[REL] v1.0.5

closes #646

.gitignore

@@ -15,6 +15,7 @@ yarn-debug.log*
 yarn-error.log*
 
 package-lock.json
+yarn.lock
 
 #ide's
 .vscode
@@ -23,4 +24,6 @@ package-lock.json
 node_modules
 
 # Extras temp file
-/tools/owl.js
+/tools/owl.js
+
+release-notes.md

README.md

@@ -1,4 +1,4 @@
-<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>
 
 _Class based components with hooks, reactive state and concurrent mode_
 
@@ -11,18 +11,31 @@ 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),
-- a small frontend router
+- concurrent mode by default,
+- a store and a frontend router
 
-Owl components are defined with ES6 classes, they use QWeb templates, an underlying
-virtual dom, integrates beautifully with hooks, and the rendering is asynchronous.
+Owl components are defined with ES6 classes, they use QWeb templates, an
+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
-are some code examples to showcase some interesting features.
+**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 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:
@@ -79,10 +92,9 @@ 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
 
@@ -90,162 +102,27 @@ 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:
 
 - [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-alpha5.js](https://github.com/odoo/owl/releases/download/v1.0.0-alpha5/owl.js)
-- [owl-1.0.0-alpha5.min.js](https://github.com/odoo/owl/releases/download/v1.0.0-alpha5/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.
+- [owl-1.0.5.js](https://github.com/odoo/owl/releases/download/v1.0.5/owl.js)
+- [owl-1.0.5.min.js](https://github.com/odoo/owl/releases/download/v1.0.5/owl.min.js)
 
 ## License
 

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

@@ -1,4 +1,4 @@
-# 🦉 Testing Owl components 🦉
+# 🦉 How to test Components 🦉
 
 ## Content
 
@@ -11,8 +11,7 @@ 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, and
-how to debug them if necessary.
+In this section, we will discuss how to write unit tests for components.
 
 ## Unit Tests
 

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: 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

@@ -1,107 +1,411 @@
-# 🦉 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
-adding an html page with a few extra files:
+- [Overview](#overview)
+- [Simple html file](#simple-html-file)
+- [With a static server](#with-a-static-server)
+- [Standard Javascript project](#standard-javascript-project)
+
+## Overview
+
+Each software project has its specific needs. Many of these needs can be solved
+with some tooling: `webpack`, `gulp`, css preprocessor, bundlers, transpilers, ...
+
+Because of that, it is usually not simple to just start a project. Some
+frameworks provide their own tooling to help with that. But then, you have to
+integrate and learn how these applications work.
+
+Owl is designed to be used with no tooling at all. Because of that, Owl can
+"easily" be integrated in a modern build toolchain. In this section, we will
+discuss a few different setups to start a project. Each of these setups has
+advantages and disadvantages in different situations.
+
+## Simple html file
+
+The simplest possible setup is the following: a simple javascript file with your
+code. To do that, let us create the following file structure:
 
 ```
-my-app/
-    index.html
-    app.css
-    app.js
-    owl-X.Y.Z.js
-    templates.xml
+hello_owl/
+  index.html
+  owl.js
+  app.js
 ```
 
-### 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>My OWL App</title>
-    <link href="app.css" rel="stylesheet" />
-    <script src="owl-X.Y.Z.js"></script>
+    <title>Hello Owl</title>
+    <script src="owl.js"></script>
+    <script src="app.js"></script>
   </head>
-  <body>
-    <div id="main"></div>
-    <script src="app.js" type="module"></script>
-  </body>
+  <body></body>
 </html>
 ```
 
-In `app.css`:
+And `app.js` should look like this:
 
-```css
-button {
-  color: darkred;
-  font-size: 30px;
-  width: 220px;
+```js
+const { Component } = owl;
+const { xml } = owl.tags;
+const { whenReady } = owl.utils;
+
+// Owl Components
+class App extends Component {
+  static template = xml`<div>Hello Owl</div>`;
+}
+
+// Setup code
+function setup() {
+  const app = new App();
+  app.mount(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 } = 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() {
+  const app = new App();
+  app.mount(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
-<templates>
-   <button t-name="clickcounter" t-on-click="increment">
-      Click Me! [<t t-esc="state.value"/>]
-    </button>
-</templates>
+Each of these features, and many others, can be done in many different ways.
+Since it is really not trivial to configure such a project, we provide here an
+example that can be used as a starting point.
+
+Our standard Owl project has the following file structure:
+
+```
+hello_owl/
+  public/
+    index.html
+  src/
+    components/
+      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
-  contain a QWeb instance (preloaded with templates), and anything else that we
-  need. In practice, it could be used to contain some user session information, some
-  configuration keys (for example, isMobile = true/false if we are in mobile mode).
+```html
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <title>Hello Owl</title>
+  </head>
+  <body></body>
+</html>
+```
 
-- a description of the user interface: there should be a root component, which can
-  have sub components
+Note that there are no `<script>` tag here. They will be injected by webpack.
+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
-- 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
+const { xml } = tags;
 
-Let us now add the javascript to make it work, in `app.js`:
-
-```javascript
-const useState = owl.hooks.useState;
-
-class ClickCounter extends owl.Component {
-  static template = "clickcounter";
-  state = useState({ value: 0 });
-
-  increment() {
-    this.state.value++;
+export class App extends Component {
+  static template = xml`<div t-on-click="update">Hello <t t-esc="state.text"/></div>`;
+  state = useState({ text: "Owl" });
+  update() {
+    this.state.text = this.state.text === "Owl" ? "World" : "Owl";
   }
 }
 
-//------------------------------------------------------------------------------
-// Application initialization
-//------------------------------------------------------------------------------
-async function start() {
-  const templates = await owl.utils.loadFile("templates.xml");
-  ClickCounter.env = { qweb: new owl.QWeb({ templates }) };
-  const counter = new ClickCounter();
-  const target = document.getElementById("main");
-  await counter.mount(target);
+// src/main.js -----------------------------------------------------------------
+import { utils } from "@odoo/owl";
+import { App } from "./components/App";
+
+function setup() {
+  const app = new App();
+  app.mount(document.body);
 }
 
-start();
+utils.whenReady(setup);
+
+// tests/components/App.test.js ------------------------------------------------
+import { App } from "../../src/components/App";
+import { makeTestFixture, nextTick, click } from "../helpers";
+
+let fixture;
+
+beforeEach(() => {
+  fixture = makeTestFixture();
+});
+
+afterEach(() => {
+  fixture.remove();
+});
+
+describe("App", () => {
+  test("Works as expected...", async () => {
+    const app = new App();
+    await app.mount(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/learning/tutorial_todoapp.md

@@ -37,7 +37,7 @@ todoapp/
     index.html
     app.css
     app.js
-    owl.min.js
+    owl.js
 ```
 
 The entry point for this application is the file `index.html`, which should have
@@ -446,7 +446,7 @@ Now, this is an interesting situation: the task is displayed by the `Task`
 component, but it is not the owner of its state, so it cannot modify it. Instead,
 we want to communicate the request to toggle a task to the `App` component.
 Since `App` is a parent of `Task`, we can
-[trigger](../reference/component.md#event-handling) an event in `Task` and listen
+[trigger](../reference/event_handling.md) an event in `Task` and listen
 for it in `App`.
 
 In `Task`, change the `input` to:

doc/miscellaneous/comparison.md

@@ -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 {
@@ -251,7 +251,7 @@ keeps track of who get data, and retrigger a render when it was changed.
 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)).
+to the store like in redux, with the `useStore` hook (see the [store documentation](../reference/store.md#connecting-a-component)).
 
 ```javascript
 const actions = {
@@ -315,7 +315,7 @@ 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.
 

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 install
+or remove 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 resolve 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 component, and is easy to integrate
+in any html page, with a simple `<script>` tag.
+
+## Template based
+
+Odoo stores template as XML document 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 developer 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 component, 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 a 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 readonly,
+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 perform 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 want 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 make choices compatible with Odoo.
+
+And that is why we built Owl 🦉.

doc/readme.md

@@ -1,14 +1,31 @@
 # 🦉 OWL Documentation 🦉
 
+## Learning Owl
+
+Are you new to Owl? This is the place to start!
+
+- [Tutorial: create a TodoList application](learning/tutorial_todoapp.md)
+- [Quick Overview](learning/overview.md)
+- [How to start an Owl project](learning/quick_start.md)
+- [How to test Components](learning/how_to_test.md)
+- [How to write Single File Components](learning/how_to_write_sfc.md)
+- [How to write debug Owl applications](learning/how_to_debug.md)
+
 ## Reference
 
+You will find here a complete reference of every feature, class or object
+provided by Owl.
+
 - [Animations](reference/animations.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)
 - [Miscellaneous Components](reference/misc.md)
 - [Observer](reference/observer.md)
@@ -18,60 +35,21 @@
 - [QWeb Engine](reference/qweb_engine.md)
 - [Router](reference/router.md)
 - [Store](reference/store.md)
+- [Slots](reference/slots.md)
 - [Tags](reference/tags.md)
 - [Utils](reference/utils.md)
 
-## Learning Resources
+## Other Topics
 
-- [Quick Start: create an (almost) empty Owl application](learning/quick_start.md)
-- [Tutorial: create a TodoList application](learning/tutorial_todoapp.md)
-- [Testing Owl components](learning/testing_components.md)
+This section provides miscellaneous document that explains some topics
+which cannot be considered either a tutorial, or reference documentation.
 
-## Miscellaneous
+- [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)
 
-- [Comparison with React/Vue](comparison.md)
-- [Tooling](tooling.md)
-- [Templates to start Owl applications (external link)](https://github.com/ged-odoo/owl-templates)
+---
 
-## Architecture
-
-This section explains in more detail the inner workings of Owl. It is targeted
-for developers working on Owl itself.
-
-- [Virtual DOM](architecture/vdom.md)
-- [Rendering](architecture/rendering.md)
-
-## Owl Content
-
-Here is a complete visual representation of everything exported by the `owl`
-global object (so, for example, `Component` is available at `owl.Component`,
-and `EventBus` is exported as `owl.core.EventBus`):
-
-```
-Component                               misc
-Context                                     AsyncRoot
-QWeb                                    router
-Store                                       Link
-useState                                    RouteComponent
-config                                      Router
-    mode                                tags
-core                                        xml
-    EventBus                            utils
-    Observer                                debounce
-hooks                                       escape
-    onWillStart                             loadJS
-    onMounted                               loadFile
-    onWillUpdateProps                       shallowEqual
-    onWillPatch                             whenReady
-    onPatched
-    onWillUnmount
-    useContext
-    useState
-    useRef
-    useSubEnv
-    useStore
-    useDispatch
-    useGetters
-```
-
-Note that for convenience, the `useState` hook is also exported at the root of the `owl` object.
+Found an issue in the documentation? A broken link? Some outdated information?
+Please open an issue or submit a PR!

doc/reference/component.md

@@ -12,12 +12,9 @@
   - [Lifecycle](#lifecycle)
   - [Root Component](#root-component)
   - [Composition](#composition)
-  - [Event Handling](#event-handling)
   - [Form Input Bindings](#form-input-bindings)
   - [References](#references)
-  - [Slots](#slots)
   - [Dynamic sub components](#dynamic-sub-components)
-  - [Error Handling](#error-handling)
   - [Functional Components](#functional-components)
   - [SVG components](#svg-components)
 
@@ -225,6 +222,10 @@ to be called in the constructor.
   }
   ```
 
+- **`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
@@ -234,12 +235,23 @@ component.
 
 We explain here all the public methods of the `Component` class.
 
-- **`mount(target)`** (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 (or document fragment). Obviously, this is asynchronous, since each children need to be
   created as well. Most applications will need to call `mount` exactly once, on
   the root component.
 
+  The `options` argument is an optional object with a `position` key. The
+  `position` key can have three possible values: `first-child`, `last-child`, `self`.
+
+  - `first-child`: with this option, the component will be prepended inside the target,
+  - `last-child` (default value): with this option, the component will be
+    appended in the target element,
+  - `self`: the target will be used as the root element for the component. This
+    means that the target has to be an HTMLElement (and not a document fragment).
+    In this situation, it is possible that the component cannot be unmounted. For
+    example, if its target is `document.body`.
+
   Note that if a component is mounted, unmounted and remounted, it will be
   automatically re-rendered to ensure that changes in its state (or something
   in the environment, or in the store, or ...) will be taken into account.
@@ -258,25 +270,25 @@ We explain here all the public methods of the `Component` class.
   // app is now visible
   ```
 
-- **`unmount()`**: in case a component needs to be detached/removed from the DOM, this
+* **`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
   can be useful if we are handling large number of components.
 
-- **`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
@@ -293,16 +305,16 @@ A solid and robust component system needs useful hooks/methods to help
 developers write components. Here is a complete description of the lifecycle of
 a owl component:
 
-| Method                                           | Description                                                  |
-| ------------------------------------------------ | ------------------------------------------------------------ |
-| **[constructor](#constructorparent-props)**      | constructor                                                  |
-| **[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)) |
+| Method                                           | Description                                                 |
+| ------------------------------------------------ | ----------------------------------------------------------- |
+| **[constructor](#constructorparent-props)**      | constructor                                                 |
+| **[willStart](#willstart)**                      | async, before first rendering                               |
+| **[mounted](#mounted)**                          | just after component is rendered and added to the DOM       |
+| **[willUpdateProps](#willupdatepropsnextprops)** | async, before props update                                  |
+| **[willPatch](#willpatch)**                      | just before the DOM is patched                              |
+| **[patched](#patchedsnapshot)**                  | just after the DOM is patched                               |
+| **[willUnmount](#willunmount)**                  | just before removing component from DOM                     |
+| **[catchError](#catcherrorerror)**               | catch errors (see [error handling page](error_handling.md)) |
 
 Notes:
 
@@ -410,7 +422,7 @@ 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.
@@ -437,8 +449,8 @@ 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
-[error handling](#error-handling).
+to (rendering) errors that occur in some sub components. See the page on
+[error handling](error_handling.md).
 
 ### Root Component
 
@@ -537,118 +549,6 @@ 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 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.
-
-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
@@ -798,62 +698,6 @@ 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
-
-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.
-
-This is what _slots_ are for.
-
-```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` 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>
-```
-
 ### Dynamic sub components
 
 It is not common, but sometimes we need a dynamic component name. In this case,
@@ -899,65 +743,6 @@ component class.
 
 Note that the `t-component` directive can only be used on `<t>` nodes.
 
-### 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 {
-  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, 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
 
 Owl does not exactly have functional components. However, there is an extremely

doc/reference/concurrency_model.md

@@ -23,7 +23,7 @@ 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 concuurent rendering works in a general way.
+how Owl manages this complexity, how concurrent rendering works in a general way.
 
 ## Rendering Components
 
@@ -120,7 +120,7 @@ Here is what Owl will do:
      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)
+     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`,
@@ -137,7 +137,7 @@ Here is what Owl will do:
 
 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](../tooling.md#single-file-component).
+such as a `css` tag, which will be used to write [single file components](../learning/how_to_write_sfc.md).
 
 ### Asynchronous Rendering
 

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`.
+
+```
+Component                               misc
+Context                                     AsyncRoot
+QWeb                                        Portal
+Store                                   router
+useState                                    Link
+config                                      RouteComponent
+    mode                                    Router
+core                                    tags
+    EventBus                                css
+    Observer                                xml
+hooks                                   utils
+    onWillStart                             debounce
+    onMounted                               escape
+    onWillUpdateProps                       loadJS
+    onWillPatch                             loadFile
+    onPatched                               shallowEqual
+    onWillUnmount                           whenReady
+    useContext
+    useState
+    useRef
+    useSubEnv
+    useStore
+    useDispatch
+    useGetters
+```
+
+Note that for convenience, the `useState` hook is also exported at the root of the `owl` object.

doc/reference/context.md

@@ -57,7 +57,7 @@ class SomeComponent extends Component {
       <t t-if=device.isMobile>
           some simplified user interface
       </t>
-      <t t-else="1">
+      <t t-else="">
           a more advanced user interface
       </t>
     </div>`;

doc/reference/environment.md

@@ -40,8 +40,8 @@ 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 explicitely setup,
-  this will be return the empty `env` object defined on `Component`)
+- 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

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_handling.md

@@ -0,0 +1,137 @@
+# 🦉 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.
+
+## 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

@@ -17,6 +17,7 @@
   - [`useContext`](#usecontext)
   - [`useRef`](#useref)
   - [`useSubEnv`](#usesubenv)
+  - [`useExternalListener`](#useexternallistener)
   - [`useStore`](#usestore)
   - [`useDispatch`](#usedispatch)
   - [`useGetters`](#usegetters)
@@ -354,6 +355,17 @@ will be added to the parent environment. Note that it will extend, not replace
 the parent environment. And of course, the parent environment will not be
 affected.
 
+### `useExternalListener`
+
+The `useExternalListener` hook helps solve a very common problem: adding and removing
+a listener on some target whenever a component is mounted/unmounted. For example,
+a dropdown menu (or its parent) may need to listen to a `click` event on `window`
+to be closed:
+
+```js
+useExternalListener(window, "click", this.closeMenu);
+```
+
 ### `useStore`
 
 The `useStore` hook is the entry point for a component to connect to the store.

doc/reference/misc.md

@@ -1,5 +1,116 @@
 # 🦉 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 } = owl;
+const { Portal } = owl.misc;
+
+class TeleportedComponent extends Component {}
+class App extends Component {
+  static components = { Portal, TeleportedComponent };
+}
+
+const app = new App();
+app.mount(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/qweb_engine.md

@@ -61,7 +61,7 @@ Its API is quite simple:
   ```
 
 - **`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)).
+  which is a virtual representation of the DOM (see [vdom doc](../miscellaneous/vdom.md)).
 
   ```js
   const vnode = qweb.render("App", component);

doc/reference/qweb_templating_language.md

@@ -28,7 +28,7 @@ generate a virtual dom representation of the HTML.
 ```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>
@@ -71,9 +71,9 @@ needs. Here is a list of all Owl specific directives:
 | `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)](#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)                         |
 
 ## Reference
@@ -101,7 +101,7 @@ 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>
 ```
 
@@ -500,6 +500,15 @@ will result in :
 </div>
 ```
 
+This can be used to define variables scoped to a sub template:
+
+```xml
+<t t-call="other-template">
+    <t t-set="var" t-value="1"/>
+</t>
+<!-- "var" does not exist here -->
+```
+
 ### Translations
 
 By default, QWeb specify that templates should be translated. If this behaviour

doc/reference/slots.md

@@ -0,0 +1,93 @@
+# 🦉 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.
+
+```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` 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.
+
+## 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).

doc/reference/store.md

@@ -25,8 +25,8 @@ 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.
+`actions`. Owl components can then connect to the store to read their relevant
+state, and they will be rerendered if the state is updated.
 
