wip

With this commit, component only render child
components if they have different props (shallow
equality). Otherwise, we trust the reactivity
system to make sure that all impacted components
are updated

.github/workflows/deploy.yml

@@ -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

.gitignore

@@ -15,6 +15,7 @@ yarn-debug.log*
 yarn-error.log*
 
 package-lock.json
+yarn.lock
 
 #ide's
 .vscode
@@ -24,3 +25,10 @@ node_modules
 
 # Extras temp file
 /tools/owl.js
+
+release-notes.md
+
+.rpt2_cache
+
+# useful in some cases
+/temp

CHANGELOG.md

@@ -0,0 +1,586 @@
+# 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))
+
+
+## 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(...)` has to be
+rewritten like this: `bus.addEventListener(...)`.
+
+### 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
+```

README.md

@@ -1,34 +1,50 @@
-<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 no nonsense 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_
 
 ## Project Overview
 
-The Odoo Web Library (OWL) is a smallish (~18kb gzipped) UI framework intended to
+The Odoo Web Library (OWL) is a smallish (~<20kb gzipped) UI framework intended to
 be the basis for the [Odoo](https://www.odoo.com/) Web Client. Owl is a modern
 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,
 - a reactivity system based on hooks,
-- a store implementation (for state management),
+- concurrent mode by default,
-- a small frontend router
 
-Owl components are defined with ES6 classes, they use QWeb templates, an underlying
+Owl components are defined with ES6 classes, they use QWeb templates, an
-virtual dom, integrates beautifully with hooks, and the rendering is asynchronous.
+underlying virtual DOM, integrates beautifully with hooks, and the rendering is
+asynchronous.
 
-**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. There
+**Try it online!** An online playground is available at
-are some code examples to showcase some interesting features.
+[https://odoo.github.io/owl/playground](https://odoo.github.io/owl/playground)
+to let you experiment with the Owl framework. There are some code examples to
+showcase some interesting features.
 
-Owl is currently mostly stable.  Possible future changes are explained in the
+Owl is currently stable.  Possible future changes are explained in the
 [roadmap](roadmap.md).
 
+## Why Owl?
+
+Why did Odoo decide to make Yet Another Framework?  This is really a question
+that deserves [a long answer](doc/miscellaneous/why_owl.md). But in short, we believe that
+while the current state of the art frameworks are excellent, they are not
+optimized for our use case, and there is still room for something else.
+
+If you are interested in a comparison with React or Vue, you will
+find some more additional information [here](doc/miscellaneous/comparison.md).
+
 ## Example
 
 Here is a short example to illustrate interactive components:
 
 ```javascript
-const { Component, useState } = owl;
+const { Component, useState, mount } = owl;
 const { xml } = owl.tags;
 
 class Counter extends Component {
@@ -50,8 +66,7 @@ class App extends Component {
   static components = { Counter };
 }
 
-const app = new App();
+mount(App, { target: document.body });
-app.mount(document.body);
 ```
 
 Note that the counter component is made reactive with the [`useState` hook](doc/reference/hooks.md#usestate).
@@ -79,10 +94,9 @@ requirements are common and code needs to be maintained by large teams.
 
 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).
+one way to define components (with classes). There is no black magic. It just
+works.
 
-If you are interested in a comparison with React or Vue, you will
-find some more information [here](doc/comparison.md).
 
 ## Documentation
 
@@ -90,161 +104,26 @@ A complete documentation for Owl can be found here:
 
 - [Main documentation page](doc/readme.md).
 
-The most important sections are:
+Some of the most important pages are:
 
-- [Quick Start](doc/learning/quick_start.md)
+- [Tutorial: TodoList application](doc/learning/tutorial_todoapp.md)
+- [How to start an Owl project](doc/learning/quick_start.md)
+- [QWeb templating language](doc/reference/qweb_templating_language.md)
 - [Component](doc/reference/component.md)
 - [Hooks](doc/reference/hooks.md)
 
-Found an issue in the documentation? A broken link? Some outdated information?
-Submit a PR!
 
-## Installing/Building
+## 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-1.0.0-alpha.js](https://github.com/odoo/owl/releases/download/v1.0.0-alpha/owl.js)
+- [owl-1.4.7](https://github.com/odoo/owl/releases/tag/v1.4.7)
-- [owl-1.0.0-alpha.min.js](https://github.com/odoo/owl/releases/download/v1.0.0-alpha/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 (owl) tests                                |
-
-## Quick Overview
-
-Owl components in an application are used to define a (dynamic) tree of components.
-
-```
-        Root
-        /   \
-       A     B
-      / \
-     C   D
-```
-
-**State:** each component can manage its own local state. It is a simple ES6
-class, there are no special rules:
-
-```js
-class Counter extends Component {
-  static template = xml`
-    <button t-on-click="increment">
-      Click Me! [<t t-esc="state.value"/>]
-    </button>`;
-
-  state = { value: 0 };
-
-  increment() {
-    this.state.value++;
-    this.render();
-  }
-}
-```
-
-The example above shows a component with a local state. Note that since there
-is nothing magical to the `state` object, we need to manually call the `render`
-function whenever we update it. This can quickly become annoying (and not
-efficient if we do it too much). There is a better way: using the `useState`
-hook, which transforms an object into a reactive version of itself:
-
-```js
-const { useState } = owl.hooks;
-
-class Counter extends 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++;
-  }
-}
-```
-
-Note that the `t-on-click` handler can even be replaced by an inline statement:
-
-```xml
-    <button t-on-click="state.value++">
-```
-
-**Props:** sub components often needs some information from their parents. This
-is done by adding the required information to the template. This will then be
-accessible by the sub component in the `props` object. Note that there is an
-important rule here: the information contained in the `props` object is not
-owned by the sub component, and should never be modified.
-
-```js
-class Child extends Component {
-  static template = xml`<div>Hello <t t-esc="props.name"/></div>`;
-}
-
-class Parent extends Component {
-  static template = xml`
-    <div>
-        <Child name="'Owl'" />
-        <Child name="'Framework'" />
-    </div>`;
-  static components = { Child };
-}
-```
-
-**Communication:** there are multiple ways to communicate information between
-components. However, the two most important ways are the following:
-
-- from parent to children: by using `props`,
-- from a children to one of its parent: by triggering events.
-
-The following example illustrate both mechanisms:
-
-```js
-class OrderLine extends Component {
-  static template = xml`
-    <div t-on-click="add">
-        <div><t t-esc="props.line.name"/></div>
-        <div>Quantity: <t t-esc="props.line.quantity"/></div>
-    </div>`;
-
-  add() {
-    this.trigger("add-to-order", { line: props.line });
-  }
-}
-
-class Parent extends Component {
-  static template = xml`
-    <div t-on-add-to-order="addToOrder">
-        <OrderLine
-            t-foreach="orders"
-            t-as="line"
-            line="line" />
-    </div>`;
-  static components = { OrderLine };
-  orders = useState([{ id: 1, name: "Coffee", quantity: 0 }, { id: 2, name: "Tea", quantity: 0 }]);
-
-  addToOrder(event) {
-    const line = event.detail.line;
-    line.quantity++;
-  }
-}
-```
-
-In this example, the `OrderLine` component trigger a `add-to-order` event. This
-will generate a DOM event which will bubble along the DOM tree. It will then be
-intercepted by the parent component, which will then get the line (from the
-`detail` key) and then increment its quantity. See the section on [event handling](doc/reference/component.md#event-handling)
-for more details on how events work.
-
-Note that this example would have also worked if the `OrderLine` component
-directly modifies the `line` object. However, this is not a good practice: this
-only works because the `props` object received by the child component is reactive,
-so the child component is then coupled to the parents implementation.
 
 ## License
 

doc/learning/environment.md

@@ -1,48 +0,0 @@
-# 🦉 Environment 🦉
-
-An environment is an object which contains a [`QWeb` instance](../reference/qweb.md).
-Whenever a root component is created, it is assigned an environment (see the
-reference section on [environment](../reference/environment.md). This environment
-is then automatically given to each sub components (and accessible in the `this.env` property).
-
-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.
-
-Some good use cases for the environment is:
-
-- some configuration keys,
-- session information,
-- generic services (such as doing rpcs, or accessing local storage).
-
-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() {
-    owl.config.env = await myEnv();
-    const app = new App();
-    await app.mount(document.body);
-}
-```

doc/learning/how_to_debug.md

@@ -0,0 +1,43 @@
+# 🦉 How to debug Owl applications 🦉
+
+Non trivial applications become quickly more difficult to understand. It is then
+useful to have a solid understanding of what is going on. To help with that,
+logging useful information is extremely valuable. There is a [javascript file](../../tools/debug.js) which can be evaluated in an application.
+
+Once it is executed, it will log a lot of information on each component main hooks. The following code is a minified version to make it easier to copy/paste:
+
+```
+function debugOwl(t,e){let n,o="[OWL_DEBUG]";function r(t){let e;try{e=JSON.stringify(t||{})}catch(t){e="<JSON error>"}return e.length>200&&(e=e.slice(0,200)+"..."),e}if(Object.defineProperty(t.Component,"current",{get:()=>n,set(s){n=s;const i=s.constructor.name;if(e.componentBlackList&&e.componentBlackList.test(i))return;if(e.componentWhiteList&&!e.componentWhiteList.test(i))return;let l;Object.defineProperty(n,"__owl__",{get:()=>l,set(n){!function(n,s,i){let l=`${s}<id=${i}>`,c=t=>console.log(`${o} ${l} ${t}`),u=t=>(!e.methodBlackList||!e.methodBlackList.includes(t))&&!(e.methodWhiteList&&!e.methodWhiteList.includes(t));u("constructor")&&c(`constructor, props=${r(n.props)}`);u("willStart")&&t.hooks.onWillStart(()=>{c("willStart")});u("mounted")&&t.hooks.onMounted(()=>{c("mounted")});u("willUpdateProps")&&t.hooks.onWillUpdateProps(t=>{c(`willUpdateProps, nextprops=${r(t)}`)});u("willPatch")&&t.hooks.onWillPatch(()=>{c("willPatch")});u("patched")&&t.hooks.onPatched(()=>{c("patched")});u("willUnmount")&&t.hooks.onWillUnmount(()=>{c("willUnmount")});const d=n.__render.bind(n);n.__render=function(...t){c("rendering template"),d(...t)};const h=n.render.bind(n);n.render=function(...t){const e=n.__owl__;let o="render";return e.isMounted||e.currentFiber||(o+=" (warning: component is not mounted, this render has no effect)"),c(o),h(...t)};const p=n.mount.bind(n);n.mount=function(...t){return c("mount"),p(...t)}}(s,i,(l=n).id)}})}}),e.logScheduler){let e=t.Component.scheduler.start,n=t.Component.scheduler.stop;t.Component.scheduler.start=function(){this.isRunning||console.log(`${o} scheduler: start running tasks queue`),e.call(this)},t.Component.scheduler.stop=function(){this.isRunning&&console.log(`${o} scheduler: stop running tasks queue`),n.call(this)}}if(e.logStore){let e=t.Store.prototype.dispatch;t.Store.prototype.dispatch=function(t,...n){return console.log(`${o} store: action '${t}' dispatched. Payload: '${r(n)}'`),e.call(this,t,...n)}}}
+debugOwl(owl, {
+  // componentBlackList: /App/,  // regexp
+  // componentWhiteList: /SomeComponent/, // regexp
+  // methodBlackList: ["mounted"], // list of method names
+  // methodWhiteList: ["willStart"], // list of method names
+  logScheduler: false,  // display/mute scheduler logs
+  logStore: true,     // display/mute store logs
+});
+```
+
+The above code, once pasted somewhere in the main javascript file of an owl
+application, will log information looking like this:
+
+```
+[OWL_DEBUG] TodoApp<id=1> constructor, props={}
+[OWL_DEBUG] TodoApp<id=1> mount
+[OWL_DEBUG] TodoApp<id=1> willStart
+[OWL_DEBUG] TodoApp<id=1> rendering template
+[OWL_DEBUG] TodoItem<id=2> constructor, props={"id":2,"completed":false,"title":"hey"}
+[OWL_DEBUG] TodoItem<id=2> willStart
+[OWL_DEBUG] TodoItem<id=3> constructor, props={"id":4,"completed":false,"title":"aaa"}
+[OWL_DEBUG] TodoItem<id=3> willStart
+[OWL_DEBUG] TodoItem<id=2> rendering template
+[OWL_DEBUG] TodoItem<id=3> rendering template
+[OWL_DEBUG] TodoItem<id=3> mounted
+[OWL_DEBUG] TodoItem<id=2> mounted
+[OWL_DEBUG] TodoApp<id=1> mounted
+```
+
+Each component has an internal `id`, which is very useful when debugging.
+
+Note that it is certainly useful to run this code at some point in an application,
+just to get a feel of what each user action implies, for the framework.

doc/learning/how_to_test.md

@@ -0,0 +1,130 @@
+# 🦉 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
+export function makeTestFixture() {
+  let fixture = document.createElement("div");
+  document.body.appendChild(fixture);
+  return fixture;
+}
+
+export function nextTick() {
+  let requestAnimationFrame = owl.Component.scheduler.requestAnimationFrame;
+  return new Promise(function(resolve) {
+    setTimeout(() => requestAnimationFrame(() => resolve()));
+  });
+}
+
+export function makeTestEnv() {
+    // application specific. It needs a way to load actual templates
+    const templates = ...;
+
+    return {
+        qweb: new QWeb(templates),
+        ..., // each service can be mocked here
+    };
+}
+```
+
+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, makeTestEnv} from '../helpers';
+
+
+//------------------------------------------------------------------------------
+// Setup
+//------------------------------------------------------------------------------
+let fixture: HTMLElement;
+let env: Env;
+
+beforeEach(() => {
+  fixture = makeTestFixture();
+  env = makeTestEnv();
+  // we set here the default environment for each component created in the test
+  Component.env = env;
+});
+
+afterEach(() => {
+  fixture.remove();
+});
+
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+describe("SomeComponent", () => {
+  test("component behaves as expected", async () => {
+    const props = {...}; // depends on the component
+    const comp = await mount(SomeComponent, { target: 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.
+
+It is sometimes useful to wait until Owl is completely done updating components
+(in particular, if we have a highly concurrent user interface). This next
+helper simply polls every 20ms the internal Owl task queue and returns a promise
+which resolves when it is empty:
+
+```js
+function afterUpdates() {
+  return new Promise((resolve, reject) => {
+    let timer = setTimeout(poll, 20);
+    let counter = 0;
+    function poll() {
+      counter++;
+      if (owl.Component.scheduler.tasks.length) {
+        if (counter > 10) {
+          reject(new Error("timeout"));
+        } else {
+          timer = setTimeout(poll);
+        }
+      } else {
+        resolve();
+      }
+    }
+  });
+}
+```

doc/learning/how_to_write_sfc.md

@@ -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.

doc/learning/overview.md

@@ -0,0 +1,133 @@
+# 🦉 Quick Overview 🦉
+
+Owl components in an application are used to define a (dynamic) tree of components.
+
+```
+        Root
+        /   \
+       A     B
+      / \
+     C   D
+```
+
+**State:** each component can manage its own local state. It is a simple ES6
+class, there are no special rules:
+
+```js
+class Counter extends Component {
+  static template = xml`
+    <button t-on-click="increment">
+      Click Me! [<t t-esc="state.value"/>]
+    </button>`;
+
+  state = { value: 0 };
+
+  increment() {
+    this.state.value++;
+    this.render();
+  }
+}
+```
+
+The example above shows a component with a local state. Note that since there
+is nothing magical to the `state` object, we need to manually call the `render`
+function whenever we update it. This can quickly become annoying (and not
+efficient if we do it too much). There is a better way: using the `useState`
+hook, which transforms an object into a reactive version of itself:
+
+```js
+const { useState } = owl.hooks;
+
+class Counter extends 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++;
+  }
+}
+```
+
+Note that the `t-on-click` handler can even be replaced by an inline statement:
+
+```xml
+    <button t-on-click="state.value++">
+```
+
+**Props:** sub components often needs some information from their parents. This
+is done by adding the required information to the template. This will then be
+accessible by the sub component in the `props` object. Note that there is an
+important rule here: the information contained in the `props` object is not
+owned by the sub component, and should never be modified.
+
+```js
+class Child extends Component {
+  static template = xml`<div>Hello <t t-esc="props.name"/></div>`;
+}
+
+class Parent extends Component {
+  static template = xml`
+    <div>
+        <Child name="'Owl'" />
+        <Child name="'Framework'" />
+    </div>`;
+  static components = { Child };
+}
+```
+
+**Communication:** there are multiple ways to communicate information between
+components. However, the two most important ways are the following:
+
+- from parent to children: by using `props`,
+- from a children to one of its parent: by triggering events.
+
+The following example illustrate both mechanisms:
+
+```js
+class OrderLine extends Component {
+  static template = xml`
+    <div t-on-click="add">
+        <div><t t-esc="props.line.name"/></div>
+        <div>Quantity: <t t-esc="props.line.quantity"/></div>
+    </div>`;
+
+  add() {
+    this.trigger("add-to-order", { line: this.props.line });
+  }
+}
+
+class Parent extends Component {
+  static template = xml`
+    <div t-on-add-to-order="addToOrder">
+        <OrderLine
+            t-foreach="orders"
+            t-as="line"
+            line="line" />
+    </div>`;
+  static components = { OrderLine };
+  orders = useState([
+    { id: 1, name: "Coffee", quantity: 0 },
+    { id: 2, name: "Tea", quantity: 0 },
+  ]);
+
+  addToOrder(event) {
+    const line = event.detail.line;
+    line.quantity++;
+  }
+}
+```
+
+In this example, the `OrderLine` component trigger a `add-to-order` event. This
+will generate a DOM event which will bubble along the DOM tree. It will then be
+intercepted by the parent component, which will then get the line (from the
+`detail` key) and then increment its quantity. See the page on [event handling](../reference/event_handling.md)
+for more details on how events work.
+
+Note that this example would have also worked if the `OrderLine` component
+directly modifies the `line` object. However, this is not a good practice: this
+only works because the `props` object received by the child component is reactive,
+so the child component is then coupled to the parents implementation.

doc/learning/quick_start.md

@@ -1,108 +1,408 @@
-# 🦉 Quick Start 🦉
+# 🦉 How to start an Owl project 🦉
 
-## Static Server
+## Content
 
-Let us assume that we have a static server running somewhere. Let us start by
+- [Overview](#overview)
-adding an html page with a few extra files:
+- [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:
 
 ```
-my-app/
+hello_owl/
   index.html
-    app.css
+  owl.js
   app.js
-    owl-X.Y.Z.js
-    templates.xml
 ```
 
-### HTML and CSS
+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.
 
-In a file `index.html`:
+Now, `index.html` should contain the following:
 
 ```html
 <!DOCTYPE html>
 <html lang="en">
   <head>
-    <meta charset="UTF-8" />
+    <title>Hello Owl</title>
-    <title>My OWL App</title>
+    <script src="owl.js"></script>
-    <link href="app.css" rel="stylesheet" />
+    <script src="app.js"></script>
-    <script src="owl-X.Y.Z.js"></script>
   </head>
-  <body>
+  <body></body>
-    <div id="main"></div>
-    <script src="app.js" type="module"></script>
-  </body>
 </html>
 ```
 
-In `app.css`:
+And `app.js` should look like this:
 
-```css
+```js
-button {
+const { Component, mount } = owl;
-  color: darkred;
+const { xml } = owl.tags;
-  font-size: 30px;
+const { whenReady } = owl.utils;
-  width: 220px;
+
+// Owl Components
+class App extends Component {
+  static template = xml`<div>Hello Owl</div>`;
+}
+
+// Setup code
+function setup() {
+  mount(App, target: { document.body })
+}
+
+whenReady(setup);
+```
+
+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/
+    app.js
+    index.html
+    main.js
+    owl.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).
+
+Now, `index.html` should contain the following:
+
+```html
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <title>Hello Owl</title>
+    <script src="owl.js"></script>
+    <script src="main.js" type="module"></script>
+  </head>
+  <body></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 `app.js` and `main.js`:
+
+```js
+// app.js ----------------------------------------------------------------------
+const { Component, mount } = owl;
+const { xml } = owl.tags;
+
+export class App extends Component {
+  static template = xml`<div>Hello Owl</div>`;
+}
+
+// main.js ---------------------------------------------------------------------
+import { App } from "./app.js";
+
+function setup() {
+  mount(App, { target: document.body });
+}
+
+owl.utils.whenReady(setup);
+```
+
+The `main.js` file import the `app.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"
+  }
 }
 ```
 
-Also, let's not forget to add a release of OWL (`owl-X.Y.Z.js`)
+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.
 
-### XML
+## Standard Javascript project
 
-In `templates.xml`:
+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.
 
-```xml
+Each of these features, and many others, can be done in many different ways.
-<templates>
+Since it is really not trivial to configure such a project, we provide here an
-   <button t-name="clickcounter" t-on-click="increment">
+example that can be used as a starting point.
-      Click Me! [<t t-esc="state.value"/>]
+
-    </button>
+Our standard Owl project has the following file structure:
-</templates>
+
+```
+hello_owl/
+  public/
+    index.html
+  src/
+    components/
+      App.js
+    main.js
+  tests/
+    components/
+      App.test.js
+    helpers.js
+  .gitignore
+  package.json
+  webpack.config.js
 ```
 
-### 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.
 
