extra.parentNode;`);
      for (let v in parentContext.variables) {
        let variable = <any>parentContext.variables[v];
        if (variable.id) {
          ctx.addLine(`let ${variable.id} = extra.vars.${variable.id}`);
        }
      }
    }
    if (parentContext) {
      ctx.addLine("    Object.assign(context, extra.scope);");
    }
    this._compileNode(elem, ctx);
    if (!parentContext) {
      if (ctx.shouldDefineResult) {
        ctx.addLine(`return result;`);
      } else {
        if (!ctx.rootNode) {
          throw new Error(`A template should have one root node (${ctx.templateName})`);
        }
        ctx.addLine(`return vn${ctx.rootNode};`);
      }
    }
    let code = ctx.generateCode();
    let template;
    try {
      template = new Function("context", "extra", code.join("\n")) as CompiledTemplate;
    } catch (e) {
      const templateName = ctx.templateName.replace(/`/g, "'");
      console.groupCollapsed(`Invalid Code generated by ${templateName}`);
      console.warn(code.join("\n"));
      console.groupEnd();
      throw new Error(
        `Invalid generated code while compiling template '${templateName}': ${e.message}`
      );
    }
    if (isDebug) {
      const tpl = this.templates[name];
      if (tpl) {
        const msg = `Template: ${tpl.elem.outerHTML}\nCompiled code:\n${template.toString()}`;
        console.log(msg);
      }
    }
    return template;
  }
  /**
   * Generate code from an xml node
   *
   */
  _compileNode(node: ChildNode, ctx: Context) {
    if (!(node instanceof Element)) {
      // this is a text node, there are no directive to apply
      let text = node.textContent!;
      if (!ctx.inPreTag) {
        if (lineBreakRE.test(text) && !text.trim()) {
          return;
        }
        text = text.replace(whitespaceRE, " ");
      }
      if (ctx.parentNode) {
        ctx.addLine(`c${ctx.parentNode}.push({text: \`${text}\`});`);
      } else if (ctx.parentTextNode) {
        ctx.addLine(`vn${ctx.parentTextNode}.text += \`${text}\`;`);
      } else {
        // this is an unusual situation: this text node is the result of the
        // template rendering.
        let nodeID = ctx.generateID();
        ctx.addLine(`var vn${nodeID} = {text: \`${text}\`};`);
        ctx.rootContext.rootNode = nodeID;
        ctx.rootContext.parentTextNode = nodeID;
      }
      return;
    }
    const firstLetter = node.tagName[0];
    if (firstLetter === firstLetter.toUpperCase()) {
      // this is a component, we modify in place the xml document to change
      // <SomeComponent ... /> to <t t-component="SomeComponent" ... />
      node.setAttribute("t-component", node.tagName);
    }
    const attributes = (<Element>node).attributes;
    const validDirectives: {
      directive: Directive;
      value: string;
      fullName: string;
    }[] = [];
    let withHandlers = false;
    // maybe this is not optimal: we iterate on all attributes here, and again
    // just after for each directive.
    for (let i = 0; i < attributes.length; i++) {
      let attrName = attributes[i].name;
      if (attrName.startsWith("t-")) {
        let dName = attrName.slice(2).split(/-|\./)[0];
        if (!(dName in QWeb.DIRECTIVE_NAMES)) {
          throw new Error(`Unknown QWeb directive: '${attrName}'`);
        }
      }
    }
    const DIR_N = QWeb.DIRECTIVES.length;
    const ATTR_N = attributes.length;
    for (let i = 0; i < DIR_N; i++) {
      let directive = QWeb.DIRECTIVES[i];
      let fullName;
      let value;
      for (let j = 0; j < ATTR_N; j++) {
        const name = attributes[j].name;
        if (
          name === "t-" + directive.name ||
          name.startsWith("t-" + directive.name + "-") ||
          name.startsWith("t-" + directive.name + ".")
        ) {
          fullName = name;
          value = attributes[j].textContent;
          validDirectives.push({ directive, value, fullName });
          if (directive.name === "on" || directive.name === "model") {
            withHandlers = true;
          }
        }
      }
    }
    for (let { directive, value, fullName } of validDirectives) {
      if (directive.atNodeEncounter) {
        const isDone = directive.atNodeEncounter({
          node,
          qweb: this,
          ctx,
          fullName,
          value
        });
        if (isDone) {
          return;
        }
      }
    }
    if (node.nodeName !== "t") {
      let nodeID = this._compileGenericNode(node, ctx, withHandlers);
      ctx = ctx.withParent(nodeID);
      let nodeHooks = {};
      let addNodeHook = function(hook, handler) {
        nodeHooks[hook] = nodeHooks[hook] || [];
        nodeHooks[hook].push(handler);
      };
      for (let { directive, value, fullName } of validDirectives) {
        if (directive.atNodeCreation) {
          directive.atNodeCreation({
            node,
            qweb: this,
            ctx,
            fullName,
            value,
            nodeID,
            addNodeHook
          });
        }
      }
      if (Object.keys(nodeHooks).length) {
        ctx.addLine(`p${nodeID}.hook = {`);
        for (let hook in nodeHooks) {
          ctx.addLine(`  ${hook}: ${NODE_HOOKS_PARAMS[hook]} => {`);
          for (let handler of nodeHooks[hook]) {
            ctx.addLine(`    ${handler}`);
          }
          ctx.addLine(`  },`);
        }
        ctx.addLine(`};`);
      }
    }
    if (node.nodeName === "pre") {
      ctx = ctx.subContext("inPreTag", true);
    }
    this._compileChildren(node, ctx);
    for (let { directive, value, fullName } of validDirectives) {
      if (directive.finalize) {
        directive.finalize({ node, qweb: this, ctx, fullName, value });
      }
    }
  }
  _compileGenericNode(node: ChildNode, ctx: Context, withHandlers: boolean = true): number {
    // nodeType 1 is generic tag
    if (node.nodeType !== 1) {
      throw new Error("unsupported node type");
    }
    const attributes = (<Element>node).attributes;
    const attrs: string[] = [];
    const props: string[] = [];
    const tattrs: number[] = [];
    function handleBooleanProps(key, val) {
      let isProp = false;
      if (node.nodeName === "input" && key === "checked") {
        let type = (<Element>node).getAttribute("type");
        if (type === "checkbox" || type === "radio") {
          isProp = true;
        }
      }
      if (node.nodeName === "option" && key === "selected") {
        isProp = true;
      }
      if (key === "disabled" && DISABLED_TAGS.indexOf(node.nodeName) > -1) {
        isProp = true;
      }
      if ((key === "readonly" && node.nodeName === "input") || node.nodeName === "textarea") {
        isProp = true;
      }
      if (isProp) {
        props.push(`${key}: _${val}`);
      }
    }
    let classObj = "";
    for (let i = 0; i < attributes.length; i++) {
      let name = attributes[i].name;
      const value = attributes[i].textContent!;
      // regular attributes
      if (!name.startsWith("t-") && !(<Element>node).getAttribute("t-attf-" + name)) {
        const attID = ctx.generateID();
        if (name === "class") {
          let classDef = value
            .trim()
            .split(/\s+/)
            .map(a => `'${a}':true`)
            .join(",");
          classObj = `_${ctx.generateID()}`;
          ctx.addLine(`let ${classObj} = {${classDef}};`);
        } else {
          ctx.addLine(`var _${attID} = '${value}';`);
          if (!name.match(/^[a-zA-Z]+$/)) {
            // attribute contains 'non letters' => we want to quote it
            name = '"' + name + '"';
          }
          attrs.push(`${name}: _${attID}`);
          handleBooleanProps(name, attID);
        }
      }
      // dynamic attributes
      if (name.startsWith("t-att-")) {
        let attName = name.slice(6);
        const v = ctx.getValue(value);
        let formattedValue = v.id || ctx.formatExpression(v);
        if (attName === "class") {
          ctx.rootContext.shouldDefineUtils = true;
          formattedValue = `utils.toObj(${formattedValue})`;
          if (classObj) {
            ctx.addLine(`Object.assign(${classObj}, ${formattedValue})`);
          } else {
            classObj = `_${ctx.generateID()}`;
            ctx.addLine(`let ${classObj} = ${formattedValue};`);
          }
        } else {
          const attID = ctx.generateID();
          if (!attName.match(/^[a-zA-Z]+$/)) {
            // attribute contains 'non letters' => we want to quote it
            attName = '"' + attName + '"';
          }
          // we need to combine dynamic with non dynamic attributes:
          // class="a" t-att-class="'yop'" should be rendered as class="a yop"
          const attValue = (<Element>node).getAttribute(attName);
          if (attValue) {
            const attValueID = ctx.generateID();
            ctx.addLine(`var _${attValueID} = ${formattedValue};`);
            formattedValue = `'${attValue}' + (_${attValueID} ? ' ' + _${attValueID} : '')`;
            const attrIndex = attrs.findIndex(att => att.startsWith(attName + ":"));
            attrs.splice(attrIndex, 1);
          }
          ctx.addLine(`var _${attID} = ${formattedValue};`);
          attrs.push(`${attName}: _${attID}`);
          handleBooleanProps(attName, attID);
        }
      }
      if (name.startsWith("t-attf-")) {
        let attName = name.slice(7);
        if (!attName.match(/^[a-zA-Z]+$/)) {
          // attribute contains 'non letters' => we want to quote it
          attName = '"' + attName + '"';
        }
        const formattedExpr = ctx.interpolate(value);
        const attID = ctx.generateID();
        let staticVal = (<Element>node).getAttribute(attName);
        if (staticVal) {
          ctx.addLine(`var _${attID} = '${staticVal} ' + ${formattedExpr};`);
        } else {
          ctx.addLine(`var _${attID} = ${formattedExpr};`);
        }
        attrs.push(`${attName}: _${attID}`);
      }
      // t-att= attributes
      if (name === "t-att") {
        let id = ctx.generateID();
        ctx.addLine(`var _${id} = ${ctx.formatExpression(value!)};`);
        tattrs.push(id);
      }
    }
    let nodeID = ctx.generateID();
    let nodeKey: any = (<Element>node).getAttribute("t-key");
    if (nodeKey) {
      nodeKey = ctx.formatExpression(nodeKey);
    } else {
      nodeKey = nodeID;
    }
    const parts = [`key:${nodeKey}`];
    if (attrs.length + tattrs.length > 0) {
      parts.push(`attrs:{${attrs.join(",")}}`);
    }
    if (props.length > 0) {
      parts.push(`props:{${props.join(",")}}`);
    }
    if (classObj) {
      parts.push(`class:${classObj}`);
    }
    if (withHandlers) {
      parts.push(`on:{}`);
    }
    ctx.addLine(`let c${nodeID} = [], p${nodeID} = {${parts.join(",")}};`);
    for (let id of tattrs) {
      ctx.addIf(`_${id} instanceof Array`);
      ctx.addLine(`p${nodeID}.attrs[_${id}[0]] = _${id}[1];`);
      ctx.addElse();
      ctx.addLine(`for (let key in _${id}) {`);
      ctx.indent();
      ctx.addLine(`p${nodeID}.attrs[key] = _${id}[key];`);
      ctx.dedent();
      ctx.addLine(`}`);
      ctx.closeIf();
    }
    ctx.addLine(`var vn${nodeID} = h('${node.nodeName}', p${nodeID}, c${nodeID});`);
    if (ctx.parentNode) {
      ctx.addLine(`c${ctx.parentNode}.push(vn${nodeID});`);
    }
    return nodeID;
  }
  _compileChildren(node: ChildNode, ctx: Context) {
    if (node.childNodes.length > 0) {
      for (let child of Array.from(node.childNodes)) {
        this._compileNode(child, ctx);
      }
    }
  }
 }
@@ -0,0 +1,241 @@
 import { onWillUnmount } from "./component/lifecycle_hooks";
 import { ComponentNode, getCurrent } from "./component/component_node";
 // Allows to get the target of a Reactive (used for making a new Reactive from the underlying object)
 const TARGET = Symbol("Target");
 // Special key to subscribe to, to be notified of key creation/deletion
 const KEYCHANGES = Symbol("Key changes");
 type ObjectKey = string | number | symbol;
 type Target = object;
 type Callback = () => void;
 type Reactive<T extends Target = Target> = T & {
  [TARGET]: any;
 };
 /**
 * Checks whether a given value can be made into a reactive object.
 *
 * @param value the value to check
 * @returns whether the value can be made reactive
 */
 function canBeMadeReactive(value: any): boolean {
  return (
    typeof value === "object" &&
    value !== null &&
    !(value instanceof Date) &&
    !(value instanceof Promise) &&
    !(value instanceof String) &&
    !(value instanceof Number)
  );
 }
 const targetToKeysToCallbacks = new WeakMap<Target, Map<ObjectKey, Set<Callback>>>();
 /**
 * Observes a given key on a target with an callback. The callback will be
 * called when the given key changes on the target.