 Note: Owl store is inspired by React Redux and VueX.
 
@@ -208,7 +208,11 @@ 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:
+means that the component needs a reference to the store. By default, it looks
+for it in the `env.store` key. However, this can be configured with the `useStore`
+hook.
+
+Every component-store interactions are 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,
@@ -229,6 +233,14 @@ const state = {
 const store = new owl.Store({ state, actions });
 ```
 
+To make it accessible to the complete application, we will put it in the
+environment:
+
+```js
+// in this example, the root component is App
+App.env.store = store;
+```
+
 A counter component can then select this value and dispatch an action like this:
 
 ```js

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
-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](../tooling.md#single-file-component).
+Tags are very small helpers intended to make it easy to write inline templates
+or styles. There are currently two tags: `css` and `xml`. With these functions,
+it is possible to write [single file components](../learning/how_to_write_sfc.md).
 
 ## XML tag
 
-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 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/tooling.md

@@ -1,107 +0,0 @@
-# 🦉 Tooling 🦉
-
-## Content
-
-- [Overview](#overview)
-- [Playground](#playground)
-- [Benchmarks](#benchmarks)
-- [Single File Component](#single-file-component)
-- [Debugging Script](#debugging-script)
-
-## 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_engine.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.
-
-## Debugging Script
-
-## Debugging
-
-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:
-
-```
-let debugSetup = {
-  // 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
-};
-{let o,t="[OWL_DEBUG]";function toStr(o){let t=JSON.stringify(o||{});return t.length>200&&(t=t.slice(0,200)+"..."),t}function debugComponent(o,e,n){let l=`${e}<id=${n}>`,r=o=>(!debugSetup.methodBlackList||!debugSetup.methodBlackList.includes(o))&&!(debugSetup.methodWhiteList&&!debugSetup.methodWhiteList.includes(o));r("constructor")&&console.log(`${t} ${l} constructor, props=${toStr(o.props)}`),r("willStart")&&owl.hooks.onWillStart(()=>{console.log(`${t} ${l} willStart`)}),r("mounted")&&owl.hooks.onMounted(()=>{console.log(`${t} ${l} mounted`)}),r("willUpdateProps")&&owl.hooks.onWillUpdateProps(o=>{console.log(`${t} ${l} willUpdateProps, nextprops=${toStr(o)}`)}),r("willPatch")&&owl.hooks.onWillPatch(()=>{console.log(`${t} ${l} willPatch`)}),r("patched")&&owl.hooks.onPatched(()=>{console.log(`${t} ${l} patched`)}),r("willUnmount")&&owl.hooks.onWillUnmount(()=>{console.log(`${t} ${l} willUnmount`)});const s=o.__render.bind(o);o.__render=function(...o){console.log(`${t} ${l} rendering template`),s(...o)};const u=o.render.bind(o);o.render=function(...o){return console.log(`${t} ${l} render`),u(...o)};const c=o.mount.bind(o);o.mount=function(...o){return console.log(`${t} ${l} mount`),c(...o)}}if(Object.defineProperty(owl.Component,"current",{get:()=>o,set(t){o=t;const e=t.constructor.name;if(debugSetup.componentBlackList&&debugSetup.componentBlackList.test(e))return;if(debugSetup.componentWhiteList&&!debugSetup.componentWhiteList.test(e))return;let n;Object.defineProperty(o,"__owl__",{get:()=>n,set(o){debugComponent(t,e,(n=o).id)}})}}),debugSetup.logScheduler){let o;Object.defineProperty(owl.Component.scheduler,"isRunning",{get:()=>o,set(e){e?console.log(`${t} scheduler: start running tasks queue`):console.log(`${t} scheduler: stop running tasks queue`),o=e}})}if(debugSetup.logStore){let o=owl.Store.prototype.dispatch;owl.Store.prototype.dispatch=function(e,...n){return console.log(`${t} store: action '${e}' dispatched. Payload: '${toStr(n)}'`),o.call(this,e,...n)}}}
-
-```
-
-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.

package.json

@@ -1,8 +1,13 @@
 {
-  "name": "owl-framework",
-  "version": "1.0.0-alpha5",
+  "name": "@odoo/owl",
+  "version": "1.0.5",
   "description": "Odoo Web Library (OWL)",
-  "main": "src/index.ts",
+  "main": "dist/owl.js",
+  "types": "dist/types/index.d.ts",
+  "files": [
+    "dist/types/",
+    "dist/owl.js"
+  ],
   "engines": {
     "node": ">=10.15.3"
   },
@@ -18,14 +23,16 @@
     "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",
+    "publish": "npm run buildcommonjs && 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"
   },
@@ -33,8 +40,10 @@
   "dependencies": {},
   "devDependencies": {
     "@types/jest": "^23.3.12",
+    "chalk": "^3.0.0",
     "cpx": "^1.5.0",
     "git-rev-sync": "^1.12.0",
+    "github-api": "^3.3.0",
     "jest": "^23.6.0",
     "jest-environment-jsdom": "^24.7.1",
     "live-server": "^1.2.1",

roadmap.md

@@ -1,47 +1,25 @@
 # 🦉 OWL Roadmap 🦉
 
-- Current version: 1.0.0-alpha5
-- Status: mostly stable
+- Current version: 1.0.5
+- 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?)
 
 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.
 

src/component/component.ts

@@ -6,6 +6,7 @@ import "./directive";
 import { Fiber } from "./fiber";
 import "./props_validation";
 import { Scheduler, scheduler } from "./scheduler";
+import { activateSheet } from "./styles";
 
 /**
  * Owl Component System
@@ -36,12 +37,18 @@ export interface Env {
   [key: string]: any;
 }
 
+export type MountPosition = "first-child" | "last-child" | "self";
+
+interface MountOptions {
+  position?: MountPosition;
+}
+
 /**
  * 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> {
+interface Internal<T extends Env> {
   // each component has a unique id, useful mostly to handle parent/child
   // relationships
   readonly id: number;
@@ -53,8 +60,8 @@ interface Internal<T extends Env, Props> {
 
   // parent and children keys are obviously useful to setup the parent-children
   // relationship.
-  parent: Component<T, any> | null;
-  children: { [key: number]: Component<T, any> };
+  parent: Component<any, T> | null;
+  children: { [key: number]: Component<any, T> };
   // 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.
@@ -66,10 +73,9 @@ interface Internal<T extends Env, Props> {
   parentLastFiberId: number;
 
   // when a rendering is initiated by a parent, it may set variables in 'scope'
-  // and 'vars' (typically when the component is rendered in a slot). We need to
+  // (typically when the component is rendered in a slot). We need to
   // store that information in case the component would be re-rendered later on.
   scope: any;
-  vars: any;
 
   boundHandlers: { [key: number]: any };
   observer: Observer | null;
@@ -81,19 +87,21 @@ interface Internal<T extends Env, Props> {
   willStartCB: Function | null;
   willUpdatePropsCB: Function | null;
   classObj: { [key: string]: boolean } | null;
-  refs: { [key: string]: Component<T, any> | HTMLElement | undefined } | null;
+  refs: { [key: string]: Component<any, T> | HTMLElement | undefined } | null;
 }
 
+export const portalSymbol = Symbol("portal"); // FIXME
+
 //------------------------------------------------------------------------------
 // Component
 //------------------------------------------------------------------------------
 let nextId = 1;
 
-export class Component<T extends Env, Props extends {}> {
-  readonly __owl__: Internal<Env, Props>;
+export class Component<Props extends {} = any, T extends Env = Env> {
+  readonly __owl__: Internal<T>;
   static template?: string | null = null;
   static _template?: string | null = null;
-  static current: Component<any, any> | null = null;
+  static current: Component | null = null;
   static components = {};
   static props?: any;
   static defaultProps?: any;
@@ -123,7 +131,7 @@ export class Component<T extends Env, Props extends {}> {
    * hand.  Other components should be created automatically by the framework (with
    * the t-component directive in a template)
    */
-  constructor(parent?: Component<T, any> | null, props?: Props) {
+  constructor(parent?: Component<any, T> | null, props?: Props) {
     Component.current = this;
 
     let constr = this.constructor as any;
@@ -191,9 +199,11 @@ export class Component<T extends Env, Props extends {}> {
       renderFn: qweb.render.bind(qweb, template),
       classObj: null,
       refs: null,
-      scope: null,
-      vars: null
+      scope: null
     };
+    if (constr.style) {
+      this.__applyStyles(constr);
+    }
   }
 
   /**
@@ -289,20 +299,36 @@ export class Component<T extends Env, Props extends {}> {
    *
    * Note that a component can be mounted an unmounted several times
    */
-  async mount(target: HTMLElement | DocumentFragment): Promise<void> {
+  async mount(target: HTMLElement | DocumentFragment, options: MountOptions = {}): Promise<void> {
+    const position = options.position || "last-child";
     const __owl__ = this.__owl__;
     if (__owl__.isMounted) {
-      return Promise.resolve();
+      if (position !== "self" && this.el!.parentNode !== target) {
+        // in this situation, we are trying to mount a component on a different
+        // target. In this case, we need to unmount first, otherwise it will
+        // not work.
+        this.unmount();
+      } else {
+        return Promise.resolve();
+      }
+    }
+    if (__owl__.currentFiber) {
+      const currentFiber = __owl__.currentFiber;
+      if (currentFiber.target === target && currentFiber.position === position) {
+        return scheduler.addFiber(currentFiber);
+      } else {
+        scheduler.rejectFiber(currentFiber, "Mounting operation cancelled");
+      }
     }
     if (!(target instanceof HTMLElement || target instanceof DocumentFragment)) {
       let message = `Component '${this.constructor.name}' cannot be mounted: the target is not a valid DOM node.`;
       message += `\nMaybe the DOM is not ready yet? (in that case, you can use owl.utils.whenReady)`;
       throw new Error(message);
     }
-    const fiber = new Fiber(null, this, false, target);
+    const fiber = new Fiber(null, this, false, target, position);
     fiber.shouldPatch = false;
     if (!__owl__.vnode) {
-      this.__prepareAndRender(fiber);
+      this.__prepareAndRender(fiber, () => {});
     } else {
       this.__render(fiber);
     }
@@ -344,9 +370,12 @@ export class Component<T extends Env, Props extends {}> {
     // currentFiber that is already rendered (isRendered is true), so we are
     // about to be mounted
     const isMounted = __owl__.isMounted;
-    const fiber = new Fiber(null, this, force, null);
+    const fiber = new Fiber(null, this, force, null, null);
     Promise.resolve().then(() => {
       if (__owl__.isMounted || !isMounted) {
+        if (fiber.isCompleted) {
+          return;
+        }
         // we are mounted (__owl__.isMounted), or if we are currently being
         // mounted (!isMounted), so we call __render
         this.__render(fiber);
@@ -397,14 +426,7 @@ export class Component<T extends Env, Props extends {}> {
    * willUnmount().
    */
   trigger(eventType: string, payload?: any) {
-    if (this.el) {
-      const ev = new OwlEvent(this, eventType, {
-        bubbles: true,
-        cancelable: true,
-        detail: payload
-      });
-      this.el.dispatchEvent(ev);
-    }
+    this.__trigger(this, eventType, payload);
   }
 
   //--------------------------------------------------------------------------
@@ -422,7 +444,7 @@ export class Component<T extends Env, Props extends {}> {
    * Note that it does not call the __callWillUnmount method to avoid visiting
    * all children many times.
    */
-  __destroy(parent: Component<any, any> | null) {
+  __destroy(parent: Component | null) {
     const __owl__ = this.__owl__;
     const isMounted = __owl__.isMounted;
     if (isMounted) {
@@ -478,18 +500,34 @@ export class Component<T extends Env, Props extends {}> {
       }
     }
   }
-
+  /**
+   * Private trigger method, allows to choose the component which triggered
+   * the event in the first place
+   */
+  __trigger(component: Component, eventType: string, payload?: any) {
+    if (this.el) {
+      const ev = new OwlEvent(component, eventType, {
+        bubbles: true,
+        cancelable: true,
+        detail: payload
+      });
+      const triggerHook = this.env[portalSymbol as any];
+      if (triggerHook) {
+        triggerHook(ev);
+      }
+      this.el.dispatchEvent(ev);
+    }
+  }
   /**
    * 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): Promise<void> {
+  async __updateProps(nextProps: Props, parentFiber: Fiber, scope: any): Promise<void> {
     this.__owl__.scope = scope;
-    this.__owl__.vars = vars;
     const shouldUpdate = parentFiber.force || this.shouldUpdate(nextProps);
     if (shouldUpdate) {
       const __owl__ = this.__owl__;
-      const fiber = new Fiber(parentFiber, this, parentFiber.force, null);
+      const fiber = new Fiber(parentFiber, this, parentFiber.force, null, null);
       if (!parentFiber.child) {
         parentFiber.child = fiber;
       } else {
@@ -521,21 +559,18 @@ export class Component<T extends Env, Props extends {}> {
    * Main patching method. We call the virtual dom patch method here to convert
    * a virtual dom vnode into some actual dom.
    */
-  __patch(vnode: VNode) {
-    const __owl__ = this.__owl__;
-    const target = __owl__.vnode || document.createElement(vnode.sel!);
-    __owl__.vnode = patch(target, vnode);
+  __patch(target: HTMLElement | VNode | DocumentFragment, vnode: VNode) {
+    this.__owl__.vnode = patch(target as any, vnode);
   }
 
   /**
    * 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
+   * subcomponent is created. It gets its scope, if any, from the
    * parent template.
    */
-  __prepare(parentFiber: Fiber, scope: any, vars: any) {
+  __prepare(parentFiber: Fiber, scope: any, cb: CallableFunction): Fiber {
     this.__owl__.scope = scope;
-    this.__owl__.vars = vars;
-    const fiber = new Fiber(parentFiber, this, parentFiber.force, null);
+    const fiber = new Fiber(parentFiber, this, parentFiber.force, null, null);
     fiber.shouldPatch = false;
     if (!parentFiber.child) {
       parentFiber.child = fiber;
@@ -543,9 +578,24 @@ export class Component<T extends Env, Props extends {}> {
       parentFiber.lastChild!.sibling = fiber;
     }
     parentFiber.lastChild = fiber;
-    return this.__prepareAndRender(fiber);
+    this.__prepareAndRender(fiber, cb);
+    return fiber;
   }
 
+  /**
+   * Apply the stylesheets defined by the component. Note that we need to make
+   * sure all inherited stylesheets are applied as well.  We then delete the
+   * `style` key from the constructor to make sure we do not apply it again.
+   */
+  private __applyStyles(constr) {
+    while (constr && constr.style) {
+      if (constr.hasOwnProperty("style")) {
+        activateSheet(constr.style, constr.name);
+        delete constr.style;
+      }
+      constr = constr.__proto__;
+    }
+  }
   __getTemplate(qweb: QWeb): string {
     let p = (<any>this).constructor;
     if (!p.hasOwnProperty("_template")) {
@@ -565,7 +615,7 @@ export class Component<T extends Env, Props extends {}> {
     }
     return p._template;
   }
-  async __prepareAndRender(fiber: Fiber) {
+  async __prepareAndRender(fiber: Fiber, cb: CallableFunction) {
     try {
       await Promise.all([this.willStart(), this.__owl__.willStartCB && this.__owl__.willStartCB()]);
     } catch (e) {
@@ -577,6 +627,7 @@ export class Component<T extends Env, Props extends {}> {
     }
     if (!fiber.isCompleted) {
       this.__render(fiber);
+      cb();
     }
   }
 

src/component/directive.ts

@@ -1,6 +1,6 @@
 import { QWeb } from "../qweb/index";
 import { INTERP_REGEXP } from "../qweb/compilation_context";
-import { MODS_CODE } from "../qweb/extensions";
+import { makeHandlerCode, MODS_CODE } from "../qweb/extensions";
 
 //------------------------------------------------------------------------------
 // t-component
@@ -23,6 +23,26 @@ QWeb.utils.defineProxy = function defineProxy(target, source) {
   }
 };
 
+QWeb.utils.assignHooks = function assignHooks(dataObj, hooks) {
+  if ("hook" in dataObj) {
+    const hookObject = dataObj.hook;
+    for (let name in hooks) {
+      const current = hookObject[name];
+      const fn = hooks[name];
+      if (current) {
+        hookObject[name] = (...args) => {
+          current(...args);
+          fn(...args);
+        };
+      } else {
+        hookObject[name] = fn;
+      }
+    }
+  } else {
+    dataObj.hook = hooks;
+  }
+};
+
 /**
  * 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
@@ -189,15 +209,15 @@ QWeb.addDirective({
   extraNames: ["props"],
   priority: 100,
   atNodeEncounter({ ctx, value, node, qweb }): boolean {
-    ctx.addLine("//COMPONENT");
-    ctx.rootContext.shouldDefineOwner = true;
+    ctx.addLine(`// Component '${value}'`);
     ctx.rootContext.shouldDefineQWeb = true;
     ctx.rootContext.shouldDefineParent = true;
     ctx.rootContext.shouldDefineUtils = true;
+    ctx.rootContext.shouldDefineScope = true;
     let hasDynamicProps = node.getAttribute("t-props") ? true : false;
 
     // t-on- events and t-transition
-    const events: [string, string[], string, string][] = [];
+    const events: [string, string][] = [];
     let transition: string = "";
     const attributes = (<Element>node).attributes;
     const props: { [key: string]: string } = {};
@@ -205,19 +225,13 @@ QWeb.addDirective({
       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]);
+        events.push([name, value]);
       } 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);
+          props[name] = ctx.formatExpression(value) || "undefined";
         }
       }
     }
@@ -226,7 +240,6 @@ QWeb.addDirective({
     let propStr = Object.keys(props)
       .map(k => k + ":" + props[k])
       .join(",");
-    let defID = ctx.generateID();
     let componentID = ctx.generateID();
 
     const templateKey = ctx.generateTemplateKey();
@@ -285,37 +298,25 @@ QWeb.addDirective({
         }
       }
       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, ${ctx.formatExpression(extraArgs)}`;
-            }
+        .map(function([name, value]) {
+          const capture = name.match(/\.capture/);
+          name = capture ? name.replace(/\.capture/, "") : name;
+          const { event, handler } = makeHandlerCode(
+            ctx,
+            name,
+            value,
+            false,
+            T_COMPONENT_MODS_CODE
+          );
+          if (capture) {
+            return `vn.elm.addEventListener('${event}', ${handler}, true);`;
           }
-          let handler = `function (e) {`;
-          handler += mods
-            .map(function(mod) {
-              return T_COMPONENT_MODS_CODE[mod];
-            })
-            .join("");
-          if (handlerValue) {
-            handler += `const fn = owner['${handlerValue}'];`;
-            handler += `if (fn) { fn.call(${params}, e); } else { owner.${handlerValue}; }`;
-          }
-          handler += `}`;
-          return `vn.elm.addEventListener('${eventName}', ${handler});`;
+          return `vn.elm.addEventListener('${event}', ${handler});`;
         })
         .join("");
       const styleExpr = tattStyle || (styleAttr ? `'${styleAttr}'` : false);
       const styleCode = styleExpr ? `vn.elm.style = ${styleExpr};` : "";
-      createHook = `vnode.data.hook = {create(_, vn){${styleCode}${eventsCode}}};`;
+      createHook = `utils.assignHooks(vnode.data, {create(_, vn){${styleCode}${eventsCode}}});`;
     }
 
     ctx.addLine(
@@ -349,25 +350,9 @@ QWeb.addDirective({
     }
 
     // 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";
-    }
+    let scope = hasSlots ? `Object.assign(Object.create(context), scope)` : "undefined";
 
     ctx.addIf(`w${componentID}`);
 