-To build an application (or a sub-part of an application), we need two things:
+Here is the content of `index.html`:
 
-- an environment: it is the global context in which we are working. It needs to
+```html
-  contain a QWeb instance (preloaded with templates), and anything else that we
+<!DOCTYPE html>
-  need. In practice, it could be used to contain some user session information, some
+<html lang="en">
-  configuration keys (for example, isMobile = true/false if we are in mobile mode).
+  <head>
+    <title>Hello Owl</title>
+  </head>
+  <body></body>
+</html>
+```
 
-- a description of the user interface: there should be a root component, which can
+Note that there are no `<script>` tag here. They will be injected by webpack.
-  have sub components
+Now, let's have a look at the javascript files:
 
-Here are a few steps that we may take to get started:
+```js
+// src/components/App.js -------------------------------------------------------
+import { Component, tags, useState } from "@odoo/owl";
 
-- get the templates
+const { xml } = tags;
-- 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`:
+export class App extends Component {
-
+  static template = xml`<div t-on-click="update">Hello <t t-esc="state.text"/></div>`;
-```javascript
+  state = useState({ text: "Owl" });
-const useState = owl.hooks.useState;
+  update() {
-
+    this.state.text = this.state.text === "Owl" ? "World" : "Owl";
-class ClickCounter extends owl.Component {
-  static template = "clickcounter";
-  state = useState({ value: 0 });
-
-  increment() {
-    this.state.value++;
   }
 }
 
-//------------------------------------------------------------------------------
+// src/main.js -----------------------------------------------------------------
-// Application initialization
+import { utils, mount } from "@odoo/owl";
-//------------------------------------------------------------------------------
+import { App } from "./components/App";
-async function start() {
+
-  const templates = await owl.utils.loadFile("templates.xml");
+function setup() {
-  const qweb = new owl.QWeb({ templates });
+  mount(App, { target: document.body });
-  owl.config.env.qweb = qweb;
-  const counter = new ClickCounter();
-  const target = document.getElementById("main");
-  await counter.mount(target);
 }
 
-start();
+utils.whenReady(setup);
+
+// tests/components/App.test.js ------------------------------------------------
+import { App } from "../../src/components/App";
+import { makeTestFixture, nextTick, click } from "../helpers";
+import { mount } from "@odoo/owl";
+
+let fixture;
+
+beforeEach(() => {
+  fixture = makeTestFixture();
+});
+
+afterEach(() => {
+  fixture.remove();
+});
+
+describe("App", () => {
+  test("Works as expected...", async () => {
+    await mount(App, { target: 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() {
+  return new Promise(function (resolve) {
+    setTimeout(() => Component.scheduler.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
 ```

doc/miscellaneous/comparison.md

@@ -4,7 +4,7 @@ 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, 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
@@ -47,7 +47,7 @@ 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
-comes with a mindset of composition and class are about inheritance. Clearly,
+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.
 
@@ -79,7 +79,7 @@ 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
+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.
@@ -127,7 +127,7 @@ 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:
+[`xml`](../reference/tags.md#xml-tag) tag helper:
 
 ```js
 class Clock extends Component {
@@ -189,95 +189,6 @@ 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
-
-Managing the state of an application is a tricky issue. Many solutions have
-been proposed these last few years. It also depends on the kind of application we
-are talking about. A small application may not need much more than a simple
-object to contain its state.
-
-However, there are some common solutions for React and Vue: redux and vuex.
-Both of them are a centralized store that own the state, and they dictate how
-the state can be mutated.
-
-**Redux**
-
-In Redux, the state is mutated by reducers. Reducers are functions
-that modify the state by returning a different object:
-
-```javascript
-  ...
-  switch (action.type) {
-    case ADD_TODO: {
-      const { id, content } = action.payload;
-      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
-check if a part of the state was changed. This is exactly what is done by the
-`connect` function: it create a _connected_ component, which is subscribed to
-the state and triggers a rerender if some part of the state was modified.
-
-**VueX**
-
-VueX is based on a different principle: the state is mutated through
-some special functions (the mutations), which modify the state in place:
-
-```javascript
-    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:
-each key from the state is silently replaced by getters and setters, and VueX
-keeps track of who get data, and retrigger a render when it was changed.
-
-**Owl**
-
-Owl store is a little bit like a mix of redux and vuex: it has actions (but not
-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, with the `useStore` hook (see the [store documentation](reference/store.md#connecting-a-component)).
-
-```javascript
-const actions = {
-  increment({ state }, val) {
-    state.counter.value += val;
-  }
-};
-
-const state = {
-  counter: { value: 0 }
-};
-const store = new owl.Store({ state, actions });
-
-class Counter extends Component {
-  static template = xml`
-      <button t-name="Counter" t-on-click="dispatch('increment')">
-        Click Me! [<t t-esc="counter.value"/>]
-      </button>`;
-  counter = useStore(state => state.counter);
-  dispatch = useDispatch();
-}
-
-owl.config.env.store = store;
-const counter = new Counter();
-```
-
 ## Hooks
 
 [Hooks](https://reactjs.org/docs/hooks-intro.html#motivation) recently took over
@@ -315,7 +226,7 @@ This work is based on the new ideas introduced by React hooks.
 
 From the way React and Vue introduce their hooks, it may look like hooks are not
 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,
+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.
 
@@ -342,4 +253,4 @@ class Example extends Component {
 
 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` and `Store` abstractions.
+`Context` abstraction.

doc/miscellaneous/why_owl.md

@@ -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 🦉.

doc/readme.md

@@ -1,88 +1,55 @@
 # 🦉 OWL Documentation 🦉
 
-## Owl Content
+## Learning Owl
 
-Owl is a javascript library that contains some core classes and function to help
+Are you new to Owl? This is the place to start!
-build applications. Here is a complete representation of its content:
 
-```
+- [Tutorial: create a TodoList application](learning/tutorial_todoapp.md)
-owl
+- [Quick Overview](learning/overview.md)
-    Component
+- [How to start an Owl project](learning/quick_start.md)
-    Context
+- [How to test Components](learning/how_to_test.md)
-    QWeb
+- [How to write Single File Components](learning/how_to_write_sfc.md)
-    Store
+- [How to write debug Owl applications](learning/how_to_debug.md)
-    useState
-    config
-        mode
-        env
-    core
-        EventBus
-        Observer
-    hooks
-        onWillStart
-        onMounted
-        onWillUpdateProps
-        onWillPatch
-        onPatched
-        onWillUnmount
-        useContext
-        useState
-        useRef
-        useSubEnv
-        useStore
-        useDispatch
-        useGetters
-    misc
-        AsyncRoot
-    router
-        Link
-        RouteComponent
-        Router
-    tags
-        xml
-    utils
-        debounce
-        escape
-        loadJS
-        loadFile
-        shallowEqual
-        whenReady
-```
-
-Note that for convenience, the `useState` hook is also exported at the root of the `owl` object.
-
-## Learning Resources
-
-- [Quick Start: create an (almost) empty Owl application](learning/quick_start.md)
-- [Environment: what it is and what it should contain](learning/environment.md)
 
 ## Reference
 
+You will find here a complete reference of every feature, class or object
+provided by Owl.
+
 - [Animations](reference/animations.md)
+- [Browser](reference/browser.md)
 - [Component](reference/component.md)
+- [Content](reference/content.md)
+- [Concurrency Model](reference/concurrency_model.md)
 - [Configuration](reference/config.md)
 - [Context](reference/context.md)
 - [Environment](reference/environment.md)
 - [Event Bus](reference/event_bus.md)
+- [Event Handling](reference/event_handling.md)
+- [Error Handling](reference/error_handling.md)
 - [Hooks](reference/hooks.md)
-- [Misc](reference/misc.md)
+- [Mounting a component](reference/mounting.md)
+- [Miscellaneous Components](reference/misc.md)
 - [Observer](reference/observer.md)
-- [QWeb](reference/qweb.md)
+- [Props](reference/props.md)
-- [Router](reference/router.md)
+- [Props Validation](reference/props_validation.md)
-- [Store](reference/store.md)
+- [QWeb Templating Language](reference/qweb_templating_language.md)
+- [QWeb Engine](reference/qweb_engine.md)
+- [Slots](reference/slots.md)
 - [Tags](reference/tags.md)
 - [Utils](reference/utils.md)
 
-## Miscellaneous
+## Other Topics
 
-- [Comparison with React/Vue](comparison.md)
+This section provides miscellaneous document that explains some topics
-- [Tooling](tooling.md)
+which cannot be considered either a tutorial, or reference documentation.
-- [Templates to start Owl applications (external link)](https://github.com/ged-odoo/owl-templates)
 
-## Architecture
+- [Owl architecture: the Virtual DOM](miscellaneous/vdom.md)
+- [Owl architecture: the rendering pipeline](miscellaneous/rendering.md)
+- [Comparison with React/Vue](miscellaneous/comparison.md)
+- [Why did Odoo built Owl?](miscellaneous/why_owl.md)
 
-This section explains in more detail the inner workings of Owl. It is more
+---
-useful for people working on Owl code.
 
-- [Virtual DOM](architecture/vdom.md)
+Found an issue in the documentation? A broken link? Some outdated information?
-- [Rendering](architecture/rendering.md)
+Please open an issue or submit a PR!

doc/reference/animations.md

@@ -52,21 +52,20 @@ 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:
 
@@ -93,3 +92,36 @@ Notes:
 
 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).
+
+## 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"/>
+```

doc/reference/browser.md

@@ -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`

doc/reference/component.md

@@ -10,19 +10,22 @@
   - [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)
-  - [Event Handling](#event-handling)
   - [Form Input Bindings](#form-input-bindings)
-  - [`t-key` Directive](#t-key-directive)
-  - [Semantics](#semantics)
-  - [Props Validation](#props-validation)
   - [References](#references)
-  - [Slots](#slots)
+  - [Dynamic sub components](#dynamic-sub-components)
-  - [Asynchronous Rendering](#asynchronous-rendering)
-  - [Error Handling](#error-handling)
   - [Functional Components](#functional-components)
-  - [SVG components](#svg-components)
+  - [SVG Components](#svg-components)
 
 ## Overview
 
@@ -42,7 +45,7 @@ OWL components are the building blocks for user interface. They are designed to
    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.md) template (which needs to be preloaded in QWeb).
+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.
 
@@ -81,7 +84,7 @@ a state object is defined, by using the `useState` hook. It is not mandatory to
 
 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.md) instance, which
+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
@@ -166,7 +169,7 @@ to be called in the constructor.
 - **`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, which contains a QWeb instance.
+- **`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,
@@ -204,13 +207,13 @@ to be called in the constructor.
 * **`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) for more information.
+  created/updated. See [Props Validation](props_validation.md) for more information.
 
   ```js
   class Counter extends owl.Component {
     static props = {
       initialValue: Number,
-      optional: true
+      optional: true,
     };
   }
   ```
@@ -223,11 +226,15 @@ to be called in the constructor.
   ```js
   class Counter extends owl.Component {
     static defaultProps = {
-      initialValue: 0
+      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
@@ -237,36 +244,69 @@ component.
 
 We explain here all the public methods of the `Component` class.
 
-- **`mount(target, renderBeforeRemount=false)`** (async): this is the main way a
+- **`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. Obviously, this is asynchronous, since each children need to be
+  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 `renderBeforeRemount` argument is useful when a component is unmounted and remounted.
+  The `options` argument is an optional object with a `position` key. The
-  In that case, we may want to rerender the component _before_ it is remounted, if
+  `position` key can have three possible values: `first-child`, `last-child`, `self`.
-  we know that its state (or something in the environment, or ...) has changed.
-  In that case, it should simply set to `true`.
 
-- **`unmount()`**: in case a component needs to be detached/removed from the DOM, this
+  - `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
+* **`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
+* **`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. This is an optimization, similar to React's `shouldComponentUpdate`. Most of the time, this should not be used, but it
+  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.
+  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,
+* **`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
@@ -284,15 +324,15 @@ developers write components. Here is a complete description of the lifecycle of
 a owl component:
 
 | Method                                           | Description                                                 |
-| ------------------------------------------------ | ------------------------------------------------------------ |
+| ------------------------------------------------ | ----------------------------------------------------------- |
-| **[constructor](#constructorparent-props)**      | constructor                                                  |
+| **[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 section](#error-handling)) |
+| **[catchError](#catcherrorerror)**               | catch errors (see [error handling page](error_handling.md)) |
 
 Notes:
 
@@ -330,6 +370,23 @@ class ClickCounter extends owl.Component {
 }
 ```
 
+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
@@ -400,7 +457,7 @@ 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 compoent is
+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.
@@ -427,8 +484,8 @@ 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 section on
+to (rendering) errors that occur in some sub components. See the page on
-[error handling](#error-handling).
+[error handling](error_handling.md).
 
 ### Root Component
 
@@ -443,8 +500,13 @@ const app = new App();
 app.mount(document.body);
 ```
 
-The root component does not have a parent nor props. It will be setup with an
+The root component does not have a parent nor `props` (see note below). It will be setup with an
-[environment](environment.md) (located in `owl.config.env`).
+[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
 
@@ -498,66 +560,8 @@ 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.
+the sub component will also be updated automatically. See the [props section](props.md)
-
+for more information.
-Note that there are restrictions on valid prop names: `class`, `style` and any
-string which starts with `t-` are not allowed.
-
-It is not common, but sometimes we need a dynamic component name and/or dynamic props. In this case,
-the `t-component` directive can also be used to accept dynamic values with string interpolation (like the [`t-attf-`](qweb.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 };
-}
-```
-
-And 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 } };
-}
-```
-
-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.
 
 **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
@@ -580,116 +584,6 @@ with a class object:
 <MyComponent t-att-class="{a: state.flagA, b: state.flagB}" />
 ```
 
-### 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.
-
-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 a [_CustomEvent_](https://developer.mozilla.org/docs/Web/Guide/Events/Creating_and_triggering_events)
-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.
-
-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", () => {
-  component.state.counter++;
-});
-```
-
-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 |
-
-```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.
-
 ### Form Input Bindings
 
 It is very common to need to be able to read the value out of an html `input` (or
@@ -783,252 +677,6 @@ update a number whenever the change is done.
 
 Note: the online playground has an example to show how it works.
 
-### `t-key` Directive
-
-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>
-```
-
-### 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. component `A` is patched into a detached DOM element. This will create the actual
-   component `A` DOM structure. The patching process will cause recursively the
-   patching of the `B`, `C`, `D` and `E` DOM trees. (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: `B`, `D`, `E`, `C`, `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 `E` (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. component `C` is patched, which will cause recursively:
-
-   2. `willUnmount` hook on `E`, then destruction of `E`,
-   3. (initial) patching of `F`, then hook `mounted` is called on `F`
-
-5. patching of `D`
-
-6. `patched` hooks are called on `D`, `C`
-
-### 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 would solve 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:
-  - `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. It is optional (not set means that we only validate the array, not its elements),
-  - `shape`: if the type was `Object`, then the `shape` key describes the interface of the object. It is optional (not set means that we only validate the object, not its elements)
-
-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
-  };
-```
-
 ### References
 
 The `useRef` hook is useful when we need a way to interact with some inside part
@@ -1085,163 +733,50 @@ 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.
 
-### Slots
+### Dynamic sub components
 
-To make generic components, it is useful to be able for a parent component to _inject_
+It is not common, but sometimes we need a dynamic component name. In this case,
-some sub template, but still be the owner. For example, a generic dialog component
+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):
-will need to render some content, some footer, but with the parent as the
-rendering context.
-
-This is what _slots_ are for.
 
 ```xml
-<div t-name="Dialog" class="modal">
+<div t-name="ParentComponent">
-  <div class="modal-title"><t t-esc="props.title"/></div>
+    <t t-component="ChildComponent{{id}}" />
-  <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` directive:
-
-```xml
-<div t-name="SomeComponent">
-  <div>some component</div>
-  <Dialog title="Some Dialog">
-    <t t-set="content">
-      <div>hey</div>
-    </t>
-    <t t-set="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.
-
-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>
-```
-
-### 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. Maybe move the asynchronous logic in a store, which then triggers (mostly)
-   synchronous renderings
-3. 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))
-4. 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>
-   ```
-
-### Error Handling
-
-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.
-
-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.
-
-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="1">
-        <t t-slot="default" />
-    </t>
 </div>
 ```
 
 ```js
-class ErrorBoundary extends Component {
+class ParentComponent {
-  state = useState({ error: false });
+  static components = { ChildComponent1, ChildComponent2 };
+  state = { id: 1 };
+}
+```
 
-  catchError() {
+There is an even more dynamic way to use `t-component`: its value can be an
-    this.state.error = true;
+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;
   }
 }
 ```
 
-Using the `ErrorBoundary` is then extremely simple:
+In this example, the component `App` selects dynamically the concrete sub
+component class.
 
-```xml
+Note that the `t-component` directive can only be used on `<t>` nodes.
-<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, 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
-});
-```
 
 ### Functional Components
 
@@ -1254,7 +789,7 @@ 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, {props.name}</h1>`;
+const Welcome = xml`<h1>Hello, <t t-esc="props.name"/></h1>`;
 
 class MyComponent extends Component {
   static template = xml`
@@ -1304,8 +839,8 @@ class RootNode extends Component {
     children: [
       { label: "b" },
       { label: "c", children: [{ label: "d" }, { label: "e" }] },
-      { label: "f", children: [{ label: "g" }] }
+      { label: "f", children: [{ label: "g" }] },
-    ]
+    ],
   };
 }
 ```

doc/reference/concurrency_model.md

@@ -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>
+   ```

doc/reference/config.md

@@ -2,10 +2,10 @@
 
 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 currently has two keys:
+global `config` object. It provides two settings:
 
-- [`mode`](#mode),
+- [`mode`](#mode) (default value: `prod`),
-- [`env`](#env).
+- [`enableTransitions`](#enabletransitions) (default value: `true`).
 
 ## Mode
 
@@ -27,30 +27,18 @@ 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.
 
-## Env
+## `enableTransitions`
 
-An Owl application needs an [environment](environment.md) to be executed. The
+Transitions are usually nice, but they can cause issues in some specific cases,
-environment has an important key: the [QWeb](qweb.md) instance, which will render
+such as automated tests. It is uncomfortable having to wait for a transition
-all templates.
+to end before moving to the next step.
 
-Whenever a root component is mounted, Owl will take the environment from
+To solve this issue, Owl can be configured to ignore the `t-transition` directive.
-`owl.config.env` and use it to setup the component (and its children).
+To do that, one only needs to set the `enableTransitions` flag to false:
-
-- if no environment was setup, an empty environment will be generated,
-- if an environment exists, but does not have a QWeb key, a new QWeb instance
-  will then be added to the environment.
-
-The correct way to customize an environment is to simply modify `owl.config.env`
-before the first component is created:
 
 ```js
-owl.config.env = {
+owl.config.enableTransitions = false;
-    _t: myTranslateFunction,
-    user: {...},
-    services: {
-        ...
-    },
-};
-const app = new App();
-app.mount(document.body);
 ```
+
+Note that it suffers from the same drawback as the "dev" mode: all compiled
+templates, if any, will keep their current behaviours.

doc/reference/content.md

@@ -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.

doc/reference/context.md

@@ -28,7 +28,7 @@ context, and add it to the environment:
 
 ```js
 const deviceContext = new Context({ isMobile: true });
-owl.config.env.deviceContext = deviceContext;
+App.env.deviceContext = deviceContext;
 ```
 
 If we want to make it completely responsive, we need to update its value whenever
@@ -57,10 +57,10 @@ class SomeComponent extends Component {
       <t t-if=device.isMobile>
           some simplified user interface
       </t>
-          <t t-else="1">
+      <t t-else="">
-             some more sopthisticated user interface
+          a more advanced user interface
       </t>
-    `;
+    </div>`;
   device = useContext(this.env.deviceContext);
 }
 ```

doc/reference/environment.md

@@ -1,7 +1,20 @@
 # 🦉 Environment 🦉
 
-An environment is an object which contains a [`QWeb` instance](qweb.md). Whenever a root component is created, it is assigned an environment. This environment
+## Content
-is then automatically given to each sub component (and accessible in the `this.env` property).
+
+- [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
@@ -9,10 +22,115 @@ is then automatically given to each sub component (and accessible in the `this.e
    A    B
 ```
 
-This way, all components share the same `QWeb` instance.
+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.
 
-Note: some additional information can be found here:
+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.
 
-- [What should go into an environment?](../learning/environment.md)
+## Setting an environment
-- [Customizing an environment](config.md#env)
 
+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.

doc/reference/error_handling.md

@@ -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
+});
+```

doc/reference/event_bus.md

@@ -7,7 +7,7 @@ triggering events, and callbacks.
 ```js
 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`.

doc/reference/event_handling.md

@@ -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.

doc/reference/hooks.md

@@ -17,9 +17,9 @@
   - [`useContext`](#usecontext)
   - [`useRef`](#useref)
   - [`useSubEnv`](#usesubenv)
-  - [`useStore`](#usestore)
+  - [`useExternalListener`](#useexternallistener)
-  - [`useDispatch`](#usedispatch)
+  - [`useComponent`](#usecomponent)
-  - [`useGetters`](#usegetters)
+  - [`useEnv`](#useenv)
   - [Making customized hooks](#making-customized-hooks)
 
 ## Overview
@@ -128,7 +128,7 @@ class SomeComponent extends Component {
 ### One rule
 
 There is only one rule: every hook for a component has to be called in the
-constructor (or in class fields):
+constructor, in the _setup_ method, or in class fields:
 
 ```js
 // ok
@@ -144,6 +144,13 @@ class SomeComponent extends Component {
   }
 }
 
+// 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() {
@@ -152,9 +159,15 @@ class SomeComponent extends Component {
 }
 ```
 
-In a hook, the `Component.current` static property is the reference to the
+As you can see, the `useState` hook does not need to be given a reference to
-component instance that is currently being created. Hooks need to be called in
+the component. This is possible because there is a way to get a reference to the
-the constructor to ensure that this reference is properly set.
+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`
 
@@ -252,7 +265,7 @@ function useLoader() {
   }
 
   onWillStart(() => updateRecord(component.props.id));
-  onWillUpdateProps(nextProps => updateRecord(nextProps.id));
+  onWillUpdateProps((nextProps) => updateRecord(nextProps.id));
 
   return record;
 }
@@ -290,6 +303,7 @@ class Parent extends Component {
     // 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)
   }
 }
 ```
@@ -297,11 +311,14 @@ class Parent extends Component {
 As shown by the example above, html elements are accessed by using the `el`
 key, and components references are accessed with `comp`.
 
-Note: if used on a component, the reference will be set in the `refs`
+Notes:
-variable between `willPatch` and `patched`.
+
+- 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.md#dynamic-attributes) and
+(like the [`t-attf-`](qweb_templating_language.md#dynamic-attributes) and
 `t-component` directives). For example,
 
 ```xml
@@ -344,20 +361,16 @@ 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.
 
-### `useStore`
+### `useExternalListener`
 
-The `useStore` hook is the entry point for a component to connect to the store.
+The `useExternalListener` hook helps solve a very common problem: adding and removing
-See the [store documentation](store.md) for more information.
+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:
 
-### `useDispatch`
+```js
-
+useExternalListener(window, "click", this.closeMenu);
-The `useDispatch` hook is the way for components to get a reference to the store
+```
-`dispatch` function. See the [store documentation](store.md) for more information.
-
-### `useGetters`
-
-The `useGetters` hook is the way for components to get a reference to the store
-getters. See the [store documentation](store.md) for more information.
 
 ### Making customized hooks
 
@@ -413,13 +426,11 @@ not the solution to every problem.
 