 *
 * @param target the target whose key should be observed
 * @param key the key to observe (or Symbol(KEYCHANGES) for key creation
 *  or deletion)
 * @param callback the function to call when the key changes
 */
 function observeTargetKey(target: Target, key: ObjectKey, callback: Callback): void {
  if (!targetToKeysToCallbacks.get(target)) {
    targetToKeysToCallbacks.set(target, new Map());
  }
  const keyToCallbacks = targetToKeysToCallbacks.get(target)!;
  if (!keyToCallbacks.get(key)) {
    keyToCallbacks.set(key, new Set());
  }
  keyToCallbacks.get(key)!.add(callback);
  if (!callbacksToTargets.has(callback)) {
    callbacksToTargets.set(callback, new Set());
  }
  callbacksToTargets.get(callback)!.add(target);
 }
 /**
 * Notify Reactives that are observing a given target that a key has changed on
 * the target.
 *
 * @param target target whose Reactives should be notified that the target was
 *  changed.
 * @param key the key that changed (or Symbol `KEYCHANGES` if a key was created
 *   or deleted)
 */
 function notifyReactives(target: Target, key: ObjectKey): void {
  const keyToCallbacks = targetToKeysToCallbacks.get(target);
  if (!keyToCallbacks) {
    return;
  }
  const callbacks = keyToCallbacks.get(key);
  if (!callbacks) {
    return;
  }
  // Loop on copy because clearReactivesForCallback will modify the set in place
  for (const callback of [...callbacks]) {
    clearReactivesForCallback(callback);
    callback();
  }
 }
 const callbacksToTargets = new WeakMap<Callback, Set<Target>>();
 /**
 * Clears all subscriptions of the Reactives associated with a given callback.
 *
 * @param callback the callback for which the reactives need to be cleared
 */
 function clearReactivesForCallback(callback: Callback): void {
  const targetsToClear = callbacksToTargets.get(callback);
  if (!targetsToClear) {
    return;
  }
  for (const target of targetsToClear) {
    const observedKeys = targetToKeysToCallbacks.get(target);
    if (!observedKeys) {
      continue;
    }
    for (const callbacks of observedKeys.values()) {
      callbacks.delete(callback);
    }
  }
  targetsToClear.clear();
 }
 const reactiveCache = new WeakMap<Target, WeakMap<Callback, Reactive>>();
 /**
 * Creates a reactive proxy for an object. Reading data on the reactive object
 * subscribes to changes to the data. Writing data on the object will cause the
 * notify callback to be called if there are suscriptions to that data. Nested
 * objects and arrays are automatically made reactive as well.
 *
 * Whenever you are notified of a change, all subscriptions are cleared, and if
 * you would like to be notified of any further changes, you should go read
 * the underlying data again. We assume that if you don't go read it again after
 * being notified, it means that you are no longer interested in that data.
 *
 * Subscriptions:
 * + Reading a property on an object will subscribe you to changes in the value
 *    of that property.
 * + Accessing an object keys (eg with Object.keys or with `for..in`) will
 *    subscribe you to the creation/deletion of keys. Checking the presence of a
 *    key on the object with 'in' has the same effect.
 * - getOwnPropertyDescriptor does not currently subscribe you to the property.
 *    This is a choice that was made because changing a key's value will trigger
 *    this trap and we do not want to subscribe by writes. This also means that
 *    Object.hasOwnProperty doesn't subscribe as it goes through this trap.
 *
 * @param target the object for which to create a reactive proxy
 * @param callback the function to call when an observed property of the
 *  reactive has changed
 * @returns a proxy that tracks changes to it
 */
 export function reactive<T extends Target>(target: T, callback: Callback = () => {}): Reactive<T> {
  if (!canBeMadeReactive(target)) {
    throw new Error(`Cannot make the given value reactive`);
  }
  const originalTarget = (target as Reactive)[TARGET];
  if (originalTarget) {
    return reactive(originalTarget, callback);
  }
  if (!reactiveCache.has(target)) {
    reactiveCache.set(target, new Map());
  }
  const reactivesForTarget = reactiveCache.get(target)!;
  if (!reactivesForTarget.has(callback)) {
    const proxy = new Proxy(target, {
      get(target: any, key: ObjectKey, proxy: Reactive<T>) {
        if (key === TARGET) {
          return target;
        }
        observeTargetKey(target, key, callback);
        const value = Reflect.get(target, key, proxy);
        if (!canBeMadeReactive(value)) {
          return value;
        }
        return reactive(value, callback);
      },
      set(target, key, value, proxy) {
        const isNewKey = !Object.hasOwnProperty.call(target, key);
        const originalValue = Reflect.get(target, key, proxy);
        const ret = Reflect.set(target, key, value, proxy);
        if (isNewKey) {
          notifyReactives(target, KEYCHANGES);
        }
        // While Array length may trigger the set trap, it's not actually set by this
        // method but is updated behind the scenes, and the trap is not called with the
        // new value. We disable the "same-value-optimization" for it because of that.
        if (originalValue !== value || (Array.isArray(target) && key === "length")) {
          notifyReactives(target, key);
        }
        return ret;
      },
      deleteProperty(target, key) {
        const ret = Reflect.deleteProperty(target, key);
        notifyReactives(target, KEYCHANGES);
        notifyReactives(target, key);
        return ret;
      },
      ownKeys(target) {
        observeTargetKey(target, KEYCHANGES, callback);
        return Reflect.ownKeys(target);
      },
      has(target, key) {
        // TODO: this observes all key changes instead of only the presence of the argument key
        observeTargetKey(target, KEYCHANGES, callback);
        return Reflect.has(target, key);
      },
    });
    reactivesForTarget.set(callback, proxy);
  }
  return reactivesForTarget.get(callback) as Reactive<T>;
 }
 /**
 * Creates a batched version of a callback so that all calls to it in the same
 * microtick will only call the original callback once.
 *
 * @param callback the callback to batch
 * @returns a batched version of the original callback
 */
 export function batched(callback: Callback): Callback {
  let called = false;
  return async () => {
    // This await blocks all calls to the callback here, then releases them sequentially
    // in the next microtick. This line decides the granularity of the batch.
    await Promise.resolve();
    if (!called) {
      called = true;
      callback();
      // wait for all calls in this microtick to fall through before resetting "called"
      // so that only the first call to the batched function calls the original callback
      await Promise.resolve();
      called = false;
    }
  };
 }
 const batchedRenderFunctions = new WeakMap<ComponentNode, Callback>();
 /**
 * Creates a reactive object that will be observed by the current component.
 * Reading data from the returned object (eg during rendering) will cause the
 * component to subscribe to that data and be rerendered when it changes.
 *
 * @param state the state to observe
 * @returns a reactive object that will cause the component to re-render on
 *  relevant changes
 * @see reactive
 */
 export function useState<T extends object>(state: T): Reactive<T> {
  const node = getCurrent()!;
  if (!batchedRenderFunctions.has(node)) {
    batchedRenderFunctions.set(
      node,
      batched(() => node.render())
    );
    onWillUnmount(() => clearReactivesForCallback(render));
  }
  const render = batchedRenderFunctions.get(node)!;
  const reactiveState = reactive(state, render);
  return reactiveState;
 }
@@ -1,48 +0,0 @@
 import { Component } from "../component/component";
 import { Destination, RouterEnv } from "./Router";
 export const LINK_TEMPLATE_NAME = "__owl__-router-link";
 export const LINK_TEMPLATE = `
    <a  t-att-class="{'router-link-active': isActive }"
        t-att-href="href"
        t-on-click="navigate">
        <t t-slot="default"/>
    </a>`;
 type Props = Destination;
 export class Link<Env extends RouterEnv> extends Component<Env, Props, {}> {
  template = LINK_TEMPLATE_NAME;
  href: string = this.env.router.destToPath(this.props);
  async willUpdateProps(nextProps) {
    this.href = this.env.router.destToPath(nextProps);
  }
  get isActive() {
    if (this.env.router.mode === "hash") {
      return (<any>document.location).hash === this.href;
    }
    return (<any>document.location).pathname === this.href;
  }
  navigate(ev) {
    // don't redirect with control keys
    if (ev.metaKey || ev.altKey || ev.ctrlKey || ev.shiftKey) {
      return;
    }
    // don't redirect on right click
    if (ev.button !== undefined && ev.button !== 0) {
      return;
    }
    // don't redirect if `target="_blank"`
    if (ev.currentTarget && ev.currentTarget.getAttribute) {
      const target = ev.currentTarget.getAttribute("target");
      if (/\b_blank\b/i.test(target)) {
        return;
      }
    }
    ev.preventDefault();
    this.env.router.navigate(this.props);
  }
 }
@@ -1,262 +0,0 @@
 import { Env } from "../component/component";
 import { QWeb } from "../qweb/index";
 import { makeDirective } from "./directive";
 import { LINK_TEMPLATE, LINK_TEMPLATE_NAME } from "./Link";
 type NavigationGuard = (info: {
  env: Env;
  to: Route | null;
  from: Route | null;
 }) => boolean | Destination;
 export interface Route {
  name: string;
  path: string;
  component?: any;
  redirect?: Destination;
  params: string[];
  beforeRouteEnter?: NavigationGuard;
 }
 export type RouteParams = { [key: string]: string | number };
 export interface RouterEnv extends Env {
  router: Router;
 }
 export interface Destination {
  path?: string;
  to?: string;
  params?: RouteParams;
 }
 interface PositiveMatchResult {
  type: "match";
  route: Route;
  params: RouteParams;
 }
 interface NegativeMatchResult {
  type: "nomatch";
 }
 interface CancelledMatch {
  type: "cancelled";
 }
 type MatchResult = PositiveMatchResult | NegativeMatchResult | CancelledMatch;
 interface Options {
  mode: Router["mode"];
 }
 const paramRegexp = /\{\{(.*?)\}\}/;
 export class Router {
  currentRoute: Route | null = null;
  currentParams: RouteParams | null = null;
  mode: "history" | "hash";
  routes: { [id: string]: Route };
  routeIds: string[];
  env: RouterEnv;
  constructor(env: Env, routes: Partial<Route>[], options: Options = { mode: "history" }) {
    env.router = this;
    this.mode = options.mode;
    this.env = env as RouterEnv;
    this.routes = {};
    this.routeIds = [];
    let nextId = 1;
    for (let partialRoute of routes) {
      if (!partialRoute.name) {
        partialRoute.name = "__route__" + nextId++;
      }
      if (partialRoute.component) {
        QWeb.register("__component__" + partialRoute.name, partialRoute.component);
      }
      if (partialRoute.redirect) {
        this.validateDestination(partialRoute.redirect);
      }
      partialRoute.params = partialRoute.path ? findParams(partialRoute.path) : [];
      this.routes[partialRoute.name] = partialRoute as Route;
      this.routeIds.push(partialRoute.name);
    }
    (this as any)._listener = () => this.matchAndApplyRules(this.currentPath());
    window.addEventListener("popstate", (this as any)._listener);
    // setup link and directive
    env.qweb.addTemplate(LINK_TEMPLATE_NAME, LINK_TEMPLATE);
    QWeb.addDirective(makeDirective(<RouterEnv>env));
  }
  //--------------------------------------------------------------------------
  // Public API
  //--------------------------------------------------------------------------
  async start() {
    const result = await this.matchAndApplyRules(this.currentPath());
    if (result.type === "match") {
      this.currentRoute = result.route;
      this.currentParams = result.params;
      const currentPath = this.routeToPath(result.route, result.params);
      if (currentPath !== this.currentPath()) {
        this.setUrlFromPath(currentPath);
      }
    }
  }
  async navigate(to: Destination): Promise<boolean> {
    const path = this.destToPath(to);
    const initialName = this.currentRouteName;
    const result = await this.matchAndApplyRules(path);
    if (result.type === "match") {
      const finalPath = this.routeToPath(result.route, result.params);
      this.setUrlFromPath(finalPath);
      this.currentRoute = result.route;
      this.currentParams = result.params;
    } else if (result.type === "nomatch") {
      this.currentRoute = null;
      this.currentParams = null;
    }
    if (this.currentRouteName !== initialName) {
      this.env.qweb.forceUpdate();
      return true;
    }
    return false;
  }
  destToPath(dest: Destination): string {
    this.validateDestination(dest);
    return dest.path || this.routeToPath(this.routes[dest.to!], dest.params!);
  }
  get currentRouteName(): string | null {
    return this.currentRoute && this.currentRoute.name;
  }
  //--------------------------------------------------------------------------
  // Private helpers
  //--------------------------------------------------------------------------
  private setUrlFromPath(path: string) {
    const url = location.origin + path;
    window.history.pushState({}, path, url);
  }
  private validateDestination(dest: Destination) {
    if ((!dest.path && !dest.to) || (dest.path && dest.to)) {
      throw new Error(`Invalid destination: ${JSON.stringify(dest)}`);
    }
  }
  private routeToPath(route: Route, params: RouteParams): string {
    const path = route.path;
    const parts = path.split("/");
    const l = parts.length;
    for (let i = 0; i < l; i++) {
      const part = parts[i];
      const match = part.match(paramRegexp);
      if (match) {
        const key = match[1].split(".")[0];