@@ -377,8 +362,7 @@ QWeb.addDirective({
       styleCode = `.then(()=>{if (w${componentID}.__owl__.isDestroyed) {return};w${componentID}.el.style=${tattStyle};});`;
     }
     ctx.addLine(
-      `w${componentID}.__updateProps(props${componentID}, extra.fiber${scopeVars &&
-        ", " + scopeVars})${styleCode};`
+      `w${componentID}.__updateProps(props${componentID}, extra.fiber, ${scope})${styleCode};`
     );
     ctx.addLine(`let pvnode = w${componentID}.__owl__.pvnode;`);
     if (registerCode) {
@@ -409,7 +393,7 @@ QWeb.addDirective({
     if (transition) {
       ctx.addLine(`const __patch${componentID} = w${componentID}.__patch;`);
       ctx.addLine(
-        `w${componentID}.__patch = fiber => {__patch${componentID}.call(w${componentID}, fiber); if(!w${componentID}.__owl__.transitionInserted){w${componentID}.__owl__.transitionInserted = true;utils.transitionInsert(w${componentID}.__owl__.vnode, '${transition}');}};`
+        `w${componentID}.__patch = (t, vn) => {__patch${componentID}.call(w${componentID}, t, vn); if(!w${componentID}.__owl__.transitionInserted){w${componentID}.__owl__.transitionInserted = true;utils.transitionInsert(w${componentID}.__owl__.vnode, '${transition}');}};`
       );
     }
     ctx.addLine(`parent.__owl__.cmap[${templateKey}] = w${componentID}.__owl__.id;`);
@@ -439,16 +423,14 @@ QWeb.addDirective({
       }
     }
 
-    ctx.addLine(`let def${defID} = w${componentID}.__prepare(extra.fiber, ${scopeVars});`);
+    ctx.addLine(
+      `let fiber = w${componentID}.__prepare(extra.fiber, ${scope}, () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; ${createHook}});`
+    );
     // hack: specify empty remove hook to prevent the node from being removed from the DOM
     const insertHook = refExpr ? `insert(vn) {${refExpr}},` : "";
     ctx.addLine(
       `let pvnode = h('dummy', {key: ${templateKey}, hook: {${insertHook}remove() {},destroy(vn) {${finalizeComponentCode}}}});`
     );
-    ctx.addLine(`const fiber = w${componentID}.__owl__.currentFiber;`);
-    ctx.addLine(
-      `def${defID}.then(function () { if (fiber.isCompleted) { return; } const vnode = fiber.vnode; pvnode.sel = vnode.sel; ${createHook}});`
-    );
     if (registerCode) {
       ctx.addLine(registerCode);
     }

src/component/fiber.ts

@@ -1,5 +1,5 @@
 import { h, VNode } from "../vdom/index";
-import { Component } from "./component";
+import { Component, MountPosition } from "./component";
 import { scheduler } from "./scheduler";
 
 /**
@@ -46,12 +46,12 @@ export class Fiber {
   // scheduler.
   counter: number = 0;
 
-  target: HTMLElement | null;
+  target: HTMLElement | DocumentFragment | null;
+  position: MountPosition | null;
 
   scope: any;
-  vars: any;
 
-  component: Component<any, any>;
+  component: Component;
   vnode: VNode | null = null;
 
   root: Fiber;
@@ -62,14 +62,20 @@ export class Fiber {
 
   error?: Error;
 
-  constructor(parent: Fiber | null, component: Component<any, any>, force, target) {
+  constructor(
+    parent: Fiber | null,
+    component: Component,
+    force: boolean,
+    target: HTMLElement | DocumentFragment | null,
+    position: MountPosition | null
+  ) {
     this.component = component;
     this.force = force;
     this.target = target;
+    this.position = position;
 
     const __owl__ = component.__owl__;
     this.scope = __owl__.scope;
-    this.vars = __owl__.vars;
 
     this.root = parent ? parent.root : this;
     this.parent = parent;
@@ -180,7 +186,6 @@ export class Fiber {
    */
   complete() {
     let component = this.component;
-    let fiber: Fiber = this;
     this.isCompleted = true;
     if (!this.target && !component.__owl__.isMounted) {
       return;
@@ -195,58 +200,73 @@ export class Fiber {
     this._walk(doWork);
     const patchLen = patchQueue.length;
 
-    try {
-      // call willPatch hook on each fiber of patchQueue
-      for (let i = 0; i < patchLen; i++) {
-        fiber = patchQueue[i];
-        if (fiber.shouldPatch) {
-          component = fiber.component;
-          if (component.__owl__.willPatchCB) {
-            component.__owl__.willPatchCB();
-          }
-          component.willPatch();
-        }
-      }
-
-      // call __patch on each fiber of (reversed) patchQueue
-      for (let i = patchLen - 1; i >= 0; i--) {
-        fiber = patchQueue[i];
+    // call willPatch hook on each fiber of patchQueue
+    for (let i = 0; i < patchLen; i++) {
+      const fiber = patchQueue[i];
+      if (fiber.shouldPatch) {
         component = fiber.component;
-        component.__patch(fiber.vnode!);
-        if (!fiber.shouldPatch && (!fiber.target || i !== 0)) {
+        if (component.__owl__.willPatchCB) {
+          component.__owl__.willPatchCB();
+        }
+        component.willPatch();
+      }
+    }
+
+    // call __patch on each fiber of (reversed) patchQueue
+    for (let i = patchLen - 1; i >= 0; i--) {
+      const fiber = patchQueue[i];
+      component = fiber.component;
+      if (fiber.target && i === 0) {
+        let target;
+        if (fiber.position === "self") {
+          target = fiber.target;
+          if ((target as HTMLElement).tagName.toLowerCase() !== fiber.vnode!.sel) {
+            throw new Error(
+              `Cannot attach '${component.constructor.name}' to target node (not same tag name)`
+            );
+          }
+        } else {
+          target = component.__owl__.vnode || document.createElement(fiber.vnode!.sel!);
+        }
+        component.__patch(target!, fiber.vnode!);
+      } else {
+        if (fiber.shouldPatch) {
+          component.__patch(component.__owl__.vnode!, fiber.vnode!);
+        } else {
+          component.__patch(document.createElement(fiber.vnode!.sel!), fiber.vnode!);
           component.__owl__.pvnode!.elm = component.__owl__.vnode!.elm;
         }
-        component.__owl__.currentFiber = null;
       }
+      component.__owl__.currentFiber = null;
+    }
 
-      // insert into the DOM (mount case)
-      let inDOM = false;
-      if (this.target) {
-        this.target.appendChild(this.component.el!);
-        inDOM = document.body.contains(this.target);
+    // insert into the DOM (mount case)
+    let inDOM = false;
+    if (this.target) {
+      switch (this.position) {
+        case "first-child":
+          this.target.prepend(this.component.el!);
+          break;
+        case "last-child":
+          this.target.appendChild(this.component.el!);
+          break;
       }
+      inDOM = document.body.contains(this.component.el);
+      this.component.env.qweb.trigger("dom-appended");
+    }
 
-      // call patched/mounted hook on each fiber of (reversed) patchQueue
-      for (let i = patchLen - 1; i >= 0; i--) {
-        fiber = patchQueue[i];
-        component = fiber.component;
-        if (fiber.shouldPatch && !this.target) {
-          component.patched();
-          if (component.__owl__.patchedCB) {
-            component.__owl__.patchedCB();
-          }
-        } else if (this.target ? inDOM : true) {
-          component.__callMounted();
+    // call patched/mounted hook on each fiber of (reversed) patchQueue
+    for (let i = patchLen - 1; i >= 0; i--) {
+      const fiber = patchQueue[i];
+      component = fiber.component;
+      if (fiber.shouldPatch && !this.target) {
+        component.patched();
+        if (component.__owl__.patchedCB) {
+          component.__owl__.patchedCB();
         }
+      } else if (this.target ? inDOM : true) {
+        component.__callMounted();
       }
-    } catch (e) {
-      // if there is no current fiber on component, we are in the situation where
-      // components were patched to the DOM, but a mounted/patched hook threw an
-      // error.  In that case, we cannot manage the error at a lower level than
-      // the root fiber, since some components may not have been properly mounted
-      // patched yet.
-      const errorFiber = component.__owl__.currentFiber ? fiber : this;
-      errorFiber.handleError(e);
     }
   }
 
@@ -285,11 +305,7 @@ export class Fiber {
     qweb.trigger("error", error);
 
     if (canCatch) {
-      // this.root.isCompleted = false
-      this.root.isCompleted = false;
-      // component.__owl__.currentFiber!.root.isCompleted = false;
       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

src/component/scheduler.ts

@@ -25,7 +25,16 @@ export class Scheduler {
     this.requestAnimationFrame = requestAnimationFrame;
   }
 
-  addFiber(fiber): Promise<void> {
+  start() {
+    this.isRunning = true;
+    this.scheduleTasks();
+  }
+
+  stop() {
+    this.isRunning = false;
+  }
+
+  addFiber(fiber: Fiber): Promise<void> {
     // if the fiber was remapped into a larger rendering fiber, it may not be a
     // root fiber.  But we only want to register root fibers
     fiber = fiber.root;
@@ -43,11 +52,22 @@ export class Scheduler {
         }
       });
       if (!this.isRunning) {
-        this.scheduleTasks();
+        this.start();
       }
     });
   }
 
+  rejectFiber(fiber: Fiber, reason: string) {
+    fiber = fiber.root;
+    const index = this.tasks.findIndex(t => t.fiber === fiber);
+    if (index >= 0) {
+      const [task] = this.tasks.splice(index, 1);
+      fiber.cancel();
+      fiber.error = new Error(reason);
+      task.callback();
+    }
+  }
+
   /**
    * Process all current tasks. This only applies to the fibers that are ready.
    * Other tasks are left unchanged.
@@ -62,9 +82,10 @@ export class Scheduler {
       }
       if (task.fiber.counter === 0) {
         if (!task.fiber.error) {
-          task.fiber.complete();
-          if (!task.fiber.isCompleted) {
-            return true;
+          try {
+            task.fiber.complete();
+          } catch (e) {
+            task.fiber.handleError(e);
           }
         }
         task.callback();
@@ -73,16 +94,16 @@ export class Scheduler {
       return true;
     });
     this.tasks = tasks.concat(this.tasks);
+    if (this.tasks.length === 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;
       }
     });
   }

src/component/styles.ts

@@ -0,0 +1,70 @@
+/**
+ * Owl Style System
+ *
+ * This files contains the Owl code related to processing (extended) css strings
+ * and creating/adding <style> tags to the document head.
+ */
+
+export const STYLESHEETS: { [id: string]: HTMLStyleElement } = {};
+
+export 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");
+}
+export function registerSheet(id: string, css: string) {
+  const sheet = document.createElement("style");
+  sheet.innerHTML = processSheet(css);
+  STYLESHEETS[id] = sheet;
+}
+
+export function activateSheet(id, name) {
+  const sheet = STYLESHEETS[id];
+  if (!sheet) {
+    throw new Error(
+      `Invalid css stylesheet for component '${name}'. Did you forget to use the 'css' tag helper?`
+    );
+  }
+  sheet.setAttribute("component", name);
+  document.head.appendChild(sheet);
+}

src/context.ts

@@ -100,11 +100,11 @@ export class Context extends EventBus {
  * to context state changes. The `useContext` method returns the context state
  */
 export function useContext(ctx: Context): any {
-  const component: Component<any, any> = Component.current!;
+  const component: Component = Component.current!;
   return useContextWithCB(ctx, component, component.render.bind(component));
 }
 
-export function useContextWithCB(ctx: Context, component: Component<any, any>, method): any {
+export function useContextWithCB(ctx: Context, component: Component, method): any {
   const __owl__ = component.__owl__;
   const id = __owl__.id;
   const mapping = ctx.mapping;

src/core/observer.ts

@@ -20,7 +20,6 @@
 export class Observer {
   rev: number = 1;
   allowMutations: boolean = true;
-  dirty: boolean = false;
   weakMap: WeakMap<any, any> = new WeakMap();
 
   notifyCB() {}

src/core/owl_event.ts

@@ -7,7 +7,7 @@ import { Component } from "../component/component";
  */
 
 export class OwlEvent<T> extends CustomEvent<T> {
-  originalComponent: Component<any, any>;
+  originalComponent: Component;
   constructor(component, eventType, options) {
     super(eventType, options);
     this.originalComponent = component;

src/hooks.ts

@@ -22,7 +22,7 @@ import { Observer } from "./core/observer";
  * trigger a rerendering of the current component.
  */
 export function useState<T>(state: T): T {
-  const component: Component<any, any> = Component.current!;
+  const component: Component = Component.current!;
   const __owl__ = component.__owl__;
   if (!__owl__.observer) {
     __owl__.observer = new Observer();
@@ -37,7 +37,7 @@ export function useState<T>(state: T): T {
 function makeLifecycleHook(method: string, reverse: boolean = false) {
   if (reverse) {
     return function(cb) {
-      const component: Component<any, any> = Component.current!;
+      const component: Component = Component.current!;
       if (component.__owl__[method]) {
         const current = component.__owl__[method];
         component.__owl__[method] = function() {
@@ -50,7 +50,7 @@ function makeLifecycleHook(method: string, reverse: boolean = false) {
     };
   } else {
     return function(cb) {
-      const component: Component<any, any> = Component.current!;
+      const component: Component = Component.current!;
       if (component.__owl__[method]) {
         const current = component.__owl__[method];
         component.__owl__[method] = function() {
@@ -66,7 +66,7 @@ function makeLifecycleHook(method: string, reverse: boolean = false) {
 
 function makeAsyncHook(method: string) {
   return function(cb) {
-    const component: Component<any, any> = Component.current!;
+    const component: Component = Component.current!;
     if (component.__owl__[method]) {
       const current = component.__owl__[method];
       component.__owl__[method] = function(...args) {
@@ -96,7 +96,7 @@ export const onWillUpdateProps = makeAsyncHook("willUpdatePropsCB");
  */
 interface Ref {
   el: HTMLElement | null;
-  comp: Component<any, any> | null;
+  comp: Component | null;
 }
 
 export function useRef(name: string): Ref {
@@ -111,7 +111,7 @@ export function useRef(name: string): Ref {
       }
       return null;
     },
-    get comp(): Component<any, any> | null {
+    get comp(): Component | null {
       const val = __owl__.refs && __owl__.refs[name];
       return val instanceof Component ? val : null;
     }
@@ -131,3 +131,32 @@ export function useSubEnv(nextEnv) {
   const component = Component.current!;
   component.env = Object.assign(Object.create(component.env), nextEnv);
 }
+
+// -----------------------------------------------------------------------------
+// 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,
+  eventParams?
+) {
+  const boundHandler = handler.bind(Component.current);
+
+  onMounted(() => target.addEventListener(eventName, boundHandler, eventParams));
+  onWillUnmount(() => target.removeEventListener(eventName, boundHandler, eventParams));
+}

src/index.ts

@@ -12,6 +12,7 @@ import * as _store from "./store";
 import * as _utils from "./utils";
 import * as _tags from "./tags";
 import { AsyncRoot } from "./misc/async_root";
+import { Portal } from "./misc/portal";
 import * as _hooks from "./hooks";
 import * as _context from "./context";
 import { Link } from "./router/link";
@@ -29,7 +30,7 @@ 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 misc = { AsyncRoot, Portal };
 export const hooks = Object.assign({}, _hooks, {
   useContext: _context.useContext,
   useDispatch: _store.useDispatch,

src/misc/async_root.ts

@@ -10,7 +10,7 @@ import { xml } from "../tags";
  * from this coordination.  This is the goal of the AsyncRoot component.
  */
 