   ```js
   function useRouter() {
-    return Component.current.env.router;
+    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.
-
-Note: the code above makes use of the `Component.current` property. This is the
-way hooks are able to get a reference to the component currently being created.

doc/reference/misc.md

@@ -1,5 +1,115 @@
 # 🦉 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

doc/reference/mounting.md

@@ -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.

doc/reference/observer.md

@@ -15,7 +15,7 @@ use cases, there is no need to directly instantiate an observer.
 For example, this code will display `update` in the console:
 
 ```javascript
-const observer = new owl.Observer();
+const observer = new owl.core.Observer();
 observer.notifyCB = () => console.log("update");
 const obj = observer.observe({ a: { b: 1 } });
 
@@ -39,14 +39,14 @@ is incremented every time the value is observed. Sometimes, it can be useful
 to obtain that number:
 
 ```js
-const observer = new owl.Observer();
+const observer = new owl.core.Observer();
 const obj = observer.observe({ a: { b: 1 } });
 
-observer.deepRevNumber(obj.a); // 1
+observer.revNumber(obj.a); // 1
 obj.a.b = 2;
 
-observer.deepRevNumber(obj.a); // 2
+observer.revNumber(obj.a); // 2
 ```
 
-The `deepRevNumber` can also return 0, which indicates that the value is not
+The `revNumber` can also return 0, which indicates that the value is not
 observed.

doc/reference/props.md

@@ -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 } };
+}
+```

doc/reference/props_validation.md

@@ -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)
+    },
+  };
+```

doc/reference/qweb_engine.md

@@ -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.

doc/reference/qweb_templating_language.md

@@ -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)
@@ -14,25 +13,25 @@
   - [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/13.0/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"/>
         </li>
@@ -40,19 +39,22 @@ To avoid element rendering, a placeholder element `<t>` is also available, which
 </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                                                    |
-| ------------------------------ | ------------------------------------------------------------ |
+| ------------------------------ | -------------------------------------------------------------- |
 | `t-esc`                        | [Outputting safely a value](#outputting-data)                  |
 | `t-raw`                        | [Outputting value, without escaping](#outputting-data)         |
 | `t-set`, `t-value`             | [Setting variables](#setting-variables)                        |
@@ -62,113 +64,24 @@ We present here a list of all standard QWeb directives:
 | `t-call`                       | [Rendering sub templates](#rendering-sub-templates)            |
 | `t-debug`, `t-log`             | [Debugging](#debugging)                                        |
 | `t-translation`                | [Disabling the translation of a node](#translations)           |
-| `t-name`                       | [Defining a template (not really a directive)](#qweb-engine) |
+| `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                                                                     |
-| ------------------------ | ----------------------------------------------------------------------------------- |
+| ------------------------ | ------------------------------------------------------------------------------- |
 | `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-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-slot`                 | [Rendering a slot](component.md#slots)                                              |
+| `t-slot`                 | [Rendering a slot](slots.md)                                                    |
 | `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();
-```
-
-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](../architecture/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).
 
 ## 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 template are handled in a special way:
@@ -192,7 +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>
 ```
 
@@ -414,6 +327,40 @@ values) or a pair `[key, value]`. For example:
 <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
@@ -479,20 +426,81 @@ into the global context.
 <!-- new_variable undefined -->
 ```
 
-Owl QWeb is used as the template engine for components. Components are frequently
+Even though Owl tries to be as declarative as possible, the DOM does not fully
-updated, and reuse as much of the previous DOM as possible. Loops offer a specific
+expose its state declaratively in the DOM tree. For example, the scrolling state,
-problem for this usecase: how does the template engine know if two rows have
+the current user selection, the focused element or the state of an input are not
-been swapped, or if the content of these rows was changed? To help Owl with that,
+set as attribute in the DOM tree. This is why we use a virtual dom
-there is an additional directive: [`t-key`](component.md#t-key-directive).
+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="state.things" t-as="thing" t-key="thing.id">
+<p t-foreach="items" t-as="item"><t t-esc="item.text"/></p>
-    <t t-esc="thing.content"/>
+```
+
+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
@@ -541,25 +549,36 @@ will result in :
 </div>
 ```
 
-### Translations
+This can be used to define variables scoped to a sub template:
 
-If properly setup, Owl QWeb engine can translate all rendered templates. To do
+```xml
-so, it needs a translate function, which takes a string and returns a string.
+<t t-call="other-template">
-
+    <t t-set="var" t-value="1"/>
-For example:
+</t>
-
+<!-- "var" does not exist here -->
-```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`:
+### 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`,
@@ -567,26 +586,8 @@ Once setup, all rendered templates will be translated using `translateFn`:
 - 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:
+See [here](qweb_engine.md#translations) for more information on how to setup a
-
+translate function in Owl QWeb.
-```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.
 
 ### Debugging
 
@@ -596,7 +597,7 @@ The javascript QWeb implementation provides two useful debugging directives:
 
 ```xml
 <t t-if="a_test">
-    <t t-debug="">
+    <t t-debug=""/>
 </t>
 ```
 

doc/reference/router.md

@@ -1,181 +0,0 @@
-# 🦉 Router 🦉
-
-## Content
-
-- [Overview](#overview)
-- [Example](#example)
-- [Reference](#reference)
-  - [Route Definition](#route-definition)
-  - [Router](#router)
-  - [Navigation Guards](#navigation-guards)
-  - [RouteComponent](#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 `<RouteComponent/>` component
-
-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;
-}
-
-owl.config.env = makeEnvironment();
-// create root component here
-```
-
-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`).
-
-`history` will use the browser [History API](https://developer.mozilla.org/en-US/docs/Web/API/History_API) as the mechanism to manage URL.\
-Example: `https://yourdomain.tld/my_custom_route`.\
-For this mechanism to work, you need a way to configure your web server accordingly.
-
-`hash` will manipulate the hash of the URL.\
-Example: `https://yourdomain.tld/index.html#/my_custom_route`.
-
-```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.
-
-### `RouteComponent`
-
-The `RouteComponent` component directs Owl to render the component associated
-to the currently active route (if any):
-
-```xml
-<div t-name="App">
-    <NavBar />
-    <RouteComponent />
-</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>
-```

doc/reference/slots.md

@@ -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}}" />
+```

doc/reference/store.md

@@ -1,326 +0,0 @@
-# 🦉 Store 🦉
-
-## Content
-
-- [Overview](#overview)
-- [Example](#example)
-- [Reference](#reference)
-  - [Store](#store)
-  - [Actions](#actions)
-  - [Getters](#getters)
-  - [Connecting a Component](#connecting-a-component)
-  - [`useStore`](#usestore)
-  - [`useDispatch`](#usedispatch)
-  - [`useGetters`](#usegetters)
-  - [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 parts 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 (or all) state, and lets 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", null, () => 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 (e) {
-      state.loginState = "error";
-    }
-  }
-};
-```
-
-The first argument to an action method is an object with four keys:
-
-- `state`: the current state of the store content,
-- `dispatch`: a function that can be used to dispatch other actions,
-- `getters`: an object containing all getters defined in the store,
-- `env`: the current environment. This is useful sometimes, in particular if
-  an action needs to apply some side effects (such as performing an rpc), and
-  the `rpc` method is located in the environment.
-
-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 partially 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 not cached.
-
-### Connecting a Component
-
-At some point, we need a way to interact with the store from a component. This
-can be done with the help of the three store hooks:
-
-- [`useStore`](#usestore) to subscribe a component to some part of the store state,
-- [`useDispatch`](#usedispatch) to get a reference to a dispatch function,
-- [`useGetters`](#usegetters) to get a reference to the getters defined in the store.
-
-Assume we have this store:
-
-```javascript
-const actions = {
-  increment({ state }, val) {
-    state.counter.value += val;
-  }
-};
-
-const state = {
-  counter: { value: 0 }
-};
-const store = new owl.Store({ state, actions });
-```
-
-A counter component can then select this value and dispatch an action like this:
-
-```js
-class Counter extends Component {
-  counter = useStore(state => state.counter);
-  dispatch = useDispatch();
-}
-
-const counter = new Counter({ store, qweb });
-```
-
-```xml
-<button t-name="Counter" t-on-click="dispatch('increment')">
-  Click Me! [<t t-esc="counter.value"/>]
-</button>
-```
-
-### `useStore`
-
-The `useStore` hook is used to select some part of the store state. It accepts
-two arguments:
-
-- a selector function, which takes the store state as first argument (and the
-  component props as second argument) and returns
-  an object or an array (which will be then observed),
-- optionally, an object with a `store` key (if we want to override the default
-  store) and an equality function (if we want to specialize the comparison).
-
-If the `useStore` callback selects a sub part of the store state, the component
-will only be rerendered whenever this part of the state changes. Otherwise, it
-will perform a strict equality check and will update the component every time this
-check fails.
-
-Also, it may not be obvious, but it is crucial to remember that the selector
-function should return an object or an array. The reason is that it needs to be
-observed, otherwise the component would not be able to react to changes.
-
-### `useDispatch`
-
-The `useDispatch` hook is useful when a component needs to be able to dispatch
-actions. It takes an optional argument, which is a store. If not given, it will
-use the store in the environment.
-
-Note that a component does not need to be connected in any other way to the store.
-For example:
-
-```js
-class DoSomethingButton extends Component {
-  static template = xml`<button t-on-click="dispatch('something')">Click</button>`;
-  dispatch = useDispatch();
-}
-```
-
-### `useGetters`
-
-The `useGetters` hook is useful when a component needs to be able to use the
-getters defined in a store. It takes an optional argument, which is a store. If
-not given, it will use the store in the environment.
-
-Note that a component does not need to be connected in any other way to the store.
-For example:
-
-```js
-class InfoButton extends Component {
-  static template = xml`<span><t t-esc="getters.somevalue()"></span>`;
-  getters = useGetters();
-}
-```
-
-### Semantics
-
-The `Store` class and the `useStore` hook 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 some other part 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 `useStore`
-  call and a `Message` component could get the data of its own
-  message,
-- since the `useStore` 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.

doc/reference/tags.md

@@ -4,16 +4,19 @@
 
 - [Overview](#overview)
 - [`xml` tag](#xml-tag)
+- [`css` tag](#css-tag)
 
 ## Overview
 
-Tags are very small helpers to make it easy to write inline templates. There is
+Tags are very small helpers intended to make it easy to write inline templates
-only one currently available tag: `xml`, but we plan to add other tags later,
+or styles. There are currently two tags: `css` and `xml`. With these functions,
-such as a `css` tag, which will be used to write [single file components](../tooling.md#single-file-component).
+it is possible to write [single file components](../learning/how_to_write_sfc.md).
 
 ## XML tag
 
-Without tags, creating a standalone component would look like this:
+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'
@@ -52,3 +55,130 @@ class MyComponent extends Component {
     ...
 }
 ```
+
+## 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;
+    }
+  `;
+}
+```

doc/reference/utils.md

@@ -19,20 +19,20 @@ 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]) {
+Promise.all([loadFile("templates.xml"), owl.utils.whenReady()]).then(function ([templates]) {
   const qweb = new owl.QWeb({ templates });
-  const app = new App({ qweb });
+  const env = { qweb };
-  app.mount(document.body);
+  await mount(App, { env, target: document.body });
 });
 ```
 
 or alternatively:
 