        parts[i] = <string>params[key];
      }
    }
    return parts.join("/");
  }
  private currentPath(): string {
    let result = this.mode === "history" ? window.location.pathname : window.location.hash.slice(1);
    return result || "/";
  }
  private match(path: string): MatchResult {
    for (let routeId of this.routeIds) {
      let route = this.routes[routeId];
      let params = this.getRouteParams(route, path);
      if (params) {
        return {
          type: "match",
          route: route,
          params: params
        };
      }
    }
    return { type: "nomatch" };
  }
  private async matchAndApplyRules(path: string): Promise<MatchResult> {
    const result = this.match(path);
    if (result.type === "match") {
      return this.applyRules(result);
    }
    return result;
  }
  private async applyRules(matchResult: PositiveMatchResult): Promise<MatchResult> {
    const route = matchResult.route;
    if (route.redirect) {
      const path = this.destToPath(route.redirect);
      return this.matchAndApplyRules(path);
    }
    if (route.beforeRouteEnter) {
      const result = await route.beforeRouteEnter({
        env: this.env,
        from: this.currentRoute,
        to: route
      });
      if (result === false) {
        return { type: "cancelled" };
      } else if (result !== true) {
        // we want to navigate to another destination
        const path = this.destToPath(result);
        return this.matchAndApplyRules(path);
      }
    }
    return matchResult;
  }
  private getRouteParams(route: Route, path: string): RouteParams | false {
    if (route.path === "*") {
      return {};
    }
    const descrParts = route.path.split("/");
    const targetParts = path.split("/");
    const l = descrParts.length;
    if (l !== targetParts.length) {
      return false;
    }
    const result = {};
    for (let i = 0; i < l; i++) {
      const descr = descrParts[i];
      let target: string | number = targetParts[i];
      const match = descr.match(paramRegexp);
      if (match) {
        const [key, suffix] = match[1].split(".");
        if (suffix === "number") {
          target = parseInt(target, 10);
        }
        result[key] = target;
      } else if (descr !== target) {
        return false;
      }
    }
    return result;
  }
 }
 function findParams(str: string): string[] {
  const globalParamRegexp = /\{\{(.*?)\}\}/g;
  const result: string[] = [];
  let m;
  do {
    m = globalParamRegexp.exec(str);
    if (m) {
      result.push(m[1].split(".")[0]);
    }
  } while (m);
  return result;
 }
@@ -1,28 +0,0 @@
 import { RouterEnv } from "./Router";
 export function makeDirective(env: RouterEnv) {
  return {
    name: "routecomponent",
    priority: 13,
    atNodeEncounter({ node }): boolean {
      let first = true;
      const router = env.router;
      for (let name of router.routeIds) {
        const route = router.routes[name];
        if (route.component) {
          // make new t t-component element
          const comp = node.ownerDocument.createElement("t");
          comp.setAttribute("t-component", "__component__" + route.name);
          comp.setAttribute(first ? "t-if" : "t-elif", `env.router.currentRouteName === '${route.name}'`);
          first = false;
          for (let param of route.params) {
            comp.setAttribute(param, `env.router.currentParams.${param}`);
          }
          node.appendChild(comp);
        }
      }
      node.removeAttribute("t-routecomponent");
      return false;
    }
  };
 }
@@ -1,119 +0,0 @@
 import { Component, Env } from "../component/component";
 //------------------------------------------------------------------------------
 // Connect function
 //------------------------------------------------------------------------------
 type HashFunction = (a: any, b: any) => number;
 export class ConnectedComponent<T extends Env, P, S> extends Component<T, P, S> {
  deep: boolean = true;
  getStore(env) {
    return env.store;
  }
  storeProps: any;
  hashFunction: HashFunction = (storeProps, options) => {
    const revFn = (this.__owl__ as any).revFn;
    const rev = revFn(storeProps);
    if (rev > 0) {
      return rev;
    }
    let hash = 0;
    for (let key in storeProps) {
      const val = storeProps[key];
      const hashVal = revFn(val);
      if (hashVal === 0) {
        if (val !== options.prevStoreProps[key]) {
          options.didChange = true;
        }
      } else {
        hash += hashVal;
      }
    }
    return hash;
  };
  static mapStoreToProps(storeState, ownProps, getters) {
    return {};
  }
  dispatch(name, ...payload) {
    return (this.__owl__ as any).store.dispatch(name, ...payload);
  }
  /**
   * Need to do this here so 'deep' can be overrided by subcomponent easily
   */
  async __prepareAndRender(
    scope?: Object,
    vars?: any
  ): ReturnType<Component<any, any, any>["__prepareAndRender"]> {
    const store = this.getStore(this.env);
    const ownProps = this.props || {};
    this.storeProps = (<any>this.constructor).mapStoreToProps(store.state, ownProps, store.getters);
    const observer = store.observer;
    const revFn = this.deep ? observer.deepRevNumber : observer.revNumber;
    (this.__owl__ as any).store = store;
    (this.__owl__ as any).revFn = revFn.bind(observer);
    (this.__owl__ as any).storeHash = this.hashFunction(this.storeProps, {
      prevStoreProps: this.storeProps
    });
    (this.__owl__ as any).rev = observer.rev;
    return super.__prepareAndRender(scope, vars);
  }
  /**
   * We do not use the mounted hook here for a subtle reason: we want the
   * updates to be called for the parents before the children.  However,
   * if we use the mounted hook, this will be done in the reverse order.
   */
  __callMounted() {
    (this.__owl__ as any).store.on("update", this, this.__checkUpdate);
    super.__callMounted();
  }
  __callWillUnmount() {
    (this.__owl__ as any).store.off("update", this);
    super.__callWillUnmount();
  }
  __destroy(parent: any) {
    (this.__owl__ as any).store.off("update", this);
    super.__destroy(parent);
  }
  async __updateProps(nextProps: P, f, p, s, v) {
    this.__updateStoreProps(nextProps);
    return super.__updateProps(nextProps, f, p, s, v);
  }
  __updateStoreProps(nextProps): boolean {
    const store = (this.__owl__ as any).store;
    const storeProps = (<any>this.constructor).mapStoreToProps(
      store.state,
      nextProps,
      store.getters
    );
    const options = { prevStoreProps: this.storeProps, didChange: false };
    const storeHash = this.hashFunction(storeProps, options);
    this.storeProps = storeProps;
    let didChange = options.didChange;
    if (storeHash !== (this.__owl__ as any).storeHash) {
      (this.__owl__ as any).storeHash = storeHash;
      didChange = true;
    }
    (this.__owl__ as any).rev = store.observer.rev;
    return didChange;
  }
  async __checkUpdate() {
    const observer = (this.__owl__ as any).store.observer;
    if (observer.rev === (this.__owl__ as any).rev) {
      // update was already done by updateProps, from parent
      return;
    }
    const didChange = this.__updateStoreProps(this.props);
    if (didChange) {
      return this.render();
    }
  }
 }
@@ -1,107 +0,0 @@
 import { Env } from "../component/component";
 import { EventBus } from "../core/event_bus";
 import { Observer } from "../core/observer";
 /**
 * Owl Store
 *
 * We have here:
 * - a Store class
 * - the ConnectedComponent class
 *
 * The Owl store is our answer to the problem of managing complex state across
 * components. The main idea is that the store owns some state, allow external
 * code to modify it through actions, and for each state changes,
 * connected component will be notified, and updated if necessary.
 *
 * Note that this code is partly inspired by VueX and React/Redux
 */
 //------------------------------------------------------------------------------
 // Store Definition
 //------------------------------------------------------------------------------
 export type Action = ({ state, dispatch, env, getters }, ...payload: any) => any;
 export type Getter = ({ state: any, getters }, payload?) => any;
 interface StoreConfig {
  env?: Env;
  state?: any;
  actions?: { [name: string]: Action };
  getters?: { [name: string]: Getter };
 }
 interface StoreOption {
  debug?: boolean;
 }
 export class Store extends EventBus {
  state: any;
  actions: any;
  mutations: any;
  debug: boolean;
  env: any;
  observer: Observer;
    getters: { [name: string]: (payload?) => any };
  constructor(config: StoreConfig, options: StoreOption = {}) {
    super();
    this.debug = options.debug || false;
    this.actions = config.actions;
    this.env = config.env;
    this.observer = new Observer();
    this.observer.notifyCB = this.__notifyComponents.bind(this);
    this.state = this.observer.observe(config.state || {});
    this.getters = {};
    if (config.getters) {
        const firstArg = {
            state: this.state,
            getters: this.getters,
        };
        for (let g in config.getters) {
            this.getters[g] = config.getters[g].bind(this, firstArg);
        }
    }
  }
  dispatch(action: string, ...payload: any): Promise<void> | void {
    if (!this.actions[action]) {
      throw new Error(`[Error] action ${action} is undefined`);
    }
    const result = this.actions[action](
      {
        dispatch: this.dispatch.bind(this),
        env: this.env,
        state: this.state,
        getters: this.getters
      },
      ...payload
    );
    return result;
  }
  /**
   * Instead of using trigger to emit an update event, we actually implement
   * our own function to do that.  The reason is that we need to be smarter than
   * a simple trigger function: we need to wait for parent components to be
   * done before doing children components.  The reason is that if an update
   * as an effect of destroying a children, we do not want to call the
   * mapStoreToProps function of the child, nor rendering it.
   *
   * This method is not optimal if we have a bunch of asynchronous components:
   * we wait sequentially for each component to be completed before updating the
   * next.  However, the only things that matters is that children are updated
   * after their parents.  So, this could be optimized by being smarter, and
   * updating all widgets concurrently, except for parents/children.
   */
  async __notifyComponents() {
    const subs = this.subscriptions.update || [];
    for (let i = 0, iLen = subs.length; i < iLen; i++) {
      const sub = subs[i];
      const shouldCallback = sub.owner ? sub.owner.__owl__.isMounted : true;
      if (shouldCallback) {
        await sub.callback.call(sub.owner);
      }
    }
  }
 }
@@ -1,97 +1,38 @@
-/**
+export class EventBus extends EventTarget {
- * Owl Utils
+  trigger(name: string, payload?: any) {
- *
+    this.dispatchEvent(new CustomEvent(name, { detail: payload }));
- * We have here a small collection of utility functions:
+  }
- *
+}
 * - whenReady
 * - loadJS
 * - loadTemplates
 * - escape
 * - debounce
 */
-export function whenReady(fn?: any) {
+export function whenReady(fn?: any): Promise<void> {
-  return new Promise(function(resolve) {
+  return new Promise(function (resolve) {
    if (document.readyState !== "loading") {
-      resolve();
+      resolve(true);
    } else {
      document.addEventListener("DOMContentLoaded", resolve, false);
    }
-  }).then(fn || function() {});
+  }).then(fn || function () {});
 }
-const loadedScripts: { [key: string]: Promise<void> } = {};
+export async function loadFile(url: string): Promise<string> {
 export function loadJS(url: string): Promise<void> {
  if (url in loadedScripts) {
    return loadedScripts[url];
  }
  const promise: Promise<void> = new Promise(function(resolve, reject) {
    const script = document.createElement("script");
    script.type = "text/javascript";
    script.src = url;
    script.onload = function() {
      resolve();
    };
    script.onerror = function() {
      reject(`Error loading file '${url}'`);
    };
    const head = document.head || document.getElementsByTagName("head")[0];
    head.appendChild(script);
  });
  loadedScripts[url] = promise;
  return promise;
 }
 export async function loadTemplates(url: string): Promise<string> {
  const result = await fetch(url);
  if (!result.ok) {
    throw new Error("Error while fetching xml templates");
  }
-  let templates = await result.text();
+  return await result.text();
  templates = templates.replace(/<!--[\s\S]*?-->/g, "");
  return templates;
 }
-export function escape(str: string | number | undefined): string {
+/*
-  if (str === undefined) {
+ * This class just transports the fact that a string is safe
-    return "";
+ * to be injected as HTML. Overriding a JS primitive is quite painful though
-  }
+ * so we need to redfine toString and valueOf.
  if (typeof str === "number") {
    return String(str);
  }
  return str
    .replace(/&/g, "&amp;")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;")
    .replace(/"/g, "&#x27;")
    .replace(/`/g, "&#x60;");
 }
 /**
 * Returns a function, that, as long as it continues to be invoked, will not
 * be triggered. The function will be called after it stops being called for
 * N milliseconds. If `immediate` is passed, trigger the function on the
 * leading edge, instead of the trailing.
 *
 * Inspired by https://davidwalsh.name/javascript-debounce-function
 */
-export function debounce(func: Function, wait: number, immediate?: boolean): Function {
+export class Markup extends String {}
-  let timeout;
+
-  return function(this: any) {
+/*
-    const context = this;
+ * Marks a value as safe, that is, a value that can be injected as HTML directly.
-    const args = arguments;
+ * It should be used to wrap the value passed to a t-out directive to allow a raw rendering.