-export class AsyncRoot extends Component<any, any> {
+export class AsyncRoot extends Component {
   static template = xml`<t t-slot="default"/>`;
 
   async __updateProps(nextProps, parentFiber) {

src/misc/portal.ts

@@ -0,0 +1,171 @@
+import { Component, portalSymbol } from "../component/component";
+import { VNode, patch } from "../vdom/index";
+import { xml } from "../tags";
+import { OwlEvent } from "../core/owl_event";
+import { useSubEnv } from "../hooks";
+
+/**
+ * Portal
+ *
+ * The Portal component allows to render a part of a component outside it's DOM.
+ * It is for example useful for dialogs: for css reasons, dialogs are in general
+ * placed in a specific spot of the DOM (e.g. directly in the body). With the
+ * Portal, a component can conditionally specify in its tempate that it contains
+ * a dialog, and where this dialog should be inserted in the DOM.
+ *
+ * The Portal component ensures that the communication between the content of
+ * the Portal and its parent properly works: business events reaching the Portal
+ * are re-triggered on an empty <portal> node located in the parent's DOM.
+ */
+
+interface Props {
+  target: string;
+}
+
+export class Portal extends Component<Props> {
+  static template = xml`<portal><t t-slot="default"/></portal>`;
+  static props = {
+    target: {
+      type: String
+    }
+  };
+
+  // boolean to indicate whether or not we must listen to 'dom-appended' event
+  // to hook on the moment when the target is inserted into the DOM (because it
+  // is not when the portal is rendered)
+  doTargetLookUp: boolean = true;
+  // set of encountered events that need to be redirected
+  _handledEvents: Set<string> = new Set();
+  // function that will be the event's tunnel (needs to be an arrow function to
+  // avoid having to rebind `this`)
+  _handlerTunnel: (f: OwlEvent<any>) => void = (ev: OwlEvent<any>) => {
+    ev.stopPropagation();
+    this.__trigger(ev.originalComponent, ev.type, ev.detail);
+  };
+  // Storing the parent's env
+  parentEnv: any = null;
+  // represents the element that is moved somewhere else
+  portal: VNode | null = null;
+  // the target where we will move `portal`
+  target: Element | null = null;
+
+  constructor(parent, props) {
+    super(parent, props);
+    this.parentEnv = parent ? parent.env : {};
+    // put a callback in the env that is propagated to children s.t. portal can
+    // register an handler to those events just before children will trigger them
+    useSubEnv({
+      [portalSymbol]: ev => {
+        if (!this._handledEvents.has(ev.type)) {
+          this.portal!.elm!.addEventListener(ev.type, this._handlerTunnel);
+          this._handledEvents.add(ev.type);
+        }
+      }
+    });
+  }
+  /**
+   * Override to revert back to a classic Component's structure
+   *
+   * @override
+   */
+  __callWillUnmount() {
+    super.__callWillUnmount();
+    this.el!.appendChild(this.portal!.elm!);
+    this.doTargetLookUp = true;
+  }
+  /**
+   * At each DOM change, we must ensure that the portal contains exactly one
+   * child
+   */
+  __checkVNodeStructure(vnode: VNode) {
+    const children = vnode.children!;
+    let countRealNodes = 0;
+    for (let child of children) {
+      if ((child as VNode).sel) {
+        countRealNodes++;
+      }
+    }
+    if (countRealNodes !== 1) {
+      throw new Error(`Portal must have exactly one non-text child (has ${countRealNodes})`);
+    }
+  }
+  /**
+   * Ensure the target is still there at whichever time we render
+   */
+  __checkTargetPresence() {
+    if (!this.target || !document.contains(this.target)) {
+      throw new Error(`Could not find any match for "${this.props.target}"`);
+    }
+  }
+  /**
+   * Move the portal's element to the target
+   */
+  __deployPortal() {
+    this.__checkTargetPresence();
+    this.target!.appendChild(this.portal!.elm!);
+  }
+  /**
+   * Override to remove from the DOM the element we have teleported
+   *
+   * @override
+   */
+  __destroy(parent) {
+    if (this.portal && this.portal.elm) {
+      const displacedElm = this.portal.elm!;
+      const parent = displacedElm.parentNode;
+      if (parent) {
+        parent.removeChild(displacedElm);
+      }
+    }
+    super.__destroy(parent);
+  }
+  /**
+   * Override to patch the element that has been teleported
+   *
+   * @override
+   */
+  __patch(target, vnode) {
+    if (this.doTargetLookUp) {
+      const target = document.querySelector(this.props.target);
+      if (!target) {
+        this.env.qweb.on("dom-appended", this, () => {
+          this.doTargetLookUp = false;
+          this.env.qweb.off("dom-appended", this);
+          this.target = document.querySelector(this.props.target);
+          this.__deployPortal();
+        });
+      } else {
+        this.doTargetLookUp = false;
+        this.target = target;
+      }
+    }
+    this.__checkVNodeStructure(vnode);
+    const shouldDeploy =
+      (!this.portal || this.el!.contains(this.portal.elm!)) && !this.doTargetLookUp;
+
+    if (!this.doTargetLookUp && !shouldDeploy) {
+      // Only on pure patching, provided the
+      // this.target's parent has not been unmounted
+      this.__checkTargetPresence();
+    }
+
+    const portalPatch = this.portal ? this.portal : document.createElement(vnode.children[0].sel);
+    this.portal = patch(portalPatch, vnode.children![0] as VNode);
+    vnode.children = [];
+
+    super.__patch(target, vnode);
+
+    if (shouldDeploy) {
+      this.__deployPortal();
+    }
+  }
+  /**
+   * Override to set the env
+   */
+  __trigger(component: Component, eventType: string, payload?: any) {
+    const env = this.env;
+    this.env = this.parentEnv;
+    super.__trigger(component, eventType, payload);
+    this.env = env;
+  }
+}

src/qweb/base_directives.ts

@@ -1,6 +1,7 @@
 import { CompilationContext } from "./compilation_context";
 import { QWeb } from "./qweb";
 import { htmlToVDOM } from "../vdom/html_to_vdom";
+import { QWebVar } from "./expression_parser";
 
 /**
  * Owl QWeb Directives
@@ -19,38 +20,40 @@ import { htmlToVDOM } from "../vdom/html_to_vdom";
 //------------------------------------------------------------------------------
 // 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) {
+  ctx.rootContext.shouldDefineScope = true;
   if (value === "0") {
-    const caller = ctx.getCaller();
-    if (caller) {
-      qweb._compileNode(caller, ctx.getInliningContext());
-      return;
-    }
-  }
-
-  if (value.xml instanceof NodeList && !value.id) {
-    for (let node of Array.from(value.xml)) {
-      qweb._compileNode(<ChildNode>node, ctx);
+    if (ctx.parentNode) {
+      // the 'zero' magical symbol is where we can find the result of the rendering
+      // of  the body of the t-call.
+      ctx.rootContext.shouldDefineUtils = true;
+      const zeroArgs = ctx.escaping
+        ? `{text: utils.vDomToString(scope[utils.zero])}`
+        : `...scope[utils.zero]`;
+      ctx.addLine(`c${ctx.parentNode}.push(${zeroArgs});`);
     }
     return;
   }
+
   let exprID: string;
   if (typeof value === "string") {
     exprID = `_${ctx.generateID()}`;
-    ctx.addLine(`var ${exprID} = ${ctx.formatExpression(value)};`);
+    ctx.addLine(`let ${exprID} = ${ctx.formatExpression(value)};`);
   } else {
-    exprID = value.id;
+    exprID = `scope.${value.id}`;
   }
-  ctx.addIf(`${exprID} || ${exprID} === 0`);
+  ctx.addIf(`${exprID} != null`);
+
   if (ctx.escaping) {
+    let protectID;
+    if (value.hasBody) {
+      protectID = ctx.startProtectScope();
+      ctx.addLine(
+        `${exprID} = ${exprID} instanceof utils.VDomArray ? utils.vDomToString(${exprID}) : ${exprID};`
+      );
+    }
     if (ctx.parentTextNode) {
       ctx.addLine(`vn${ctx.parentTextNode}.text += ${exprID};`);
     } else if (ctx.parentNode) {
@@ -59,26 +62,30 @@ function compileValueNode(value: any, node: Element, qweb: QWeb, ctx: Compilatio
       let nodeID = ctx.generateID();
       ctx.rootContext.rootNode = nodeID;
       ctx.rootContext.parentTextNode = nodeID;
-      ctx.addLine(`var vn${nodeID} = {text: ${exprID}};`);
+      ctx.addLine(`let vn${nodeID} = {text: ${exprID}};`);
       if (ctx.rootContext.shouldDefineResult) {
         ctx.addLine(`result = vn${nodeID}`);
       }
     }
+    if (value.hasBody) {
+      ctx.stopProtectScope(protectID);
+    }
   } else {
     ctx.rootContext.shouldDefineUtils = true;
-    ctx.addLine(`c${ctx.parentNode}.push(...utils.htmlToVDOM(${exprID}));`);
+    if (value.hasBody) {
+      ctx.addLine(
+        `const vnodeArray = ${exprID} instanceof utils.VDomArray ? ${exprID} : utils.htmlToVDOM(${exprID});`
+      );
+      ctx.addLine(`c${ctx.parentNode}.push(...vnodeArray);`);
+    } else {
+      ctx.addLine(`c${ctx.parentNode}.push(...utils.htmlToVDOM(${exprID}));`);
+    }
   }
   if (node.childNodes.length) {
     ctx.addElse();
     qweb._compileChildren(node, ctx);
   }
 
-  if (value.xml instanceof NodeList && value.id) {
-    ctx.addElse();
-    for (let node of Array.from(value.xml)) {
-      qweb._compileNode(<ChildNode>node, ctx);
-    }
-  }
   ctx.closeIf();
 }
 
@@ -109,24 +116,51 @@ QWeb.addDirective({
   name: "set",
   extraNames: ["value"],
   priority: 60,
-  atNodeEncounter({ node, ctx }): boolean {
+  atNodeEncounter({ node, qweb, ctx }): boolean {
+    ctx.rootContext.shouldDefineScope = true;
     const variable = node.getAttribute("t-set")!;
     let value = node.getAttribute("t-value")!;
-    ctx.variables[variable] = ctx.variables[variable] || {};
+    ctx.variables[variable] = ctx.variables[variable] || ({} as QWebVar);
     let qwebvar = ctx.variables[variable];
+    const hasBody = node.hasChildNodes();
 
+    qwebvar.id = variable;
+    qwebvar.expr = `scope.${variable}`;
     if (value) {
       const formattedValue = ctx.formatExpression(value);
-      if (ctx.variables.hasOwnProperty(variable) && qwebvar.id) {
-        ctx.addLine(`${qwebvar.id} = ${formattedValue}`);
-      } else {
-        const varName = `_${ctx.generateID()}`;
-        ctx.addLine(`var ${varName} = ${formattedValue};`);
-        qwebvar.id = varName;
-        qwebvar.expr = formattedValue;
+      let scopeExpr = `scope`;
+      if (ctx.protectedScopeNumber) {
+        ctx.rootContext.shouldDefineUtils = true;
+        scopeExpr = `utils.getScope(scope, '${variable}')`;
+      }
+      ctx.addLine(`${scopeExpr}.${variable} = ${formattedValue};`);
+      qwebvar.value = formattedValue;
+    }
+
+    if (hasBody) {
+      ctx.rootContext.shouldDefineUtils = true;
+      if (value) {
+        ctx.addIf(`!(${qwebvar.expr})`);
+      }
+      const tempParentNodeID = ctx.generateID();
+      const _parentNode = ctx.parentNode;
+      ctx.parentNode = tempParentNodeID;
+
+      ctx.addLine(`let c${tempParentNodeID} = new utils.VDomArray();`);
+      const nodeCopy = node.cloneNode(true) as Element;
+      for (let attr of ["t-set", "t-value", "t-if", "t-else", "t-elif"]) {
+        nodeCopy.removeAttribute(attr);
+      }
+      qweb._compileNode(nodeCopy, ctx);
+
+      ctx.addLine(`${qwebvar.expr} = c${tempParentNodeID}`);
+      qwebvar.value = `c${tempParentNodeID}`;
+      qwebvar.hasBody = true;
+
+      ctx.parentNode = _parentNode;
+      if (value) {
+        ctx.closeIf();
       }
-    } else {
-      qwebvar.xml = node.childNodes;
     }
     return true;
   }
@@ -140,7 +174,7 @@ QWeb.addDirective({
   priority: 20,
   atNodeEncounter({ node, ctx }): boolean {
     let cond = ctx.getValue(node.getAttribute("t-if")!);
-    ctx.addIf(typeof cond === "string" ? ctx.formatExpression(cond) : cond.id!);
+    ctx.addIf(typeof cond === "string" ? ctx.formatExpression(cond) : `scope.${cond.id!}`);
     return false;
   },
   finalize({ ctx }) {
@@ -153,7 +187,9 @@ QWeb.addDirective({
   priority: 30,
   atNodeEncounter({ node, ctx }): boolean {
     let cond = ctx.getValue(node.getAttribute("t-elif")!);
-    ctx.addLine(`else if (${typeof cond === "string" ? ctx.formatExpression(cond) : cond.id}) {`);
+    ctx.addLine(
+      `else if (${typeof cond === "string" ? ctx.formatExpression(cond) : `scope.${cond.id}`}) {`
+    );
     ctx.indent();
     return false;
   },
@@ -182,6 +218,10 @@ QWeb.addDirective({
   name: "call",
   priority: 50,
   atNodeEncounter({ node, qweb, ctx }): boolean {
+    // Step 1: sanity checks
+    // ------------------------------------------------
+    ctx.rootContext.shouldDefineScope = true;
+    ctx.rootContext.shouldDefineUtils = true;
     if (node.nodeName !== "t") {
       throw new Error("Invalid tag for t-call directive (should be 't')");
     }
@@ -190,77 +230,65 @@ QWeb.addDirective({
     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.allowMultipleRoots = true;
-    qweb._compileNode(nodeCopy, tempCtx);
-    const vars = Object.assign({}, ctx.variables, tempCtx.variables);
-
-    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;
+    // Step 2: compile target template in sub templates
+    // ------------------------------------------------
+    if (!qweb.subTemplates[subTemplate]) {
+      qweb.subTemplates[subTemplate] = true;
+      const subTemplateFn = qweb._compile(subTemplate, nodeTemplate.elem, ctx, true);
+      qweb.subTemplates[subTemplate] = subTemplateFn;
     }
-    templateMap[subTemplate] = true;
 
-    if (hasNewVariables) {
-      ctx.addLine("{");
+    // Step 3: compile t-call body if necessary
+    // ------------------------------------------------
+    let hasBody = node.hasChildNodes();
+    let protectID;
+    if (hasBody) {
+      // we add a sub scope to protect the ambient scope
+      ctx.addLine(`{`);
       ctx.indent();
-      // add new variables, if any
-      for (let key in tempCtx.variables) {
-        const v = tempCtx.variables[key];
-        if (v.expr) {
-          ctx.addLine(`let ${v.id} = ${v.expr};`);
-        }
-        // todo: handle XML variables...
+      protectID = ctx.startProtectScope();
+      const nodeCopy = node.cloneNode(true) as Element;
+      for (let attr of ["t-if", "t-else", "t-elif", "t-call"]) {
+        nodeCopy.removeAttribute(attr);
       }
-    }
-    qweb._compileNode(nodeTemplate.elem, subCtx);
-
-    // close new scope
-    if (hasNewVariables) {
+      const parentNode = ctx.parentNode;
+      ctx.parentNode = "__0";
+      // this local scope is intended to trap c__0
+      ctx.addLine(`{`);
+      ctx.indent();
+      ctx.addLine("let c__0 = [];");
+      qweb._compileNode(nodeCopy, ctx);
+      ctx.rootContext.shouldDefineUtils = true;
+      ctx.addLine("scope[utils.zero] = c__0;");
+      ctx.parentNode = parentNode;
       ctx.dedent();
-      ctx.addLine("}");
+      ctx.addLine(`}`);
+    }
+
+    // Step 4: add the appropriate function call to current component
+    // ------------------------------------------------
+    const callingScope = hasBody ? "scope" : "Object.assign(Object.create(context), scope)";
+    const parentComponent = `utils.getComponent(context)`;
+    const key = ctx.generateTemplateKey();
+    const parentNode = ctx.parentNode ? `c${ctx.parentNode}` : "result";
+    const extra = `Object.assign({}, extra, {parentNode: ${parentNode}, parent: ${parentComponent}, key: ${key}})`;
+    if (ctx.parentNode) {
+      ctx.addLine(`this.subTemplates['${subTemplate}'].call(this, ${callingScope}, ${extra});`);
+    } else {
+      // this is a t-call with no parentnode, we need to extract the result
+      ctx.rootContext.shouldDefineResult = true;
+      ctx.addLine(`result = []`);
+      ctx.addLine(`this.subTemplates['${subTemplate}'].call(this, ${callingScope}, ${extra});`);
+      ctx.addLine(`result = result[0]`);
+    }
+
+    // Step 5: restore previous scope
+    // ------------------------------------------------
+    if (hasBody) {
+      ctx.stopProtectScope(protectID);
+      ctx.dedent();
+      ctx.addLine(`}`);
     }
 
     return true;
@@ -275,29 +303,31 @@ QWeb.addDirective({
   extraNames: ["as"],
   priority: 10,
   atNodeEncounter({ node, qweb, ctx }): boolean {
-    ctx.rootContext.shouldProtectContext = true;
+    ctx.rootContext.shouldDefineScope = 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} = ${ctx.formatExpression(elems)};`);
+    ctx.addLine(`let _${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} = _${arrayID};`);
+    ctx.addLine(`let _${keysID} = _${valuesID} = _${arrayID};`);
     ctx.addIf(`!(_${arrayID} instanceof Array)`);
     ctx.addLine(`_${keysID} = Object.keys(_${arrayID});`);
     ctx.addLine(`_${valuesID} = Object.values(_${arrayID});`);
     ctx.closeIf();
-    ctx.addLine(`var _length${keysID} = _${keysID}.length;`);
+    ctx.addLine(`let _length${keysID} = _${keysID}.length;`);
+    let varsID = ctx.startProtectScope(true);
     const loopVar = `i${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}]`);
+
+    ctx.addLine(`scope.${name}_first = ${loopVar} === 0`);
+    ctx.addLine(`scope.${name}_last = ${loopVar} === _length${keysID} - 1`);
+    ctx.addLine(`scope.${name}_index = ${loopVar}`);
+    ctx.addLine(`scope.${name} = _${keysID}[${loopVar}]`);
+    ctx.addLine(`scope.${name}_value = _${valuesID}[${loopVar}]`);
     const nodeCopy = <Element>node.cloneNode(true);
     let shouldWarn =
       !nodeCopy.hasAttribute("t-key") &&
@@ -309,11 +339,19 @@ QWeb.addDirective({
         `Directive t-foreach should always be used with a t-key! (in template: '${ctx.templateName}')`
       );
     }
+    if (nodeCopy.hasAttribute("t-key")) {
+      const expr = ctx.formatExpression(nodeCopy.getAttribute("t-key")!);
+      ctx.addLine(`let key${ctx.loopNumber} = ${expr};`);
+      nodeCopy.removeAttribute("t-key");
+    } else {
+      ctx.addLine(`let key${ctx.loopNumber} = i${ctx.loopNumber};`);
+    }
 
     nodeCopy.removeAttribute("t-foreach");
     qweb._compileNode(nodeCopy, ctx);
     ctx.dedent();
     ctx.addLine("}");
+    ctx.stopProtectScope(varsID);
     return true;
   }
 });

src/qweb/compilation_context.ts

@@ -1,4 +1,4 @@
-import { compileExpr, QWebVar } from "./expression_parser";
+import { compileExpr, compileExprToArray, QWebVar } from "./expression_parser";
 
 export const INTERP_REGEXP = /\{\{.*?\}\}/g;
 //------------------------------------------------------------------------------
@@ -10,36 +10,30 @@ export class CompilationContext {
   code: string[] = [];
   variables: { [key: string]: QWebVar } = {};
   escaping: boolean = false;
-  parentNode: number | null = null;
+  parentNode: number | null | string = null;
   parentTextNode: number | null = null;
   rootNode: number | null = null;
   indentLevel: number = 0;
   rootContext: CompilationContext;
-  caller: Element | undefined;
-  shouldDefineOwner: boolean = false;
   shouldDefineParent: boolean = false;
+  shouldDefineScope: boolean = false;
+  protectedScopeNumber: number = 0;
   shouldDefineQWeb: boolean = false;
   shouldDefineUtils: boolean = false;
   shouldDefineRefs: boolean = false;
   shouldDefineResult: 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 = "";
-  templates: { [key: string]: boolean } = {};
-  callingLevel: number = 0;
-  inliningLevel: number = 0;
+  hasKey0: boolean = false;
+  keyStack: boolean[] = [];
 