 ```js
-owl.utils.whenReady(function() {
+owl.utils.whenReady(function () {
   const qweb = new owl.QWeb();
-  const app = new App({ qweb });
+  const env = { qweb };
-  app.mount(document.body);
+  await mount(App, { env, target: document.body });
 });
 ```
 

doc/tooling.md

@@ -1,80 +0,0 @@
-# 🦉 Tooling 🦉
-
-## Content
-
-- [Overview](#overview)
-- [Playground](#playground)
-- [Benchmarks](#benchmarks)
-- [Single File Component](#single-file-component)
-
-## 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`).
-
-## 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.
-
-## Single File Component
-
-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 currently has a small helper that makes it easy to define a
-template inside a javascript (or typescript) file: the [`xml`](reference/tags.md#xml-tag)
-helper. With this, a template is automatically registered to [QWeb](reference/qweb.md).
-
-This means that the template and the javascript code can be defined in the same
-file. It is not currently possible to add css to the same file, but Owl may
-get a `css` tag helper later.
-
-```js
-const { Component } = owl;
-const { xml } = owl.tags;
-
-// -----------------------------------------------------------------------------
-// TEMPLATE
-// -----------------------------------------------------------------------------
-const TEMPLATE = xml/* xml */ `
-	<div class="main two-columns">
-		<Sidebar/>
-		<Content />
-	</div>`;
-
-// -----------------------------------------------------------------------------
-// CODE
-// -----------------------------------------------------------------------------
-class MyComponent extends Component {
-  static template = TEMPLATE;
-  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.

package.json

@@ -1,57 +1,73 @@
 {
-  "name": "owl-framework",
+  "name": "@odoo/owl",
-  "version": "1.0.0-alpha",
+  "version": "1.4.7",
   "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": ">=10.15.3"
+    "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",
     "test:watch": "jest --watch",
     "tools:serve": "python3 tools/server.py || python tools/server.py",
     "tools": "npm run build && npm run tools:serve",
     "pretools:watch": "npm run build",
     "tools:watch": "npm-run-all  --parallel tools:serve \"build:* -- --watch\"",
-    "prettier": "prettier {src/*.ts,src/**/*.ts,tests/*.ts,tests/**/*.ts,doc/*.md,doc/**/*.md} --write"
+    "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": "LGPL",
+  "license": "LGPL-3.0-only",
   "bugs": {
     "url": "https://github.com/odoo/owl/issues"
   },
   "homepage": "https://github.com/odoo/owl#readme",
-  "dependencies": {},
   "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-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": "^0.30.0",
     "sass": "^1.16.1",
     "source-map-support": "^0.5.10",
-    "ts-jest": "^23.10.5",
+    "ts-jest": "^27.0.5",
-    "typescript": "^3.6.4",
+    "typescript": "4.5.2",
     "uglify-es": "^3.3.9"
   },
   "jest": {
+    "testEnvironment": "jsdom",
     "roots": [
       "<rootDir>/src",
       "<rootDir>/tests"
     ],
+    "setupFiles": [
+      "./tests/mocks/mockEventTarget.js"
+    ],
     "transform": {
       "^.+\\.ts?$": "ts-jest"
     },
@@ -67,6 +83,7 @@
     ]
   },
   "prettier": {
-    "printWidth": 100
+    "printWidth": 100,
+    "endOfLine": "auto"
   }
 }

roadmap.md

@@ -1,47 +1,27 @@
 # 🦉 OWL Roadmap 🦉
 
-- Current version: 1.0.0-alpha
+- Current version: 1.4.7
-- Status: mostly stable
+- Status: stable
 
 This roadmap is only an attempt at predicting Owl's future.  Everything may
 change!
 
 
-### November 2019
-
-Owl will be used in various Odoo projects. We plan to:
-
-- fix any issues encountered
-- maybe cleanup slightly the router API
-- improve the documentation
-- improve error handling, add more helpful error messages
-
-### December 2019
-
-If all goes well, Owl will be upgraded to beta status. From then, no API change,
-even small, is expected.
-
-### End of 2019
-
-Release v1.0
-
-- API should be stable,
-- we will use semantic versioning,
-- we will maintain a changelog and an upgrade guide.
-
 ### 1.x
 
 - add chrome and firefox devtools,
-- add support for single file components,
 - fix every bugs,
 - improve documentation,
 - small backward compatible improvements.
 
-### 2.x (2021? 2022?)
+### 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,
+- 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.
 

rollup.config.js

@@ -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
+    }),
+  ]
 };

src/app/app.ts

@@ -0,0 +1,72 @@
+import { Component } from "../component/component";
+import { ComponentNode } from "../component/component_node";
+import { MountOptions } from "../component/fibers";
+import { Scheduler } from "../component/scheduler";
+import { TemplateSet } from "./template_set";
+
+// reimplement dev mode stuff see last change in 0f7a8289a6fb8387c3c1af41c6664b2a8448758f
+
+export interface Env {
+  [key: string]: any;
+}
+
+export interface AppConfig {
+  dev?: boolean;
+  env?: Env;
+  translatableAttributes?: string[];
+  translateFn?: (s: string) => string;
+}
+
+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 = Object.freeze({});
+  scheduler = new Scheduler(window.requestAnimationFrame.bind(window));
+  root: ComponentNode | null = null;
+
+  constructor(Root: T, props?: any) {
+    super();
+    this.Root = Root;
+    this.props = props;
+  }
+
+  configure(config: AppConfig): App<T> {
+    if (config.dev) {
+      this.dev = config.dev;
+      console.info(DEV_MSG);
+    }
+    if (config.env) {
+      this.env = Object.freeze(Object.assign({}, config.env));
+    }
+    if (config.translateFn) {
+      this.translateFn = config.translateFn;
+    }
+    if (config.translatableAttributes) {
+      this.translatableAttributes = config.translatableAttributes;
+    }
+    return this;
+  }
+
+  mount(target: HTMLElement, options?: MountOptions): Promise<InstanceType<T>> {
+    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");
+    }
+    const node = new ComponentNode(this.Root, this.props, this);
+    this.root = node;
+    return node.mountComponent(target, options);
+  }
+
+  destroy() {
+    if (this.root) {
+      this.root.destroy();
+    }
+  }
+}

src/app/template_helpers.ts

@@ -0,0 +1,135 @@
+import { BDom, multi, text, toggler } from "../blockdom";
+import { validateProps } from "../component/props_validation";
+import { Markup } from "../utils";
+import { html } from "../blockdom/index";
+
+/**
+ * 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 callSlot(
+  ctx: any,
+  parent: any,
+  key: string,
+  name: string,
+  defaultSlot?: (ctx: any, key: string) => BDom,
+  dynamic?: boolean
+): BDom {
+  const slots = ctx.__owl__.slots;
+  const slotFn = slots[name];
+  const slotBDom = slotFn ? slotFn(parent, key) : null;
+  if (defaultSlot) {
+    let child1: BDom | undefined = undefined;
+    let child2: BDom | undefined = undefined;
+    if (slotBDom) {
+      child1 = dynamic ? toggler(name, slotBDom) : slotBDom;
+    } else {
+      child2 = defaultSlot(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;
+}
+
+/*
+ * 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 (typeof value === "string") {
+    safeKey = "string_unsafe";
+    block = text(value);
+  } else {
+    // Assuming it is a block
+    safeKey = "block_safe";
+    block = value;
+  }
+  return toggler(safeKey, block);
+}
+
+export const UTILS = {
+  withDefault,
+  zero: Symbol("zero"),
+  isBoundary,
+  callSlot,
+  capture,
+  withKey,
+  prepareList,
+  setContextValue,
+  shallowEqual,
+  toNumber,
+  validateProps,
+  safeOutput,
+};

src/app/template_set.ts

@@ -0,0 +1,65 @@
+import { createBlock, html, list, multi, text, toggler } 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 };
+
+export const globalTemplates: { [key: string]: string | Node } = {};
+
+export class TemplateSet {
+  rawTemplates: typeof globalTemplates = Object.create(globalTemplates);
+  templates: { [name: string]: Template } = {};
+  translateFn?: (s: string) => string;
+  translatableAttributes?: string[];
+  utils: typeof UTILS;
+  dev?: boolean;
+
+  constructor() {
+    const call = (subTemplate: string, ctx: any, parent: any) => {
+      const template = this.getTemplate(subTemplate);
+      return toggler(subTemplate, template(ctx, parent));
+    };
+
+    const getTemplate = (name: string) => this.getTemplate(name);
+    this.utils = Object.assign({}, UTILS, { getTemplate, call });
+  }
+
+  addTemplate(name: string, template: string | Node, options: { allowDuplicate?: boolean } = {}) {
+    if (name in this.rawTemplates && !options.allowDuplicate) {
+      throw new Error(`Template ${name} already defined`);
+    }
+    this.rawTemplates[name] = template;
+  }
+
+  addTemplates(xml: string | Document, options: { allowDuplicate?: boolean } = {}) {
+    xml = xml instanceof Document ? xml : new DOMParser().parseFromString(xml, "text/xml");
+    for (const template of xml.querySelectorAll("[t-name]")) {
+      const name = template.getAttribute("t-name")!;
+      template.removeAttribute("t-name");
+      this.addTemplate(name, template, options);
+    }
+  }
+
+  getTemplate(name: string): Template {
+    if (!(name in this.templates)) {
+      const rawTemplate = this.rawTemplates[name];
+      if (rawTemplate === undefined) {
+        throw new Error(`Missing template: "${name}"`);
+      }
+      const templateFn = compile(rawTemplate, {
+        name,
+        dev: this.dev,
+        translateFn: this.translateFn,
+        translatableAttributes: this.translatableAttributes,
+      });
+
+      // 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];
+  }
+}

src/blockdom/attributes.ts

@@ -0,0 +1,155 @@
+import type { Setter } from "./block_compiler";
+
+const { setAttribute, 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.
+ */
+
+export function createAttrUpdater(attr: string): Setter<HTMLElement> {
+  return function (this: HTMLElement, value: any) {
+    if (value !== false) {
+      setAttribute.call(this, attr, value === true ? "" : 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;
+}

src/blockdom/block_compiler.ts

@@ -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): 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);
+  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[];
+  forceRef?: 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 isActive = false;
+      let currentNS = parent && parent.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("");
+        isActive = true;
+      }
+      if (tagName.startsWith("block-child-")) {
+        domParentTree!.forceRef = true;
+        const index = parseInt(tagName.slice(12), 10);
+        info.push({ type: "child", idx: index });
+        el = document.createTextNode("");
+        isActive = true;
+      }
+      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-")) {
+            isActive = true;
+            const idx = parseInt(attrName.slice(14), 10);
+            info.push({
+              type: "handler",
+              idx,
+              event: attrValue,
+            });
+          } else if (attrName.startsWith("block-attribute-")) {
+            isActive = true;
+            const idx = parseInt(attrName.slice(16), 10);
+            info.push({
+              type: "attribute",
+              idx,
+              name: attrValue,
+              tag: tagName,
+            });
+          } else if (attrName === "block-attributes") {
+            isActive = true;
+            info.push({
+              type: "attributes",
+              idx: parseInt(attrValue, 10),
+            });
+          } else if (attrName === "block-ref") {
+            isActive = true;
+            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: isActive ? 1 : 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 });
+          isActive = true;
+          tree.refN = 1;
+        } 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 (isActive) {
+        let cur: IntermediateTree | null = tree;
+        while ((cur = cur.parent)) {
+          cur.refN++;
+        }
+      }
+      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 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,
+  toIdx?: 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;
+    toIdx = tree.refN - 1;
+  }
+  if (tree.refN) {
+    const initialIdx = fromIdx!;
+    const isRef = tree.forceRef || tree.info.length > 0;
+    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, toIdx);
+    }
+
+    // left
+    if (firstChild) {
+      ctx.collectors.push({ idx: fromIdx!, prevIdx: initialIdx, getVal: nodeGetFirstChild });
+      buildContext(tree.firstChild!, ctx, fromIdx!, toIdx! - nextSibling);
+    }
+  }
+
+  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): 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;
+    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() {
+      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);
+}

src/blockdom/config.ts

@@ -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;
+  },
+};

src/blockdom/events.ts

@@ -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;
+}

src/blockdom/html.ts

@@ -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);
+}

src/blockdom/index.ts

@@ -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 } 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;
+}

src/blockdom/list.ts

@@ -0,0 +1,240 @@
+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;
+
+  constructor(children: VNode[]) {
+    this.children = children;
+  }
+
+  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) {
+      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;
+    // let noFullRemove = this.hasNoComponent;
+
+    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) {
+      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[]): VNode<VList> {
+  return new VList(children);
+}
+
+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;
+}

src/blockdom/multi.ts

@@ -0,0 +1,134 @@
+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;
+
+  constructor(children: (VNode | undefined)[]) {
+    this.children = children;
+  }
+
+  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) {
+      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)[]): VNode<VMulti> {
+  return new VMulti(children);
+}

src/blockdom/text.ts

@@ -0,0 +1,70 @@
+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;
+
+class VText {
+  text: string;
+  parentEl?: HTMLElement | undefined;
+  el?: Text;
+
+  constructor(text: string) {
+    this.text = text;
+  }
+
+  mount(parent: HTMLElement, afterNode: Node | null) {
+    this.parentEl = parent;
+    const node = document.createTextNode(toText(this.text));
+    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);
+  }
+
+  patch(other: VText) {
+    const text2 = other.text;
+    if (this.text !== text2) {
+      characterDataSetData.call(this.el!, toText(text2));
+      this.text = text2;
+    }
+  }
+
+  beforeRemove() {}
+
+  remove() {
+    nodeRemoveChild.call(this.parentEl, this.el!);
+  }
+
+  firstNode(): Node {
+    return this.el!;
+  }
+
+  toString() {
+    return this.text;
+  }
+}
+
+export function text(str: string): VNode<VText> {
+  return new VText(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 || "";
+  }
+}

src/blockdom/toggler.ts

@@ -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);
+}

src/compiler/index.ts

@@ -0,0 +1,30 @@
+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;
+}
+let nextId = 1;
+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");
+  const name = options.name || `template_${nextId++}`;
+
+  // code generation
+  const codeGenerator = new CodeGenerator(name, ast, { ...options, hasSafeContext });
+  const code = codeGenerator.generateCode();
+
+  // template function
+  return new Function("bdom, helpers", code) as TemplateFunction;
+}

src/compiler/inline_expressions.ts

@@ -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];
-    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];
+    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)) {
       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));
+    }
+    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 {
-          token.value = `context['${token.value}']`;
+        localVars.add(token.value); //] = { id: token.value, expr: token.value };
       }
     }
+
+    if (isVar) {
+      token.varName = token.value;
+      if (!localVars.has(token.value)) {
+        token.originalValue = token.value;
+        token.value = `ctx['${token.value}']`;
       }
-    result += token.value;
     }
-  return result;
+    i++;
+  }
+  // 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 + "`";
 }

src/compiler/parser.ts

@@ -0,0 +1,888 @@
+// -----------------------------------------------------------------------------
+// AST Type definition
+// -----------------------------------------------------------------------------
+
+export const enum ASTType {
+  Text,
+  Comment,
+  DomNode,
+  Multi,
+  TEsc,
+  TIf,
+  TSet,
+  TCall,
+  TOut,
+  TForEach,
+  TKey,
+  TComponent,
+  TDebug,
+  TLog,
+  TSlot,
+  TCallBlock,
+  TTranslation,
+}
+
+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[];
+}
+
+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;
+}
+
+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;
+  isOnlyChild: boolean;
+  hasNoComponent: 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]: AST };
+}
+
+export interface ASTSlot {
+  type: ASTType.TSlot;
+  name: 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 type AST =
+  | ASTText
+  | ASTComment
+  | ASTDomNode
+  | ASTMulti
+  | ASTTEsc
+  | ASTTif
+  | ASTTSet
+  | ASTTCall
+  | ASTTOut
+  | ASTTForEach
+  | ASTTKey
+  | ASTComponent
+  | ASTSlot
+  | ASTTCallBlock
+  | ASTLog
+  | ASTDebug
+  | ASTTranslation;
+
+// -----------------------------------------------------------------------------
+// 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!;
+  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) ||
+    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;
+  }
+  const children: AST[] = [];
+  for (let child of node.childNodes) {
+    const ast = parseNode(child, ctx);
+    if (ast) {
+      children.push(ast);
+    }
+  }
+  switch (children.length) {
+    case 0:
+      return null;
+    case 1:
+      return children[0];
+    default:
+      return {
+        type: ASTType.Multi,
+        content: children,
+      };
+  }
+}
+
+// -----------------------------------------------------------------------------
+// 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*$/;
+
+function parseDOMNode(node: Element, ctx: ParsingContext): AST | null {
+  const { tagName } = node;
+  const dynamicTag = node.getAttribute("t-tag");
+  node.removeAttribute("t-tag");
+  if (tagName === "t" && !dynamicTag) {
+    return null;
+  }
+  const children: AST[] = [];
+  if (tagName === "pre") {
+    ctx.inPreTag = true;
+  }
+  const shouldAddSVGNS = tagName === "svg" || (tagName === "g" && !ctx.inSVG);
+  ctx.inSVG = ctx.inSVG || shouldAddSVGNS;
+  const ns = shouldAddSVGNS ? "http://www.w3.org/2000/svg" : null;
+  const ref = node.getAttribute("t-ref");
+  node.removeAttribute("t-ref");
+
+  for (let child of node.childNodes) {
+    const ast = parseNode(child, ctx);
+    if (ast) {
+      children.push(ast);
+    }
+  }
+
+  const nodeAttrsNames = node.getAttributeNames();
+  const attrs: ASTDomNode["attrs"] = {};
+  const on: ASTDomNode["on"] = {};
+  let model: ASTDomNode["model"] = null;
+
+  for (let attr of nodeAttrsNames) {
+    const value = node.getAttribute(attr)!;
+    if (attr.startsWith("t-on")) {
+      if (attr === "t-on") {
+        throw new Error("Missing event name with t-on directive");
+      }
+      on[attr.slice(5)] = value;
+    } else if (attr.startsWith("t-model")) {
+      if (!["input", "select", "textarea"].includes(tagName)) {
+        throw new Error("The t-model directive only works with <input>, <textarea> and <select>");
+      }
+
+      let baseExpr, expr;
+      if (hasDotAtTheEnd.test(value)) {
+        const index = value.lastIndexOf(".");
+        baseExpr = value.slice(0, index);
+        expr = `'${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;
+    }
+  }
+  if (children.length === 1 && children[0].type === ASTType.TForEach) {
+    children[0].isOnlyChild = true;
+  }
+  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,
+    key,
+    isOnlyChild: false,
+    hasNoComponent: hasNoComponent(body),
+    hasNoFirst,
+    hasNoLast,
+    hasNoIndex,
+    hasNoValue,
+  };
+}
+
+/**
+ * @returns true if we are sure the ast does not contain any component
+ */
+function hasNoComponent(ast: AST): boolean {
+  switch (ast.type) {
+    case ASTType.TComponent:
+    case ASTType.TOut:
+    case ASTType.TCall:
+    case ASTType.TCallBlock:
+    case ASTType.TSlot:
+      return false;
+    case ASTType.TSet:
+    case ASTType.Text:
+    case ASTType.Comment:
+    case ASTType.TEsc:
+      return true;
+    case ASTType.TKey:
+      return hasNoComponent(ast.content);
+    case ASTType.TDebug:
+    case ASTType.TLog:
+    case ASTType.TTranslation:
+      return ast.content ? hasNoComponent(ast.content) : true;
+    case ASTType.TForEach:
+      return ast.hasNoComponent;
+    case ASTType.Multi:
+    case ASTType.DomNode: {
+      for (let elem of ast.content) {
+        if (!hasNoComponent(elem)) {
+          return false;
+        }
+      }
+      return true;
+    }
+    case ASTType.TIf: {
+      if (!hasNoComponent(ast.content)) {
+        return false;
+      }
+      if (ast.tElif) {
+        for (let elem of ast.tElif) {
+          if (!hasNoComponent(elem.content)) {
+            return false;
+          }
+        }
+      }
+      if (ast.tElse && !hasNoComponent(ast.tElse)) {
+        return false;
+      }
+      return true;
+    }
+  }
+}
+
+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: tcall },
+      };
+    }
+  }
+  const body: AST[] = [];
+  for (let child of node.childNodes) {
+    const ast = parseNode(child, ctx);
+    if (ast) {
+      body.push(ast);
+    }
+  }
+
+  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);
+  if (!content) {
+    throw new Error("hmmm");
+  }
+
+  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();
+  }
+
+  return {
+    type: ASTType.TIf,
+    condition,
+    content,
+    tElif: tElifs.length ? tElifs : null,
+    tElse,
+  };
+}
+
+// -----------------------------------------------------------------------------
+// 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 = [];
+    for (let child of node.childNodes) {
+      let childAst = parseNode(child, ctx);
+      if (childAst) {
+        body.push(childAst);
+      }
+    }
+  }
+  return { type: ASTType.TSet, name, value, defaultValue, body };
+}
+
+// -----------------------------------------------------------------------------
+// Components
+// -----------------------------------------------------------------------------
+
+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-on-")) {
+      throw new Error(
+        "t-on is no longer supported on Component node. Consider passing a callback in props."
+      );
+    } 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) {
+      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) {
+        slots[name] = slotAst;
+      }
+    }
+
+    // default slot
+    const defaultContent = parseChildNodes(clone, ctx);
+    if (defaultContent) {
+      slots.default = 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;
+  }
+  return {
+    type: ASTType.TSlot,
+    name: node.getAttribute("t-slot")!,
+    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),
+  };
+}
+
+// -----------------------------------------------------------------------------
+// helpers
+// -----------------------------------------------------------------------------
+
+function parseChildNodes(node: Element, ctx: ParsingContext): AST | null {
+  const children: AST[] = [];
+  for (let child of node.childNodes) {
+    const childAst = parseNode(child, ctx);
+    if (childAst) {
+      children.push(childAst);
+    }
+  }
+  switch (children.length) {
+    case 0:
+      return null;
+    case 1:
+      return children[0];
+    default:
+      return { type: ASTType.Multi, content: children };
+  }
+}
+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);
+  }
+  let tbranch = doc.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"
+      );
+    }
+  }
+
+  return doc;
+}

src/component/component.ts

@@ -1,655 +1,34 @@
-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 { config } from "../config";
-import "./directive";
-import { Fiber } from "./fiber";
-import "./props_validation";
-import { scheduler } from "./scheduler";
 
-/**
+export type Props = { [key: string]: any };
- * Owl Component System
- *
- * This file introduces a declarative and composable component system. It
- * contains:
- *
- * - the Env interface (generic type for the environment)
- * - the Internal interface (the owl specific metadata attached to a component)
- * - the Component class
- */
 
-//------------------------------------------------------------------------------
+// -----------------------------------------------------------------------------
-// Types/helpers
+//  Component Class
-//------------------------------------------------------------------------------
+// -----------------------------------------------------------------------------
 
-/**
+export class Component {
- * An Env (environment) is an object that will be (mostly) shared between all
+  static template: string = "";
- * components of an Owl application.  It is the location which should contain
+  static style: string = "";
- * 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;
-  depth: number;
-  vnode: VNode | null;
-  pvnode: VNode | null;
-  isMounted: boolean;
-  isDestroyed: boolean;
-
-  // parent and children keys are obviously useful to setup the parent-children
-  // relationship.
-  parent: Component<T, any> | null;
-  children: { [key: number]: Component<T, 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 };
-
-  currentFiber: Fiber | null;
-
-  boundHandlers: { [key: number]: any };
-  observer: Observer | null;
-  renderFn: CompiledTemplate;
-  mountedCB: Function | null;
-  willUnmountCB: Function | null;
-  willPatchCB: Function | null;
-  patchedCB: Function | null;
-  willStartCB: Function | null;
-  willUpdatePropsCB: Function | null;