-    function later() {
+ */
-      timeout = null;
+export function markup(value: any) {
-      if (!immediate) {
+  return new Markup(value);
        func.apply(context, args);
      }
    }
    const callNow = immediate && !timeout;
    clearTimeout(timeout);
    timeout = setTimeout(later, wait);
    if (callNow) {
      func.apply(context, args);
    }
  };
 }
@@ -1,9 +0,0 @@
 import { attrsModule, classModule, eventListenersModule, propsModule } from "./modules";
 import { init } from "./vdom";
 //------------------------------------------------------------------------------
 // patch
 //------------------------------------------------------------------------------
 export { h, VNode } from "./vdom";
 export const patch = init([eventListenersModule, attrsModule, propsModule, classModule]);
@@ -1,234 +0,0 @@
 import { Module, VNode, VNodeData } from "./vdom";
 //------------------------------------------------------------------------------
 // module/props.ts
 //------------------------------------------------------------------------------
 function updateProps(oldVnode: VNode, vnode: VNode): void {
  var key: string,
    cur: any,
    old: any,
    elm = vnode.elm,
    oldProps = (oldVnode.data as VNodeData).props,
    props = (vnode.data as VNodeData).props;
  if (!oldProps && !props) return;
  if (oldProps === props) return;
  oldProps = oldProps || {};
  props = props || {};
  for (key in oldProps) {
    if (!props[key]) {
      delete (elm as any)[key];
    }
  }
  for (key in props) {
    cur = props[key];
    old = oldProps[key];
    if (old !== cur && (key !== "value" || (elm as any)[key] !== cur)) {
      (elm as any)[key] = cur;
    }
  }
 }
 export const propsModule = {
  create: updateProps,
  update: updateProps
 } as Module;
 //------------------------------------------------------------------------------
 // module/eventlisteners.ts
 //------------------------------------------------------------------------------
 function invokeHandler(handler: any, vnode?: VNode, event?: Event): void {
  if (typeof handler === "function") {
    // call function handler
    handler.call(vnode, event, vnode);
  } else if (typeof handler === "object") {
    // call handler with arguments
    if (typeof handler[0] === "function") {
      // special case for single argument for performance
      if (handler.length === 2) {
        handler[0].call(vnode, handler[1], event, vnode);
      } else {
        var args = handler.slice(1);
        args.push(event);
        args.push(vnode);
        handler[0].apply(vnode, args);
      }
    } else {
      // call multiple handlers
      for (let i = 0, iLen = handler.length; i < iLen; i++) {
        invokeHandler(handler[i], vnode, event);
      }
    }
  }
 }
 function handleEvent(event: Event, vnode: VNode) {
  var name = event.type,
    on = (vnode.data as VNodeData).on;
  // call event handler(s) if exists
  if (on && on[name]) {
    invokeHandler(on[name], vnode, event);
  }
 }
 function createListener() {
  return function handler(event: Event) {
    handleEvent(event, (handler as any).vnode);
  };
 }
 function updateEventListeners(oldVnode: VNode, vnode?: VNode): void {
  var oldOn = (oldVnode.data as VNodeData).on,
    oldListener = (oldVnode as any).listener,
    oldElm: Element = oldVnode.elm as Element,
    on = vnode && (vnode.data as VNodeData).on,
    elm: Element = (vnode && vnode.elm) as Element,
    name: string;
  // optimization for reused immutable handlers
  if (oldOn === on) {
    return;
  }
  // remove existing listeners which no longer used
  if (oldOn && oldListener) {
    // if element changed or deleted we remove all existing listeners unconditionally
    if (!on) {
      for (name in oldOn) {
        // remove listener if element was changed or existing listeners removed
        oldElm.removeEventListener(name, oldListener, false);
      }
    } else {
      for (name in oldOn) {
        // remove listener if existing listener removed
        if (!on[name]) {
          oldElm.removeEventListener(name, oldListener, false);
        }
      }
    }
  }
  // add new listeners which has not already attached
  if (on) {
    // reuse existing listener or create new
    var listener = ((vnode as any).listener = (oldVnode as any).listener || createListener());
    // update vnode for listener
    listener.vnode = vnode;
    // if element changed or added we add all needed listeners unconditionally
    if (!oldOn) {
      for (name in on) {
        // add listener if element was changed or new listeners added
        elm.addEventListener(name, listener, false);
      }
    } else {
      for (name in on) {
        // add listener if new listener added
        if (!oldOn[name]) {
          elm.addEventListener(name, listener, false);
        }
      }
    }
  }
 }
 export const eventListenersModule = {
  create: updateEventListeners,
  update: updateEventListeners,
  destroy: updateEventListeners
 } as Module;
 //------------------------------------------------------------------------------
 // attributes.ts
 //------------------------------------------------------------------------------
 const xlinkNS = "http://www.w3.org/1999/xlink";
 const xmlNS = "http://www.w3.org/XML/1998/namespace";
 const colonChar = 58;
 const xChar = 120;
 function updateAttrs(oldVnode: VNode, vnode: VNode): void {
  var key: string,
    elm: Element = vnode.elm as Element,
    oldAttrs = (oldVnode.data as VNodeData).attrs,
    attrs = (vnode.data as VNodeData).attrs;
  if (!oldAttrs && !attrs) return;
  if (oldAttrs === attrs) return;
  oldAttrs = oldAttrs || {};
  attrs = attrs || {};
  // update modified attributes, add new attributes
  for (key in attrs) {
    const cur = attrs[key];
    const old = oldAttrs[key];
    if (old !== cur) {
      if (cur === true) {
        elm.setAttribute(key, "");
      } else if (cur === false) {
        elm.removeAttribute(key);
      } else {
        if (key.charCodeAt(0) !== xChar) {
          elm.setAttribute(key, cur);
        } else if (key.charCodeAt(3) === colonChar) {
          // Assume xml namespace
          elm.setAttributeNS(xmlNS, key, cur);
        } else if (key.charCodeAt(5) === colonChar) {
          // Assume xlink namespace
          elm.setAttributeNS(xlinkNS, key, cur);
        } else {
          elm.setAttribute(key, cur);
        }
      }
    }
  }
  // remove removed attributes
  // use `in` operator since the previous `for` iteration uses it (.i.e. add even attributes with undefined value)
  // the other option is to remove all attributes with value == undefined
  for (key in oldAttrs) {
    if (!(key in attrs)) {
      elm.removeAttribute(key);
    }
  }
 }
 export const attrsModule = {
  create: updateAttrs,
  update: updateAttrs
 } as Module;
 //------------------------------------------------------------------------------
 // class.ts
 //------------------------------------------------------------------------------
 function updateClass(oldVnode: VNode, vnode: VNode): void {
  var cur: any,
    name: string,
    elm: Element,
    oldClass = (oldVnode.data as VNodeData).class,
    klass = (vnode.data as VNodeData).class;
  if (!oldClass && !klass) return;
  if (oldClass === klass) return;
  oldClass = oldClass || {};
  klass = klass || {};
  elm = vnode.elm as Element;
  for (name in oldClass) {
    if (!klass[name]) {
      elm.classList.remove(name);
    }
  }
  for (name in klass) {
    cur = klass[name];
    if (cur !== oldClass[name]) {
      (elm.classList as any)[cur ? "add" : "remove"](name);
    }
  }
 }
 export const classModule = { create: updateClass, update: updateClass } as Module;
@@ -1,624 +0,0 @@
 /**
 * Owl VDOM
 *
 * This file contains an implementation of a virtual DOM, which is a system that
 * can generate in-memory representations of a DOM tree, compare them, and
 * eventually change a concrete DOM tree to match its representation, in an
 * hopefully efficient way.
 *
 * Note that this code is a fork of Snabbdom, slightly tweaked/optimized for our
 * needs (see https://github.com/snabbdom/snabbdom).
 *
 * The main exported values are:
 * - interface VNode
 * - h function (a helper function to generate a vnode)
 * - patch function (to apply a vnode to an actual DOM node)
 */
 // because those in TypeScript are too restrictive: https://github.com/Microsoft/TSJS-lib-generator/pull/237
 declare global {
  interface Element {
    setAttribute(name: string, value: string | number | boolean): void;
    setAttributeNS(
      namespaceURI: string,
      qualifiedName: string,
      value: string | number | boolean
    ): void;
  }
 }
 type Props = Record<string, any>;
 type Attrs = Record<string, string | number | boolean>;
 type On = { [N in keyof HTMLElementEventMap]?: (ev: HTMLElementEventMap[N]) => void } & {
  [event: string]: EventListener;
 };
 export interface Module {
  pre: PreHook;
  create: CreateHook;
  update: UpdateHook;
  destroy: DestroyHook;
  remove: RemoveHook;
  post: PostHook;
 }
 //------------------------------------------------------------------------------
 // vnode.ts
 //------------------------------------------------------------------------------
 type Key = string | number;
 export interface VNode {
  sel: string | undefined;
  data: VNodeData | undefined;
  children: Array<VNode | string> | undefined;
  elm: Node | undefined;
  text: string | undefined;
  key: Key | undefined;
 }
 export interface VNodeData {
  props?: Props;
  attrs?: Attrs;
  on?: On;
  hook?: Hooks;
  key?: Key;
  ns?: string; // for SVGs
  [key: string]: any; // for any other 3rd party module
 }
 function vnode(
  sel: string | undefined,
  data: any | undefined,
  children: Array<VNode | string> | undefined,
  text: string | undefined,
  elm: Element | Text | undefined
 ): VNode {
  let key = data === undefined ? undefined : data.key;
  return { sel, data, children, text, elm, key };
 }
 //------------------------------------------------------------------------------
 // snabbdom.ts
 //------------------------------------------------------------------------------
 function isUndef(s: any): boolean {
  return s === undefined;
 }
 function isDef(s: any): boolean {
  return s !== undefined;
 }
 type VNodeQueue = Array<VNode>;
 const emptyNode = vnode("", {}, [], undefined, undefined);
 function sameVnode(vnode1: VNode, vnode2: VNode): boolean {
  return vnode1.key === vnode2.key && vnode1.sel === vnode2.sel;
 }
 function isVnode(vnode: any): vnode is VNode {
  return vnode.sel !== undefined;
 }
 type KeyToIndexMap = { [key: string]: number };
 type ArraysOf<T> = { [K in keyof T]: (T[K])[] };
 type ModuleHooks = ArraysOf<Module>;
 function createKeyToOldIdx(
  children: Array<VNode>,
  beginIdx: number,
  endIdx: number
 ): KeyToIndexMap {
  let i: number,
    map: KeyToIndexMap = {},
    key: Key | undefined,
    ch;
  for (i = beginIdx; i <= endIdx; ++i) {
    ch = children[i];
    if (ch != null) {
      key = ch.key;
      if (key !== undefined) map[key] = i;
    }
  }
  return map;
 }
 const hooks: (keyof Module)[] = ["create", "update", "remove", "destroy", "pre", "post"];
 export function init(modules: Array<Partial<Module>>, domApi?: DOMAPI) {
  let i: number,
    j: number,
    cbs = {} as ModuleHooks;
  const api: DOMAPI = domApi !== undefined ? domApi : htmlDomApi;
  for (i = 0; i < hooks.length; ++i) {
    cbs[hooks[i]] = [];
    for (j = 0; j < modules.length; ++j) {
      const hook = modules[j][hooks[i]];
      if (hook !== undefined) {
        (cbs[hooks[i]] as Array<any>).push(hook);
      }
    }
  }
  function emptyNodeAt(elm: Element) {
    const id = elm.id ? "#" + elm.id : "";
    const c = elm.className ? "." + elm.className.split(" ").join(".") : "";
    return vnode(api.tagName(elm).toLowerCase() + id + c, {}, [], undefined, elm);
  }
  function createRmCb(childElm: Node, listeners: number) {
    return function rmCb() {
      if (--listeners === 0) {
        const parent = api.parentNode(childElm);
        api.removeChild(parent, childElm);
      }
    };
  }
  function createElm(vnode: VNode, insertedVnodeQueue: VNodeQueue): Node {
    let i: any,
      iLen: number,
      data = vnode.data;
    if (data !== undefined) {
      if (isDef((i = data.hook)) && isDef((i = i.init))) {
        i(vnode);
        data = vnode.data;
      }
    }
    let children = vnode.children,
      sel = vnode.sel;
    if (sel === "!") {
      if (isUndef(vnode.text)) {
        vnode.text = "";
      }
      vnode.elm = api.createComment(vnode.text as string);
    } else if (sel !== undefined) {
      // Parse selector
      const hashIdx = sel.indexOf("#");
      const dotIdx = sel.indexOf(".", hashIdx);
      const hash = hashIdx > 0 ? hashIdx : sel.length;
      const dot = dotIdx > 0 ? dotIdx : sel.length;
      const tag = hashIdx !== -1 || dotIdx !== -1 ? sel.slice(0, Math.min(hash, dot)) : sel;
      const elm = (vnode.elm =
        isDef(data) && isDef((i = (data as VNodeData).ns))
          ? api.createElementNS(i, tag)
          : api.createElement(tag));
      if (hash < dot) elm.setAttribute("id", sel.slice(hash + 1, dot));
      if (dotIdx > 0) elm.setAttribute("class", sel.slice(dot + 1).replace(/\./g, " "));
      for (i = 0, iLen = cbs.create.length; i < iLen; ++i) cbs.create[i](emptyNode, vnode);
      if (array(children)) {
        for (i = 0, iLen = children.length; i < iLen; ++i) {
          const ch = children[i];
          if (ch != null) {
            api.appendChild(elm, createElm(ch as VNode, insertedVnodeQueue));
          }
        }
      } else if (primitive(vnode.text)) {
        api.appendChild(elm, api.createTextNode(vnode.text));
      }
      i = (vnode.data as VNodeData).hook; // Reuse variable
      if (isDef(i)) {
        if (i.create) i.create(emptyNode, vnode);
        if (i.insert) insertedVnodeQueue.push(vnode);
      }
    } else {
      vnode.elm = api.createTextNode(vnode.text as string);