   constructor(name?: string) {
     this.rootContext = this;
     this.templateName = name || "noname";
-    this.templates[this.templateName] = true;
-    this.addLine("var h = this.h;");
+    this.addLine("let h = this.h;");
   }
 
   generateID(): number {
@@ -54,47 +48,31 @@ export class CompilationContext {
    * Such a key is necessary when we need to associate an id to some element
    * generated by a template (for example, a component)
    */
-  generateTemplateKey(): string {
+  generateTemplateKey(prefix: string = ""): string {
     const id = this.generateID();
-    let locationExpr = `\`__${this.generateID()}__`;
-    for (let i = 0; i < this.loopNumber - 1; i++) {
-      locationExpr += `\${i${i + 1}}__`;
+    if (this.loopNumber === 0 && !this.hasKey0) {
+      return `'${prefix}__${id}__'`;
     }
-    if (this.currentKey) {
-      const k = this.currentKey;
-      this.addLine(`let k${id} = ${locationExpr}\` + ${k};`);
-    } else {
-      locationExpr += this.loopNumber ? `\${i${this.loopNumber}}__\`` : "`";
-      this.addLine(`let k${id} = ${locationExpr};`);
+    let key = `\`${prefix}__${id}__`;
+    let start = this.hasKey0 ? 0 : 1;
+    for (let i = start; i < this.loopNumber + 1; i++) {
+      key += `\${key${i}}__`;
     }
+    this.addLine(`let k${id} = ${key}\`;`);
     return `k${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.shouldDefineScope) {
+      this.code.unshift("    let scope = Object.create(context);");
+    }
     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;");
@@ -131,19 +109,15 @@ export class CompilationContext {
   subContext(key: keyof CompilationContext, value: any): CompilationContext {
     const newContext = Object.create(this);
     newContext[key] = value;
-    if (key === "caller") {
-      newContext.callingLevel++;
-      newContext.inliningLevel++;
-    }
     return newContext;
   }
 
   indent() {
-    this.indentLevel++;
+    this.rootContext.indentLevel++;
   }
 
   dedent() {
-    this.indentLevel--;
+    this.rootContext.indentLevel--;
   }
 
   addLine(line: string): number {
@@ -152,11 +126,6 @@ export class CompilationContext {
     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();
@@ -172,27 +141,6 @@ export class CompilationContext {
     this.dedent();
     this.addLine("}");
   }
-  /**
-   * Recursively (inverse) fetches the `caller` of a context
-   * Useful to determine to which t-call a t-raw="0" refers
-   */
-  getCaller(targetLevel?: number): Element | null {
-    if (targetLevel === undefined) {
-      targetLevel = this.inliningLevel;
-    }
-    if (targetLevel === this.callingLevel) {
-      return this.caller || null;
-    }
-    const proto = (this as any).__proto__;
-    return proto ? proto.getCaller(targetLevel) : null;
-  }
-  /**
-   * Marks the context with the current recursive level
-   * in which we are for inlining archs (t-raw="0")
-   */
-  getInliningContext(): CompilationContext {
-    return this.subContext("inliningLevel", this.inliningLevel - 1);
-  }
 
   getValue(val: any): QWebVar | string {
     return val in this.variables ? this.getValue(this.variables[val]) : val;
@@ -205,8 +153,27 @@ export class CompilationContext {
    * - replace already defined variables by their internal name
    */
   formatExpression(expr: string): string {
+    this.rootContext.shouldDefineScope = true;
     return compileExpr(expr, this.variables);
   }
+  captureExpression(expr: string): string {
+    this.rootContext.shouldDefineScope = true;
+    const argId = this.generateID();
+    const tokens = compileExprToArray(expr, this.variables);
+    const done = new Set();
+    return tokens
+      .map(tok => {
+        if (tok.varName) {
+          if (!done.has(tok.varName)) {
+            done.add(tok.varName);
+            this.addLine(`const ${tok.varName}_${argId} = ${tok.value};`);
+          }
+          tok.value = `${tok.varName}_${argId}`;
+        }
+        return tok.value;
+      })
+      .join("");
+  }
 
   /**
    * Perform string interpolation on the given string. Note that if the whole
@@ -225,4 +192,19 @@ export class CompilationContext {
     let r = s.replace(/\{\{.*?\}\}/g, s => "${" + this.formatExpression(s.slice(2, -2)) + "}");
     return "`" + r + "`";
   }
+  startProtectScope(codeBlock?: boolean): number {
+    const protectID = this.generateID();
+    this.rootContext.protectedScopeNumber++;
+    this.rootContext.shouldDefineScope = true;
+    const scopeExpr = codeBlock
+      ? `Object.create(scope);`
+      : `Object.assign(Object.create(context), scope);`;
+    this.addLine(`let _origScope${protectID} = scope;`);
+    this.addLine(`scope = ${scopeExpr}`);
+    return protectID;
+  }
+  stopProtectScope(protectID: number) {
+    this.rootContext.protectedScopeNumber--;
+    this.addLine(`scope = _origScope${protectID};`);
+  }
 }

src/qweb/expression_parser.ts

@@ -39,9 +39,10 @@ const WORD_REPLACEMENT = {
 };
 
 export interface QWebVar {
-  id?: string;
-  expr?: string;
-  xml?: NodeList;
+  id: string; // foo
+  expr: string; // scope.foo (local variables => only foo)
+  value?: string; // 1 + 3
+  hasBody?: boolean;
 }
 
 //------------------------------------------------------------------------------
@@ -63,7 +64,9 @@ type TKind =
 interface Token {
   type: TKind;
   value: string;
+  originalValue?: string;
   size?: number;
+  varName?: string;
 }
 
 const STATIC_TOKEN_MAP: { [key: string]: TKind } = {
@@ -79,7 +82,7 @@ const STATIC_TOKEN_MAP: { [key: string]: TKind } = {
 
 // note that the space after typeof is relevant. It makes sure that the formatted
 // expression has a space after typeof
-const OPERATORS = ".,===,==,+,!==,!=,!,||,&&,>=,>,<=,<,?,-,*,/,%,typeof ".split(",");
+const OPERATORS = "...,.,===,==,+,!==,!=,!,||,&&,>=,>,<=,<,?,-,*,/,%,typeof ,=>,=,;,in ".split(",");
 
 type Tokenizer = (expr: string) => Token | false;
 
@@ -227,35 +230,60 @@ 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, scope: { [key: string]: QWebVar }): Token[] {
+  scope = Object.create(scope);
   const tokens = tokenize(expr);
-  let result = "";
   for (let i = 0; i < tokens.length; i++) {
     let token = tokens[i];
+    let prevToken = tokens[i - 1];
+    let nextToken = tokens[i + 1];
+    let isVar = token.type === "SYMBOL" && !RESERVED_WORDS.includes(token.value);
     if (token.type === "SYMBOL" && !RESERVED_WORDS.includes(token.value)) {
-      // we need to find if it is a variable
-      let isVar = true;
-      let prevToken = tokens[i - 1];
       if (prevToken) {
         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]) {
-          token.value = vars[token.value].id!;
-        } else {
-          token.value = `context['${token.value}']`;
+    }
+    if (nextToken && nextToken.type === "OPERATOR" && nextToken.value === "=>") {
+      if (token.type === "RIGHT_PAREN") {
+        let j = i - 1;
+        while (j > 0 && tokens[j].type !== "LEFT_PAREN") {
+          if (tokens[j].type === "SYMBOL" && tokens[j].originalValue) {
+            tokens[j].value = tokens[j].originalValue!;
+            scope[tokens[j].value] = { id: tokens[j].value, expr: tokens[j].value };
+          }
+          j--;
         }
+      } else {
+        scope[token.value] = { id: token.value, expr: token.value };
+      }
+    }
+
+    if (isVar) {
+      token.varName = token.value;
+      if (token.value in scope && "id" in scope[token.value]) {
+        token.value = scope[token.value].expr!;
+      } else {
+        token.originalValue = token.value;
+        token.value = `scope['${token.value}']`;
       }
     }
-    result += token.value;
   }
-  return result;
+  return tokens;
+}
+
+export function compileExpr(expr: string, scope: { [key: string]: QWebVar }): string {
+  return compileExprToArray(expr, scope)
+    .map(t => t.value)
+    .join("");
 }

src/qweb/extensions.ts

@@ -26,49 +26,70 @@ export const MODS_CODE = {
   stop: "e.stopPropagation();"
 };
 
+interface HandlerInfo {
+  event: string;
+  handler: string;
+}
+
+const FNAMEREGEXP = /^[$A-Z_][0-9A-Z_$]*$/i;
+
+export function makeHandlerCode(
+  ctx,
+  fullName,
+  value,
+  putInCache: boolean,
+  modcodes = MODS_CODE
+): HandlerInfo {
+  let [event, ...mods] = fullName.slice(5).split(".");
+  if (mods.includes("capture")) {
+    event = "!" + event;
+  }
+  if (!event) {
+    throw new Error("Missing event name with t-on directive");
+  }
+  let code: string;
+  // check if it is a method with no args, a method with args or an expression
+  let args: string = "";
+  const name: string = value.replace(/\(.*\)/, function(_args) {
+    args = _args.slice(1, -1);
+    return "";
+  });
+  const isMethodCall = name.match(FNAMEREGEXP);
+
+  // then generate code
+  if (isMethodCall) {
+    ctx.rootContext.shouldDefineUtils = true;
+    const comp = `utils.getComponent(context)`;
+    if (args) {
+      const argId = ctx.generateID();
+      ctx.addLine(`let args${argId} = [${ctx.formatExpression(args)}];`);
+      code = `${comp}['${name}'](...args${argId}, e);`;
+      putInCache = false;
+    } else {
+      code = `${comp}['${name}'](e);`;
+    }
+  } else {
+    // if we get here, then it is an expression
+    // we need to capture every variable in it
+    putInCache = false;
+    code = ctx.captureExpression(value);
+  }
+  const modCode = mods.map(mod => modcodes[mod]).join("");
+  let handler = `function (e) {if (!context.__owl__.isMounted){return}${modCode}${code}}`;
+  if (putInCache) {
+    const key = ctx.generateTemplateKey(event);
+    ctx.addLine(`extra.handlers[${key}] = extra.handlers[${key}] || ${handler};`);
+    handler = `extra.handlers[${key}]`;
+  }
+  return { event, handler };
+}
+
 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}'] = ${handler};`);
-    }
+    const { event, handler } = makeHandlerCode(ctx, fullName, value, true);
+    ctx.addLine(`p${nodeID}.on['${event}'] = ${handler};`);
   }
 });
 
@@ -162,6 +183,13 @@ function toMs(s: string): number {
 }
 
 function whenTransitionEnd(elm: HTMLElement, cb) {
+  if (!elm.parentNode) {
+    // if we get here, this means that the element was removed for some other
+    // reasons, and in that case, we don't want to work on animation since nothing
+    // will be displayed anyway.
+    return;
+  }
+
   const styles = window.getComputedStyle(elm);
   const delays: Array<string> = (styles.transitionDelay || "").split(", ");
   const durations: Array<string> = (styles.transitionDuration || "").split(", ");
@@ -195,9 +223,8 @@ QWeb.addDirective({
 QWeb.addDirective({
   name: "slot",
   priority: 80,
-  atNodeEncounter({ ctx, value }): boolean {
+  atNodeEncounter({ ctx, value, node, qweb }): boolean {
     const slotKey = ctx.generateID();
-    ctx.rootContext.shouldDefineOwner = true;
     ctx.addLine(
       `const slot${slotKey} = this.constructor.slots[context.__owl__.slotId + '_' + '${value}'];`
     );
@@ -211,11 +238,17 @@ QWeb.addDirective({
       ctx.addLine(`result = {}`);
     }
     ctx.addLine(
-      `slot${slotKey}.call(this, context.__owl__.parent, Object.assign({}, extra, {parentNode: ${parentNode}, vars: extra.vars, parent: extra.parent || owner}));`
+      `slot${slotKey}.call(this, context.__owl__.scope, Object.assign({}, extra, {parentNode: ${parentNode}, parent: extra.parent || context}));`
     );
     if (!ctx.parentNode) {
       ctx.addLine(`utils.defineProxy(result, ${parentNode}[0]);`);
     }
+    if (node.hasChildNodes()) {
+      ctx.addElse();
+      const nodeCopy = <Element>node.cloneNode(true);
+      nodeCopy.removeAttribute("t-slot");
+      qweb._compileNode(nodeCopy, ctx);
+    }
     ctx.closeIf();
     return true;
   }
@@ -281,9 +314,20 @@ QWeb.addDirective({
 QWeb.addDirective({
   name: "key",
   priority: 45,
-  atNodeEncounter({ ctx, value }) {
-    let id = ctx.generateID();
-    ctx.addLine(`const nodeKey${id} = ${ctx.formatExpression(value)};`);
-    ctx.currentKey = `nodeKey${id}`;
+  atNodeEncounter({ ctx, value, node }) {
+    if (ctx.loopNumber === 0) {
+      ctx.keyStack.push(ctx.rootContext.hasKey0);
+      ctx.rootContext.hasKey0 = true;
+    }
+    ctx.addLine("{");
+    ctx.indent();
+    ctx.addLine(`let key${ctx.loopNumber} = ${ctx.formatExpression(value)};`);
+  },
+  finalize({ ctx }) {
+    ctx.dedent();
+    ctx.addLine("}");
+    if (ctx.loopNumber === 0) {
+      ctx.rootContext.hasKey0 = ctx.keyStack.pop() as boolean;
+    }
   }
 });

src/qweb/qweb.ts

@@ -1,7 +1,7 @@
 import { EventBus } from "../core/event_bus";
 import { h, patch, VNode } from "../vdom/index";
 import { CompilationContext } from "./compilation_context";
-import { shallowEqual } from "../utils";
+import { shallowEqual, escape } from "../utils";
 import { addNS } from "../vdom/vdom";
 
 /**
@@ -86,7 +86,12 @@ interface Utils {
   [key: string]: any;
 }
 
+function isComponent(obj) {
+  return obj && obj.hasOwnProperty("__owl__");
+}
+
 const UTILS: Utils = {
+  zero: Symbol("zero"),
   toObj(expr) {
     if (typeof expr === "string") {
       expr = expr.trim();
@@ -105,6 +110,37 @@ const UTILS: Utils = {
   shallowEqual,
   addNameSpace(vnode) {
     addNS(vnode.data, vnode.children, vnode.sel);
+  },
+  VDomArray: class VDomArray extends Array {},
+  vDomToString: function(vdom: VNode[]): string {
+    return vdom
+      .map(vnode => {
+        if (vnode.sel) {
+          const node = document.createElement(vnode.sel);
+          const result = patch(node, vnode);
+          return (<HTMLElement>result.elm).outerHTML;
+        } else {
+          return vnode.text;
+        }
+      })
+      .join("");
+  },
+  getComponent(obj) {
+    while (obj && !isComponent(obj)) {
+      obj = obj.__proto__;
+    }
+    return obj;
+  },
+  getScope(obj, property: string) {
+    const obj0 = obj;
+    while (obj && !obj.hasOwnProperty(property)) {
+      const newObj = obj.__proto__;
+      if (!newObj || isComponent(newObj)) {
+        return obj0;
+      }
+      obj = newObj;
+    }
+    return obj;
   }
 };
 
@@ -138,6 +174,10 @@ function parseXML(xml: string): Document {
   return doc;
 }
 
+function escapeQuotes(str: string): string {
+  return str.replace(/\'/g, "\\'");
+}
+
 //------------------------------------------------------------------------------
 // QWeb rendering engine
 //------------------------------------------------------------------------------
@@ -171,7 +211,7 @@ export class QWeb extends EventBus {
   // 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 = {};
+  subTemplates = {};
 
   isUpdating: boolean = false;
   translateFn?: QWebConfig["translateFn"];
@@ -292,10 +332,11 @@ export class QWeb extends EventBus {
         ) {
           throw new Error("Only one conditional branching directive is allowed per node");
         }
-        // All text nodes between branch nodes are removed
+        // 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) {
+          if (textNode.nodeValue.trim().length && textNode.nodeType !== 8) {
             throw new Error("text is not allowed between branching directives");
           }
           textNode.remove();
@@ -333,8 +374,17 @@ export class QWeb extends EventBus {
       return vnode.text!;
     }
     const node = document.createElement(vnode.sel);
-    const result = patch(node, vnode);
-    return (<HTMLElement>result.elm).outerHTML;
+    const elem = patch(node, vnode).elm as HTMLElement;
+    function escapeTextNodes(node) {
+      if (node.nodeType === 3) {
+        node.textContent = escape(node.textContent);
+      }
+      for (let n of node.childNodes) {
+        escapeTextNodes(n);
+      }
+    }
+    escapeTextNodes(elem);
+    return elem.outerHTML;
   }
 
   /**
@@ -353,31 +403,29 @@ export class QWeb extends EventBus {
     });
   }
 
-  _compile(name: string, elem: Element, parentContext?: CompilationContext): CompiledTemplate {
+  _compile(
+    name: string,
+    elem: Element,
+    parentContext?: CompilationContext,
+    defineKey?: boolean
+  ): 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.parentNode = parentContext.parentNode || ctx.generateID();
       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 (defineKey) {
+        ctx.addLine(`let key0 = extra.key || "";`);
+        ctx.hasKey0 = true;
       }
     }
-    if (parentContext) {
-      ctx.addLine("    Object.assign(context, extra.fiber.scope);");
-    }
     this._compileNode(elem, ctx);
 
     if (!parentContext) {
@@ -392,12 +440,13 @@ export class QWeb extends EventBus {
     }
 
     let code = ctx.generateCode();
+    const templateName = ctx.templateName.replace(/`/g, "'").slice(0, 200);
+    code.unshift(`    // Template name: "${templateName}"`);
 
     let template;
     try {
-      template = new Function("context", "extra", code.join("\n")) as CompiledTemplate;
+      template = new Function("context, extra", code.join("\n")) as CompiledTemplate;
     } catch (e) {
-      const templateName = ctx.templateName.replace(/`/g, "'");
       console.groupCollapsed(`Invalid Code generated by ${templateName}`);
       console.warn(code.join("\n"));
       console.groupEnd();
@@ -446,7 +495,7 @@ export class QWeb extends EventBus {
         // this is an unusual situation: this text node is the result of the
         // template rendering.
         let nodeID = ctx.generateID();
-        ctx.addLine(`var vn${nodeID} = {text: \`${text}\`};`);
+        ctx.addLine(`let vn${nodeID} = {text: \`${text}\`};`);
         ctx.addLine(`result = vn${nodeID};`);
         ctx.rootContext.rootNode = nodeID;
         ctx.rootContext.parentTextNode = nodeID;
@@ -454,10 +503,6 @@ export class QWeb extends EventBus {
       return;
     }
 