-  classObj: { [key: string]: boolean } | null;
-  refs: { [key: string]: Component<T, any> | HTMLElement | undefined } | null;
-}
-
-//------------------------------------------------------------------------------
-// Component
-//------------------------------------------------------------------------------
-let nextId = 1;
-
-export class Component<T extends Env, Props extends {}> {
-  readonly __owl__: Internal<Env, Props>;
-  static template?: string | null = null;
-  static _template?: string | null = null;
-  static current: Component<any, any> | null = null;
-  static components = {};
   static props?: any;
-  static defaultProps?: any;
 
-  /**
+  props: any;
-   * The `el` is the root element of the component.  Note that it could be null:
+  env: Env;
-   * this is the case if the component is not mounted yet, or is destroyed.
+  __owl__: ComponentNode;
-   */
+
-  get el(): HTMLElement | null {
+  constructor(props: any, env: Env, node: ComponentNode) {
-    return this.__owl__.vnode ? (<any>this).__owl__.vnode.elm : null;
+    this.props = props;
+    this.env = env;
+    this.__owl__ = node;
+  }
+  get el(): HTMLElement | Text | undefined {
+    const node = this.__owl__;
+    return node.bdom ? (node.bdom.firstNode() as any) : undefined;
   }
 
-  env: T;
+  setup() {}
-  props: Props;
 
-  //--------------------------------------------------------------------------
+  render(deep: boolean = false): Promise<void> {
-  // Lifecycle
+    return this.__owl__.render(deep);
-  //--------------------------------------------------------------------------
-
-  /**
-   * Creates an instance of Component.
-   *
-   * 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>, props?: Props) {
-    Component.current = this;
-
-    const id: number = nextId++;
-    let depth;
-    if (parent) {
-      const defaultProps = (<any>this.constructor).defaultProps;
-      if (defaultProps) {
-        props = this.__applyDefaultProps(props, defaultProps);
-      }
-      this.props = <Props>props;
-      if (QWeb.dev) {
-        QWeb.utils.validateProps(this.constructor, this.props);
-      }
-      this.env = parent.env;
-      const __powl__ = parent.__owl__;
-      __powl__.children[id] = this;
-      depth = __powl__.depth + 1;
-    } else {
-      // we are the root component
-      this.env = config.env as T;
-      this.props = undefined as unknown as 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);
-        }
-      });
-      depth = 0;
-    }
-
-    const qweb = this.env.qweb;
-
-    this.__owl__ = {
-      id: id,
-      depth: depth,
-      vnode: null,
-      pvnode: null,
-      isMounted: false,
-      isDestroyed: false,
-      parent: parent || null,
-      children: {},
-      cmap: {},
-      currentFiber: null,
-      boundHandlers: {},
-      mountedCB: null,
-      willUnmountCB: null,
-      willPatchCB: null,
-      patchedCB: null,
-      willStartCB: null,
-      willUpdatePropsCB: null,
-      observer: null,
-      renderFn: qweb.render.bind(qweb, this.__getTemplate(qweb)),
-      classObj: null,
-      refs: null
-    };
-  }
-
-  /**
-   * 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() {}
-
-  /**
-   * mounted is a hook that is called each time a component is attached to the
-   * 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
-   */
-  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.
-   */
-  patched() {}
-
-  /**
-   * 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.
-   *
-   * It needs to be implemented by a component that is designed to handle the
-   * error properly.
-   */
-  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 Promise.resolve();
-    }
-    if (__owl__.vnode && !renderBeforeRemount) {
-      target.appendChild(this.el!);
-      if (document.body.contains(target)) {
-        this.__callMounted();
-      }
-      return;
-    }
-    return new Promise((resolve, reject) => {
-      const fiber = new Fiber(null, this, undefined, undefined, false);
-      scheduler.addFiber(fiber, err => {
-        if (err) {
-          reject(err);
-          return;
-        }
-        if (!__owl__.isDestroyed) {
-          this.__patch(fiber.vnode);
-          target.appendChild(this.el!);
-          if (document.body.contains(target)) {
-            this.__callMounted();
-          }
-        }
-        resolve();
-      });
-      if (!__owl__.vnode) {
-        this.__prepareAndRender(fiber);
-      } else {
-        this.__render(fiber);
-      }
-    });
-  }
-
-  /**
-   * 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 && !__owl__.currentFiber) ||
-      (__owl__.currentFiber && !__owl__.currentFiber.isRendered)
-    ) {
-      return;
-    }
-    return new Promise((resolve, reject) => {
-      const fiber = new Fiber(null, this, undefined, undefined, force);
-      scheduler.addFiber(fiber.root, err => {
-        if (err) {
-          reject(err);
-          return;
-        }
-        if (__owl__.isMounted && fiber === fiber.root) {
-          fiber.patchComponents();
-        }
-        resolve();
-      });
-      this.__render(fiber);
-    });
-  }
-
-  /**
-   * 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;
-  }
-
-  /**
-   * 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> | null) {
-    const __owl__ = this.__owl__;
-    const isMounted = __owl__.isMounted;
-    if (isMounted) {
-      if (__owl__.willUnmountCB) {
-        __owl__.willUnmountCB();
-      }
-      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;
-    try {
-      this.mounted();
-      if (__owl__.mountedCB) {
-        __owl__.mountedCB();
-      }
-    } catch (e) {
-      console.error(e); // TODO : add a test
-    }
-  }
-
-  __callWillUnmount() {
-    const __owl__ = this.__owl__;
-    if (__owl__.willUnmountCB) {
-      __owl__.willUnmountCB();
-    }
-    this.willUnmount();
-    __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,
-    parentFiber: Fiber,
-    scope: any,
-    vars: any,
-    previousSibling?: Fiber | null
-  ): Promise<void> {
-    const shouldUpdate = parentFiber.force || this.shouldUpdate(nextProps);
-    if (shouldUpdate) {
-      const __owl__ = this.__owl__;
-      const fiber = new Fiber(parentFiber, this, scope, vars, parentFiber.force);
-      if (!parentFiber.child) {
-        parentFiber.child = fiber;
-      } else {
-        previousSibling!.sibling = fiber;
-      }
-
-      const defaultProps = (<any>this.constructor).defaultProps;
-      if (defaultProps) {
-        nextProps = this.__applyDefaultProps(nextProps, defaultProps);
-      }
-      if (QWeb.dev) {
-        QWeb.utils.validateProps(this.constructor, nextProps);
-      }
-      await Promise.all([
-        this.willUpdateProps(nextProps),
-        __owl__.willUpdatePropsCB && __owl__.willUpdatePropsCB(nextProps)
-      ]);
-      if (fiber.isCancelled) {
-        return;
-      }
-      this.props = nextProps;
-
-      this.__render(fiber);
-    }
-  }
-
-  /**
-   * 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);
-    __owl__.currentFiber = null;
-  }
-
-  /**
-   * The __prepare method is only called by the t-component directive, when a
-   * subcomponent is created. It gets its scope and vars, if any, from the
-   * parent template.
-   */
-  __prepare(parentFiber: Fiber, scope: any, vars: any, previousSibling?: Fiber | null) {
-    const fiber = new Fiber(parentFiber, this, scope, vars, parentFiber.force);
-    fiber.shouldPatch = false;
-    if (!parentFiber.child) {
-      parentFiber.child = fiber;
-    } else {
-      previousSibling!.sibling = fiber;
-    }
-    return this.__prepareAndRender(fiber);
-  }
-
-  __getTemplate(qweb: QWeb): string {
-    let p = (<any>this).constructor;
-    if (!p.hasOwnProperty("_template")) {
-      if (p.template) {
-        p._template = p.template;
-      } else {
-        // here, the component and none of its superclasses defines a static `template`
-        // key. So we fall back on looking for a template matching its name (or
-        // one of its subclass).
-
-        let template: string;
-        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 {
-          p._template = template;
-        }
-      }
-    }
-    return p._template;
-  }
-  async __prepareAndRender(fiber: Fiber) {
-    try {
-      await Promise.all([this.willStart(), this.__owl__.willStartCB && this.__owl__.willStartCB()]);
-    } catch (e) {
-      fiber.handleError(e);
-      fiber.vnode = h("div"); // -> we render this div at the end
-      return Promise.resolve();
-    }
-    if (this.__owl__.isDestroyed) {
-      return Promise.resolve();
-    }
-    if (!fiber.isCancelled) {
-      this.__render(fiber);
-    }
-  }
-
-  __render(fiber: Fiber) {
-    const __owl__ = this.__owl__;
-    if (__owl__.observer) {
-      __owl__.observer.allowMutations = false;
-    }
-    let vnode;
-    try {
-      vnode = __owl__.renderFn!(this, {
-        handlers: __owl__.boundHandlers,
-        fiber: fiber
-      });
-    } catch (e) {
-      vnode = __owl__.vnode || h("div");
-      fiber.handleError(e);
-    }
-    fiber.vnode = vnode;
-    if (__owl__.observer) {
-      __owl__.observer.allowMutations = true;
-    }
-
-    // we apply 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);
-    }
-    fiber.root.counter--;
-    fiber.isRendered = true;
-  }
-
-  /**
-   * Only called by qweb t-component directive
-   */
-  __mount(fiber: Fiber, elm: HTMLElement): VNode {
-    if (fiber !== this.__owl__.currentFiber) {
-      fiber = this.__owl__.currentFiber!; // TODO: check if we can remove fiber arg
-    }
-    const vnode = fiber.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);
-    __owl__.currentFiber = null;
-    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();
-    }
-  }
-
-  /**
-   * 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;
   }
 }

src/component/component_node.ts

@@ -0,0 +1,329 @@
+import type { App, Env } from "../app/app";
+import { BDom, VNode } from "../blockdom";
+import { clearReactivesForCallback, Reactive, reactive } from "../reactivity";
+import { batched, Callback } from "../utils";
+import { Component, Props } from "./component";
+import { fibersInError, handleError } from "./error_handling";
+import {
+  Fiber,
+  makeChildFiber,
+  makeRootFiber,
+  MountFiber,
+  MountOptions,
+  RootFiber,
+  __internal__destroyed
+} from "./fibers";
+import { applyDefaultProps } from "./props_validation";
+import { STATUS } from "./status";
+import { applyStyles } from "./style";
+
+let currentNode: ComponentNode | null = null;
+
+export function getCurrent(): ComponentNode | null {
+  return currentNode;
+}
+
+// -----------------------------------------------------------------------------
+// Integration with reactivity system (useState)
+// -----------------------------------------------------------------------------
+
+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> {
+  if (!batchedRenderFunctions.has(currentNode!)) {
+    batchedRenderFunctions.set(
+      currentNode!,
+      batched(() => currentNode!.render())
+    );
+  }
+  const render = batchedRenderFunctions.get(currentNode!)!;
+  const reactiveState = reactive(state, render);
+
+  // manual implementation of onWillUnmount to break cyclic dependency
+  currentNode!.willUnmount.unshift( clearReactivesForCallback.bind(null, render))
+  return reactiveState;
+}
+
+// -----------------------------------------------------------------------------
+// component function (used in compiled template code)
+// -----------------------------------------------------------------------------
+function arePropsDifferent(props1: Props, props2: Props): boolean {
+  for (let k in props1) {
+    if (props1[k] !== props2[k]) {
+      return true;
+    }
+  }
+  return false;
+}
+export function component(
+  name: string | typeof Component,
+  props: any,
+  key: string,
+  ctx: ComponentNode,
+  parent: any,
+  hasSlots: boolean = false
+): ComponentNode {
+  console.warn('asdf')
+  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) {
+    console.warn('coucou');
+    if (hasSlots || parentFiber.deep || arePropsDifferent(node.component.props, props)) {
+      console.warn('coucou3');
+      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 class
+// -----------------------------------------------------------------------------
+
+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);
+  slots: any = {};
+  refs: any = {};
+
+  willStart: LifecycleHook[] = [];
+  willUpdateProps: LifecycleHook[] = [];
+  willUnmount: LifecycleHook[] = [];
+  mounted: LifecycleHook[] = [];
+  willPatch: LifecycleHook[] = [];
+  patched: LifecycleHook[] = [];
+  destroyed: 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;
+    // if (props) {
+    //   props = useState(props);
+    // }
+    this.component = new C(props, env, this) as any;
+    this.renderFn = app.getTemplate(C.template).bind(this.component, this.component, this);
+    if (C.style) {
+      applyStyles(C);
+    }
+    this.component.setup();
+  }
+
+  mountComponent(target: any, options?: MountOptions): Promise<InstanceType<T>> {
+    const fiber = new MountFiber(this, target, options);
+    this.app.scheduler.addFiber(fiber);
+    this.initiateRender(fiber);
+    return fiber.promise.then(() => this.component);
+  }
+
+  async initiateRender(fiber: Fiber | MountFiber) {
+    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(deep: boolean = false) {
+    let fiber = this.fiber;
+    if (fiber && !fiber.bdom && !fibersInError.has(fiber)) {
+      return fiber.root.promise;
+    }
+    if (!this.bdom && !fiber) {
+      // should find a way to return the future mounting promise
+      return;
+    }
+    fiber = makeRootFiber(this);
+    fiber.deep = deep;
+    this.app.scheduler.addFiber(fiber);
+    await Promise.resolve();
+    if (this.status === STATUS.DESTROYED) {
+      return;
+    }
+    if (this.fiber === fiber) {
+      this._render(fiber);
+    }
+    return fiber.root.promise;
+  }
+
+  _render(fiber: Fiber | RootFiber) {
+    try {
+      fiber.bdom = this.renderFn();
+      fiber.root.counter--;
+    } catch (e) {
+      handleError({ node: this, error: e });
+    }
+  }
+
+  destroy() {
+    if (this.status === STATUS.MOUNTED) {
+      callWillUnmount(this);
+      this.bdom!.remove();
+    }
+    callDestroyed(this);
+
+    function callWillUnmount(node: ComponentNode) {
+      const component = node.component;
+      for (let cb of node.willUnmount) {
+        cb.call(component);
+      }
+      for (let child of Object.values(node.children)) {
+        if (child.status === STATUS.MOUNTED) {
+          callWillUnmount(child);
+        }
+      }
+    }
+
+    function callDestroyed(node: ComponentNode) {
+      const component = node.component;
+      node.status = STATUS.DESTROYED;
+      for (let child of Object.values(node.children)) {
+        callDestroyed(child);
+      }
+      for (let cb of node.destroyed) {
+        cb.call(component);
+      }
+    }
+  }
+
+  async updateAndRender(props: any, parentFiber: Fiber) {
+    // update
+    const fiber = makeChildFiber(this, parentFiber);
+    if (this.willPatch.length) {
+      parentFiber.root.willPatch.push(fiber);
+    }
+    if (this.patched.length) {
+      parentFiber.root.patched.push(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;
+    }
+    this.component.props = props;
+    this._render(fiber);
+  }
+
+  // ---------------------------------------------------------------------------
+  // 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() {
+    if (!this.fiber) {
+      // component was not rendered => no need to do anything
+      return;
+    }
+    this.bdom!.patch(this!.fiber!.bdom!, false);
+    this.fiber!.appliedToDom = true;
+    this.fiber = null;
+  }
+
+  beforeRemove() {
+    visitRemovedNodes(this);
+  }
+
+  remove() {
+    this.bdom!.remove();
+  }
+}
+
+function visitRemovedNodes(node: ComponentNode) {
+  if (node.status === STATUS.MOUNTED) {
+    const component = node.component;
+    for (let cb of node.willUnmount) {
+      cb.call(component);
+    }
+  }
+  for (let child of Object.values(node.children)) {
+    visitRemovedNodes(child);
+  }
+  node.status = STATUS.DESTROYED;
+  if (node.destroyed.length) {
+    __internal__destroyed.push(node);
+  }
+}

src/component/directive.ts

@@ -1,478 +0,0 @@
-import { QWeb } from "../qweb/index";
-import { INTERP_REGEXP } from "../qweb/compilation_context";
-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"],
-  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 hasDynamicProps = node.getAttribute("t-props") ? 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 handlerValue = value.replace(/\(.*\)/, function(args) {
-          extraArgs = args.slice(1, -1);
-          return "";
-        });
-        events.push([eventName, mods, handlerValue, 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);
-        }
-      }
-    }
-
-    // computing the props string representing the props object
-    let propStr = Object.keys(props)
-      .map(k => k + ":" + props[k])
-      .join(",");
-    let defID = ctx.generateID();
-    let componentID = ctx.generateID();
-
-    let locationExpr = `\`__${ctx.generateID()}__`;
-    for (let i = 0; i < ctx.loopNumber - 1; i++) {
-      locationExpr += `\${i${i + 1}}__`;
-    }
-    if (ctx.lastNodeKey || ctx.currentKey) {
-      const k = ctx.lastNodeKey || ctx.currentKey;
-      ctx.addLine(`let templateId${componentID} = ${locationExpr}\` + ${k};`);
-    } else {
-      locationExpr += ctx.loopNumber ? `\${i${ctx.loopNumber}}__\`` : "`";
-      ctx.addLine(`let templateId${componentID} = ${locationExpr};`);
-    }
-    const templateId = `templateId${componentID}`;
-
-    let ref = node.getAttribute("t-ref");
-    let refExpr = "";
-    let refKey: string = "";
-    if (ref) {
-      ctx.rootContext.shouldDefineRefs = true;
-      refKey = `ref${ctx.generateID()}`;
-      ctx.addLine(`const ${refKey} = ${ctx.interpolate(ref)};`);
-      refExpr = `context.__owl__.refs[${refKey}] = w${componentID};`;
-    }
-    let transitionsInsertCode = "";
-    if (transition) {
-      transitionsInsertCode = `utils.transitionInsert(vn, '${transition}');`;
-    }
-    let finalizeComponentCode = `w${componentID}.destroy();`;
-    if (ref) {
-      finalizeComponentCode += `delete context.__owl__.refs[${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} = ${tattExpr};`);
-        }
-      }
-      let eventsCode = events
-        .map(function([eventName, mods, handlerValue, extraArgs]) {
-          let params = "owner";
-          if (extraArgs) {
-            if (ctx.loopNumber) {
-              let argId = ctx.generateID();
-              // we need to evaluate the arguments now, because the handler will
-              // be set asynchronously later when the widget is ready, and the
-              // context might be different.
-              ctx.addLine(`let arg${argId} = ${ctx.formatExpression(extraArgs)};`);
-              params = `owner, arg${argId}`;
-            } else {
-              params = `owner, ${ctx.formatExpression(extraArgs)}`;
-            }
-          }
-          let handler = `function (e) {`;
-          handler += mods
-            .map(function(mod) {
-              return T_COMPONENT_MODS_CODE[mod];
-            })
-            .join("");
-          if (handlerValue) {
-            handler += `const fn = owner['${handlerValue}'];`;
-            handler += `if (fn) { fn.call(${params}, e); } else { owner.${handlerValue}; }`;
-          }
-          handler += `}`;
-          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;`
-    );
-    let shouldProxy = !ctx.parentNode;
-    if (shouldProxy) {
-      let id = ctx.generateID();
-      ctx.rootContext.rootNode = id;
-      shouldProxy = true;
-      ctx.rootContext.shouldDefineResult = true;
-      ctx.addLine(`let vn${id} = {};`);
-      ctx.addLine(`result = vn${id};`);
-    }
-    if (hasDynamicProps) {
-      const dynamicProp = ctx.formatExpression(node.getAttribute("t-props")!);
-      ctx.addLine(`let props${componentID} = Object.assign({${propStr}}, ${dynamicProp});`);
-    } else {
-      ctx.addLine(`let props${componentID} = {${propStr}};`);
-    }
-    ctx.addIf(
-      `w${componentID} && w${componentID}.__owl__.currentFiber && !w${componentID}.__owl__.vnode`
-    );
-    ctx.addLine(`w${componentID}.destroy();`);
-    ctx.addLine(`w${componentID} = false;`);
-    ctx.closeIf();
-
-    let registerCode = "";
-    if (shouldProxy) {
-      registerCode = `utils.defineProxy(vn${ctx.rootNode}, pvnode);`;
-    }
-
-    // SLOTS
-    const varDefs: string[] = [];
-    const hasSlots = node.childNodes.length;
-    if (hasSlots) {
-      ctx.rootContext.shouldTrackScope = true;
-      for (let v of Object.values(ctx.variables)) {
-        if (v["id"]) {
-          varDefs.push(v["id"]);
-        }
-      }
-    }
-
-    let scopeVars;
-    if (hasSlots) {
-      let scope = ctx.scopeVars.length ? `Object.assign({}, scope)` : `{}`;
-      let vars = varDefs.length ? `{${varDefs.join(",")}}` : "undefined";
-      scopeVars = `${scope}, ${vars}`;
-    } else {
-      scopeVars = "undefined, undefined";
-    }
-
-    ctx.addIf(`w${componentID}`);
-
-    // need to update component
-    let styleCode = "";
-    if (tattStyle) {
-      styleCode = `.then(()=>{if (w${componentID}.__owl__.isDestroyed) {return};w${componentID}.el.style=${tattStyle};});`;
-    }
-    ctx.addLine(
-      `w${componentID}.__updateProps(props${componentID}, extra.fiber${scopeVars &&
-        ", " + scopeVars}, sibling)${styleCode};`
-    );
-    ctx.addLine(`let pvnode = w${componentID}.__owl__.pvnode;`);
-    if (registerCode) {
-      ctx.addLine(registerCode);
-    }
-    if (ctx.parentNode) {
-      ctx.addLine(`c${ctx.parentNode}.push(pvnode);`);
-    }
-
-    ctx.addElse();
-
-    // new component
-    let dynamicFallback = "";
-    if (!value.match(INTERP_REGEXP)) {
-      dynamicFallback = `|| ${ctx.formatExpression(value)}`;
-    }
-    const interpValue = ctx.interpolate(value);
-    ctx.addLine(`let componentKey${componentID} = ${interpValue};`);
-    ctx.addLine(
-      `let W${componentID} = context.constructor.components[componentKey${componentID}] || QWeb.components[componentKey${componentID}]${dynamicFallback};`
-    );
-
-    // maybe only do this in dev mode...
-    ctx.addLine(
-      `if (!W${componentID}) {throw new Error('Cannot find the definition of component "' + componentKey${componentID} + '"')}`
-    );
-    ctx.addLine(`w${componentID} = new W${componentID}(parent, props${componentID});`);
-    ctx.addLine(`parent.__owl__.cmap[${templateId}] = w${componentID}.__owl__.id;`);
-
-    if (hasSlots) {
-      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;
-        }
-      }
-      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[`${slotId}_default`] = slotFn;
-      }
-    }
-
-    ctx.addLine(`let def${defID} = w${componentID}.__prepare(extra.fiber, ${scopeVars}, sibling);`);
-    // hack: specify empty remove hook to prevent the node from being removed from the DOM
-    ctx.addLine(
-      `let pvnode = h('dummy', {key: ${templateId}, hook: {insert(vn) { let nvn=w${componentID}.__mount(fiber, pvnode.elm);pvnode.elm=nvn.elm;${refExpr}${transitionsInsertCode}},remove() {},destroy(vn) {${finalizeComponentCode}}}});`
-    );
-    ctx.addLine(`const fiber = w${componentID}.__owl__.currentFiber;`);
-    ctx.addLine(
-      `def${defID}.then(function () {if (w${componentID}.__owl__.isDestroyed) {return;} const vnode = fiber.vnode; pvnode.sel = vnode.sel; ${createHook}});`
-    );
-    if (registerCode) {
-      ctx.addLine(registerCode);
-    }
-    if (ctx.parentNode) {
-      ctx.addLine(`c${ctx.parentNode}.push(pvnode);`);
-    }
-    ctx.addLine(`w${componentID}.__owl__.pvnode = pvnode;`);
-
-    ctx.closeIf();
-
-    if (classObj) {
-      ctx.addLine(`w${componentID}.__owl__.classObj=${classObj};`);
-    }
-
-    ctx.addLine(`sibling = w${componentID}.__owl__.currentFiber || sibling;`);
-
-    return true;
-  }
-});

src/component/error_handling.ts

@@ -0,0 +1,57 @@
+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) {
+    if (isFirstRound && fiber) {
+      fiber.root.counter--;
+    }
+
+    let propagate = true;
+    for (const h of errorHandlers) {
+      try {
+        h(error);
+        propagate = false;
+      } catch (e) {
+        error = e;
+      }
+    }
+
+    if (propagate) {
+      return _handleError(node.parent, error);
+    }
+    return true;
+  } else {
+    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!;
+
+  fibersInError.set(fiber.root, error);
+
+  const handled = _handleError(node, error, true);
+  if (!handled) {
+    try {
+      node.app.destroy();
+    } catch (e) {}
+  }
+  return handled;
+}

src/component/fiber.ts

@@ -1,226 +0,0 @@
-import { VNode } from "../vdom/index";
-import { Component } from "./component";
-import { scheduler } from "./scheduler";
-
-/**
- * Owl Fiber Class
- *
- * Fibers are small abstractions designed to contain all the internal state
- * associated with a "rendering work unit", relative to a specific component.
- *
- * A rendering will cause the creation of a fiber for each impacted components.
- *
- * Fibers capture all that necessary information, which is critical to owl
- * asynchronous rendering pipeline. Fibers can be cancelled, can be in different
- * states and in general determine the state of the rendering.
- */
-
-export class Fiber {
-  // The force attribute determines if a rendering should bypass the `shouldUpdate`
-  // method potentially implemented by a component. It is usually set to false.
-  force: boolean;
-
-  // isCancelled means that the rendering corresponding to this fiber and its
-  // children is cancelled. No extra work should be done.
-  isCancelled: boolean = false;
-
-  // the fibers corresponding to component updates (updateProps) need to call
-  // the willPatch and patched hooks from the corresponding component. However,
-  // fibers corresponding to a new component do not need to do that. So, the
-  // shouldPatch hook is the boolean that we check whenever we need to apply
-  // a patch.
-  shouldPatch: boolean = true;
-
-  // isRendered is the last state of a fiber. If true, this means that it has
-  // been rendered and is inert (so, it should not be taken into account when
-  // counting the number of active fibers).
-  isRendered: boolean = false;
-
-  // the counter number is a critical information. It is only necessary for a