    }
    return vnode.elm;
  }
  function addVnodes(
    parentElm: Node,
    before: Node | null,
    vnodes: Array<VNode>,
    startIdx: number,
    endIdx: number,
    insertedVnodeQueue: VNodeQueue
  ) {
    for (; startIdx <= endIdx; ++startIdx) {
      const ch = vnodes[startIdx];
      if (ch != null) {
        api.insertBefore(parentElm, createElm(ch, insertedVnodeQueue), before);
      }
    }
  }
  function invokeDestroyHook(vnode: VNode) {
    let i: any,
      iLen: number,
      j: number,
      jLen: number,
      data = vnode.data;
    if (data !== undefined) {
      if (isDef((i = data.hook)) && isDef((i = i.destroy))) i(vnode);
      for (i = 0, iLen = cbs.destroy.length; i < iLen; ++i) cbs.destroy[i](vnode);
      if (vnode.children !== undefined) {
        for (j = 0, jLen = vnode.children.length; j < jLen; ++j) {
          i = vnode.children[j];
          if (i != null && typeof i !== "string") {
            invokeDestroyHook(i);
          }
        }
      }
    }
  }
  function removeVnodes(
    parentElm: Node,
    vnodes: Array<VNode>,
    startIdx: number,
    endIdx: number
  ): void {
    for (; startIdx <= endIdx; ++startIdx) {
      let i: any,
        iLen: number,
        listeners: number,
        rm: () => void,
        ch = vnodes[startIdx];
      if (ch != null) {
        if (isDef(ch.sel)) {
          invokeDestroyHook(ch);
          listeners = cbs.remove.length + 1;
          rm = createRmCb(ch.elm as Node, listeners);
          for (i = 0, iLen = cbs.remove.length; i < iLen; ++i) cbs.remove[i](ch, rm);
          if (isDef((i = ch.data)) && isDef((i = i.hook)) && isDef((i = i.remove))) {
            i(ch, rm);
          } else {
            rm();
          }
        } else {
          // Text node
          api.removeChild(parentElm, ch.elm as Node);
        }
      }
    }
  }
  function updateChildren(
    parentElm: Node,
    oldCh: Array<VNode>,
    newCh: Array<VNode>,
    insertedVnodeQueue: VNodeQueue
  ) {
    let oldStartIdx = 0,
      newStartIdx = 0;
    let oldEndIdx = oldCh.length - 1;
    let oldStartVnode = oldCh[0];
    let oldEndVnode = oldCh[oldEndIdx];
    let newEndIdx = newCh.length - 1;
    let newStartVnode = newCh[0];
    let newEndVnode = newCh[newEndIdx];
    let oldKeyToIdx: any;
    let idxInOld: number;
    let elmToMove: VNode;
    let before: any;
    while (oldStartIdx <= oldEndIdx && newStartIdx <= newEndIdx) {
      if (oldStartVnode == null) {
        oldStartVnode = oldCh[++oldStartIdx]; // Vnode might have been moved left
      } else if (oldEndVnode == null) {
        oldEndVnode = oldCh[--oldEndIdx];
      } else if (newStartVnode == null) {
        newStartVnode = newCh[++newStartIdx];
      } else if (newEndVnode == null) {
        newEndVnode = newCh[--newEndIdx];
      } else if (sameVnode(oldStartVnode, newStartVnode)) {
        patchVnode(oldStartVnode, newStartVnode, insertedVnodeQueue);
        oldStartVnode = oldCh[++oldStartIdx];
        newStartVnode = newCh[++newStartIdx];
      } else if (sameVnode(oldEndVnode, newEndVnode)) {
        patchVnode(oldEndVnode, newEndVnode, insertedVnodeQueue);
        oldEndVnode = oldCh[--oldEndIdx];
        newEndVnode = newCh[--newEndIdx];
      } else if (sameVnode(oldStartVnode, newEndVnode)) {
        // Vnode moved right
        patchVnode(oldStartVnode, newEndVnode, insertedVnodeQueue);
        api.insertBefore(
          parentElm,
          oldStartVnode.elm as Node,
          api.nextSibling(oldEndVnode.elm as Node)
        );
        oldStartVnode = oldCh[++oldStartIdx];
        newEndVnode = newCh[--newEndIdx];
      } else if (sameVnode(oldEndVnode, newStartVnode)) {
        // Vnode moved left
        patchVnode(oldEndVnode, newStartVnode, insertedVnodeQueue);
        api.insertBefore(parentElm, oldEndVnode.elm as Node, oldStartVnode.elm as Node);
        oldEndVnode = oldCh[--oldEndIdx];
        newStartVnode = newCh[++newStartIdx];
      } else {
        if (oldKeyToIdx === undefined) {
          oldKeyToIdx = createKeyToOldIdx(oldCh, oldStartIdx, oldEndIdx);
        }
        idxInOld = oldKeyToIdx[newStartVnode.key as string];
        if (isUndef(idxInOld)) {
          // New element
          api.insertBefore(
            parentElm,
            createElm(newStartVnode, insertedVnodeQueue),
            oldStartVnode.elm as Node
          );
          newStartVnode = newCh[++newStartIdx];
        } else {
          elmToMove = oldCh[idxInOld];
          if (elmToMove.sel !== newStartVnode.sel) {
            api.insertBefore(
              parentElm,
              createElm(newStartVnode, insertedVnodeQueue),
              oldStartVnode.elm as Node
            );
          } else {
            patchVnode(elmToMove, newStartVnode, insertedVnodeQueue);
            oldCh[idxInOld] = undefined as any;
            api.insertBefore(parentElm, elmToMove.elm as Node, oldStartVnode.elm as Node);
          }
          newStartVnode = newCh[++newStartIdx];
        }
      }
    }
    if (oldStartIdx <= oldEndIdx || newStartIdx <= newEndIdx) {
      if (oldStartIdx > oldEndIdx) {
        before = newCh[newEndIdx + 1] == null ? null : newCh[newEndIdx + 1].elm;
        addVnodes(parentElm, before, newCh, newStartIdx, newEndIdx, insertedVnodeQueue);
      } else {
        removeVnodes(parentElm, oldCh, oldStartIdx, oldEndIdx);
      }
    }
  }
  function patchVnode(oldVnode: VNode, vnode: VNode, insertedVnodeQueue: VNodeQueue) {
    let i: any, iLen: number, hook: any;
    if (isDef((i = vnode.data)) && isDef((hook = i.hook)) && isDef((i = hook.prepatch))) {
      i(oldVnode, vnode);
    }
    const elm = (vnode.elm = oldVnode.elm as Node);
    let oldCh = oldVnode.children;
    let ch = vnode.children;
    if (oldVnode === vnode) return;
    if (vnode.data !== undefined) {
      for (i = 0, iLen = cbs.update.length; i < iLen; ++i) cbs.update[i](oldVnode, vnode);
      i = vnode.data.hook;
      if (isDef(i) && isDef((i = i.update))) i(oldVnode, vnode);
    }
    if (isUndef(vnode.text)) {
      if (isDef(oldCh) && isDef(ch)) {
        if (oldCh !== ch)
          updateChildren(elm, oldCh as Array<VNode>, ch as Array<VNode>, insertedVnodeQueue);
      } else if (isDef(ch)) {
        if (isDef(oldVnode.text)) api.setTextContent(elm, "");
        addVnodes(
          elm,
          null,
          ch as Array<VNode>,
          0,
          (ch as Array<VNode>).length - 1,
          insertedVnodeQueue
        );
      } else if (isDef(oldCh)) {
        removeVnodes(elm, oldCh as Array<VNode>, 0, (oldCh as Array<VNode>).length - 1);
      } else if (isDef(oldVnode.text)) {
        api.setTextContent(elm, "");
      }
    } else if (oldVnode.text !== vnode.text) {
      if (isDef(oldCh)) {
        removeVnodes(elm, oldCh as Array<VNode>, 0, (oldCh as Array<VNode>).length - 1);
      }
      api.setTextContent(elm, vnode.text as string);
    }
    if (isDef(hook) && isDef((i = hook.postpatch))) {
      i(oldVnode, vnode);
    }
  }
  return function patch(oldVnode: VNode | Element, vnode: VNode): VNode {
    let i: number, iLen: number, elm: Node, parent: Node;
    const insertedVnodeQueue: VNodeQueue = [];
    for (i = 0, iLen = cbs.pre.length; i < iLen; ++i) cbs.pre[i]();
    if (!isVnode(oldVnode)) {
      oldVnode = emptyNodeAt(oldVnode);
    }
    if (sameVnode(oldVnode, vnode)) {
      patchVnode(oldVnode, vnode, insertedVnodeQueue);
    } else {
      elm = oldVnode.elm as Node;
      parent = api.parentNode(elm);
      createElm(vnode, insertedVnodeQueue);
      if (parent !== null) {
        api.insertBefore(parent, vnode.elm as Node, api.nextSibling(elm));
        removeVnodes(parent, [oldVnode], 0, 0);
      }
    }
    for (i = 0, iLen = insertedVnodeQueue.length; i < iLen; ++i) {
      (((insertedVnodeQueue[i].data as VNodeData).hook as Hooks).insert as any)(
        insertedVnodeQueue[i]
      );
    }
    for (i = 0, iLen = cbs.post.length; i < iLen; ++i) cbs.post[i]();
    return vnode;
  };
 }
 //------------------------------------------------------------------------------
 // is.ts
 //------------------------------------------------------------------------------
 const array = Array.isArray;
 function primitive(s: any): s is string | number {
  return typeof s === "string" || typeof s === "number";
 }
 //------------------------------------------------------------------------------
 // htmldomapi.ts
 //------------------------------------------------------------------------------
 interface DOMAPI {
  createElement: (tagName: any) => HTMLElement;
  createElementNS: (namespaceURI: string, qualifiedName: string) => Element;
  createTextNode: (text: string) => Text;
  createComment: (text: string) => Comment;
  insertBefore: (parentNode: Node, newNode: Node, referenceNode: Node | null) => void;
  removeChild: (node: Node, child: Node) => void;
  appendChild: (node: Node, child: Node) => void;
  parentNode: (node: Node) => Node;
  nextSibling: (node: Node) => Node;
  tagName: (elm: Element) => string;
  setTextContent: (node: Node, text: string | null) => void;
 }
 function createElement(tagName: any): HTMLElement {
  return document.createElement(tagName);
 }
 function createElementNS(namespaceURI: string, qualifiedName: string): Element {
  return document.createElementNS(namespaceURI, qualifiedName);
 }
 function createTextNode(text: string): Text {
  return document.createTextNode(text);
 }
 function createComment(text: string): Comment {
  return document.createComment(text);
 }
 function insertBefore(parentNode: Node, newNode: Node, referenceNode: Node | null): void {
  parentNode.insertBefore(newNode, referenceNode);
 }
 function removeChild(node: Node, child: Node): void {
  node.removeChild(child);
 }
 function appendChild(node: Node, child: Node): void {
  node.appendChild(child);
 }
 function parentNode(node: Node): Node | null {
  return node.parentNode;
 }
 function nextSibling(node: Node): Node | null {
  return node.nextSibling;
 }
 function tagName(elm: Element): string {
  return elm.tagName;
 }
 function setTextContent(node: Node, text: string | null): void {
  node.textContent = text;
 }
 const htmlDomApi = {
  createElement,
  createElementNS,
  createTextNode,
  createComment,
  insertBefore,
  removeChild,
  appendChild,
  parentNode,
  nextSibling,
  tagName,
  setTextContent,
 } as DOMAPI;
 //------------------------------------------------------------------------------
 // hooks.ts
 //------------------------------------------------------------------------------
 type PreHook = () => any;
 type InitHook = (vNode: VNode) => any;
 type CreateHook = (emptyVNode: VNode, vNode: VNode) => any;
 type InsertHook = (vNode: VNode) => any;
 type PrePatchHook = (oldVNode: VNode, vNode: VNode) => any;
 type UpdateHook = (oldVNode: VNode, vNode: VNode) => any;
 type PostPatchHook = (oldVNode: VNode, vNode: VNode) => any;
 type DestroyHook = (vNode: VNode) => any;
 type RemoveHook = (vNode: VNode, removeCallback: () => void) => any;
 type PostHook = () => any;
 interface Hooks {
  pre?: PreHook;
  init?: InitHook;
  create?: CreateHook;
  insert?: InsertHook;
  prepatch?: PrePatchHook;
  update?: UpdateHook;
  postpatch?: PostPatchHook;
  destroy?: DestroyHook;
  remove?: RemoveHook;
  post?: PostHook;
 }
 //------------------------------------------------------------------------------
 // h.ts
 //------------------------------------------------------------------------------
 type VNodes = Array<VNode>;
 type VNodeChildElement = VNode | string | number | undefined | null;
 type ArrayOrElement<T> = T | T[];
 type VNodeChildren = ArrayOrElement<VNodeChildElement>;
 function addNS(data: any, children: VNodes | undefined, sel: string | undefined): void {
  data.ns = "http://www.w3.org/2000/svg";
  if (sel !== "foreignObject" && children !== undefined) {
    for (let i = 0, iLen = children.length; i < iLen; ++i) {
      let childData = children[i].data;
      if (childData !== undefined) {
        addNS(childData, (children[i] as VNode).children as VNodes, children[i].sel);
      }
    }
  }
 }
 export function h(sel: string): VNode;
 export function h(sel: string, data: VNodeData): VNode;
 export function h(sel: string, children: VNodeChildren): VNode;
 export function h(sel: string, data: VNodeData, children: VNodeChildren): VNode;
 export function h(sel: any, b?: any, c?: any): VNode {
  var data: VNodeData = {},
    children: any,
    text: any,
    i: number,
    iLen: number;
  if (c !== undefined) {
    data = b;
    if (array(c)) {
      children = c;
    } else if (primitive(c)) {
      text = c;
    } else if (c && c.sel) {
      children = [c];
    }
  } else if (b !== undefined) {
    if (array(b)) {
      children = b;
    } else if (primitive(b)) {
      text = b;
    } else if (b && b.sel) {
      children = [b];
    } else {
      data = b;
    }
  }
  if (children !== undefined) {
    for (i = 0, iLen = children.length; i < iLen; ++i) {
      if (primitive(children[i]))
        children[i] = vnode(undefined, undefined, undefined, children[i], undefined);
    }
  }
  if (
    sel[0] === "s" &&
    sel[1] === "v" &&
    sel[2] === "g" &&
    (sel.length === 3 || sel[3] === "." || sel[3] === "#")
  ) {
    addNS(data, children, sel);
  }
  return vnode(sel, data, children, text, undefined);
 }
@@ -1,131 +0,0 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 exports[`animations t-transition combined with component 1`] = `
 "function anonymous(context,extra
 ) {
    let utils = this.constructor.utils;
    let QWeb = this.constructor;
    let parent = context;
    let owner = context;
    var h = this.h;
    let c1 = [], p1 = {key:1};
    var vn1 = h('div', p1, c1);
    //COMPONENT
    let def3;
    let w4 = 4 in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap[4]] : false;
    let _2_index = c1.length;
    c1.push(null);
    let props4 = {};
    if (w4 && w4.__owl__.renderPromise && !w4.__owl__.vnode) {