-    if (ctx !== ctx.rootContext) {
-      ctx = ctx.subContext("currentKey", ctx.currentKey);
-    }
-
     const firstLetter = node.tagName[0];
     if (firstLetter === firstLetter.toUpperCase()) {
       // this is a component, we modify in place the xml document to change
@@ -650,15 +695,16 @@ export class QWeb extends EventBus {
       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}};`);
+          if ((value = value.trim())) {
+            let classDef = value
+              .split(/\s+/)
+              .map(a => `'${escapeQuotes(a)}':true`)
+              .join(",");
+            classObj = `_${ctx.generateID()}`;
+            ctx.addLine(`let ${classObj} = {${classDef}};`);
+          }
         } else {
-          ctx.addLine(`var _${attID} = '${value}';`);
+          ctx.addLine(`let _${attID} = '${escapeQuotes(value)}';`);
           if (!name.match(/^[a-zA-Z]+$/)) {
             // attribute contains 'non letters' => we want to quote it
             name = '"' + name + '"';
@@ -672,7 +718,7 @@ export class QWeb extends EventBus {
       if (name.startsWith("t-att-")) {
         let attName = name.slice(6);
         const v = ctx.getValue(value);
-        let formattedValue = typeof v === "string" ? ctx.formatExpression(v) : v.id;
+        let formattedValue = typeof v === "string" ? ctx.formatExpression(v) : `scope.${v.id}`;
 
         if (attName === "class") {
           ctx.rootContext.shouldDefineUtils = true;
@@ -694,12 +740,12 @@ export class QWeb extends EventBus {
           const attValue = (<Element>node).getAttribute(attName);
           if (attValue) {
             const attValueID = ctx.generateID();
-            ctx.addLine(`var _${attValueID} = ${formattedValue};`);
+            ctx.addLine(`let _${attValueID} = ${formattedValue};`);
             formattedValue = `'${attValue}' + (_${attValueID} ? ' ' + _${attValueID} : '')`;
             const attrIndex = attrs.findIndex(att => att.startsWith(attName + ":"));
             attrs.splice(attrIndex, 1);
           }
-          ctx.addLine(`var _${attID} = ${formattedValue};`);
+          ctx.addLine(`let _${attID} = ${formattedValue};`);
           attrs.push(`${attName}: _${attID}`);
           handleBooleanProps(attName, attID);
         }
@@ -715,9 +761,9 @@ export class QWeb extends EventBus {
         const attID = ctx.generateID();
         let staticVal = (<Element>node).getAttribute(attName);
         if (staticVal) {
-          ctx.addLine(`var _${attID} = '${staticVal} ' + ${formattedExpr};`);
+          ctx.addLine(`let _${attID} = '${staticVal} ' + ${formattedExpr};`);
         } else {
-          ctx.addLine(`var _${attID} = ${formattedExpr};`);
+          ctx.addLine(`let _${attID} = ${formattedExpr};`);
         }
         attrs.push(`${attName}: _${attID}`);
       }
@@ -725,13 +771,13 @@ export class QWeb extends EventBus {
       // t-att= attributes
       if (name === "t-att") {
         let id = ctx.generateID();
-        ctx.addLine(`var _${id} = ${ctx.formatExpression(value!)};`);
+        ctx.addLine(`let _${id} = ${ctx.formatExpression(value!)};`);
         tattrs.push(id);
       }
     }
     let nodeID = ctx.generateID();
-    let nodeKey = ctx.currentKey || nodeID;
-    const parts = [`key:${nodeKey}`];
+    let key = ctx.loopNumber || ctx.hasKey0 ? `\`\${key${ctx.loopNumber}}_${nodeID}\`` : nodeID;
+    const parts = [`key:${key}`];
     if (attrs.length + tattrs.length > 0) {
       parts.push(`attrs:{${attrs.join(",")}}`);
     }
@@ -757,9 +803,12 @@ export class QWeb extends EventBus {
       ctx.addLine(`}`);
       ctx.closeIf();
     }
-    ctx.addLine(`var vn${nodeID} = h('${node.nodeName}', p${nodeID}, c${nodeID});`);
+    ctx.addLine(`let vn${nodeID} = h('${node.nodeName}', p${nodeID}, c${nodeID});`);
     if (ctx.parentNode) {
       ctx.addLine(`c${ctx.parentNode}.push(vn${nodeID});`);
+    } else if (ctx.loopNumber || ctx.hasKey0) {
+      ctx.rootContext.shouldDefineResult = true;
+      ctx.addLine(`result = vn${nodeID};`);
     }
 
     return nodeID;

src/router/link.ts

@@ -4,7 +4,7 @@ import { Destination, RouterEnv } from "./router";
 
 type Props = Destination;
 
-export class Link<Env extends RouterEnv> extends Component<Env, Props> {
+export class Link<Env extends RouterEnv> extends Component<Props, Env> {
   static template = xml`
     <a  t-att-class="{'router-link-active': isActive }"
         t-att-href="href"

src/router/route_component.ts

@@ -1,7 +1,7 @@
 import { Component } from "../component/component";
 import { xml } from "../tags";
 
-export class RouteComponent extends Component<any, {}> {
+export class RouteComponent extends Component {
   static template = xml`
     <t>
         <t

src/store.ts

@@ -83,7 +83,7 @@ interface SelectorOptions {
 const isStrictEqual = (a, b) => a === b;
 
 export function useStore(selector, options: SelectorOptions = {}): any {
-  const component: Component<any, any> = Component.current!;
+  const component: Component = Component.current!;
   const componentId = component.__owl__.id;
   const store = options.store || (component.env.store as Store);
   if (!(store instanceof Store)) {
@@ -132,7 +132,7 @@ export function useStore(selector, options: SelectorOptions = {}): any {
     __destroy.call(component, parent);
   };
 
-  if (typeof result !== "object") {
+  if (typeof result !== "object" || result === null) {
     return result;
   }
   return new Proxy(result, {
@@ -141,6 +141,9 @@ export function useStore(selector, options: SelectorOptions = {}): any {
     },
     set(target, k, v) {
       throw new Error("Store state should only be modified through actions");
+    },
+    has(target, k) {
+      return k in result;
     }
   });
 }

src/tags.ts

@@ -1,4 +1,5 @@
 import { QWeb } from "./qweb/index";
+import { registerSheet } from "./component/styles";
 
 /**
  * Owl Tags
@@ -25,3 +26,19 @@ export function xml(strings, ...args) {
   QWeb.registerTemplate(name, value);
   return name;
 }
+
+/**
+ * CSS tag helper for defining inline stylesheets.  With this, one can simply define
+ * an inline stylesheet with just the following code:
+ * ```js
+ *   class A extends Component {
+ *     static style = css`.component-a { color: red; }`;
+ *   }
+ * ```
+ */
+export function css(strings, ...args) {
+  const name = `__sheet__${QWeb.nextId++}`;
+  const value = String.raw(strings, ...args);
+  registerSheet(name, value);
+  return name;
+}

src/utils.ts

@@ -58,12 +58,9 @@ export function escape(str: string | number | undefined): string {
   if (typeof str === "number") {
     return String(str);
   }
-  return str
-    .replace(/&/g, "&")
-    .replace(/</g, "&lt;")
-    .replace(/>/g, "&gt;")
-    .replace(/"/g, "&#x27;")
-    .replace(/`/g, "&#x60;");
+  const p = document.createElement("p");
+  p.textContent = str;
+  return p.innerHTML;
 }
 
 /**

src/vdom/modules.ts

@@ -70,8 +70,12 @@ function handleEvent(event: Event, vnode: VNode) {
     on = (vnode.data as VNodeData).on;
 
   // call event handler(s) if exists
-  if (on && on[name]) {
-    invokeHandler(on[name], vnode, event);
+  if (on) {
+    if (on[name]) {
+      invokeHandler(on[name], vnode, event);
+    } else if (on["!" + name]) {
+      invokeHandler(on["!" + name], vnode, event);
+    }
   }
 }
 
@@ -100,13 +104,17 @@ function updateEventListeners(oldVnode: VNode, vnode?: VNode): void {
     if (!on) {
       for (name in oldOn) {
         // remove listener if element was changed or existing listeners removed
-        oldElm.removeEventListener(name, oldListener, false);
+        const capture = name.charAt(0) === "!";
+        name = capture ? name.slice(1) : name;
+        oldElm.removeEventListener(name, oldListener, capture);
       }
     } else {
       for (name in oldOn) {
         // remove listener if existing listener removed
         if (!on[name]) {
-          oldElm.removeEventListener(name, oldListener, false);
+          const capture = name.charAt(0) === "!";
+          name = capture ? name.slice(1) : name;
+          oldElm.removeEventListener(name, oldListener, capture);
         }
       }
     }
@@ -123,13 +131,17 @@ function updateEventListeners(oldVnode: VNode, vnode?: VNode): void {
     if (!oldOn) {
       for (name in on) {
         // add listener if element was changed or new listeners added
-        elm.addEventListener(name, listener, false);
+        const capture = name.charAt(0) === "!";
+        name = capture ? name.slice(1) : name;
+        elm.addEventListener(name, listener, capture);
       }
     } else {
       for (name in on) {
         // add listener if new listener added
         if (!oldOn[name]) {
-          elm.addEventListener(name, listener, false);
+          const capture = name.charAt(0) === "!";
+          name = capture ? name.slice(1) : name;
+          elm.addEventListener(name, listener, capture);
         }
       }
     }
@@ -219,7 +231,7 @@ function updateClass(oldVnode: VNode, vnode: VNode): void {
   elm = vnode.elm as Element;
 
   for (name in oldClass) {
-    if (!klass[name]) {
+    if (name && !klass[name]) {
       elm.classList.remove(name);
     }
   }

tests/__snapshots__/animations.test.ts.snap

@@ -1,154 +1,149 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`animations t-transition combined with component 1`] = `
-"function anonymous(context,extra
+"function anonymous(context, extra
 ) {
+    // Template name: \\"Parent\\"
     let utils = this.constructor.utils;
     let QWeb = this.constructor;
     let parent = context;
-    let owner = context;
-    var h = this.h;
+    let scope = Object.create(context);
+    let h = this.h;
     let c1 = [], p1 = {key:1};
-    var vn1 = h('div', p1, c1);
-    //COMPONENT
-    let k4 = \`__5__\`;
-    let w3 = k4 in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap[k4]] : false;
-    let props3 = {};
-    if (w3 && w3.__owl__.currentFiber && !w3.__owl__.vnode) {
-        w3.destroy();
-        w3 = false;
+    let vn1 = h('div', p1, c1);
+    // Component 'Child'
+    let w2 = '__3__' in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap['__3__']] : false;
+    let props2 = {};
+    if (w2 && w2.__owl__.currentFiber && !w2.__owl__.vnode) {
+        w2.destroy();
+        w2 = false;
     }
-    if (w3) {
-        w3.__updateProps(props3, extra.fiber, undefined, undefined);
-        let pvnode = w3.__owl__.pvnode;
+    if (w2) {
+        w2.__updateProps(props2, extra.fiber, undefined);
+        let pvnode = w2.__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);
-        const __patch3 = w3.__patch;
-        w3.__patch = fiber => {__patch3.call(w3, fiber); if(!w3.__owl__.transitionInserted){w3.__owl__.transitionInserted = true;utils.transitionInsert(w3.__owl__.vnode, 'chimay');}};
-        parent.__owl__.cmap[k4] = w3.__owl__.id;
-        let def2 = w3.__prepare(extra.fiber, undefined, undefined);
-        let pvnode = h('dummy', {key: k4, hook: {remove() {},destroy(vn) {let finalize = () => {
-          w3.destroy();
+        let componentKey2 = \`Child\`;
+        let W2 = context.constructor.components[componentKey2] || QWeb.components[componentKey2]|| scope['Child'];
+        if (!W2) {throw new Error('Cannot find the definition of component \\"' + componentKey2 + '\\"')}
+        w2 = new W2(parent, props2);
+        const __patch2 = w2.__patch;
+        w2.__patch = (t, vn) => {__patch2.call(w2, t, vn); if(!w2.__owl__.transitionInserted){w2.__owl__.transitionInserted = true;utils.transitionInsert(w2.__owl__.vnode, 'chimay');}};
+        parent.__owl__.cmap['__3__'] = w2.__owl__.id;
+        let fiber = w2.__prepare(extra.fiber, undefined, () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+        let pvnode = h('dummy', {key: '__3__', hook: {remove() {},destroy(vn) {let finalize = () => {
+          w2.destroy();
         };
-        delete w3.__owl__.transitionInserted;
+        delete w2.__owl__.transitionInserted;
         utils.transitionRemove(vn, 'chimay', finalize);}}});
-        const fiber = w3.__owl__.currentFiber;
-        def2.then(function () { if (fiber.isCompleted) { return; } const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
         c1.push(pvnode);
-        w3.__owl__.pvnode = pvnode;
+        w2.__owl__.pvnode = pvnode;
     }
-    w3.__owl__.parentLastFiberId = extra.fiber.id;
+    w2.__owl__.parentLastFiberId = extra.fiber.id;
     return vn1;
 }"
 `;
 
 exports[`animations t-transition combined with t-component and t-if 1`] = `
-"function anonymous(context,extra
+"function anonymous(context, extra
 ) {
+    // Template name: \\"Parent\\"
     let utils = this.constructor.utils;
     let QWeb = this.constructor;
     let parent = context;
-    let owner = context;
-    var h = this.h;
+    let scope = Object.create(context);
+    let h = this.h;
     let c1 = [], p1 = {key:1};
-    var vn1 = h('div', p1, c1);
-    if (context['state'].display) {
-        //COMPONENT
-        let k4 = \`__5__\`;
-        let w3 = k4 in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap[k4]] : false;
-        let props3 = {};
-        if (w3 && w3.__owl__.currentFiber && !w3.__owl__.vnode) {
-            w3.destroy();
-            w3 = false;
+    let vn1 = h('div', p1, c1);
+    if (scope['state'].display) {
+        // Component 'Child'
+        let w2 = '__3__' in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap['__3__']] : false;
+        let props2 = {};
+        if (w2 && w2.__owl__.currentFiber && !w2.__owl__.vnode) {
+            w2.destroy();
+            w2 = false;
         }
-        if (w3) {
-            w3.__updateProps(props3, extra.fiber, undefined, undefined);
-            let pvnode = w3.__owl__.pvnode;
+        if (w2) {
+            w2.__updateProps(props2, extra.fiber, undefined);
+            let pvnode = w2.__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);
-            const __patch3 = w3.__patch;
-            w3.__patch = fiber => {__patch3.call(w3, fiber); if(!w3.__owl__.transitionInserted){w3.__owl__.transitionInserted = true;utils.transitionInsert(w3.__owl__.vnode, 'chimay');}};
-            parent.__owl__.cmap[k4] = w3.__owl__.id;
-            let def2 = w3.__prepare(extra.fiber, undefined, undefined);
-            let pvnode = h('dummy', {key: k4, hook: {remove() {},destroy(vn) {let finalize = () => {
-          w3.destroy();
+            let componentKey2 = \`Child\`;
+            let W2 = context.constructor.components[componentKey2] || QWeb.components[componentKey2]|| scope['Child'];
+            if (!W2) {throw new Error('Cannot find the definition of component \\"' + componentKey2 + '\\"')}
+            w2 = new W2(parent, props2);
+            const __patch2 = w2.__patch;
+            w2.__patch = (t, vn) => {__patch2.call(w2, t, vn); if(!w2.__owl__.transitionInserted){w2.__owl__.transitionInserted = true;utils.transitionInsert(w2.__owl__.vnode, 'chimay');}};
+            parent.__owl__.cmap['__3__'] = w2.__owl__.id;
+            let fiber = w2.__prepare(extra.fiber, undefined, () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+            let pvnode = h('dummy', {key: '__3__', hook: {remove() {},destroy(vn) {let finalize = () => {
+          w2.destroy();
         };
-        delete w3.__owl__.transitionInserted;
+        delete w2.__owl__.transitionInserted;
         utils.transitionRemove(vn, 'chimay', finalize);}}});
-            const fiber = w3.__owl__.currentFiber;
-            def2.then(function () { if (fiber.isCompleted) { return; } const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
             c1.push(pvnode);
-            w3.__owl__.pvnode = pvnode;
+            w2.__owl__.pvnode = pvnode;
         }
-        w3.__owl__.parentLastFiberId = extra.fiber.id;
+        w2.__owl__.parentLastFiberId = extra.fiber.id;
     }
     return vn1;
 }"
 `;
 
 exports[`animations t-transition combined with t-component, remove and re-add before transitionend 1`] = `
-"function anonymous(context,extra
+"function anonymous(context, extra
 ) {
+    // Template name: \\"__template__2\\"
     let utils = this.constructor.utils;
     let QWeb = this.constructor;
     let parent = context;
-    let owner = context;
-    var h = this.h;
+    let scope = Object.create(context);
+    let h = this.h;
     let c1 = [], p1 = {key:1};
-    var vn1 = h('div', p1, c1);
-    if (context['state'].flag) {
-        //COMPONENT
-        let k4 = \`__5__\`;
-        let w3 = k4 in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap[k4]] : false;
-        let props3 = {};
-        if (w3 && w3.__owl__.currentFiber && !w3.__owl__.vnode) {
-            w3.destroy();
-            w3 = false;
+    let vn1 = h('div', p1, c1);
+    if (scope['state'].flag) {
+        // Component 'Child'
+        let w2 = '__3__' in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap['__3__']] : false;
+        let props2 = {};
+        if (w2 && w2.__owl__.currentFiber && !w2.__owl__.vnode) {
+            w2.destroy();
+            w2 = false;
         }
-        if (w3) {
-            w3.__updateProps(props3, extra.fiber, undefined, undefined);
-            let pvnode = w3.__owl__.pvnode;
+        if (w2) {
+            w2.__updateProps(props2, extra.fiber, undefined);
+            let pvnode = w2.__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);
-            const __patch3 = w3.__patch;
-            w3.__patch = fiber => {__patch3.call(w3, fiber); if(!w3.__owl__.transitionInserted){w3.__owl__.transitionInserted = true;utils.transitionInsert(w3.__owl__.vnode, 'chimay');}};
-            parent.__owl__.cmap[k4] = w3.__owl__.id;
-            let def2 = w3.__prepare(extra.fiber, undefined, undefined);
-            let pvnode = h('dummy', {key: k4, hook: {remove() {},destroy(vn) {let finalize = () => {
-          w3.destroy();
+            let componentKey2 = \`Child\`;
+            let W2 = context.constructor.components[componentKey2] || QWeb.components[componentKey2]|| scope['Child'];
+            if (!W2) {throw new Error('Cannot find the definition of component \\"' + componentKey2 + '\\"')}
+            w2 = new W2(parent, props2);
+            const __patch2 = w2.__patch;
+            w2.__patch = (t, vn) => {__patch2.call(w2, t, vn); if(!w2.__owl__.transitionInserted){w2.__owl__.transitionInserted = true;utils.transitionInsert(w2.__owl__.vnode, 'chimay');}};
+            parent.__owl__.cmap['__3__'] = w2.__owl__.id;
+            let fiber = w2.__prepare(extra.fiber, undefined, () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+            let pvnode = h('dummy', {key: '__3__', hook: {remove() {},destroy(vn) {let finalize = () => {
+          w2.destroy();
         };
-        delete w3.__owl__.transitionInserted;
+        delete w2.__owl__.transitionInserted;
         utils.transitionRemove(vn, 'chimay', finalize);}}});
-            const fiber = w3.__owl__.currentFiber;
-            def2.then(function () { if (fiber.isCompleted) { return; } const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
             c1.push(pvnode);
-            w3.__owl__.pvnode = pvnode;
+            w2.__owl__.pvnode = pvnode;
         }
-        w3.__owl__.parentLastFiberId = extra.fiber.id;
+        w2.__owl__.parentLastFiberId = extra.fiber.id;
     }
     return vn1;
 }"
 `;
 