-  // root fiber.  For that fiber, this number counts the number of active sub
-  // fibers.  When that number reaches 0, the fiber can be applied by the
-  // scheduler.
-  counter: number = 0;
-
-  scope: any;
-  vars: any;
-
-  component: Component<any, any>;
-  vnode: VNode | null = null;
-
-  root: Fiber;
-  child: Fiber | null = null;
-  sibling: Fiber | null = null;
-  parent: Fiber | null = null;
-
-  error?: Error;
-
-  constructor(parent: Fiber | null, component: Component<any, any>, scope, vars, force) {
-    this.force = force;
-    this.scope = scope;
-    this.vars = vars;
-    this.component = component;
-
-    this.root = parent ? parent.root : this;
-    this.parent = parent;
-
-    let oldFiber = component.__owl__.currentFiber;
-    if (oldFiber && !oldFiber.isCancelled) {
-      this._remapFiber(oldFiber);
-    }
-
-    this.root.counter++;
-
-    component.__owl__.currentFiber = this;
-  }
-
-  /**
-   * In some cases, a rendering initiated at some component can detect that it
-   * should be part of a larger rendering initiated somewhere up the component
-   * tree.  In that case, it needs to cancel the previous rendering and
-   * remap itself as a part of the current parent rendering.
-   */
-  _remapFiber(oldFiber: Fiber) {
-    oldFiber.cancel();
-    if (oldFiber === oldFiber.root) {
-      oldFiber.root.counter++;
-    }
-    if (oldFiber.parent && !this.parent) {
-      // re-map links
-      this.parent = oldFiber.parent;
-      this.root = this.parent.root;
-      this.sibling = oldFiber.sibling;
-      if (this.parent.child === oldFiber) {
-        this.parent.child = this;
-      } else {
-        let current = this.parent.child!;
-        while (true) {
-          if (current.sibling === oldFiber) {
-            current.sibling = this;
-            break;
-          }
-          current = current.sibling!;
-        }
-      }
-    }
-  }
-
-  /**
-   * This function has been taken from
-   * https://medium.com/react-in-depth/the-how-and-why-on-reacts-usage-of-linked-list-in-fiber-67f1014d0eb7
-   */
-  _walk(doWork: (f: Fiber) => Fiber | null) {
-    let root = this;
-    let current: Fiber = this;
-    while (true) {
-      const child = doWork(current);
-      if (child) {
-        current = child;
-        continue;
-      }
-      if (current === root) {
-        return;
-      }
-      while (!current.sibling) {
-        if (!current.parent || current.parent === root) {
-          return;
-        }
-        current = current.parent;
-      }
-      current = current.sibling;
-    }
-  }
-
-  /**
-   * Apply the given patch queue from a fiber.
-   *   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 reverse order
-   */
-  patchComponents() {
-    const patchQueue: Fiber[] = [];
-    const doWork: (Fiber) => Fiber | null = function(f) {
-      if (f.shouldPatch) {
-        patchQueue.push(f);
-      }
-      return f.child;
-    };
-    this._walk(doWork);
-    let component: Component<any, any> = this.component;
-    const patchLen = patchQueue.length;
-    try {
-      for (let i = 0; i < patchLen; i++) {
-        component = patchQueue[i].component;
-        if (component.__owl__.willPatchCB) {
-          component.__owl__.willPatchCB();
-        }
-        component.willPatch();
-      }
-    } catch (e) {
-      console.error(e);
-    }
-    for (let i = 0; i < patchLen; i++) {
-      const fiber = patchQueue[i];
-      component = fiber.component;
-      component.__patch(fiber.vnode);
-    }
-    try {
-      for (let i = patchLen - 1; i >= 0; i--) {
-        component = patchQueue[i].component;
-        component.patched();
-        if (component.__owl__.patchedCB) {
-          component.__owl__.patchedCB();
-        }
-      }
-    } catch (e) {
-      console.error(e);
-    }
-  }
-
-  /**
-   * Cancel a fiber and all its children.
-   */
-  cancel() {
-    this._walk(f => {
-      if (!f.isRendered) {
-        f.root.counter--;
-      }
-      f.isCancelled = true;
-      return f.child;
-    });
-  }
-
-  /**
-   * 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.
-   */
-  handleError(error: Error) {
-    let canCatch = false;
-    let component = this.component;
-    let qweb = component.env.qweb;
-    let root = component;
-    while (component && !(canCatch = !!component.catchError)) {
-      root = component;
-      component = component.__owl__.parent!;
-    }
-    qweb.trigger("error", error);
-
-    if (canCatch) {
-      setTimeout(() => {
-        console.error(error);
-        component.catchError!(error);
-      });
-    } else {
-      // the 3 next lines aim to mark the root fiber as being in error, and
-      // to force it to end, without waiting for its children
-      this.root.counter = 0;
-      this.root.error = error;
-      scheduler.flush();
-      root.destroy();
-    }
-  }
-}

src/component/fibers.ts

@@ -0,0 +1,215 @@
+import type { BDom } from "../blockdom";
+import { mount } from "../blockdom";
+import type { ComponentNode } from "./component_node";
+import { STATUS } from "./status";
+import { fibersInError, handleError } from "./error_handling";
+
+export function makeChildFiber(node: ComponentNode, parent: Fiber): Fiber {
+  let current = node.fiber;
+  if (current) {
+    // current is necessarily a rootfiber here
+    let root = parent.root;
+    cancelFibers(root, current.children);
+    current.children = [];
+    current.parent = parent;
+    root.counter++;
+    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);
+    }
+    return current;
+  }
+  const fiber = new RootFiber(node);
+  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;
+  deep: boolean = false;
+
+  constructor(node: ComponentNode, parent: Fiber | null) {
+    this.node = node;
+    node.fiber = this;
+    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;
+  resolve: any;
+  promise: Promise<any>;
+  reject: any;
+
+  // only add stuff in this if they have registered some hooks
+  willPatch: Fiber[] = [];
+  patched: Fiber[] = [];
+  mounted: Fiber[] = [];
+
+  constructor(node: ComponentNode) {
+    super(node, null);
+    this.counter = 1;
+
+    this.promise = new Promise((resolve, reject) => {
+      this.resolve = resolve;
+      this.reject = reject;
+    });
+  }
+
+  complete() {
+    const node = this.node;
+    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);
+      this.appliedToDom = true;
+
+      // Step 3: calling all destroyed hooks
+      for (let node of __internal__destroyed) {
+        for (let cb of node.destroyed) {
+          cb();
+        }
+      }
+      __internal__destroyed.length = 0;
+
+      // 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();
+          }
+        }
+      }
+      // unregistering the fiber
+      node.fiber = null;
+    } catch (e) {
+      if (!handleError({ fiber: current || this, error: e })) {
+        this.reject(e);
+      }
+    }
+  }
+}
+
+export let __internal__destroyed: ComponentNode[] = [];
+
+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);
+    this.target = target;
+    this.position = options.position || "last-child";
+  }
+  complete() {
+    let current: Fiber | undefined = this;
+    try {
+      const node = this.node;
+      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);
+      }
+      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();
+          }
+        }
+      }
+      node.fiber = null;
+    } catch (e) {
+      if (!handleError({ fiber: current as Fiber, error: e })) {
+        this.reject(e);
+      }
+    }
+  }
+}

src/component/handler.ts

@@ -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;
+};

src/component/lifecycle_hooks.ts

@@ -0,0 +1,72 @@
+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 onDestroyed(fn: () => Promise<void> | void | any) {
+  const node = getCurrent()!;
+  node.destroyed.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;
+  };
+}
+
+export function onError(fn: (error: Error) => void | any) {
+  const node = getCurrent()!;
+  let handlers = nodeErrorHandlers.get(node);
+  if (handlers) {
+    handlers.push(fn);
+  } else {
+    handlers = [];
+    handlers.push(fn);
+    nodeErrorHandlers.set(node, handlers);
+  }
+}

src/component/props_validation.ts

@@ -1,4 +1,20 @@
-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
@@ -10,24 +26,28 @@ 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;
+
+  const propsDef = ComponentClass.props;
   if (propsDef instanceof Array) {
     // list of strings (prop names)
-    for (let i = 0, l = propsDef.length; i < l; i++) {
+    for (const propName of propsDef) {
-      const propName = propsDef[i];
       if (propName[propName.length - 1] === "?") {
         // optional prop
         break;
       }
       if (!(propName in props)) {
-        throw new Error(`Missing props '${propsDef[i]}' (component '${Widget.name}')`);
+        throw new Error(`Missing props '${propName}' (component '${ComponentClass.name}')`);
       }
     }
     for (let key in props) {
       if (!propsDef.includes(key) && !propsDef.includes(key + "?")) {
-        throw new Error(`Unknown prop '${key}' given to component '${Widget.name}'`);
+        throw new Error(`Unknown prop '${key}' given to component '${ComponentClass.name}'`);
       }
     }
   } else if (propsDef) {
@@ -35,19 +55,27 @@ QWeb.utils.validateProps = function(Widget, props: Object) {
     for (let propName in propsDef) {
       if (props[propName] === undefined) {
         if (propsDef[propName] && !propsDef[propName].optional) {
-          throw new Error(`Missing props '${propName}' (component '${Widget.name}')`);
+          throw new Error(`Missing props '${propName}' (component '${ComponentClass.name}')`);
         } else {
-          break;
+          continue;
         }
       }
-      let isValid = isValidProp(props[propName], propsDef[propName]);
+      let isValid;
+      try {
+        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;
+      }
       if (!isValid) {
-        throw new Error(`Props '${propName}' of invalid type in component '${Widget.name}'`);
+        throw new Error(`Invalid Prop '${propName}' in component '${ComponentClass.name}'`);
       }
     }
     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 +84,7 @@ 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 +108,30 @@ 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;
 }

src/component/scheduler.ts

@@ -1,70 +1,82 @@
-import { Fiber } from "./fiber";
+import { Fiber, RootFiber } from "./fibers";
+import { fibersInError } from "./error_handling";
+import { STATUS } from "./status";
 
-/**
+// -----------------------------------------------------------------------------
- * Owl Scheduler Class
+//  Scheduler
- *
+// -----------------------------------------------------------------------------
- * The scheduler is the part of Owl that will effectively apply a rendering
- * whenever a fiber is ready.
- *
- * Briefly, it can be used to register root fibers.  Whenever there is an
- * active root fiber, it will poll continuously each animation frame (so, about
- * once every 16ms) and whenever a root fiber is ready, it will apply it.
- */
-
-interface Task {
-  fiber: Fiber;
-  callback: (err?: Error) => void;
-}
 
 export class Scheduler {
-  tasks: Task[] = [];
+  tasks: Set<RootFiber> = new Set();
   isRunning: boolean = false;
-  requestAnimationFrame: typeof window.requestAnimationFrame;
+  requestAnimationFrame: Window["requestAnimationFrame"];
 
-  constructor(requestAnimationFrame) {
+  constructor(requestAnimationFrame: Window["requestAnimationFrame"]) {
     this.requestAnimationFrame = requestAnimationFrame;
   }
 
-  addFiber(fiber, callback) {
+  start() {
-    this.tasks.push({ fiber, callback });
+    this.isRunning = true;
-    if (this.isRunning) {
-      return;
-    }
     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() {
-    let tasks = this.tasks;
+    this.tasks.forEach((fiber) => {
-    this.tasks = [];
+      if (fiber.root !== fiber) {
-    tasks = tasks.filter(task => {
+        // this is wrong! should be something like
-      if (task.fiber.isCancelled) {
+        // if (this.tasks.has(fiber.root)) {
-        return false;
+        //   // parent rendering has completed
+        //   fiber.resolve();
+        //   this.tasks.delete(fiber);
+        // }
+        this.tasks.delete(fiber);
+        return;
       }
-      if (task.fiber.counter === 0) {
+      const hasError = fibersInError.has(fiber);
-        task.callback(task.fiber.error);
+      if (hasError && fiber.counter !== 0) {
-        return false;
+        this.tasks.delete(fiber);
+        fiber.reject(fibersInError.get(fiber));
+        return;
+      }
+      if (fiber.node.status === STATUS.DESTROYED) {
+        this.tasks.delete(fiber);
+        return;
+      }
+
+      if (fiber.counter === 0) {
+        if (!hasError) {
+          fiber.complete();
+          fiber.resolve();
+        }
+        this.tasks.delete(fiber);
       }
-      return true;
     });
-    this.tasks = tasks.concat(this.tasks);
+    if (this.tasks.size === 0) {
+      this.stop();
+    }
   }
 
   scheduleTasks() {
-    this.isRunning = true;
     this.requestAnimationFrame(() => {
       this.flush();
-      if (this.tasks.length > 0) {
+      if (this.isRunning) {
         this.scheduleTasks();
-      } else {
-        this.isRunning = false;
       }
     });
   }
 }
-
-const raf = window.requestAnimationFrame.bind(window);
-export const scheduler = new Scheduler(raf);

src/component/status.ts

@@ -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";
+  }
+}

src/component/style.ts

@@ -0,0 +1,88 @@
+import { Component } from "./component";
+
+export const globalStylesheets: { [key: string]: HTMLStyleElement } = {};
+
+export function registerSheet(id: string, css: string) {
+  const sheet = document.createElement("style");
+  sheet.innerHTML = processSheet(css);
+  globalStylesheets[id] = sheet;
+}
+
+/**
+ * Apply the stylesheets defined by the component. Note that we need to make
+ * sure all inherited stylesheets are applied as well, in a reverse order to
+ * ensure that <style/> will be applied to the DOM in the order they are
+ * included in the document. We then delete the `style` key from the constructor
+ * to make sure we do not apply it again.
+ */
+export function applyStyles(ComponentClass: typeof Component) {
+  const toApply: [string, string][] = [];
+  while (ComponentClass && ComponentClass.style) {
+    if (ComponentClass.hasOwnProperty("style")) {
+      toApply.push([ComponentClass.style, ComponentClass.name]);
+      delete (ComponentClass as any).style;
+    }
+    ComponentClass = Object.getPrototypeOf(ComponentClass);
+  }
+  while (toApply.length) {
+    const [styleId, componentName] = toApply.pop()!;
+    activateSheet(styleId, componentName);
+  }
+}
+
+function activateSheet(id: string, name: string) {
+  const sheet = globalStylesheets[id];
+  if (!sheet) {
+    throw new Error(
+      `Invalid css stylesheet for component '${name}'. Did you forget to use the 'css' tag helper?`
+    );
+  }
+  sheet.dataset.component = name;
+  document.head.appendChild(sheet);
+}
+
+function processSheet(str: string): string {
+  const tokens = str.split(/(\{|\}|;)/).map((s) => s.trim());
+  const selectorStack: string[][] = [];
+  const parts: string[] = [];
+  let rules: string[] = [];
+  function generateSelector(stackIndex: number, parentSelector?: string) {
+    const parts: string[] = [];
+    for (const selector of selectorStack[stackIndex]) {
+      let part = (parentSelector && parentSelector + " " + selector) || selector;
+      if (part.includes("&")) {
+        part = selector.replace(/&/g, parentSelector || "");
+      }
+      if (stackIndex < selectorStack.length - 1) {
+        part = generateSelector(stackIndex + 1, part);
+      }
+      parts.push(part);
+    }
+    return parts.join(", ");
+  }
+  function generateRules() {
+    if (rules.length) {
+      parts.push(generateSelector(0) + " {");
+      parts.push(...rules);
+      parts.push("}");
+      rules = [];
+    }
+  }
+  while (tokens.length) {
+    let token = tokens.shift()!;
+    if (token === "}") {
+      generateRules();
+      selectorStack.pop();
+    } else {
+      if (tokens[0] === "{") {
+        generateRules();
+        selectorStack.push(token.split(/\s*,\s*/));
+        tokens.shift();
+      }
+      if (tokens[0] === ";") {
+        rules.push("  " + token + ";");
+      }
+    }
+  }
+  return parts.join("\n");
+}

src/config.ts

@@ -1,48 +0,0 @@
-import { QWeb } from "./qweb/index";
-import { Env } from "./component/component";
-
-/**
- * This file creates and exports the OWL 'config' object, with keys:
- *  - 'mode': 'prod' or 'dev',
- *  - 'env': the environment to use in root components.
- */
-
-interface Config {
-  env: Env;
-  mode: string;
-}
-
-export const config = {} as Config;
-
-Object.defineProperty(config, "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.`);
-    }
-  },
-});
-
-let env:Env;
-Object.defineProperty(config, "env", {
-  get() {
-    if (!env) {
-      env = {} as Env;
-    }
-    if (!env.qweb) {
-      env.qweb = new QWeb();
-    }
-    return env;
-  },
-  set(newEnv: Env) {
-    env = newEnv;
-  },
-});

src/context.ts

@@ -1,143 +0,0 @@
-import { Component } from "./component/component";
-import { scheduler } from "./component/scheduler";
-import { EventBus } from "./core/event_bus";
-import { Observer } from "./core/observer";
-import { onWillUnmount } from "./hooks";
-/**
- * The `Context` object provides a way to share data between an arbitrary number
- * of component. 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.
- */
-
-function partitionBy<T>(arr: T[], fn: (t: T) => boolean) {
-  let lastGroup: T[] | false = false;
-  let lastValue;
-  return arr.reduce((acc: T[][], cur) => {
-    let curVal = fn(cur);
-    if (lastGroup) {
-      if (curVal === lastValue) {
-        lastGroup.push(cur);
-      } else {
-        lastGroup = false;
-      }
-    }
-    if (!lastGroup) {
-      lastGroup = [cur];
-      acc.push(lastGroup);
-    }
-    lastValue = curVal;
-    return acc;
-  }, []);
-}
-
-export class Context extends EventBus {
-  state: any;
-  observer: Observer;
-  rev: number = 1;
-  // mapping from component id to last observed context id
-  mapping: { [componentId: number]: number } = {};
-
-  constructor(state: Object = {}) {
-    super();
-    this.observer = new Observer();
-    this.observer.notifyCB = this.__notifyComponents.bind(this);
-    this.state = this.observer.observe(state);
-    this.subscriptions.update = [];
-  }
-
-  /**
-   * 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.  More precisely, if an update
-   * as an effect of destroying a children, we do not want to call any code
-   * from the child, and certainly not render it.
-   *
-   * This method implements a simple grouping algorithm by depth. If we have
-   * connected components of depths [2, 4,4,4,4, 3,8,8], the Context will notify
-   * them in the following groups: [2], [4,4,4,4], [3], [8,8]. Each group will
-   * be updated sequentially, but each components in a given group will be done in
-   * parallel.
-   *
-   * This is a very simple algorithm, but it avoids checking if a given
-   * component is a child of another.
-   */
-  async __notifyComponents() {
-    const rev = ++this.rev;
-    const subscriptions = this.subscriptions.update;
-    const groups = partitionBy(subscriptions, s => (s.owner ? s.owner.__owl__.depth : -1));
-    for (let group of groups) {
-      const proms = Promise.all(
-        group.map(sub => {
-          if (sub.owner ? sub.owner.__owl__.isMounted : true) {
-            return sub.callback.call(sub.owner, rev);
-          }
-        })
-      );
-      // at this point, each component in the current group has registered a
-      // top level fiber in the scheduler. It could happen that rendering these
-      // components is done (if they have no children).  This is why we manually
-      // flush the scheduler.  This will force the scheduler to check
-      // immediately if they are done, which will cause their rendering
-      // promise to resolve earlier, which means that there is a chance of
-      // processing the next group in the same frame.
-      scheduler.flush();
-      await proms;
-    }
-  }
-}
-
-/**
- * The`useContext` hook is the normal way for a component to register themselve
- * to context state changes. The `useContext` method returns the context state
- */
-export function useContext(ctx: Context): any {
-  const component: Component<any, any> = Component.current!;
-  return useContextWithCB(ctx, component, component.render.bind(component));
-}
-
-export function useContextWithCB(ctx: Context, component: Component<any, any>, method): any {
-  const __owl__ = component.__owl__;
-  const id = __owl__.id;
-  const mapping = ctx.mapping;
-  if (id in mapping) {
-    return ctx.state;
-  }
-  if (!__owl__.observer) {
-    __owl__.observer = new Observer();
-    __owl__.observer.notifyCB = component.render.bind(component);
-  }
-  const currentCB = __owl__.observer.notifyCB;
-  __owl__.observer.notifyCB = function() {
-    if (ctx.rev > mapping[id]) {
-      // in this case, the context has been updated since we were rendering
-      // last, and we do not need to render here with the observer. A
-      // rendering is coming anyway, with the correct props.
-      return;
-    }
-    currentCB();
-  };
-
-  mapping[id] = 0;
-  const renderFn = __owl__.renderFn;
-  __owl__.renderFn = function(comp, params) {
-    mapping[id] = ctx.rev;
-    return renderFn(comp, params);
-  };
-  ctx.on("update", component, async contextRev => {
-    if (mapping[id] < contextRev) {
-      mapping[id] = contextRev;
-      await method();
-    }
-  });
-  onWillUnmount(() => {
-    ctx.off("update", component);
-    delete mapping[id];
-  });
-  return ctx.state;
-}

src/core/event_bus.ts

@@ -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 = {};
-  }
-}

src/core/observer.ts

@@ -1,103 +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<T>(value: T, parent?: any): T {
-    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;
-  }
-
-  _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,
-      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);
-    let parent = target;
-    do {
-      metadata = this.weakMap.get(parent);
-      metadata.rev++;
-    } while ((parent = metadata.parent) && parent !== target);
-  }
-}

src/hooks.ts

@@ -1,90 +1,6 @@
-import { Component } from "./component/component";
+import type { Env } from "./app/app";
-import { Observer } from "./core/observer";
+import { getCurrent } from "./component/component_node";
-
+import { onMounted, onPatched, onWillPatch, onWillUnmount } from "./component/lifecycle_hooks";
-/**
- * Owl Hook System
- *
- * This file introduces the concept of hooks, similar to React or Vue hooks.
- * We have currently an implementation of:
- * - useState (reactive state)
- * - onMounted
- * - onWillUnmount
- * - useRef
- */
-
-// -----------------------------------------------------------------------------
-// useState
-// -----------------------------------------------------------------------------
-
-/**
- * This is the main way a component can be made reactive.  The useState hook
- * will return an observed object (or array).  Changes to that value will then
- * trigger a rerendering of the current component.
- */
-export function useState<T>(state: T): T {
-  const component: Component<any, any> = Component.current!;
-  const __owl__ = component.__owl__;
-  if (!__owl__.observer) {
-    __owl__.observer = new Observer();
-    __owl__.observer.notifyCB = component.render.bind(component);
-  }
-  return __owl__.observer.observe(state);
-}
-
-// -----------------------------------------------------------------------------
-// Life cycle hooks
-// -----------------------------------------------------------------------------
-function makeLifecycleHook(method: string, reverse: boolean = false) {
-  if (reverse) {
-    return function(cb) {
-      const component: Component<any, any> = Component.current!;
-      if (component.__owl__[method]) {
-        const current = component.__owl__[method];
-        component.__owl__[method] = function() {
-          current.call(component);
-          cb.call(component);
-        };
-      } else {
-        component.__owl__[method] = cb;
-      }
-    };
-  } else {
-    return function(cb) {
-      const component: Component<any, any> = Component.current!;
-      if (component.__owl__[method]) {
-        const current = component.__owl__[method];
-        component.__owl__[method] = function() {
-          cb.call(component);
-          current.call(component);
-        };
-      } else {
-        component.__owl__[method] = cb;
-      }
-    };
-  }
-}
-
-function makeAsyncHook(method: string) {
-  return function(cb) {
-    const component: Component<any, any> = Component.current!;
-    if (component.__owl__[method]) {
-      const current = component.__owl__[method];
-      component.__owl__[method] = function(...args) {
-        return Promise.all[(current.call(component, ...args), cb.call(component, ...args))];
-      };
-    } else {
-      component.__owl__[method] = cb;
-    }
-  };
-}
-
-export const onMounted = makeLifecycleHook("mountedCB", true);
-export const onWillUnmount = makeLifecycleHook("willUnmountCB");
-export const onWillPatch = makeLifecycleHook("willPatchCB");
-export const onPatched = makeLifecycleHook("patchedCB", true);
-
-export const onWillStart = makeAsyncHook("willStartCB");
-export const onWillUpdateProps = makeAsyncHook("willUpdatePropsCB");
 
 // -----------------------------------------------------------------------------
 // useRef
@@ -94,35 +10,112 @@ export const onWillUpdateProps = makeAsyncHook("willUpdatePropsCB");
  * The purpose of this hook is to allow components to get a reference to a sub
  * html node or component.
  */
-interface Ref {
+export function useRef<T extends HTMLElement = HTMLElement>(name: string): { el: T | null } {
-  el: HTMLElement | null;
+  const node = getCurrent()!;
-  comp: Component<any, any> | null;
-}
-
-export function useRef(name: string): Ref {
-  const __owl__ = Component.current!.__owl__;
   return {
-    get el(): HTMLElement | null {
+    get el(): T | null {
-      const val = __owl__.refs && __owl__.refs[name];
+      return node.refs[name] || null;
-      return val instanceof HTMLElement ? val : null;
     },