        if (utils.shallowEqual(props4, w4.__owl__.renderProps)) {
            def3 = w4.__owl__.renderPromise;
        } else {
            w4.destroy();
            w4 = false;
        }
    }
    if (!w4) {
        let componentKey4 = \`Child\`;
        let W4 = context.components && context.components[componentKey4] || QWeb.components[componentKey4];
        if (!W4) {throw new Error('Cannot find the definition of component \\"' + componentKey4 + '\\"')}
        w4 = new W4(parent, props4);
        parent.__owl__.cmap[4] = w4.__owl__.id;
        def3 = w4.__prepare();
        def3 = def3.then(vnode=>{let pvnode=h(vnode.sel, {key: 4, hook: {insert(vn) {let nvn=w4.__mount(vnode, pvnode.elm);pvnode.elm=nvn.elm;utils.transitionInsert(vn, 'chimay');},remove() {},destroy(vn) {let finalize = () => {
          w4.destroy();
        };
        utils.transitionRemove(vn, 'chimay', finalize);}}});c1[_2_index]=pvnode;w4.__owl__.pvnode = pvnode;});
    } else {
        def3 = def3 || w4.__updateProps(props4, extra.forceUpdate, extra.patchQueue);
        def3 = def3.then(()=>{if (w4.__owl__.isDestroyed) {return};let pvnode=w4.__owl__.pvnode;c1[_2_index]=pvnode;});
    }
    extra.promises.push(def3);
    return vn1;
 }"
 `;
 exports[`animations t-transition combined with t-component and t-if 1`] = `
 "function anonymous(context,extra
 ) {
    let utils = this.constructor.utils;
    let QWeb = this.constructor;
    let parent = context;
    let owner = context;
    var h = this.h;
    let c1 = [], p1 = {key:1};
    var vn1 = h('div', p1, c1);
    if (context['state'].display) {
        //COMPONENT
        let def3;
        let w4 = 4 in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap[4]] : false;
        let _2_index = c1.length;
        c1.push(null);
        let props4 = {};
        if (w4 && w4.__owl__.renderPromise && !w4.__owl__.vnode) {
            if (utils.shallowEqual(props4, w4.__owl__.renderProps)) {
                def3 = w4.__owl__.renderPromise;
            } else {
                w4.destroy();
                w4 = false;
            }
        }
        if (!w4) {
            let componentKey4 = \`Child\`;
            let W4 = context.components && context.components[componentKey4] || QWeb.components[componentKey4];
            if (!W4) {throw new Error('Cannot find the definition of component \\"' + componentKey4 + '\\"')}
            w4 = new W4(parent, props4);
            parent.__owl__.cmap[4] = w4.__owl__.id;
            def3 = w4.__prepare();
            def3 = def3.then(vnode=>{let pvnode=h(vnode.sel, {key: 4, hook: {insert(vn) {let nvn=w4.__mount(vnode, pvnode.elm);pvnode.elm=nvn.elm;utils.transitionInsert(vn, 'chimay');},remove() {},destroy(vn) {let finalize = () => {
          w4.destroy();
        };
        utils.transitionRemove(vn, 'chimay', finalize);}}});c1[_2_index]=pvnode;w4.__owl__.pvnode = pvnode;});
        } else {
            def3 = def3 || w4.__updateProps(props4, extra.forceUpdate, extra.patchQueue);
            def3 = def3.then(()=>{if (w4.__owl__.isDestroyed) {return};let pvnode=w4.__owl__.pvnode;c1[_2_index]=pvnode;});
        }
        extra.promises.push(def3);
    }
    return vn1;
 }"
 `;
 exports[`animations t-transition with no delay/duration 1`] = `
 "function anonymous(context,extra
 ) {
    let utils = this.constructor.utils;
    var h = this.h;
    let c1 = [], p1 = {key:1};
    var vn1 = h('span', p1, c1);
    p1.hook = {
      insert: vn => {
        utils.transitionInsert(vn, 'jupiler');
      },
      remove: (vn, rm) => {
        utils.transitionRemove(vn, 'jupiler', rm);
      },
    };
    c1.push({text: \`blue\`});
    return vn1;
 }"
 `;
 exports[`animations t-transition, on a simple node (insert) 1`] = `
 "function anonymous(context,extra
 ) {
    let utils = this.constructor.utils;
    var h = this.h;
    let c1 = [], p1 = {key:1};
    var vn1 = h('span', p1, c1);
    p1.hook = {
      insert: vn => {
        utils.transitionInsert(vn, 'chimay');
      },
      remove: (vn, rm) => {
        utils.transitionRemove(vn, 'chimay', rm);
      },
    };
    c1.push({text: \`blue\`});
    return vn1;
 }"
 `;
@@ -0,0 +1,384 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 exports[`Reactivity: useState concurrent renderings 1`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component } = bdom;
  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue, toNumber, safeOutput } = helpers;
  let block1 = createBlock(\`<span><block-text-0/><block-text-1/></span>\`);
  return function template(ctx, node, key = \\"\\") {
    let d1 = ctx['context'][ctx['props'].key].n;
    let d2 = ctx['state'].x;
    return block1([d1, d2]);
  }
 }"
 `;
 exports[`Reactivity: useState concurrent renderings 2`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component } = bdom;
  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue, toNumber, safeOutput } = helpers;
  let block1 = createBlock(\`<p><block-child-0/></p>\`);
  return function template(ctx, node, key = \\"\\") {
    let b2 = component(\`ComponentC\`, {key: ctx['props'].key}, key + \`__1\`, node, ctx);
    return block1([], [b2]);
  }
 }"
 `;
 exports[`Reactivity: useState concurrent renderings 3`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component } = bdom;
  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue, toNumber, safeOutput } = helpers;
  let block1 = createBlock(\`<div><block-child-0/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let b2 = component(\`ComponentB\`, {key: ctx['context'].key}, key + \`__1\`, node, ctx);
    return block1([], [b2]);
  }
 }"
 `;
 exports[`Reactivity: useState destroyed component before being mounted is inactive 1`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<div><block-child-0/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let b2;
    if (ctx['state'].flag) {
      b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
    }
    return block1([], [b2]);
  }
 }"
 `;
 exports[`Reactivity: useState destroyed component before being mounted is inactive 2`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<span><block-text-0/></span>\`);
  return function template(ctx, node, key = \\"\\") {
    let txt1 = ctx['contextObj'].a;
    return block1([txt1]);
  }
 }"
 `;
 exports[`Reactivity: useState destroyed component is inactive 1`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<div><block-child-0/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let b2;
    if (ctx['state'].flag) {
      b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
    }
    return block1([], [b2]);
  }
 }"
 `;
 exports[`Reactivity: useState destroyed component is inactive 2`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<span><block-text-0/></span>\`);
  return function template(ctx, node, key = \\"\\") {
    let txt1 = ctx['contextObj'].a;
    return block1([txt1]);
  }
 }"
 `;
 exports[`Reactivity: useState one components can subscribe twice to same context 1`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<div><block-text-0/><block-text-1/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let txt1 = ctx['contextObj1'].a;
    let txt2 = ctx['contextObj2'].b;
    return block1([txt1, txt2]);
  }
 }"
 `;
 exports[`Reactivity: useState parent and children subscribed to same context 1`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<div><block-child-0/><block-text-0/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
    let txt1 = ctx['contextObj'].b;
    return block1([txt1], [b2]);
  }
 }"
 `;
 exports[`Reactivity: useState parent and children subscribed to same context 2`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<span><block-text-0/></span>\`);
  return function template(ctx, node, key = \\"\\") {
    let txt1 = ctx['contextObj'].a;
    return block1([txt1]);
  }
 }"
 `;
 exports[`Reactivity: useState several nodes on different level use same context 1`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component } = bdom;
  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue, toNumber, safeOutput } = helpers;
  let block1 = createBlock(\`<div><block-text-0/> <block-text-1/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let d1 = ctx['contextObj'].a;
    let d2 = ctx['contextObj'].b;
    return block1([d1, d2]);
  }
 }"
 `;
 exports[`Reactivity: useState several nodes on different level use same context 2`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component } = bdom;
  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue, toNumber, safeOutput } = helpers;
  let block1 = createBlock(\`<div><block-text-0/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let d1 = ctx['contextObj'].b;
    return block1([d1]);
  }
 }"
 `;
 exports[`Reactivity: useState several nodes on different level use same context 3`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component } = bdom;
  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue, toNumber, safeOutput } = helpers;
  let block1 = createBlock(\`<div><block-text-0/><block-child-0/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let d1 = ctx['contextObj'].a;
    let b2 = component(\`L3A\`, {}, key + \`__1\`, node, ctx);
    return block1([d1], [b2]);
  }
 }"
 `;
 exports[`Reactivity: useState several nodes on different level use same context 4`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component } = bdom;
  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue, toNumber, safeOutput } = helpers;
  let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let b2 = component(\`L2A\`, {}, key + \`__1\`, node, ctx);
    let b3 = component(\`L2B\`, {}, key + \`__2\`, node, ctx);
    return block1([], [b2, b3]);
  }
 }"
 `;
 exports[`Reactivity: useState two components are updated in parallel 1`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
    let b3 = component(\`Child\`, {}, key + \`__2\`, node, ctx);
    return block1([], [b2, b3]);
  }
 }"
 `;
 exports[`Reactivity: useState two components are updated in parallel 2`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<span><block-text-0/></span>\`);
  return function template(ctx, node, key = \\"\\") {
    let txt1 = ctx['contextObj'].value;
    return block1([txt1]);
  }
 }"
 `;
 exports[`Reactivity: useState two components can subscribe to same context 1`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
    let b3 = component(\`Child\`, {}, key + \`__2\`, node, ctx);
    return block1([], [b2, b3]);
  }
 }"
 `;
 exports[`Reactivity: useState two components can subscribe to same context 2`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<span><block-text-0/></span>\`);
  return function template(ctx, node, key = \\"\\") {
    let txt1 = ctx['contextObj'].value;
    return block1([txt1]);
  }
 }"
 `;
 exports[`Reactivity: useState two independent components on different levels are updated in parallel 1`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
    let b3 = component(\`Parent\`, {}, key + \`__2\`, node, ctx);
    return block1([], [b2, b3]);
  }
 }"
 `;
 exports[`Reactivity: useState two independent components on different levels are updated in parallel 2`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<span><block-text-0/></span>\`);
  return function template(ctx, node, key = \\"\\") {
    let txt1 = ctx['contextObj'].value;
    return block1([txt1]);
  }
 }"
 `;
 exports[`Reactivity: useState two independent components on different levels are updated in parallel 3`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<div><block-child-0/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
    return block1([], [b2]);
  }
 }"
 `;
 exports[`Reactivity: useState useContext=useState hook is reactive, for one component 1`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<div><block-text-0/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let txt1 = ctx['contextObj'].value;
    return block1([txt1]);
  }
 }"
 `;
 exports[`Reactivity: useState useless atoms should be deleted 1`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let { prepareList, withKey } = helpers;
  let block1 = createBlock(\`<div><block-child-0/> Total: <block-text-0/> Count: <block-text-1/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    ctx = Object.create(ctx);
    const [k_block2, v_block2, l_block2, c_block2] = prepareList(Object.keys(ctx['state']));
    for (let i1 = 0; i1 < l_block2; i1++) {
      ctx[\`id\`] = v_block2[i1];
      let key1 = ctx['id'];
      c_block2[i1] = withKey(component(\`Quantity\`, {id: ctx['id']}, key + \`__1__\${key1}\`, node, ctx), key1);
    }
    ctx = ctx.__proto__;
    let b2 = list(c_block2);
    let txt1 = ctx['total'];
    let txt2 = Object.keys(ctx['state']).length;
    return block1([txt1, txt2], [b2]);
  }
 }"
 `;
 exports[`Reactivity: useState useless atoms should be deleted 2`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<div><block-text-0/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let txt1 = ctx['state'].quantity;
    return block1([txt1]);
  }
 }"
 `;
 exports[`Reactivity: useState very simple use, with initial value 1`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<div><block-text-0/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let txt1 = ctx['contextObj'].value;
    return block1([txt1]);
  }
 }"
 `;
@@ -1,404 +0,0 @@
 import { Component, Env } from "../src/component/component";
 import { QWeb } from "../src/qweb/index";
 import {
  makeDeferred,
  makeTestFixture,
  makeTestEnv,
  nextTick,
  patchNextFrame,
  renderToDOM,
  unpatchNextFrame
 } from "./helpers";
 //------------------------------------------------------------------------------
 // Setup and helpers
 //------------------------------------------------------------------------------
 // We create before each test:
 // - fixture: a div, appended to the DOM, intended to be the target of dom
 //   manipulations.  Note that it is removed after each test.