 exports[`animations t-transition with no delay/duration 1`] = `
-"function anonymous(context,extra
+"function anonymous(context, extra
 ) {
+    // Template name: \\"test\\"
     let utils = this.constructor.utils;
-    var h = this.h;
+    let h = this.h;
     let c1 = [], p1 = {key:1};
-    var vn1 = h('span', p1, c1);
+    let vn1 = h('span', p1, c1);
     p1.hook = {
       insert: vn => {
         utils.transitionInsert(vn, 'jupiler');
@@ -163,12 +158,34 @@ exports[`animations t-transition with no delay/duration 1`] = `
 `;
 
 exports[`animations t-transition, on a simple node (insert) 1`] = `
-"function anonymous(context,extra
+"function anonymous(context, extra
 ) {
+    // Template name: \\"test\\"
     let utils = this.constructor.utils;
-    var h = this.h;
+    let h = this.h;
     let c1 = [], p1 = {key:1};
-    var vn1 = h('span', p1, c1);
+    let 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;
+}"
+`;
+
+exports[`animations t-transition, on a simple node, not in the DOM 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"test\\"
+    let utils = this.constructor.utils;
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('span', p1, c1);
     p1.hook = {
       insert: vn => {
         utils.transitionInsert(vn, 'chimay');

tests/animations.test.ts

@@ -78,6 +78,7 @@ describe("animations", () => {
       def.resolve();
     });
     let node: HTMLElement = <HTMLElement>renderToDOM(qweb, "test");
+    fixture.appendChild(node);
 
     expect(node.className).toBe("chimay-enter chimay-enter-active");
     await def; // wait for the mocked repaint to be done
@@ -85,6 +86,27 @@ describe("animations", () => {
     expect(node.className).toBe("");
   });
 
+  test("t-transition, on a simple node, not in the DOM", async () => {
+    expect.assertions(5);
+    qweb.addTemplate("test", `<span t-transition="chimay">blue</span>`);
+
+    let def = makeDeferred();
+    patchNextFrame(cb => {
+      expect(node.className).toBe("chimay-enter chimay-enter-active");
+      cb();
+      expect(node.className).toBe("chimay-enter-active chimay-enter-to");
+      def.resolve();
+    });
+    let node: HTMLElement = <HTMLElement>renderToDOM(qweb, "test");
+
+    expect(node.className).toBe("chimay-enter chimay-enter-active");
+    await def; // wait for the mocked repaint to be done
+    node.dispatchEvent(new Event("transitionend"));
+    // we check here that the css classes have not been removed, since the
+    // element is not in the dom, we actually do not want to do anything.
+    expect(node.className).toBe("chimay-enter-active chimay-enter-to");
+  });
+
   test("t-transition with no delay/duration", async () => {
     expect.assertions(4);
     qweb.addTemplate("test", `<span t-transition="jupiler">blue</span>`);
@@ -97,6 +119,7 @@ describe("animations", () => {
       def.resolve();
     });
     let node: HTMLElement = <HTMLElement>renderToDOM(qweb, "test");
+    fixture.appendChild(node);
     expect(node.className).toBe("jupiler-enter jupiler-enter-active");
     await def;
   });
@@ -254,11 +277,11 @@ describe("animations", () => {
     widget.state.display = false;
     patchNextFrame(cb => {
       expect(fixture.innerHTML).toBe(
-        '<div><span class="chimay-leave chimay-leave-active" data-owl-key="__5__">blue</span></div>'
+        '<div><span class="chimay-leave chimay-leave-active" data-owl-key="__3__">blue</span></div>'
       );
       cb();
       expect(fixture.innerHTML).toBe(
-        '<div><span class="chimay-leave-active chimay-leave-to" data-owl-key="__5__">blue</span></div>'
+        '<div><span class="chimay-leave-active chimay-leave-to" data-owl-key="__3__">blue</span></div>'
       );
       def.resolve();
     });
@@ -371,7 +394,7 @@ describe("animations", () => {
 
     await def; // wait for the mocked repaint to be done
     widget.el!.querySelector("span")!.dispatchEvent(new Event("transitionend")); // mock end of css transition
-    expect(fixture.innerHTML).toBe('<div><span class="" data-owl-key="__5__">blue</span></div>');
+    expect(fixture.innerHTML).toBe('<div><span class="" data-owl-key="__3__">blue</span></div>');
   });
 
   test("transitionInsert is called the correct amount of times", async () => {
@@ -405,14 +428,14 @@ describe("animations", () => {
     widget.state.flag = false;
     await nextTick();
     expect(fixture.innerHTML).toBe(
-      '<div><span class="chimay-leave-active chimay-leave-to" data-owl-key="__5__">blue</span></div>'
+      '<div><span class="chimay-leave-active chimay-leave-to" data-owl-key="__3__">blue</span></div>'
     );
     expect(QWeb.utils.transitionInsert).toBeCalledTimes(1);
 
     widget.state.flag = true;
     await nextTick();
     expect(fixture.innerHTML).toBe(
-      '<div><span class="chimay-enter-active chimay-enter-to" data-owl-key="__5__">blue</span></div>'
+      '<div><span class="chimay-enter-active chimay-enter-to" data-owl-key="__3__">blue</span></div>'
     );
     expect(QWeb.utils.transitionInsert).toBeCalledTimes(2);
 
@@ -423,7 +446,7 @@ describe("animations", () => {
 
     expect(QWeb.utils.transitionInsert).toBeCalledTimes(3);
     widget.el!.querySelector("span")!.dispatchEvent(new Event("transitionend"));
-    expect(fixture.innerHTML).toBe('<div><span class="" data-owl-key="__5__">blue</span></div>');
+    expect(fixture.innerHTML).toBe('<div><span class="" data-owl-key="__3__">blue</span></div>');
     QWeb.utils.transitionInsert = oldTransitionInsert;
   });
 });

tests/component/__snapshots__/class_style.test.ts.snap

@@ -0,0 +1,156 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`class and style attributes with t-component dynamic t-att-style is properly added and updated on widget root el 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"ParentWidget\\"
+    let utils = this.constructor.utils;
+    let QWeb = this.constructor;
+    let parent = context;
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    // Component 'child'
+    const _4 = scope['state'].style;
+    let w2 = '__3__' in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap['__3__']] : false;
+    let props2 = {};
+    if (w2 && w2.__owl__.currentFiber && !w2.__owl__.vnode) {
+        w2.destroy();
+        w2 = false;
+    }
+    if (w2) {
+        w2.__updateProps(props2, extra.fiber, undefined).then(()=>{if (w2.__owl__.isDestroyed) {return};w2.el.style=_4;});;
+        let pvnode = w2.__owl__.pvnode;
+        c1.push(pvnode);
+    } else {
+        let componentKey2 = \`child\`;
+        let W2 = context.constructor.components[componentKey2] || QWeb.components[componentKey2]|| scope['child'];
+        if (!W2) {throw new Error('Cannot find the definition of component \\"' + componentKey2 + '\\"')}
+        w2 = new W2(parent, props2);
+        parent.__owl__.cmap['__3__'] = w2.__owl__.id;
+        let fiber = w2.__prepare(extra.fiber, undefined, () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; utils.assignHooks(vnode.data, {create(_, vn){vn.elm.style = _4;}});});
+        let pvnode = h('dummy', {key: '__3__', hook: {remove() {},destroy(vn) {w2.destroy();}}});
+        c1.push(pvnode);
+        w2.__owl__.pvnode = pvnode;
+    }
+    w2.__owl__.parentLastFiberId = extra.fiber.id;
+    return vn1;
+}"
+`;
+
+exports[`class and style attributes with t-component t-att-class is properly added/removed on widget root el (v2) 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"ParentWidget\\"
+    let utils = this.constructor.utils;
+    let QWeb = this.constructor;
+    let parent = context;
+    context.__owl__.refs = context.__owl__.refs || {};
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    // Component 'Child'
+    const ref4 = \`child\`;
+    let _5 = {'a':true};
+    Object.assign(_5, {b:scope['state'].b})
+    let w2 = '__3__' in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap['__3__']] : false;
+    let props2 = {};
+    if (w2 && w2.__owl__.currentFiber && !w2.__owl__.vnode) {
+        w2.destroy();
+        w2 = false;
+    }
+    if (w2) {
+        w2.__updateProps(props2, extra.fiber, undefined);
+        let pvnode = w2.__owl__.pvnode;
+        c1.push(pvnode);
+    } else {
+        let componentKey2 = \`Child\`;
+        let W2 = context.constructor.components[componentKey2] || QWeb.components[componentKey2]|| scope['Child'];
+        if (!W2) {throw new Error('Cannot find the definition of component \\"' + componentKey2 + '\\"')}
+        w2 = new W2(parent, props2);
+        parent.__owl__.cmap['__3__'] = w2.__owl__.id;
+        let fiber = w2.__prepare(extra.fiber, undefined, () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; utils.assignHooks(vnode.data, {create(_, vn){}});});
+        let pvnode = h('dummy', {key: '__3__', hook: {insert(vn) {context.__owl__.refs[ref4] = w2;},remove() {},destroy(vn) {w2.destroy();delete context.__owl__.refs[ref4];}}});
+        c1.push(pvnode);
+        w2.__owl__.pvnode = pvnode;
+    }
+    w2.__owl__.classObj=_5;
+    w2.__owl__.parentLastFiberId = extra.fiber.id;
+    return vn1;
+}"
+`;
+
+exports[`class and style attributes with t-component t-att-class is properly added/removed on widget root el (v2) 2`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Child\\"
+    let utils = this.constructor.utils;
+    let scope = Object.create(context);
+    let h = this.h;
+    let _7 = {'c':true};
+    Object.assign(_7, utils.toObj({d:scope['state'].d}))
+    let c8 = [], p8 = {key:8,class:_7};
+    let vn8 = h('span', p8, c8);
+    return vn8;
+}"
+`;
+
+exports[`class and style attributes with t-component t-att-class is properly added/removed on widget root el (v3) 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"ParentWidget\\"
+    let utils = this.constructor.utils;
+    let QWeb = this.constructor;
+    let parent = context;
+    context.__owl__.refs = context.__owl__.refs || {};
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    // Component 'Child'
+    const ref4 = \`child\`;
+    let _5 = {'a':true};
+    Object.assign(_5, utils.toObj(scope['state'].b?'b':''))
+    let w2 = '__3__' in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap['__3__']] : false;
+    let props2 = {};
+    if (w2 && w2.__owl__.currentFiber && !w2.__owl__.vnode) {
+        w2.destroy();
+        w2 = false;
+    }
+    if (w2) {
+        w2.__updateProps(props2, extra.fiber, undefined);
+        let pvnode = w2.__owl__.pvnode;
+        c1.push(pvnode);
+    } else {
+        let componentKey2 = \`Child\`;
+        let W2 = context.constructor.components[componentKey2] || QWeb.components[componentKey2]|| scope['Child'];
+        if (!W2) {throw new Error('Cannot find the definition of component \\"' + componentKey2 + '\\"')}
+        w2 = new W2(parent, props2);
+        parent.__owl__.cmap['__3__'] = w2.__owl__.id;
+        let fiber = w2.__prepare(extra.fiber, undefined, () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; utils.assignHooks(vnode.data, {create(_, vn){}});});
+        let pvnode = h('dummy', {key: '__3__', hook: {insert(vn) {context.__owl__.refs[ref4] = w2;},remove() {},destroy(vn) {w2.destroy();delete context.__owl__.refs[ref4];}}});
+        c1.push(pvnode);
+        w2.__owl__.pvnode = pvnode;
+    }
+    w2.__owl__.classObj=_5;
+    w2.__owl__.parentLastFiberId = extra.fiber.id;
+    return vn1;
+}"
+`;
+
+exports[`class and style attributes with t-component t-att-class is properly added/removed on widget root el (v3) 2`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Child\\"
+    let utils = this.constructor.utils;
+    let scope = Object.create(context);
+    let h = this.h;
+    let _7 = {'c':true};
+    Object.assign(_7, utils.toObj(scope['state'].d?'d':''))
+    let c8 = [], p8 = {key:8,class:_7};
+    let vn8 = h('span', p8, c8);
+    return vn8;
+}"
+`;

tests/component/__snapshots__/props_validation.test.ts.snap

@@ -1,41 +1,39 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`props validation props are validated in dev mode (code snapshot) 1`] = `
-"function anonymous(context,extra
+"function anonymous(context, extra
 ) {
+    // Template name: \\"App\\"
     let utils = this.constructor.utils;
     let QWeb = this.constructor;
     let parent = context;
-    let owner = context;
-    var h = this.h;
+    let scope = Object.create(context);
+    let h = this.h;
     let c1 = [], p1 = {key:1};
-    var vn1 = h('div', p1, c1);
-    //COMPONENT
-    let k4 = \`__5__\`;
-    let w3 = k4 in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap[k4]] : false;
-    let props3 = {message:1};
-    if (w3 && w3.__owl__.currentFiber && !w3.__owl__.vnode) {
-        w3.destroy();
-        w3 = false;
+    let vn1 = h('div', p1, c1);
+    // Component 'Child'
+    let w2 = '__3__' in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap['__3__']] : false;
+    let props2 = {message:1};
+    if (w2 && w2.__owl__.currentFiber && !w2.__owl__.vnode) {
+        w2.destroy();
+        w2 = false;
     }
-    if (w3) {
-        w3.__updateProps(props3, extra.fiber, undefined, undefined);
-        let pvnode = w3.__owl__.pvnode;
+    if (w2) {
+        w2.__updateProps(props2, extra.fiber, undefined);
+        let pvnode = w2.__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[k4] = w3.__owl__.id;
-        let def2 = w3.__prepare(extra.fiber, undefined, undefined);
-        let pvnode = h('dummy', {key: k4, hook: {remove() {},destroy(vn) {w3.destroy();}}});
-        const fiber = w3.__owl__.currentFiber;
-        def2.then(function () { if (fiber.isCompleted) { return; } const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+        let componentKey2 = \`Child\`;
+        let W2 = context.constructor.components[componentKey2] || QWeb.components[componentKey2]|| scope['Child'];
+        if (!W2) {throw new Error('Cannot find the definition of component \\"' + componentKey2 + '\\"')}
+        w2 = new W2(parent, props2);
+        parent.__owl__.cmap['__3__'] = w2.__owl__.id;
+        let fiber = w2.__prepare(extra.fiber, undefined, () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+        let pvnode = h('dummy', {key: '__3__', hook: {remove() {},destroy(vn) {w2.destroy();}}});
         c1.push(pvnode);
-        w3.__owl__.pvnode = pvnode;
+        w2.__owl__.pvnode = pvnode;
     }
-    w3.__owl__.parentLastFiberId = extra.fiber.id;
+    w2.__owl__.parentLastFiberId = extra.fiber.id;
     return vn1;
 }"
 `;