-    get comp(): Component<any, any> | null {
-      const val = __owl__.refs && __owl__.refs[name];
-      return val instanceof Component ? val : null;
-    }
   };
 }
 
 // -----------------------------------------------------------------------------
-// useSubEnv
+// 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(nextEnv) {
+export function useSubEnv(envExtension: Env) {
-  const component = Component.current!;
+  const node = getCurrent()!;
-  component.env = Object.assign(Object.create(component.env), nextEnv);
+  node.childEnv = Object.freeze(Object.assign({}, node.childEnv, envExtension));
+}
+
+// -----------------------------------------------------------------------------
+// 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;
+  });
+
+  let shouldReapplyOnPatch = false;
+  onWillPatch(() => {
+    const newDeps = computeDependencies();
+    shouldReapplyOnPatch = newDeps.some((val, i) => val !== dependencies[i]);
+    if (shouldReapplyOnPatch) {
+      cleanup();
+      dependencies = newDeps;
+    }
+  });
+  onPatched(() => {
+    if (shouldReapplyOnPatch) {
+      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));
 }

src/index.ts

@@ -1,39 +1,76 @@
-/**
+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 { config } from "./config";
+  text,
-import * as _store from "./store";
+  toggler,
-import * as _utils from "./utils";
+} from "./blockdom";
-import * as _tags from "./tags";
+import { mainEventHandler } from "./component/handler";
-import { AsyncRoot } from "./misc/async_root";
-import * as _hooks from "./hooks";
-import * as _context from "./context";
-import { Link } from "./router/link";
-import { RouteComponent } from "./router/route_component";
-import { Router } from "./router/router";
 
-export { Component } from "./component/component";
+config.shouldNormalizeDom = false;
-export { QWeb };
+config.mainEventHandler = mainEventHandler;
-export { config };
+
+export const blockDom = {
+  config,
+  // bdom entry points
+  mount: blockMount,
+  patch,
+  remove,
+  // bdom block types
+  list,
+  multi,
+  text,
+  toggler,
+  createBlock,
+  html,
+};
+
+import type { AppConfig } from "./app/app";
+import { App } from "./app/app";
+import { Component } from "./component/component";
+import { getCurrent } from "./component/component_node";
+export { useState } from "./component/component_node";
+
+export { App, Component };
+
+export async function mount<T extends typeof Component>(
+  C: T,
+  target: HTMLElement,
+  config: AppConfig = {}
+): Promise<InstanceType<T>> {
+  const app = new App(C);
+  return app.configure(config).mount(target);
+}
+
+export function useComponent(): Component {
+  const current = getCurrent();
+  return current!.component;
+}
+
+export { status } from "./component/status";
+export { Portal } from "./portal";
+export { Memo } from "./memo";
+export { css, xml } from "./tags";
+export { 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,
+  onDestroyed,
+  onError,
+} from "./component/lifecycle_hooks";
 
-export const Context = _context.Context;
-export const useState = _hooks.useState;
-export const core = { EventBus, Observer };
-export const router = { Router, RouteComponent, Link };
-export const Store = _store.Store;
-export const utils = _utils;
-export const tags = _tags;
-export const misc = { AsyncRoot };
-export const hooks = Object.assign({}, _hooks, {
-  useContext: _context.useContext,
-  useDispatch: _store.useDispatch,
-  useGetters: _store.useGetters,
-  useStore: _store.useStore
-});
 export const __info__ = {};

src/memo.ts

@@ -0,0 +1,47 @@
+import { Component } from "./component/component";
+import type { ComponentNode } from "./component/component_node";
+import { xml } from "./tags";
+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 (p1[k] !== p2[k]) {
+      return false;
+    }
+  }
+  return true;
+}

src/misc/async_root.ts

@@ -1,19 +0,0 @@
-import { Component } from "../component/component";
-import { xml } from "../tags";
-
-/**
- * AsyncRoot
- *
- * Owl is by default asynchronous, and the user interface will wait for all its
- * subcomponents to be rendered before updating the DOM. This is most of the
- * time what we want, but in some cases, it makes sense to "detach" a component
- * from this coordination.  This is the goal of the AsyncRoot component.
- */
-
-export class AsyncRoot extends Component<any, any> {
-  static template = xml`<t t-slot="default"/>`;
-
-  async __updateProps(nextProps, parentFiber) {
-    this.render(parentFiber.force);
-  }
-}

src/portal.ts

@@ -0,0 +1,70 @@
+import type { ComponentNode } from "./component/component_node";
+import { Component } from "./component/component";
+import { xml } from "./tags";
+import { BDom, text, VNode } from "./blockdom";
+
+const VText: any = text("").constructor;
+
+class VPortal extends VText implements Partial<VNode<VPortal>> {
+  //   selector: string;
+  realBDom: BDom | null;
+  target: HTMLElement | null = null;
+
+  constructor(selector: string, realBDom: BDom) {
+    super("");
+    this.selector = selector;
+    this.realBDom = realBDom;
+  }
+  mount(parent: HTMLElement, anchor: ChildNode) {
+    super.mount(parent, anchor);
+    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);
+    }
+  }
+}
+
+export class Portal extends Component {
+  static template = xml`<t t-slot="default"/>`;
+  static props = {
+    target: {
+      type: String,
+    },
+  };
+
+  constructor(props: any, env: any, node: ComponentNode) {
+    super(props, env, node);
+    node._render = function (fiber: any) {
+      const bdom = new VPortal(props.target, this.renderFn());
+      fiber.bdom = bdom;
+      fiber.root.counter--;
+    };
+  }
+}

src/qweb/base_directives.ts

@@ -1,337 +0,0 @@
-import { CompilationContext } from "./compilation_context";
-import { QWebExprVar } from "./expression_parser";
-import { QWeb } from "./qweb";
-import { htmlToVDOM } from "../vdom/html_to_vdom";
-
-/**
- * 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;
-};
-
-QWeb.utils.htmlToVDOM = htmlToVDOM;
-
-function compileValueNode(value: any, node: Element, qweb: QWeb, ctx: CompilationContext) {
-  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: ${exprID}};`);
-      if (ctx.rootContext.shouldDefineResult) {
-        ctx.addLine(`result = vn${nodeID}`);
-      }
-    }
-  } else {
-    ctx.rootContext.shouldDefineUtils = true;
-    ctx.addLine(`c${ctx.parentNode}.push(...utils.htmlToVDOM(${exprID}));`);
-  }
-  if (node.childNodes.length) {
-    ctx.addElse();
-    qweb._compileChildren(node, ctx);
-  }
-
-  ctx.closeIf();
-}
-
-QWeb.addDirective({
-  name: "esc",
-  priority: 70,
-  atNodeEncounter({ node, qweb, ctx }): boolean {
-    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 {
-    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} = ${formattedValue};`);
-        ctx.variables[variable] = {
-          id: varName,
-          expr: formattedValue
-        };
-      }
-    } else {
-      ctx.variables[variable] = {
-        xml: node.childNodes
-      };
-    }
-    return true;
-  }
-});
-
-//------------------------------------------------------------------------------
-// t-if, t-elif, t-else
-//------------------------------------------------------------------------------
-QWeb.addDirective({
-  name: "if",
-  priority: 20,
-  atNodeEncounter({ node, ctx }): boolean {
-    let cond = ctx.getValue(node.getAttribute("t-if")!);
-    ctx.addIf(typeof cond === "string" ? ctx.formatExpression(cond) : cond.id);
-    return false;
-  },
-  finalize({ ctx }) {
-    ctx.closeIf();
-  }
-});
-
-QWeb.addDirective({
-  name: "elif",
-  priority: 30,
-  atNodeEncounter({ node, ctx }): boolean {
-    let cond = ctx.getValue(node.getAttribute("t-elif")!);
-    ctx.addLine(`else if (${typeof cond === "string" ? ctx.formatExpression(cond) : cond.id}) {`);
-    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 "${subTemplate}" (t-call)`);
-    }
-    const nodeCopy = node.cloneNode(true) as Element;
-    nodeCopy.removeAttribute("t-call");
-
-    // extract variables from nodecopy
-    const tempCtx = new CompilationContext();
-    tempCtx.nextID = ctx.rootContext.nextID;
-    tempCtx.allowMultipleRoots = true;
-    qweb._compileNode(nodeCopy, tempCtx);
-    const vars = Object.assign({}, ctx.variables, tempCtx.variables);
-    ctx.rootContext.nextID = tempCtx.nextID;
-
-    const templateMap = Object.create(ctx.templates);
-    // open new scope, if necessary
-    const hasNewVariables = Object.keys(tempCtx.variables).length > 0;
-
-    // compile sub template
-    let subCtx = ctx.subContext("caller", nodeCopy).subContext("variables", Object.create(vars));
-    subCtx = subCtx.subContext("templates", templateMap);
-
-    if (templateMap[subTemplate]) {
-      // OUCH, IT IS A RECURSIVE TEMPLATE SITUATION...
-      // This is a tricky situation... We obviously cannot inline the compiled
-      // template. So, what we need to do is to compile it, and make sure we
-      // properly transfer everything from the current scope to the sub template.
-      ctx.rootContext.shouldTrackScope = true;
-      ctx.rootContext.shouldDefineOwner = true;
-      let subTemplateName;
-      if (ctx.hasParentWidget) {
-        subTemplateName = ctx.templateName;
-      } else {
-        subTemplateName = `__${ctx.generateID()}`;
-        subCtx.variables = {};
-        let id = 0;
-        for (let v in vars) {
-          subCtx.variables[v] = vars[v];
-          (vars[v] as any).id = `_v${id++}`;
-        }
-        const subTemplateFn = qweb._compile(subTemplateName, nodeTemplate.elem, subCtx);
-        qweb.recursiveFns[subTemplateName] = subTemplateFn;
-      }
-      let varCode = `{}`;
-      if (Object.keys(vars).length) {
-        let id = 0;
-        const content = Object.values(vars)
-          .map((v: any) => `_v${id++}: ${v.expr}`)
-          .join(",");
-        varCode = `{${content}}`;
-      }
-      ctx.addLine(
-        `this.recursiveFns['${subTemplateName}'].call(this, context, Object.assign({}, extra, {parentNode: c${ctx.parentNode}, fiber: {vars: ${varCode}, scope}}));`
-      );
-      return true;
-    }
-    templateMap[subTemplate] = true;
-
-    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} = ${(<QWebExprVar>v).expr};`);
-        }
-        // todo: handle XML variables...
-      }
-    }
-    qweb._compileNode(nodeTemplate.elem, subCtx);
-
-    // close new scope
-    if (hasNewVariables) {
-      ctx.dedent();
-      ctx.addLine("}");
-    }
-
-    return true;
-  }
-});
-
-//------------------------------------------------------------------------------
-// t-foreach
-//------------------------------------------------------------------------------
-QWeb.addDirective({
-  name: "foreach",
-  extraNames: ["as"],
-  priority: 10,
-  atNodeEncounter({ node, qweb, ctx }): boolean {
-    ctx.rootContext.shouldProtectContext = true;
-    ctx = ctx.subContext("loopNumber", ctx.loopNumber + 1);
-    const elems = node.getAttribute("t-foreach")!;
-    const name = node.getAttribute("t-as")!;
-    let arrayID = ctx.generateID();
-    ctx.addLine(`var _${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;`);
-    const loopVar = `i${ctx.loopNumber}`;
-    ctx.addLine(`for (let ${loopVar} = 0; ${loopVar} < _length${keysID}; ${loopVar}++) {`);
-    ctx.indent();
-    ctx.addToScope(name + "_first", `${loopVar} === 0`);
-    ctx.addToScope(name + "_last", `${loopVar} === _length${keysID} - 1`);
-    ctx.addToScope(name + "_index", loopVar);
-    ctx.addToScope(name, `_${keysID}[${loopVar}]`);
-    ctx.addToScope(name + "_value", `_${valuesID}[${loopVar}]`);
-    const nodeCopy = <Element>node.cloneNode(true);
-    let shouldWarn =
-      !nodeCopy.hasAttribute("t-key") &&
-      node.children.length === 1 &&
-      node.children[0].tagName !== "t" &&
-      !node.children[0].hasAttribute("t-key");
-    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})`);
-  }
-});

src/qweb/compilation_context.ts

@@ -1,183 +0,0 @@
-import { compileExpr, QWebVar, QWebExprVar } from "./expression_parser";
-
-export const INTERP_REGEXP = /\{\{.*?\}\}/g;
-//------------------------------------------------------------------------------
-// Compilation Context
-//------------------------------------------------------------------------------
-
-export class CompilationContext {
-  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: CompilationContext;
-  caller: Element | undefined;
-  shouldDefineOwner: boolean = false;
-  shouldDefineParent: boolean = false;
-  shouldDefineQWeb: boolean = false;
-  shouldDefineUtils: boolean = false;
-  shouldDefineRefs: boolean = false;
-  shouldDefineResult: boolean = true;
-  shouldDefineSibling: boolean = true;
-  shouldProtectContext: boolean = false;
-  shouldTrackScope: boolean = false;
-  loopNumber: number = 0;
-  inPreTag: boolean = false;
-  templateName: string;
-  allowMultipleRoots: boolean = false;
-  hasParentWidget: boolean = false;
-  scopeVars: any[] = [];
-  currentKey: string = "";
-  lastNodeKey: string = ""; // temp variable to communicate to previous caller
-  templates: { [key: string]: boolean } = {};
-
-  constructor(name?: string) {
-    this.rootContext = this;
-    this.templateName = name || "noname";
-    this.templates[this.templateName] = true;
-    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.shouldDefineSibling) {
-      this.code.unshift("    let sibling = null;");
-    }
-    if (this.shouldDefineRefs) {
-      this.code.unshift("    context.__owl__.refs = context.__owl__.refs || {};");
-    }
-    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): CompilationContext {
-    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;
-    }
-    if (!this.parentNode && this.rootContext.shouldDefineResult) {
-      this.addLine(`result = vn${node};`);
-    }
-    return this.subContext("parentNode", node);
-  }
-
-  subContext(key: keyof CompilationContext, value: any): CompilationContext {
-    const newContext = Object.create(this);
-    newContext[key] = value;
-    return newContext;
-  }
-
-  indent() {
-    this.indentLevel++;
-  }
-
-  dedent() {
-    this.indentLevel--;
-  }
-
-  addLine(line: string): number {
-    const prefix = new Array(this.indentLevel + 2).join("    ");
-    this.code.push(prefix + line);
-    return this.code.length - 1;
-  }
-
-  addToScope(key: string, expr: string) {
-    const index = this.addLine(`context.${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): QWebExprVar | string {
-    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 ${x}`
-   *   '{{x ? 'a': 'b'}}' -> (x ? 'a' : 'b')
-   */
-  interpolate(s: string): string {
-    let matches = s.match(INTERP_REGEXP);
-    if (matches && matches[0].length === s.length) {
-      return `(${this.formatExpression(s.slice(2, -2))})`;
-    }
-
-    let r = s.replace(/\{\{.*?\}\}/g, s => "${" + this.formatExpression(s.slice(2, -2)) + "}");
-    return "`" + r + "`";
-  }
-}

src/qweb/extensions.ts

@@ -1,276 +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 "";
-    });
-    let params = extraArgs ? `owner, ${ctx.formatExpression(extraArgs)}` : "owner";
-    let handler = `function (e) {`;
-    handler += mods
-      .map(function(mod) {
-        return MODS_CODE[mod];
-      })
-      .join("");
-    if (handlerName) {
-      if (!extraArgs) {
-        handler += `const fn = context['${handlerName}'];`;
-        handler += `if (fn) { fn.call(${params}, e); } else { context.${handlerName}; }`;
-        handler += `}`;
-        ctx.addLine(
-          `extra.handlers['${eventName}' + ${nodeID}] = extra.handlers['${eventName}' + ${nodeID}] || ${handler};`
-        );
-        ctx.addLine(`p${nodeID}.on['${eventName}'] = extra.handlers['${eventName}' + ${nodeID}];`);
-      } else {
-        const handlerKey = `handler${ctx.generateID()}`;
-        ctx.addLine(
-          `const ${handlerKey} = context['${handlerName}'] && context['${handlerName}'].bind(${params});`
-        );
-        handler += `if (${handlerKey}) { ${handlerKey}(e); } else { context.${value}; }`;
-        handler += `}`;
-        ctx.addLine(`p${nodeID}.on['${eventName}'] = ${handler};`);
-      }
-    } else {
-      handler += "}";
-      ctx.addLine(`p${nodeID}.on['${eventName}'] = ${handler};`);
-    }
-  }
-});
-
-//------------------------------------------------------------------------------
-// t-ref
-//------------------------------------------------------------------------------
-QWeb.addDirective({
-  name: "ref",
-  priority: 95,
-  atNodeCreation({ ctx, value, addNodeHook }) {
-    ctx.rootContext.shouldDefineRefs = true;
-    const refKey = `ref${ctx.generateID()}`;
-    ctx.addLine(`const ${refKey} = ${ctx.interpolate(value)};`);
-    addNodeHook("create", `context.__owl__.refs[${refKey}] = n.elm;`);
-    addNodeHook("destroy", `delete context.__owl__.refs[${refKey}];`);
-  }
-});
-
-//------------------------------------------------------------------------------
-// t-transition
-//------------------------------------------------------------------------------
-QWeb.utils.nextFrame = function(cb: () => void) {
-  requestAnimationFrame(() => requestAnimationFrame(cb));
-};
-
-QWeb.utils.transitionInsert = function(vn: VNode, name: string) {
-  const elm = <HTMLElement>vn.elm;
-  // remove potential duplicated vnode that is currently being removed, to
-  // prevent from having twice the same node in the DOM during an animation
-  const dup = elm.parentElement && elm.parentElement!.querySelector(`*[data-owl-key='${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-slot
-//------------------------------------------------------------------------------
-QWeb.addDirective({
-  name: "slot",
-  priority: 80,
-  atNodeEncounter({ ctx, value }): boolean {
-    const slotKey = ctx.generateID();
-    ctx.rootContext.shouldDefineOwner = true;
-    ctx.addLine(
-      `const slot${slotKey} = this.constructor.slots[context.__owl__.slotId + '_' + '${value}'];`
-    );
-    ctx.addIf(`slot${slotKey}`);
-    let parentNode = `c${ctx.parentNode}`;
-    if (!ctx.parentNode) {
-      ctx.rootContext.shouldDefineResult = true;
-      ctx.rootContext.shouldDefineUtils = true;
-      parentNode = `children${ctx.nextID++}`;
-      ctx.addLine(`let ${parentNode}= []`);
-      ctx.addLine(`result = {}`);
-    }
-    ctx.addLine(
-      `slot${slotKey}.call(this, context.__owl__.parent, Object.assign({}, extra, {parentNode: ${parentNode}, vars: extra.vars, parent: owner}));`
-    );
-    if (!ctx.parentNode) {
-      ctx.addLine(`utils.defineProxy(result, ${parentNode}[0]);`);
-    }
-    ctx.closeIf();
-    return true;
-  }
-});
-
-//------------------------------------------------------------------------------
-// t-model
-//------------------------------------------------------------------------------
-QWeb.utils.toNumber = function(val: string): number | string {
-  const n = parseFloat(val);
-  return isNaN(n) ? val : n;
-};
-
-QWeb.addDirective({
-  name: "model",
-  priority: 42,
-  atNodeCreation({ ctx, nodeID, value, node, fullName, addNodeHook }) {
-    const type = node.getAttribute("type");
-    let handler;
-    let event = fullName.includes(".lazy") ? "change" : "input";
-    const expr = ctx.formatExpression(value);
-    if (node.tagName === "select") {
-      ctx.addLine(`p${nodeID}.props = {value: ${expr}};`);
-      addNodeHook("create", `n.elm.value=${expr};`);
-      event = "change";
-      handler = `(ev) => {${expr} = ev.target.value}`;
-    } else if (type === "checkbox") {
-      ctx.addLine(`p${nodeID}.props = {checked: ${expr}};`);
-      handler = `(ev) => {${expr} = ev.target.checked}`;
-    } else if (type === "radio") {
-      const nodeValue = node.getAttribute("value")!;
-      ctx.addLine(`p${nodeID}.props = {checked:${expr} === '${nodeValue}'};`);
-      handler = `(ev) => {${expr} = ev.target.value}`;
-      event = "click";
-    } else {
-      ctx.addLine(`p${nodeID}.props = {value: ${expr}};`);
-      const trimCode = fullName.includes(".trim") ? ".trim()" : "";
-      let valueCode = `ev.target.value${trimCode}`;
-      if (fullName.includes(".number")) {
-        ctx.rootContext.shouldDefineUtils = true;
-        valueCode = `utils.toNumber(${valueCode})`;
-      }
-      handler = `(ev) => {${expr} = ${valueCode}}`;
-    }
-    ctx.addLine(
-      `extra.handlers['${event}' + ${nodeID}] = extra.handlers['${event}' + ${nodeID}] || (${handler});`
-    );
-    ctx.addLine(`p${nodeID}.on['${event}'] = extra.handlers['${event}' + ${nodeID}];`);
-  }
-});
-
-//------------------------------------------------------------------------------
-// t-key
-//------------------------------------------------------------------------------
-QWeb.addDirective({
-  name: "key",
-  priority: 45,
-  atNodeEncounter({ ctx, value }) {
-    let id = ctx.generateID();
-    ctx.addLine(`const nodeKey${id} = ${ctx.formatExpression(value)};`);
-    ctx.lastNodeKey = `nodeKey${id}`;
-  }
-});

src/qweb/index.ts

@@ -1,4 +0,0 @@
-import "./base_directives";
-import "./extensions";
-
-export { CompiledTemplate, QWeb } from "./qweb";

src/qweb/qweb.ts

@@ -1,769 +0,0 @@
-import { EventBus } from "../core/event_bus";
-import { h, patch, VNode } from "../vdom/index";
-import { CompilationContext } from "./compilation_context";
-import { shallowEqual } from "../utils";
-import { addNS } from "../vdom/vdom";
-
-/**
- * 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: CompilationContext;
-  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;
-}
-
-interface QWebConfig {
-  templates?: string;
-  translateFn?(text: string): string;
-}
-
-//------------------------------------------------------------------------------
-// Const/global stuff/helpers
-//------------------------------------------------------------------------------
-
-const DISABLED_TAGS = ["input", "textarea", "button", "select", "option", "optgroup"];
-
-const TRANSLATABLE_ATTRS = ["label", "title", "placeholder", "alt"];
-
-const lineBreakRE = /[\r\n]/;
-const whitespaceRE = /\s+/g;
-
-const NODE_HOOKS_PARAMS = {
-  create: "(_, n)",
-  insert: "vn",
-  remove: "(vn, rm)",
-  destroy: "()"
-};
-
-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,
-  addNameSpace(vnode) {
-    addNS(vnode.data, vnode.children, vnode.sel);
-  }
-};
-
-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${"-".repeat(columnIndex - 1)}^`;
-          }
-        }
-      }
-    }
-    throw new Error(msg);
-  }
-  return doc;
-}
-
-//------------------------------------------------------------------------------
-// QWeb rendering engine
-//------------------------------------------------------------------------------
-
-export class QWeb extends EventBus {
-  templates: { [name: string]: Template };
-  static utils = UTILS;
-  static components = Object.create(null);
-
-  static DIRECTIVE_NAMES: { [key: string]: 1 } = {
-    name: 1,
-    att: 1,
-    attf: 1,
-    translation: 1
-  };
-  static DIRECTIVES: Directive[] = [];
-
-  static TEMPLATES: { [name: string]: Template } = {};
-
-  static nextId: number = 1;
-
-  h = h;
-  // dev mode enables better error messages or more costly validations
-  static dev: boolean = false;
-
-  // slots contains sub templates defined with t-set inside t-component nodes, and
-  // are meant to be used by the t-slot directive.
-  static slots = {};
-  static nextSlotId = 1;
-
-  // recursiveTemplates contains sub templates called with t-call, but which
-  // ends up in recursive situations.  This is very similar to the slot situation,
-  // as in we need to propagate the scope.
-  recursiveFns = {};
-
-  isUpdating: boolean = false;
-  translateFn?: QWebConfig["translateFn"];
-
-  constructor(config: QWebConfig = {}) {
-    super();
-    this.templates = Object.create(QWeb.TEMPLATES);
-    if (config.templates) {
-      this.addTemplates(config.templates);
-    }
-    if (config.translateFn) {
-      this.translateFn = config.translateFn;
-    }
-  }
-
-  static addDirective(directive: Directive) {
-    if (directive.name in QWeb.DIRECTIVE_NAMES) {
-      throw new Error(`Directive "${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 registerComponent(name: string, Component: any) {
-    if (QWeb.components[name]) {
-      throw new Error(`Component '${name}' has already been registered`);
-    }
-    QWeb.components[name] = Component;
-  }
-
-  /**
-   * Register globally a template.  All QWeb instances will obtain their
-   * templates from their own template map, and then, from the global static
-   * TEMPLATES property.
-   */
-  static registerTemplate(name: string, template: string) {
-    if (QWeb.TEMPLATES[name]) {
-      throw new Error(`Template '${name}' has already been registered`);
-    }
-    const qweb = new QWeb();
-    qweb.addTemplate(name, template);
-    QWeb.TEMPLATES[name] = qweb.templates[name];
-  }
-
-  /**
-   * 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: function(this: QWeb, 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 ${name} does not exist`);
-    }
-    return template.fn.call(this, context, extra);
-  }
-
-  /**
-   * Render a template to a html string.
-   *
-   * Note that this is more limited than the `render` method: it is not suitable
-   * to render a full component tree, since this is an asynchronous operation.
-   * This method can only render templates without components.
-   */
-  renderToString(name: string, context: EvalContext = {}, extra?: any): string {
-    const vnode = this.render(name, context, extra);
-    if (vnode.sel === undefined) {
-      return vnode.text!;
-    }
-    const node = document.createElement(vnode.sel);
-    const result = patch(node, vnode);
-    return (<HTMLElement>result.elm).outerHTML;
-  }
-
-  /**
-   * Force all widgets connected to this QWeb instance to rerender themselves.
-   *
-   * This method is mostly useful for external code that want to modify the
-   * application in some cases.  For example, a router plugin.
-   */
-  forceUpdate() {
-    this.isUpdating = true;
-    Promise.resolve().then(() => {
-      if (this.isUpdating) {
-        this.isUpdating = false;
-        this.trigger("update");
-      }
-    });
-  }
-
-  _compile(name: string, elem: Element, parentContext?: CompilationContext): CompiledTemplate {
-    const isDebug = elem.attributes.hasOwnProperty("t-debug");
-    const ctx = new CompilationContext(name);
-    if (elem.tagName !== "t") {
-      ctx.shouldDefineResult = false;
-    }
-    if (parentContext) {
-      ctx.templates = Object.create(parentContext.templates);