 // - qweb: a new QWeb instance
 // - env: a WEnv, necessary to create new components
 // - cssEl: a stylesheet injected into the dom
 let fixture: HTMLElement;
 let qweb: QWeb;
 let env: Env;
 let cssEl: HTMLElement;
 beforeEach(() => {
  fixture = makeTestFixture();
  env = makeTestEnv();
  qweb = new QWeb();
 });
 afterEach(() => {
  fixture.remove();
 });
 class Widget extends Component<any, any, any> {}
 //------------------------------------------------------------------------------
 // Tests
 //------------------------------------------------------------------------------
 describe("animations", () => {
  beforeEach(() => {
    cssEl = document.createElement("style");
    let css = `
      .chimay-enter-active, .chimay-leave-active {
        transition-property: opacity;
        transition-duration: 0.1s;
      }
      .chimay-enter, .chimay-leave-to {
        opacity: 0;
      }
    `;
    cssEl.textContent = css.trim();
    document.head.appendChild(cssEl);
  });
  afterEach(() => {
    document.head.removeChild(cssEl);
    unpatchNextFrame();
  });
  test("t-transition, on a simple node (insert)", async () => {
    expect.assertions(5);
    qweb.addTemplate("test", `<span t-transition="chimay">blue</span>`);
    let def = makeDeferred();
    patchNextFrame(cb => {
      expect(node.className).toBe("chimay-enter chimay-enter-active");
      cb();
      expect(node.className).toBe("chimay-enter-active chimay-enter-to");
      def.resolve();
    });
    let node: HTMLElement = <HTMLElement>renderToDOM(qweb, "test");
    expect(node.className).toBe("chimay-enter chimay-enter-active");
    await def; // wait for the mocked repaint to be done
    node.dispatchEvent(new Event("transitionend")); // mock end of css transition
    expect(node.className).toBe("");
  });
  test("t-transition with no delay/duration", async () => {
    expect.assertions(4);
    qweb.addTemplate("test", `<span t-transition="jupiler">blue</span>`);
    let def = makeDeferred();
    patchNextFrame(cb => {
      expect(node.className).toBe("jupiler-enter jupiler-enter-active");
      cb();
      expect(node.className).toBe("");
      def.resolve();
    });
    let node: HTMLElement = <HTMLElement>renderToDOM(qweb, "test");
    expect(node.className).toBe("jupiler-enter jupiler-enter-active");
    await def;
  });
  test("t-transition on a conditional node", async () => {
    expect.assertions(7);
    env.qweb.addTemplate(
      "TestWidget",
      `<div><span t-if="!state.hide" t-transition="chimay">blue</span></div>`
    );
    class TestWidget extends Widget {
      state = { hide: false };
    }
    const widget = new TestWidget(env);
    // insert widget into the DOM
    let def = makeDeferred();
    var spanNode;
    patchNextFrame(cb => {
      expect(spanNode.className).toBe("chimay-enter chimay-enter-active");
      cb();
      expect(spanNode.className).toBe("chimay-enter-active chimay-enter-to");
      def.resolve();
    });
    await widget.mount(fixture);
    spanNode = widget.el!.children[0];
    expect(spanNode.className).toBe("chimay-enter chimay-enter-active");
    await def; // wait for the mocked repaint to be done
    spanNode.dispatchEvent(new Event("transitionend")); // mock end of css transition
    expect(spanNode.className).toBe("");
    // remove span from the DOM
    def = makeDeferred();
    widget.state.hide = true;
    patchNextFrame(cb => {
      expect(spanNode.className).toBe("chimay-leave chimay-leave-active");
      cb();
      expect(spanNode.className).toBe("chimay-leave-active chimay-leave-to");
      def.resolve();
    });
    await def; // wait for the mocked repaint to be done
    spanNode.dispatchEvent(new Event("transitionend")); // mock end of css transition
    expect(spanNode.className).toBe("");
  });
  test("t-transition combined with t-ref", async () => {
    expect.assertions(5);
    env.qweb.addTemplate(
      "TestWidget",
      `<div><span t-ref="span" t-transition="chimay">blue</span></div>`
    );
    class TestWidget extends Widget {
      state = { hide: false };
    }
    const widget = new TestWidget(env);
    // insert widget into the DOM
    let def = makeDeferred();
    var spanNode;
    patchNextFrame(cb => {
      expect(spanNode.className).toBe("chimay-enter chimay-enter-active");
      cb();
      expect(spanNode.className).toBe("chimay-enter-active chimay-enter-to");
      def.resolve();
    });
    await widget.mount(fixture);
    spanNode = widget.el!.children[0];
    expect(widget.refs.span).toBe(spanNode);
    expect(spanNode.className).toBe("chimay-enter chimay-enter-active");
    await def; // wait for the mocked repaint to be done
    spanNode.dispatchEvent(new Event("transitionend")); // mock end of css transition
    expect(spanNode.className).toBe("");
  });
  test("t-transition combined with component", async () => {
    expect.assertions(5);
    env.qweb.addTemplate("Parent", `<div><Child t-transition="chimay"/></div>`);
    env.qweb.addTemplate("Child", `<span>blue</span>`);
    class Parent extends Widget {
      components = { Child: Child };
    }
    class Child extends Widget {}
    const widget = new Parent(env);
    let def = makeDeferred();
    var spanNode;
    patchNextFrame(cb => {
      expect(fixture.innerHTML).toBe(
        '<div><span class="chimay-enter chimay-enter-active">blue</span></div>'
      );
      cb();
      expect(fixture.innerHTML).toBe(
        '<div><span class="chimay-enter-active chimay-enter-to">blue</span></div>'
      );
      def.resolve();
    });
    await widget.mount(fixture);
    spanNode = widget.el!.children[0];
    expect(env.qweb.templates.Parent.fn.toString()).toMatchSnapshot();
    expect(fixture.innerHTML).toBe(
      '<div><span class="chimay-enter chimay-enter-active">blue</span></div>'
    );
    await def; // wait for the mocked repaint to be done
    spanNode.dispatchEvent(new Event("transitionend")); // mock end of css transition
    expect(fixture.innerHTML).toBe('<div><span class="">blue</span></div>');
  });
  test("t-transition combined with t-component and t-if", async () => {
    expect.assertions(8);
    env.qweb.addTemplate(
      "Parent",
      `<div><t t-if="state.display" t-component="Child" t-transition="chimay"/></div>`
    );
    env.qweb.addTemplate("Child", `<span>blue</span>`);
    class Parent extends Widget {
      components = { Child: Child };
      state = { display: true };
    }
    class Child extends Widget {}
    const widget = new Parent(env);
    let def = makeDeferred();
    var spanNode;
    patchNextFrame(cb => {
      expect(fixture.innerHTML).toBe(
        '<div><span class="chimay-enter chimay-enter-active">blue</span></div>'
      );
      cb();
      expect(fixture.innerHTML).toBe(
        '<div><span class="chimay-enter-active chimay-enter-to">blue</span></div>'
      );
      def.resolve();
    });
    await widget.mount(fixture);
    spanNode = widget.el!.children[0];
    expect(env.qweb.templates.Parent.fn.toString()).toMatchSnapshot();
    expect(fixture.innerHTML).toBe(
      '<div><span class="chimay-enter chimay-enter-active">blue</span></div>'
    );
    await def; // wait for the mocked repaint to be done
    spanNode.dispatchEvent(new Event("transitionend")); // mock end of css transition
    expect(fixture.innerHTML).toBe('<div><span class="">blue</span></div>');
    // remove span from the DOM
    def = makeDeferred();
    widget.state.display = false;
    patchNextFrame(cb => {
      expect(fixture.innerHTML).toBe(
        '<div><span class="chimay-leave chimay-leave-active" data-owl-key="4">blue</span></div>'
      );
      cb();
      expect(fixture.innerHTML).toBe(
        '<div><span class="chimay-leave-active chimay-leave-to" data-owl-key="4">blue</span></div>'
      );
      def.resolve();
    });
    await def; // wait for the mocked repaint to be done
    spanNode.dispatchEvent(new Event("transitionend")); // mock end of css transition
    expect(fixture.innerHTML).toBe("<div></div>");
  });
  test("t-transition combined with t-mounted", async () => {
    env.qweb.addTemplate(
      "TestWidget",
      `<div><span t-if="state.flag" t-mounted="f" t-transition="chimay">blue</span></div>`
    );
    class TestWidget extends Widget {
      state = { flag: false };
      f() {}
    }
    const widget = new TestWidget(env);
    widget.f = jest.fn();
    await widget.mount(fixture);
    patchNextFrame(cb => cb());
    expect(widget.f).toHaveBeenCalledTimes(0);
    widget.state.flag = true;
    await nextTick();
    expect(widget.f).toHaveBeenCalledTimes(1);
    unpatchNextFrame();
  });
  test("t-transition, remove and re-add before transitionend", async () => {
    expect.assertions(11);
    env.qweb.addTemplates(
      `<templates>
        <div t-name="Parent">
          <button t-on-click="toggle">Toggle</button>
          <span t-if="state.flag" t-transition="chimay">blue</span>
        </div>
      </templates>`
    );
    class Parent extends Widget {
      constructor(parent) {
        super(parent);
        this.state = { flag: false };
      }
      toggle() {
        this.state.flag = !this.state.flag;
      }
    }
    const widget = new Parent(env);
    await widget.mount(fixture);
    let button = widget.el!.querySelector("button");
    let def = makeDeferred();
    let phase = "enter";
    patchNextFrame(cb => {
      let spans = fixture.querySelectorAll("span");
      expect(spans.length).toBe(1);
      expect(spans[0].className).toBe(`chimay-${phase} chimay-${phase}-active`);
      cb();
      expect(spans[0].className).toBe(`chimay-${phase}-active chimay-${phase}-to`);
      def.resolve();
    });
    // click display the span
    button!.click();
    await def; // wait for the mocked repaint to be done
    widget.el!.querySelector("span")!.dispatchEvent(new Event("transitionend")); // mock end of css transition
    expect(fixture.innerHTML).toBe('<div><button>Toggle</button><span class="">blue</span></div>');
    // click to remove the span, and click again to re-add it before transitionend
    def = makeDeferred();
    phase = "leave";
    button!.click();
    await def; // wait for the mocked repaint to be done
    def = makeDeferred();
    phase = "enter";
    button!.click();
    await def; // wait for the mocked repaint to be done
    widget.el!.querySelector("span")!.dispatchEvent(new Event("transitionend")); // mock end of css transition
    expect(fixture.innerHTML).toBe('<div><button>Toggle</button><span class="">blue</span></div>');
  });
  test("t-transition combined with t-component, remove and re-add before transitionend", async () => {
    expect.assertions(11);
    env.qweb.addTemplates(
      `<templates>
        <div t-name="Parent">
          <button t-on-click="toggle">Toggle</button>
          <t t-if="state.flag" t-component="Child" t-transition="chimay"/>
        </div>
        <span t-name="Child">blue</span>
      </templates>`
    );
    class Child extends Widget {}
    class Parent extends Widget {
      components = { Child };
      constructor(parent) {
        super(parent);
        this.state = { flag: false };
      }
      toggle() {
        this.state.flag = !this.state.flag;
      }
    }
    const widget = new Parent(env);
    await widget.mount(fixture);
    let button = widget.el!.querySelector("button");
    let def = makeDeferred();
    let phase = "enter";
    patchNextFrame(cb => {
      let spans = fixture.querySelectorAll("span");
      expect(spans.length).toBe(1);
      expect(spans[0].className).toBe(`chimay-${phase} chimay-${phase}-active`);
      cb();
      expect(spans[0].className).toBe(`chimay-${phase}-active chimay-${phase}-to`);
      def.resolve();
    });
    // click display the span
    button!.click();
    await def; // wait for the mocked repaint to be done
    widget.el!.querySelector("span")!.dispatchEvent(new Event("transitionend")); // mock end of css transition
    expect(fixture.innerHTML).toBe('<div><button>Toggle</button><span class="">blue</span></div>');
    // click to remove the span, and click again to re-add it before transitionend
    def = makeDeferred();
    phase = "leave";
    button!.click();
    await def; // wait for the mocked repaint to be done
    def = makeDeferred();
    phase = "enter";
    button!.click();
    await def; // wait for the mocked repaint to be done
    widget.el!.querySelector("span")!.dispatchEvent(new Event("transitionend")); // mock end of css transition
    expect(fixture.innerHTML).toBe('<div><button>Toggle</button><span class="">blue</span></div>');
  });
 });
@@ -0,0 +1,43 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 exports[`app App supports env with getters/setters 1`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<div><block-text-0/> <block-text-1/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let txt1 = ctx['env'].someVal;
    let txt2 = Object.keys(ctx['env'].services);
    return block1([txt1, txt2]);
  }
 }"
 `;
 exports[`app can configure an app with props 1`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<div><block-text-0/></div>\`);
  return function template(ctx, node, key = \\"\\") {
    let txt1 = ctx['props'].value;
    return block1([txt1]);
  }
 }"
 `;
 exports[`app destroy remove the widget from the DOM 1`] = `
 "function anonymous(bdom, helpers
 ) {
  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
  let block1 = createBlock(\`<div/>\`);
  return function template(ctx, node, key = \\"\\") {
    return block1();
  }
 }"
 `;
@@ -0,0 +1,62 @@
 import { App, Component, xml } from "../../src";
 import { status } from "../../src/component/status";
 import { makeTestFixture, snapshotEverything, nextTick, elem } from "../helpers";
 let fixture: HTMLElement;
 snapshotEverything();
 beforeEach(() => {
  fixture = makeTestFixture();
 });
 describe("app", () => {
  test("destroy remove the widget from the DOM", async () => {
    class SomeComponent extends Component {
      static template = xml`<div/>`;
    }
    const app = new App(SomeComponent);
    const comp = await app.mount(fixture);
    const el = elem(comp);
    expect(document.contains(el)).toBe(true);
    app.destroy();
    expect(document.contains(el)).toBe(false);
    expect(status(comp)).toBe("destroyed");
  });
  test("App supports env with getters/setters", async () => {
    let someVal = "maggot";
    const services: any = { serv1: "" };
    const env = {
      get someVal() {
        return someVal;
      },
      services,
    };
    class SomeComponent extends Component {
      static template = xml`<div><t t-esc="env.someVal" /> <t t-esc="Object.keys(env.services)" /></div>`;
    }
    const app = new App(SomeComponent, { env });
    const comp = await app.mount(fixture);
    expect(fixture.innerHTML).toBe("<div>maggot serv1</div>");
    someVal = "brain";
    services.serv2 = "";
    comp.render();
    await nextTick();
    expect(fixture.innerHTML).toBe("<div>brain serv1,serv2</div>");
  });
  test("can configure an app with props", async () => {
    class SomeComponent extends Component {
      static template = xml`<div t-esc="props.value"/>`;
    }
    const app = new App(SomeComponent, { props: { value: 333 } });
    await app.mount(fixture);
    expect(fixture.innerHTML).toBe("<div>333</div>");
  });
 });
@@ -0,0 +1,297 @@
 import { createBlock, mount, patch, remove, text } from "../../src/blockdom";
 import { makeTestFixture } from "./helpers";
 //------------------------------------------------------------------------------
 // Setup and helpers
 //------------------------------------------------------------------------------
 let fixture: HTMLElement;
 beforeEach(() => {
  fixture = makeTestFixture();
 });
 afterEach(() => {
  fixture.remove();
 });
 describe("adding/patching blocks", () => {
  test("simple block", async () => {
    const block = createBlock("<div>foo</div>");
    const tree = block();
    expect(tree.el).toBe(undefined);
    mount(tree, fixture);
    expect(tree.el).not.toBe(undefined);
    expect(fixture.innerHTML).toBe("<div>foo</div>");
  });
  test("block with dynamic content", async () => {
    const block = createBlock("<div><p><block-text-0/></p></div>");
    const tree = block(["foo"]);
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe("<div><p>foo</p></div>");
    patch(tree, block(["bar"]));
    expect(fixture.innerHTML).toBe("<div><p>bar</p></div>");
    patch(tree, block(["foo"]));
    expect(fixture.innerHTML).toBe("<div><p>foo</p></div>");
  });
  test("block with 2 dynamic text nodes", async () => {
    const block = createBlock("<div><p><block-text-0/></p><span><block-text-1/></span></div>");
    const tree = block(["foo", "bar"]);
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe("<div><p>foo</p><span>bar</span></div>");
    patch(tree, block(["appa", "yip yip"]));
    expect(fixture.innerHTML).toBe("<div><p>appa</p><span>yip yip</span></div>");
  });
  test("block with multiple references", async () => {
    const block1 = createBlock(
      "<div><block-text-0/><p><block-text-1/><block-text-2/></p><block-text-3/></div>"
    );
    const tree = block1(["1", "2", "3", "4"]);
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe("<div>1<p>23</p>4</div>");
  });
  test("falsy values in block nodes", () => {
    const cases = [
      [false, "false"],
      [undefined, ""],
      [null, ""],
      [0, "0"],
      ["", ""],
    ];
    const block = createBlock("<p><block-text-0/></p>");
    for (let [value, result] of cases) {
      const fixture = makeTestFixture();
      mount(block([value as any]), fixture);
      expect(fixture.innerHTML).toBe(`<p>${result}</p>`);
    }
  });
 });
 describe("sub blocks", () => {
  test("block with subblock (only child)", async () => {
    const block1 = createBlock("<div><block-child-0/></div>");
    const block2 = createBlock("<p>yip yip</p>");
    const tree = block1([], [block2()]);
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe("<div><p>yip yip</p></div>");
  });
  test("block with subblock (first child with sibling)", async () => {
    const block1 = createBlock("<div><block-child-0/><span>something</span></div>");
    const block2 = createBlock("<p>yip yip</p>");
    const tree = block1([], [block2()]);
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe("<div><p>yip yip</p><span>something</span></div>");
  });
  test("block with subblock (last child with sibling)", async () => {
    const block1 = createBlock("<div><span>something</span><block-child-0/></div>");
    const block2 = createBlock("<p>yip yip</p>");
    const tree = block1([], [block2()]);
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe("<div><span>something</span><p>yip yip</p></div>");
  });
  test("block with 2 subblocks", async () => {
    const block1 = createBlock("<div><block-child-0/><block-child-1/></div>");
    const block2 = createBlock("<p>yip yip</p>");
    const tree = block1([], [block2(), text("appa")]);
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe("<div><p>yip yip</p>appa</div>");
  });
  test("block with subblock with siblings", async () => {
    const block1 = createBlock("<div><p>1</p><block-child-0/><p>2</p></div>");
    const block2 = createBlock("<p>yip yip</p>");
    const tree = block1([], [block2()]);
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe("<div><p>1</p><p>yip yip</p><p>2</p></div>");
  });
  test("block with text, subblock and siblings", async () => {
    let block1 = createBlock(`<div><p>before<block-child-0/>after</p><block-child-1/></div>`);
    let tree = block1([], [text("water"), text("fire")]);
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe("<div><p>beforewaterafter</p>fire</div>");
  });
  test("block with conditional child", async () => {
    const block1 = createBlock("<div><p><block-child-0/></p></div>");
    const block2 = createBlock("<span>foo</span>");
    const tree = block1();
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe("<div><p></p></div>");
    patch(tree, block1([], [block2()]));
    expect(fixture.innerHTML).toBe("<div><p><span>foo</span></p></div>");
    patch(tree, block1());
    expect(fixture.innerHTML).toBe("<div><p></p></div>");
  });
  test("block with subblock with dynamic content", async () => {
    const block1 = createBlock("<div><block-child-0/></div>");
    const block2 = createBlock("<p><block-text-0/></p>");
    const tree = block1([], [block2(["yip yip"])]);
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe("<div><p>yip yip</p></div>");
    patch(tree, block1([], [block2(["foo"])]));
    expect(fixture.innerHTML).toBe("<div><p>foo</p></div>");
  });
  test("block with dynamic content and subblock", async () => {
    const block1 = createBlock("<div><block-child-0/><p><block-text-0/></p></div>");
    const block2 = createBlock("<p>sub block</p>");
    const tree = block1(["yip yip"], [block2()]);
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe("<div><p>sub block</p><p>yip yip</p></div>");
    patch(tree, block1(["foo"], [block2()]));
    expect(fixture.innerHTML).toBe("<div><p>sub block</p><p>foo</p></div>");
  });
 });
 describe("remove elem blocks", () => {
  test("elem block can be removed", async () => {
    const block = createBlock("<div>foo</div>");
    const tree = block();
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe("<div>foo</div>");
    remove(tree);
    expect(fixture.innerHTML).toBe("");
    expect(fixture.childNodes.length).toBe(0);
  });
 });
 describe("misc", () => {
  test("constructed block as correct number of refs", () => {
    const block = createBlock("<p><p><block-text-0/></p><block-text-1/></p>");
    const tree = block(["a", "b"]);
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe("<p><p>a</p>b</p>");
    expect((tree as any).refs.length).toBe(2);
  });
  test("block vnode can be used as text", () => {
    const block = createBlock("<p>a</p>");
    mount(text(block() as any), fixture);
    expect(fixture.textContent).toBe("<p>a</p>");
  });
  test("block vnode can be used to represent a <tr>", () => {
    const block = createBlock("<tr><td>tomato</td></tr>");
    const tree = block();
    const fixture = document.createElement("table");
    mount(tree, fixture);
    expect(fixture.outerHTML).toBe("<table><tr><td>tomato</td></tr></table>");
  });
  test("block vnode with <tr> can be used as text ", () => {
    const block = createBlock("<tr><td>tomato</td></tr>");
    mount(text(block() as any), fixture);
    expect(fixture.textContent).toBe("<tr><td>tomato</td></tr>");
  });
  test("call toString for function/objects if used as inline text in block", () => {
    const block = createBlock("<p><block-text-0/><block-text-1/></p>");
    const f = () => 3;
    const g = () => 4;
    g.toString = () => "tostring";
    mount(block([f, g]), fixture);
    expect(fixture.innerHTML).toBe("<p>() =&gt; 3tostring</p>");
  });
  test("block with 2 subblocks: variation", async () => {
    const block = createBlock("<a><b><c><block-child-0/>2</c></b><block-child-1/></a>");
    const tree = block([], [text("1"), text("3")]);
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe("<a><b><c>12</c></b>3</a>");
  });
  test("block with 2 subblocks: another variation", async () => {
    const block = createBlock(
      `<a block-attribute-0="hello"><b><c><block-child-0/>2</c></b><block-child-1/></a>`
    );
    const tree = block(["world"], [text("1"), text("3")]);
    mount(tree, fixture);
    expect(fixture.innerHTML).toBe(`<a hello="world"><b><c>12</c></b>3</a>`);
  });
  test("namespace is not propagated to siblings", () => {
    const block = createBlock(`<div><svg block-ns="someNameSpace"><g/></svg><div></div></div>`);
    const fixture = makeTestFixture();
    mount(block(), fixture);
    expect(fixture.innerHTML).toBe("<div><svg><g></g></svg><div></div></div>");
    expect(fixture.querySelector("svg")!.namespaceURI).toBe("someNameSpace");
    expect(fixture.querySelector("g")!.namespaceURI).toBe("someNameSpace");
    const allDivs = fixture.querySelectorAll("div");
    expect(Array.from(allDivs).map((el) => el.namespaceURI)).toEqual([
      "http://www.w3.org/1999/xhtml",
      "http://www.w3.org/1999/xhtml",
    ]);
  });
  //     test.skip("reusing a block skips patching process", async () => {
  //       const block = createBlock('<div><block-text-0/></div>');
  //       const foo = block(["foo"]);
  //       const bar = block(["bar"]);
  //       let fooCounter = 0;
  //       let barCounter = 0;
  //       let fooValue = "foo";
  //       let barValue = "bar";
  //       Object.defineProperty(foo.data, 0, {
  //         get() {
  //           fooCounter++;
  //           return fooValue;
  //         },
  //       });
  //       Object.defineProperty(bar.data, 0, {
  //         get() {
  //           barCounter++;
  //           return barValue;
  //         },
  //         set(val) {
  //           barValue = val;
  //         },
  //       });
  //       const bdom = multi([foo, bar]);
  //       mount(bdom, fixture);
  //       expect(fooCounter).toBe(1);
  //       expect(barCounter).toBe(1);
  //       expect(fixture.innerHTML).toBe("<div>foo</div><div>bar</div>");
  //       patch(bdom, multi([foo, block(["otherbar"])]));
  //       expect(fixture.innerHTML).toBe("foootherbar");
  //       expect(fooCounter).toBe(1);
  //       expect(barCounter).toBe(2);
  //     });
 });
--- a/Show More
+++ b/Show More