-      ctx.variables = Object.create(parentContext.variables);
-      ctx.nextID = parentContext.nextID + 1;
-      ctx.parentNode = parentContext.parentNode || ctx.nextID++;
-      ctx.allowMultipleRoots = true;
-      ctx.hasParentWidget = true;
-      ctx.shouldDefineResult = false;
-      ctx.addLine(`let c${ctx.parentNode} = extra.parentNode;`);
-
-      for (let v in parentContext.variables) {
-        let variable = <any>parentContext.variables[v];
-        if (variable.id) {
-          ctx.addLine(`let ${variable.id} = extra.fiber.vars.${variable.id}`);
-        }
-      }
-    }
-    if (parentContext) {
-      ctx.addLine("    Object.assign(context, extra.fiber.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: CompilationContext) {
-    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 (this.translateFn) {
-        if ((node.parentNode as any).getAttribute("t-translation") !== "off") {
-          text = this.translateFn(text);
-        }
-      }
-      if (ctx.parentNode) {
-        if (node.nodeType === 3) {
-          ctx.addLine(`c${ctx.parentNode}.push({text: \`${text}\`});`);
-        } else if (node.nodeType === 8) {
-          ctx.addLine(`c${ctx.parentNode}.push(h('!', \`${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.addLine(`result = vn${nodeID};`);
-        ctx.rootContext.rootNode = nodeID;
-        ctx.rootContext.parentTextNode = nodeID;
-      }
-      return;
-    }
-
-    const firstLetter = node.tagName[0];
-    if (firstLetter === firstLetter.toUpperCase()) {
-      // this is a component, we modify in place the xml document to change
-      // <SomeComponent ... /> to <t t-component="SomeComponent" ... />
-      node.setAttribute("t-component", node.tagName);
-    }
-    const attributes = (<Element>node).attributes;
-
-    const validDirectives: {
-      directive: Directive;
-      value: string;
-      fullName: string;
-    }[] = [];
-
-    const finalizers: typeof validDirectives = [];
-
-    // maybe this is not optimal: we iterate on all attributes here, and again
-    // just after for each directive.
-    for (let i = 0; i < attributes.length; i++) {
-      let attrName = attributes[i].name;
-      if (attrName.startsWith("t-")) {
-        let dName = attrName.slice(2).split(/-|\./)[0];
-        if (!(dName in QWeb.DIRECTIVE_NAMES)) {
-          throw new Error(`Unknown QWeb directive: '${attrName}'`);
-        }
-        if (node.tagName !== "t" && (attrName === "t-esc" || attrName === "t-raw")) {
-          const tNode = document.createElement("t");
-          tNode.setAttribute(attrName, node.getAttribute(attrName)!);
-          for (let child of Array.from(node.childNodes)) {
-            tNode.appendChild(child);
-          }
-          node.appendChild(tNode);
-          node.removeAttribute(attrName);
-        }
-      }
-    }
-
-    const DIR_N = QWeb.DIRECTIVES.length;
-    const ATTR_N = attributes.length;
-    let withHandlers = false;
-    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.finalize) {
-        finalizers.push({ directive, value, fullName });
-      }
-      if (directive.atNodeEncounter) {
-        const isDone = directive.atNodeEncounter({
-          node,
-          qweb: this,
-          ctx,
-          fullName,
-          value
-        });
-        if (isDone) {
-          for (let { directive, value, fullName } of finalizers) {
-            directive.finalize!({ node, qweb: this, ctx, fullName, value });
-          }
-          return;
-        }
-      }
-    }
-
-    if (node.nodeName !== "t") {
-      let nodeID = this._compileGenericNode(node, ctx, withHandlers);
-      ctx = ctx.withParent(nodeID);
-      ctx = ctx.subContext("currentKey", ctx.lastNodeKey);
-      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(`    ${handler}`);
-          }
-          ctx.addLine(`  },`);
-        }
-        ctx.addLine(`};`);
-      }
-    }
-    if (node.nodeName === "pre") {
-      ctx = ctx.subContext("inPreTag", true);
-    }
-
-    this._compileChildren(node, ctx);
-    // svg support
-    // we hadd svg namespace if it is a svg or if it is a g, but only if it is
-    // the root node.  This is the easiest way to support svg sub components:
-    // they need to have a g tag as root. Otherwise, we would need a complete
-    // list of allowed svg tags.
-    const shouldAddNS =
-      node.nodeName === "svg" || (node.nodeName === "g" && ctx.rootNode === ctx.parentNode);
-    if (shouldAddNS) {
-      ctx.rootContext.shouldDefineUtils = true;
-      ctx.addLine(`utils.addNameSpace(vn${ctx.parentNode});`);
-    }
-
-    for (let { directive, value, fullName } of finalizers) {
-      directive.finalize!({ node, qweb: this, ctx, fullName, value });
-    }
-  }
-
-  _compileGenericNode(
-    node: ChildNode,
-    ctx: CompilationContext,
-    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;
-      let value = attributes[i].textContent!;
-
-      if (this.translateFn && TRANSLATABLE_ATTRS.includes(name)) {
-        value = this.translateFn(value);
-      }
-
-      // 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}: _${attID}`);
-          handleBooleanProps(name, attID);
-        }
-      }
-
-      // dynamic attributes
-      if (name.startsWith("t-att-")) {
-        let attName = name.slice(6);
-        const v = ctx.getValue(value);
-        let formattedValue = typeof v === "string" ? ctx.formatExpression(v) : v.id;
-
-        if (attName === "class") {
-          ctx.rootContext.shouldDefineUtils = true;
-          formattedValue = `utils.toObj(${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} = ${ctx.formatExpression(value!)};`);
-        tattrs.push(id);
-      }
-    }
-    let nodeID = ctx.generateID();
-    let nodeKey = ctx.lastNodeKey || nodeID;
-    const parts = [`key:${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: CompilationContext) {
-    if (node.childNodes.length > 0) {
-      for (let child of Array.from(node.childNodes)) {
-        this._compileNode(child, ctx);
-      }
-    }
-  }
-}

src/reactivity.ts

@@ -0,0 +1,190 @@
+import { Callback } from "./utils";
+
+// 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;
+export 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);
+}
+/**
+ * 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
+ */
+export 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);
+    }
+  }
+}
+
+const reactiveCache = new WeakMap<Target, Map<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);
+    if (!callbacksToTargets.has(callback)) {
+      callbacksToTargets.set(callback, new Set());
+    }
+    callbacksToTargets.get(callback)!.add(target);
+  }
+  return reactivesForTarget.get(callback) as Reactive<T>;
+}
+

src/router/link.ts

@@ -1,48 +0,0 @@
-import { Component } from "../component/component";
-import { xml } from "../tags";
-import { Destination, RouterEnv } from "./router";
-
-type Props = Destination;
-
-export class Link<Env extends RouterEnv> extends Component<Env, Props> {
-  static template = xml`
-    <a  t-att-class="{'router-link-active': isActive }"
-        t-att-href="href"
-        t-on-click="navigate">
-        <t t-slot="default"/>
-    </a>
-  `;
-
-  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);
-  }
-}

src/router/route_component.ts

@@ -1,18 +0,0 @@
-import { Component } from "../component/component";
-import { xml } from "../tags";
-
-export class RouteComponent extends Component<any, {}> {
-  static template = xml`
-    <t>
-        <t
-            t-if="routeComponent"
-            t-component="routeComponent"
-            t-key="env.router.currentRouteName"
-            t-props="env.router.currentParams" />
-    </t>
-  `;
-
-  get routeComponent(): any {
-    return this.env.router.currentRoute && this.env.router.currentRoute.component;
-  }
-}

src/router/router.ts

@@ -1,275 +0,0 @@
-import { Env } from "../component/component";
-import { QWeb } from "../qweb/index";
-import { shallowEqual } from "../utils";
-
-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.registerComponent("__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);
-    }
-  }
-
-  //--------------------------------------------------------------------------
-  // Public API
-  //--------------------------------------------------------------------------
-
-  async start() {
-    (this as any)._listener = ev => this._navigate(this.currentPath(), ev);
-    window.addEventListener("popstate", (this as any)._listener);
-    if (this.mode === "hash") {
-      window.addEventListener("hashchange", (this as any)._listener);
-    }
-    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);
-    return this._navigate(path);
-  }
-  async _navigate(path: string, ev?: any): Promise<boolean> {
-    const initialName = this.currentRouteName;
-    const initialParams = this.currentParams;
-    const result = await this.matchAndApplyRules(path);
-    if (result.type === "match") {
-      const finalPath = this.routeToPath(result.route, result.params);
-      const isPopStateEvent = ev && ev instanceof PopStateEvent;
-      if (!isPopStateEvent) {
-        this.setUrlFromPath(finalPath);
-      }
-      this.currentRoute = result.route;
-      this.currentParams = result.params;
-    } else if (result.type === "nomatch") {
-      this.currentRoute = null;
-      this.currentParams = null;
-    }
-    const didChange =
-      this.currentRouteName !== initialName || !shallowEqual(this.currentParams, initialParams);
-    if (didChange) {
-      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 separator = this.mode === "hash" ? location.pathname : "";
-    const url = location.origin + separator + path;
-    if (url !== window.location.href) {
-      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];
-      }
-    }
-    const prefix = this.mode === "hash" ? "#" : "";
-    return prefix + 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 {};
-    }
-    if (path.startsWith("#")) {
-      path = path.slice(1);
-    }
-    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;
-}

src/store.ts

@@ -1,141 +0,0 @@
-import { Component } from "./component/component";
-import { Env } from "./component/component";
-import { Context, useContextWithCB } from "./context";
-import { onWillUpdateProps } from "./hooks";
-
-/**
- * Owl Store
- *
- * We have here:
- * - a Store class
- * - useStore hook
- * - useDispatch hook
- * - useGetters hook
- *
- * 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 };
-}
-
-export class Store extends Context {
-  actions: any;
-  env: any;
-  getters: { [name: string]: (payload?) => any };
-  updateFunctions: { [key: number]: (() => boolean)[] };
-
-  constructor(config: StoreConfig) {
-    super(config.state);
-    this.actions = config.actions;
-    this.env = config.env;
-    this.getters = {};
-    this.updateFunctions = [];
-    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;
-  }
-}
-
-interface SelectorOptions {
-  store?: Store;
-  isEqual?: (a: any, b: any) => boolean;
-}
-
-const isStrictEqual = (a, b) => a === b;
-
-export function useStore(selector, options: SelectorOptions = {}): any {
-  const component: Component<any, any> = Component.current!;
-  const store = options.store || (component.env.store as Store);
-  let result = selector(store.state, component.props);
-  const hashFn = store.observer.revNumber.bind(store.observer);
-  let revNumber = hashFn(result) || result;
-  const isEqual = options.isEqual || isStrictEqual;
-  if (!store.updateFunctions[component.__owl__.id]) {
-    store.updateFunctions[component.__owl__.id] = [];
-  }
-  const updateFunctions = store.updateFunctions[component.__owl__.id];
-  updateFunctions.push(function(): boolean {
-    const oldResult = result;
-    result = selector(store!.state, component.props);
-    const newRevNumber = hashFn(result);
-    if (
-      (newRevNumber > 0 && revNumber !== newRevNumber) ||
-      (newRevNumber === 0 && !isEqual(oldResult, result))
-    ) {
-      revNumber = newRevNumber;
-      return true;
-    }
-    return false;
-  });
-
-  useContextWithCB(store, component, function(): Promise<void> | void {
-    let shouldRender = false;
-    updateFunctions.forEach(function(updateFn) {
-      shouldRender = updateFn() || shouldRender;
-    });
-    if (shouldRender) {
-      return component.render();
-    }
-  });
-  onWillUpdateProps(props => {
-    delete store.updateFunctions[component.__owl__.id];
-    result = selector(store.state, props);
-  });
-  return new Proxy(result, {
-    get(target, k) {
-      return result[k];
-    },
-    set(target, k, v) {
-      result[k] = v;
-      return true;
-    }
-  });
-}
-
-export function useDispatch(store?: Store): Store["dispatch"] {
-  store = store || (Component.current!.env.store as Store);
-  return store.dispatch.bind(store);
-}
-
-export function useGetters(store?: Store): Store["getters"] {
-  store = store || (Component.current!.env.store as Store);
-  return store.getters;
-}

src/tags.ts

@@ -1,27 +1,28 @@
-import { QWeb } from "./qweb/index";
+import { registerSheet } from "./component/style";
+import { globalTemplates } from "./app/template_set";
 
-/**
+// -----------------------------------------------------------------------------
- * Owl Tags
+//  Global templates
- *
+// -----------------------------------------------------------------------------
- * We have here a (very) small collection of tag functions:
- *
- * - xml
- *
- * The plan is to add a few other tags such as css, globalcss.
- */
 
-/**
+export function xml(strings: TemplateStringsArray, ...args: any[]) {
- * XML tag helper for defining templates.  With this, one can simply define
+  const name = `__template__${xml.nextId++}`;
- * an inline template with just the template xml:
- * ```js
- *   class A extends Component {
- *     static template = xml`<div>some template</div>`;
- *   }
- * ```
- */
-export function xml(strings, ...args) {
-  const name = `__template__${QWeb.nextId++}`;
   const value = String.raw(strings, ...args);
-  QWeb.registerTemplate(name, value);
+  globalTemplates[name] = value;
   return name;
 }
+
+xml.nextId = 1;
+
+// -----------------------------------------------------------------------------
+//  Global stylesheets
+// -----------------------------------------------------------------------------
+
+export function css(strings: TemplateStringsArray, ...args: any[]) {
+  const name = `__sheet__${css.nextId++}`;
+  const value = String.raw(strings, ...args);
+  registerSheet(name, value);
+  return name;
+}
+
+css.nextId = 1;

src/utils.ts

@@ -1,46 +1,43 @@
-/**
+export type Callback = () => void;
- * Owl Utils
- *
- * We have here a small collection of utility functions:
- *
- * - whenReady
- * - loadJS
- * - loadFile
- * - escape
- * - debounce
- */
 
-export function whenReady(fn?: any) {
+/**
-  return new Promise(function(resolve) {
+ * 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;
+    }
+  };
+}
+
+export class EventBus extends EventTarget {
+  trigger(name: string, payload?: any) {
+    this.dispatchEvent(new CustomEvent(name, { detail: payload }));
+  }
+}
+
+export function whenReady(fn?: any): Promise<void> {
+  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 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 loadFile(url: string): Promise<string> {
@@ -51,54 +48,17 @@ export async function loadFile(url: string): Promise<string> {
   return await result.text();
 }
 
-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;
-    const args = arguments;
-    function later() {
-      timeout = null;
-      if (!immediate) {
-        func.apply(context, args);
-      }
-    }
-    const callNow = immediate && !timeout;
-    clearTimeout(timeout);
-    timeout = setTimeout(later, wait);
-    if (callNow) {
-      func.apply(context, args);
-    }
-  };
-}
 
-export function shallowEqual(p1, p2): boolean {
+/*
-  for (let k in p1) {
+ * Marks a value as safe, that is, a value that can be injected as HTML directly.
-    if (p1[k] !== p2[k]) {
+ * It should be used to wrap the value passed to a t-out directive to allow a raw rendering.
-      return false;
+ */
-    }
+export function markup(value: any) {
-  }
+  return new Markup(value);
-  return true;
 }

src/vdom/html_to_vdom.ts

@@ -1,29 +0,0 @@
-import { VNode, h } from "./vdom";
-
-const parser = new DOMParser();
-
-export function htmlToVDOM(html: string): VNode[] {
-  const doc = parser.parseFromString(html, "text/html");
-  const result: VNode[] = [];
-  for (let child of doc.body.childNodes) {
-    result.push(htmlToVNode(child));
-  }
-  return result;
-}
-
-function htmlToVNode(node: ChildNode): VNode {
-  if (!(node instanceof Element)) {
-    return { text: node.textContent! } as VNode;
-  }
-  const attrs = {};
-  for (let attr of node.attributes) {
-    attrs[attr.name] = attr.textContent;
-  }
-  const children: VNode[] = [];
-  if (node.hasChildNodes) {
-    for (let c of node.childNodes) {
-      children.push(htmlToVNode(c));
-    }
-  }
-  return h((node as Element).tagName, { attrs }, children);
-}

src/vdom/index.ts

@@ -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]);

src/vdom/modules.ts

@@ -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;

src/vdom/vdom.ts

@@ -1,614 +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) {
-      const elm = (vnode.elm =
-        isDef(data) && isDef((i = (data as VNodeData).ns))
-          ? api.createElementNS(i, sel)
-          : api.createElement(sel));
-      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>;
-
-export function addNS(data: any, children: VNodes | undefined, sel: string | undefined): void {
-  if (sel === "dummy") {
-    // we do not need to add the namespace on dummy elements, they come from a
-    // subcomponent, which will handle the namespace itself
-    return;
-  }
-  data.ns = "http://www.w3.org/2000/svg";
-  if (sel !== "foreignObject" && children !== undefined) {
-    for (let i = 0, iLen = children.length; i < iLen; ++i) {
-      const child = children[i];
-      let childData = child.data;
-      if (childData !== undefined) {
-        addNS(childData, (child as VNode).children as VNodes, child.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);
-    }
-  }
-  return vnode(sel, data, children, text, undefined);
-}

tests/__snapshots__/animations.test.ts.snap

@@ -1,133 +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;
-    let sibling = null;
-    var h = this.h;
-    let c1 = [], p1 = {key:1};
-    var vn1 = h('div', p1, c1);
-    //COMPONENT
-    let templateId3 = \`__4__\`;
-    let w3 = templateId3 in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap[templateId3]] : false;
-    let props3 = {};
-    if (w3 && w3.__owl__.currentFiber && !w3.__owl__.vnode) {
-        w3.destroy();
-        w3 = false;
-    }
-    if (w3) {
-        w3.__updateProps(props3, extra.fiber, undefined, undefined, sibling);
-        let pvnode = w3.__owl__.pvnode;
-        c1.push(pvnode);
-    } else {
-        let componentKey3 = \`Child\`;
-        let W3 = context.constructor.components[componentKey3] || QWeb.components[componentKey3]|| context['Child'];
-        if (!W3) {throw new Error('Cannot find the definition of component \\"' + componentKey3 + '\\"')}
-        w3 = new W3(parent, props3);
-        parent.__owl__.cmap[templateId3] = w3.__owl__.id;
-        let def2 = w3.__prepare(extra.fiber, undefined, undefined, sibling);
-        let pvnode = h('dummy', {key: templateId3, hook: {insert(vn) { let nvn=w3.__mount(fiber, pvnode.elm);pvnode.elm=nvn.elm;utils.transitionInsert(vn, 'chimay');},remove() {},destroy(vn) {let finalize = () => {
-          w3.destroy();
-        };
-        utils.transitionRemove(vn, 'chimay', finalize);}}});
-        const fiber = w3.__owl__.currentFiber;
-        def2.then(function () {if (w3.__owl__.isDestroyed) {return;} const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
-        c1.push(pvnode);
-        w3.__owl__.pvnode = pvnode;
-    }
-    sibling = w3.__owl__.currentFiber || sibling;
-    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;
-    let sibling = null;
-    var h = this.h;
-    let c1 = [], p1 = {key:1};
-    var vn1 = h('div', p1, c1);
-    if (context['state'].display) {
-        //COMPONENT
-        let templateId3 = \`__4__\`;
-        let w3 = templateId3 in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap[templateId3]] : false;
-        let props3 = {};
-        if (w3 && w3.__owl__.currentFiber && !w3.__owl__.vnode) {
-            w3.destroy();
-            w3 = false;
-        }
-        if (w3) {
-            w3.__updateProps(props3, extra.fiber, undefined, undefined, sibling);
-            let pvnode = w3.__owl__.pvnode;
-            c1.push(pvnode);
-        } else {
-            let componentKey3 = \`Child\`;
-            let W3 = context.constructor.components[componentKey3] || QWeb.components[componentKey3]|| context['Child'];
-            if (!W3) {throw new Error('Cannot find the definition of component \\"' + componentKey3 + '\\"')}
-            w3 = new W3(parent, props3);
-            parent.__owl__.cmap[templateId3] = w3.__owl__.id;
-            let def2 = w3.__prepare(extra.fiber, undefined, undefined, sibling);
-            let pvnode = h('dummy', {key: templateId3, hook: {insert(vn) { let nvn=w3.__mount(fiber, pvnode.elm);pvnode.elm=nvn.elm;utils.transitionInsert(vn, 'chimay');},remove() {},destroy(vn) {let finalize = () => {
-          w3.destroy();
-        };
-        utils.transitionRemove(vn, 'chimay', finalize);}}});
-            const fiber = w3.__owl__.currentFiber;
-            def2.then(function () {if (w3.__owl__.isDestroyed) {return;} const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
-            c1.push(pvnode);
-            w3.__owl__.pvnode = pvnode;
-        }
-        sibling = w3.__owl__.currentFiber || sibling;
-    }
-    return vn1;
-}"
-`;
-
-exports[`animations t-transition with no delay/duration 1`] = `
-"function anonymous(context,extra
-) {
-    let utils = this.constructor.utils;
-    let sibling = null;
-    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;
-    let sibling = null;
-    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;
-}"
-`;

tests/__snapshots__/reactivity.test.ts.snap

@@ -0,0 +1,401 @@
+// 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 } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue, toNumber, safeOutput } = helpers;
+  
+  let block1 = createBlock(\`<span><block-text-0/></span>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let d1 = ctx['contextObj'].a;
+    return block1([d1]);
+  }
+}"
+`;
+
+exports[`Reactivity: useState destroyed component before being mounted is inactive 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-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 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/></span>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let d1 = ctx['contextObj'].a;
+    return block1([d1]);
+  }
+}"
+`;
+
+exports[`Reactivity: useState destroyed component is inactive 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-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 one components can subscribe twice to 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['contextObj1'].a;
+    let d2 = ctx['contextObj2'].b;
+    return block1([d1, d2]);
+  }
+}"
+`;
+
+exports[`Reactivity: useState parent and children subscribed to 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(\`<span><block-text-0/></span>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let d1 = ctx['contextObj'].a;
+    return block1([d1]);
+  }
+}"
+`;
+
+exports[`Reactivity: useState parent and children subscribed to 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-child-0/><block-text-0/></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
+    let d1 = ctx['contextObj'].b;
+    return block1([d1], [b2]);
+  }
+}"
+`;
+
+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 } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue, toNumber, safeOutput } = helpers;
+  
+  let block1 = createBlock(\`<span><block-text-0/></span>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let d1 = ctx['contextObj'].value;
+    return block1([d1]);
+  }
+}"
+`;
+
+exports[`Reactivity: useState two components are updated in parallel 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-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 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/></span>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let d1 = ctx['contextObj'].value;
+    return block1([d1]);
+  }
+}"
+`;
+
+exports[`Reactivity: useState two components can subscribe to 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-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 independent components on different levels are updated in parallel 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/></span>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let d1 = ctx['contextObj'].value;
+    return block1([d1]);
+  }
+}"
+`;
+
+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 } = 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(\`Child\`, {}, key + \`__1\`, node, ctx);
+    return block1([], [b2]);
+  }
+}"
+`;
+
+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 } = 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(\`Child\`, {}, key + \`__1\`, node, ctx);
+    let b3 = component(\`Parent\`, {}, key + \`__2\`, node, ctx);
+    return block1([], [b2, b3]);
+  }
+}"
+`;
+
+exports[`Reactivity: useState useContext=useState hook is reactive, for one component 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/></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let d1 = ctx['contextObj'].value;
+    return block1([d1]);
+  }
+}"
+`;
+
+exports[`Reactivity: useState useless atoms should be deleted 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/></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let d1 = ctx['state'].quantity;
+    return block1([d1]);
+  }
+}"
+`;
+
+exports[`Reactivity: useState useless atoms should be deleted 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-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 d1 = ctx['total'];
+    let d2 = Object.keys(ctx['state']).length;
+    return block1([d1, d2], [b2]);
+  }
+}"
+`;
+
+exports[`Reactivity: useState very simple use, with initial value 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/></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let d1 = ctx['contextObj'].value;
+    return block1([d1]);
+  }
+}"
+`;