tests/component/__snapshots__/slots.test.ts.snap

@@ -0,0 +1,488 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`t-slot directive can define and call slots 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Parent\\"
+    let utils = this.constructor.utils;
+    let QWeb = this.constructor;
+    let parent = context;
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    // Component 'Dialog'
+    let w2 = '__3__' in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap['__3__']] : false;
+    let props2 = {};
+    if (w2 && w2.__owl__.currentFiber && !w2.__owl__.vnode) {
+        w2.destroy();
+        w2 = false;
+    }
+    if (w2) {
+        w2.__updateProps(props2, extra.fiber, Object.assign(Object.create(context), scope));
+        let pvnode = w2.__owl__.pvnode;
+        c1.push(pvnode);
+    } else {
+        let componentKey2 = \`Dialog\`;
+        let W2 = context.constructor.components[componentKey2] || QWeb.components[componentKey2]|| scope['Dialog'];
+        if (!W2) {throw new Error('Cannot find the definition of component \\"' + componentKey2 + '\\"')}
+        w2 = new W2(parent, props2);
+        parent.__owl__.cmap['__3__'] = w2.__owl__.id;
+        w2.__owl__.slotId = 1;
+        let fiber = w2.__prepare(extra.fiber, Object.assign(Object.create(context), scope), () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+        let pvnode = h('dummy', {key: '__3__', hook: {remove() {},destroy(vn) {w2.destroy();}}});
+        c1.push(pvnode);
+        w2.__owl__.pvnode = pvnode;
+    }
+    w2.__owl__.parentLastFiberId = extra.fiber.id;
+    return vn1;
+}"
+`;
+
+exports[`t-slot directive can define and call slots 2`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Dialog\\"
+    let h = this.h;
+    let c6 = [], p6 = {key:6};
+    let vn6 = h('div', p6, c6);
+    let c7 = [], p7 = {key:7};
+    let vn7 = h('div', p7, c7);
+    c6.push(vn7);
+    const slot8 = this.constructor.slots[context.__owl__.slotId + '_' + 'header'];
+    if (slot8) {
+        slot8.call(this, context.__owl__.scope, Object.assign({}, extra, {parentNode: c7, parent: extra.parent || context}));
+    }
+    let c9 = [], p9 = {key:9};
+    let vn9 = h('div', p9, c9);
+    c6.push(vn9);
+    const slot10 = this.constructor.slots[context.__owl__.slotId + '_' + 'footer'];
+    if (slot10) {
+        slot10.call(this, context.__owl__.scope, Object.assign({}, extra, {parentNode: c9, parent: extra.parent || context}));
+    }
+    return vn6;
+}"
+`;
+
+exports[`t-slot directive can define and call slots 3`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"slot_header_template\\"
+    let h = this.h;
+    let c1 = extra.parentNode;
+    let c4 = [], p4 = {key:4};
+    let vn4 = h('span', p4, c4);
+    c1.push(vn4);
+    c4.push({text: \`header\`});
+}"
+`;
+
+exports[`t-slot directive can define and call slots 4`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"slot_footer_template\\"
+    let h = this.h;
+    let c1 = extra.parentNode;
+    let c5 = [], p5 = {key:5};
+    let vn5 = h('span', p5, c5);
+    c1.push(vn5);
+    c5.push({text: \`footer\`});
+}"
+`;
+
+exports[`t-slot directive content is the default slot 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"slot_default_template\\"
+    let h = this.h;
+    let c1 = extra.parentNode;
+    let c4 = [], p4 = {key:4};
+    let vn4 = h('span', p4, c4);
+    c1.push(vn4);
+    c4.push({text: \`sts rocks\`});
+}"
+`;
+
+exports[`t-slot directive dafault slots can define a default content 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"__template__1\\"
+    let h = this.h;
+    let c4 = [], p4 = {key:4};
+    let vn4 = h('span', p4, c4);
+    const slot5 = this.constructor.slots[context.__owl__.slotId + '_' + 'default'];
+    if (slot5) {
+        slot5.call(this, context.__owl__.scope, Object.assign({}, extra, {parentNode: c4, parent: extra.parent || context}));
+    } else {
+        c4.push({text: \`default content\`});
+    }
+    return vn4;
+}"
+`;
+
+exports[`t-slot directive default slot work with text nodes 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"slot_default_template\\"
+    let h = this.h;
+    let c1 = extra.parentNode;
+    c1.push({text: \`sts rocks\`});
+}"
+`;
+
+exports[`t-slot directive multiple roots are allowed in a default slot 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"slot_default_template\\"
+    let h = this.h;
+    let c1 = extra.parentNode;
+    let c4 = [], p4 = {key:4};
+    let vn4 = h('span', p4, c4);
+    c1.push(vn4);
+    c4.push({text: \`sts\`});
+    let c5 = [], p5 = {key:5};
+    let vn5 = h('span', p5, c5);
+    c1.push(vn5);
+    c5.push({text: \`rocks\`});
+}"
+`;
+
+exports[`t-slot directive multiple roots are allowed in a named slot 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"slot_content_template\\"
+    let h = this.h;
+    let c1 = extra.parentNode;
+    let c4 = [], p4 = {key:4};
+    let vn4 = h('span', p4, c4);
+    c1.push(vn4);
+    c4.push({text: \`sts\`});
+    let c5 = [], p5 = {key:5};
+    let vn5 = h('span', p5, c5);
+    c1.push(vn5);
+    c5.push({text: \`rocks\`});
+}"
+`;
+
+exports[`t-slot directive named slots can define a default content 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"__template__1\\"
+    let h = this.h;
+    let c4 = [], p4 = {key:4};
+    let vn4 = h('span', p4, c4);
+    const slot5 = this.constructor.slots[context.__owl__.slotId + '_' + 'header'];
+    if (slot5) {
+        slot5.call(this, context.__owl__.scope, Object.assign({}, extra, {parentNode: c4, parent: extra.parent || context}));
+    } else {
+        c4.push({text: \`default content\`});
+    }
+    return vn4;
+}"
+`;
+
+exports[`t-slot directive refs are properly bound in slots 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"slot_footer_template\\"
+    let utils = this.constructor.utils;
+    context.__owl__.refs = context.__owl__.refs || {};
+    let h = this.h;
+    let c1 = extra.parentNode;
+    let c8 = [], p8 = {key:8,on:{}};
+    let vn8 = h('button', p8, c8);
+    c1.push(vn8);
+    extra.handlers['click__9__'] = extra.handlers['click__9__'] || function (e) {if (!context.__owl__.isMounted){return}utils.getComponent(context)['doSomething'](e);};
+    p8.on['click'] = extra.handlers['click__9__'];
+    const ref10 = \`myButton\`;
+    p8.hook = {
+      create: (_, n) => {
+        context.__owl__.refs[ref10] = n.elm;
+      },
+      destroy: () => {
+        delete context.__owl__.refs[ref10];
+      },
+    };
+    c8.push({text: \`do something\`});
+}"
+`;
+
+exports[`t-slot directive slots are rendered with proper context 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"slot_footer_template\\"
+    let utils = this.constructor.utils;
+    let h = this.h;
+    let c1 = extra.parentNode;
+    let c8 = [], p8 = {key:8,on:{}};
+    let vn8 = h('button', p8, c8);
+    c1.push(vn8);
+    extra.handlers['click__9__'] = extra.handlers['click__9__'] || function (e) {if (!context.__owl__.isMounted){return}utils.getComponent(context)['doSomething'](e);};
+    p8.on['click'] = extra.handlers['click__9__'];
+    c8.push({text: \`do something\`});
+}"
+`;
+
+exports[`t-slot directive slots are rendered with proper context, part 2 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Link\\"
+    let scope = Object.create(context);
+    let h = this.h;
+    let _11 = scope['props'].to;
+    let c12 = [], p12 = {key:12,attrs:{href: _11}};
+    let vn12 = h('a', p12, c12);
+    const slot13 = this.constructor.slots[context.__owl__.slotId + '_' + 'default'];
+    if (slot13) {
+        slot13.call(this, context.__owl__.scope, Object.assign({}, extra, {parentNode: c12, parent: extra.parent || context}));
+    }
+    return vn12;
+}"
+`;
+
+exports[`t-slot directive slots are rendered with proper context, part 2 2`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"App\\"
+    let utils = this.constructor.utils;
+    let QWeb = this.constructor;
+    let parent = context;
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    let c2 = [], p2 = {key:2};
+    let vn2 = h('u', p2, c2);
+    c1.push(vn2);
+    let _3 = scope['state'].users;
+    if (!_3) { throw new Error('QWeb error: Invalid loop expression')}
+    let _4 = _5 = _3;
+    if (!(_3 instanceof Array)) {
+        _4 = Object.keys(_3);
+        _5 = Object.values(_3);
+    }
+    let _length4 = _4.length;
+    let _origScope6 = scope;
+    scope = Object.create(scope);
+    for (let i1 = 0; i1 < _length4; i1++) {
+        scope.user_first = i1 === 0
+        scope.user_last = i1 === _length4 - 1
+        scope.user_index = i1
+        scope.user = _4[i1]
+        scope.user_value = _5[i1]
+        let key1 = scope['user'].id;
+        let c7 = [], p7 = {key:\`\${key1}_7\`};
+        let vn7 = h('li', p7, c7);
+        c2.push(vn7);
+        // Component 'Link'
+        let k9 = \`__9__\${key1}__\`;
+        let w8 = k9 in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap[k9]] : false;
+        let props8 = {to:'/user/'+scope['user'].id};
+        if (w8 && w8.__owl__.currentFiber && !w8.__owl__.vnode) {
+            w8.destroy();
+            w8 = false;
+        }
+        if (w8) {
+            w8.__updateProps(props8, extra.fiber, Object.assign(Object.create(context), scope));
+            let pvnode = w8.__owl__.pvnode;
+            c7.push(pvnode);
+        } else {
+            let componentKey8 = \`Link\`;
+            let W8 = context.constructor.components[componentKey8] || QWeb.components[componentKey8]|| scope['Link'];
+            if (!W8) {throw new Error('Cannot find the definition of component \\"' + componentKey8 + '\\"')}
+            w8 = new W8(parent, props8);
+            parent.__owl__.cmap[k9] = w8.__owl__.id;
+            w8.__owl__.slotId = 1;
+            let fiber = w8.__prepare(extra.fiber, Object.assign(Object.create(context), scope), () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+            let pvnode = h('dummy', {key: k9, hook: {remove() {},destroy(vn) {w8.destroy();}}});
+            c7.push(pvnode);
+            w8.__owl__.pvnode = pvnode;
+        }
+        w8.__owl__.parentLastFiberId = extra.fiber.id;
+    }
+    scope = _origScope6;
+    return vn1;
+}"
+`;
+
+exports[`t-slot directive slots are rendered with proper context, part 2 3`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"slot_default_template\\"
+    let scope = Object.create(context);
+    let h = this.h;
+    let c7 = extra.parentNode;
+    c7.push({text: \`User \`});
+    let _10 = scope['user'].name;
+    if (_10 != null) {
+        c7.push({text: _10});
+    }
+}"
+`;
+
+exports[`t-slot directive slots are rendered with proper context, part 3 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"Link\\"
+    let scope = Object.create(context);
+    let h = this.h;
+    let _10 = scope['props'].to;
+    let c11 = [], p11 = {key:11,attrs:{href: _10}};
+    let vn11 = h('a', p11, c11);
+    const slot12 = this.constructor.slots[context.__owl__.slotId + '_' + 'default'];
+    if (slot12) {
+        slot12.call(this, context.__owl__.scope, Object.assign({}, extra, {parentNode: c11, parent: extra.parent || context}));
+    }
+    return vn11;
+}"
+`;
+
+exports[`t-slot directive slots are rendered with proper context, part 3 2`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"App\\"
+    let utils = this.constructor.utils;
+    let QWeb = this.constructor;
+    let parent = context;
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    let c2 = [], p2 = {key:2};
+    let vn2 = h('u', p2, c2);
+    c1.push(vn2);
+    let _3 = scope['state'].users;
+    if (!_3) { throw new Error('QWeb error: Invalid loop expression')}
+    let _4 = _5 = _3;
+    if (!(_3 instanceof Array)) {
+        _4 = Object.keys(_3);
+        _5 = Object.values(_3);
+    }
+    let _length4 = _4.length;
+    let _origScope6 = scope;
+    scope = Object.create(scope);
+    for (let i1 = 0; i1 < _length4; i1++) {
+        scope.user_first = i1 === 0
+        scope.user_last = i1 === _length4 - 1
+        scope.user_index = i1
+        scope.user = _4[i1]
+        scope.user_value = _5[i1]
+        let key1 = scope['user'].id;
+        let c7 = [], p7 = {key:\`\${key1}_7\`};
+        let vn7 = h('li', p7, c7);
+        c2.push(vn7);
+        utils.getScope(scope, 'userdescr').userdescr = 'User '+scope['user'].name;
+        // Component 'Link'
+        let k9 = \`__9__\${key1}__\`;
+        let w8 = k9 in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap[k9]] : false;
+        let props8 = {to:'/user/'+scope['user'].id};
+        if (w8 && w8.__owl__.currentFiber && !w8.__owl__.vnode) {
+            w8.destroy();
+            w8 = false;
+        }
+        if (w8) {
+            w8.__updateProps(props8, extra.fiber, Object.assign(Object.create(context), scope));
+            let pvnode = w8.__owl__.pvnode;
+            c7.push(pvnode);
+        } else {
+            let componentKey8 = \`Link\`;
+            let W8 = context.constructor.components[componentKey8] || QWeb.components[componentKey8]|| scope['Link'];
+            if (!W8) {throw new Error('Cannot find the definition of component \\"' + componentKey8 + '\\"')}
+            w8 = new W8(parent, props8);
+            parent.__owl__.cmap[k9] = w8.__owl__.id;
+            w8.__owl__.slotId = 1;
+            let fiber = w8.__prepare(extra.fiber, Object.assign(Object.create(context), scope), () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+            let pvnode = h('dummy', {key: k9, hook: {remove() {},destroy(vn) {w8.destroy();}}});
+            c7.push(pvnode);
+            w8.__owl__.pvnode = pvnode;
+        }
+        w8.__owl__.parentLastFiberId = extra.fiber.id;
+    }
+    scope = _origScope6;
+    return vn1;
+}"
+`;
+
+exports[`t-slot directive slots are rendered with proper context, part 3 3`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"slot_default_template\\"
+    let scope = Object.create(context);
+    let h = this.h;
+    let c7 = extra.parentNode;
+    if (scope.userdescr != null) {
+        c7.push({text: scope.userdescr});
+    }
+}"
+`;
+
+exports[`t-slot directive slots are rendered with proper context, part 4 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"App\\"
+    let utils = this.constructor.utils;
+    let QWeb = this.constructor;
+    let parent = context;
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    scope.userdescr = 'User '+scope['state'].user.name;
+    // Component 'Link'
+    let w2 = '__3__' in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap['__3__']] : false;
+    let props2 = {to:'/user/'+scope['state'].user.id};
+    if (w2 && w2.__owl__.currentFiber && !w2.__owl__.vnode) {
+        w2.destroy();
+        w2 = false;
+    }
+    if (w2) {
+        w2.__updateProps(props2, extra.fiber, Object.assign(Object.create(context), scope));
+        let pvnode = w2.__owl__.pvnode;
+        c1.push(pvnode);
+    } else {
+        let componentKey2 = \`Link\`;
+        let W2 = context.constructor.components[componentKey2] || QWeb.components[componentKey2]|| scope['Link'];
+        if (!W2) {throw new Error('Cannot find the definition of component \\"' + componentKey2 + '\\"')}
+        w2 = new W2(parent, props2);
+        parent.__owl__.cmap['__3__'] = w2.__owl__.id;
+        w2.__owl__.slotId = 1;
+        let fiber = w2.__prepare(extra.fiber, Object.assign(Object.create(context), scope), () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+        let pvnode = h('dummy', {key: '__3__', hook: {remove() {},destroy(vn) {w2.destroy();}}});
+        c1.push(pvnode);
+        w2.__owl__.pvnode = pvnode;
+    }
+    w2.__owl__.parentLastFiberId = extra.fiber.id;
+    return vn1;
+}"
+`;
+
+exports[`t-slot directive slots are rendered with proper context, part 4 2`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"slot_default_template\\"
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = extra.parentNode;
+    if (scope.userdescr != null) {
+        c1.push({text: scope.userdescr});
+    }
+}"
+`;
+
+exports[`t-slot directive template can just return a slot 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"__template__2\\"
+    let utils = this.constructor.utils;
+    let result;
+    let h = this.h;
+    const slot6 = this.constructor.slots[context.__owl__.slotId + '_' + 'default'];
+    if (slot6) {
+        let children7= []
+        result = {}
+        slot6.call(this, context.__owl__.scope, Object.assign({}, extra, {parentNode: children7, parent: extra.parent || context}));
+        utils.defineProxy(result, children7[0]);
+    }
+    return result;
+}"
+`;

tests/component/class_style.test.ts

@@ -0,0 +1,271 @@
+import { Component, Env } from "../../src/component/component";
+import { QWeb } from "../../src/qweb/qweb";
+import { xml } from "../../src/tags";
+import { useState, useRef } from "../../src/hooks";
+import { makeTestFixture, makeTestEnv, nextTick } from "../helpers";
+
+//------------------------------------------------------------------------------
+// Setup and helpers
+//------------------------------------------------------------------------------
+
+// We create before each test:
+// - fixture: a div, appended to the DOM, intended to be the target of dom
+//   manipulations.  Note that it is removed after each test.
+// - env: a WEnv, necessary to create new components
+
+let fixture: HTMLElement;
+let env: Env;
+
+beforeEach(() => {
+  fixture = makeTestFixture();
+  env = makeTestEnv();
+  Component.env = env;
+});
+
+afterEach(() => {
+  fixture.remove();
+});
+
+describe("class and style attributes with t-component", () => {
+  test("class is properly added on widget root el", async () => {
+    class Child extends Component {
+      static template = xml`<div class="c"/>`;
+    }
+    class ParentWidget extends Component {
+      static template = xml`<div><Child class="a b"/></div>`;
+      static components = { Child };
+    }
+    const widget = new ParentWidget();
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe(`<div><div class="c a b"></div></div>`);
+  });
+
+  test("empty class attribute is not added on widget root el", async () => {
+    class Child extends Component {
+      static template = xml`<span/>`;
+    }
+    class Parent extends Component {
+      static template = xml`<div><Child class=""/></div>`;
+      static components = { Child };
+    }
+    const widget = new Parent();
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe(`<div><span></span></div>`);
+  });
+
+  test("t-att-class is properly added/removed on widget root el", async () => {
+    class Child extends Component {
+      static template = xml`<div class="c"/>`;
+    }
+    class ParentWidget extends Component {
+      static template = xml`<div><Child t-att-class="{a:state.a, b:state.b}"/></div>`;
+      static components = { Child };
+      state = useState({ a: true, b: false });
+    }
+    const widget = new ParentWidget();
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe(`<div><div class="c a"></div></div>`);
+    expect(QWeb.TEMPLATES[ParentWidget.template].fn.toString());
+
+    widget.state.a = false;
+    widget.state.b = true;
+    await nextTick();
+    expect(fixture.innerHTML).toBe(`<div><div class="c b"></div></div>`);
+  });
+
+  test("class with extra whitespaces", async () => {
+    env.qweb.addTemplate(
+      "ParentWidget",
+      `<div>
+              <Child class="a  b c   d"/>
+        </div>`
+    );
+    class Child extends Component {}
+    class ParentWidget extends Component {
+      static components = { Child };
+    }
+    env.qweb.addTemplate("Child", `<div/>`);
+    const widget = new ParentWidget();
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe(`<div><div class="a b c d"></div></div>`);
+  });
+
+  test("t-att-class is properly added/removed on widget root el (v2)", async () => {
+    env.qweb.addTemplates(`
+        <templates>
+          <div t-name="ParentWidget">
+            <Child class="a" t-att-class="{ b: state.b }" t-ref="child"/>
+          </div>
+          <span t-name="Child" class="c" t-att-class="{ d: state.d }"/>
+        </templates>`);
+
+    class Child extends Component {
+      state = useState({ d: true });
+    }
+    class ParentWidget extends Component {
+      static components = { Child };
+      state = useState({ b: true });
+      child = useRef("child");
+    }
+    const widget = new ParentWidget();
+    await widget.mount(fixture);
+
+    const span = fixture.querySelector("span")!;
+    expect(span.className).toBe("c d a b");
+
+    widget.state.b = false;
+    await nextTick();
+    expect(span.className).toBe("c d a");
+
+    (widget.child.comp as Child).state.d = false;
+    await nextTick();
+    expect(span.className).toBe("c a");
+
+    widget.state.b = true;
+    await nextTick();
+    expect(span.className).toBe("c a b");
+
+    (widget.child.comp as Child).state.d = true;
+    await nextTick();
+    expect(span.className).toBe("c a b d");
+    expect(env.qweb.templates.ParentWidget.fn.toString()).toMatchSnapshot();
+    expect(env.qweb.templates.Child.fn.toString()).toMatchSnapshot();
+  });
+
+  test("t-att-class is properly added/removed on widget root el (v3)", async () => {
+    env.qweb.addTemplates(`
+        <templates>
+          <div t-name="ParentWidget">
+            <Child class="a" t-att-class="state.b ? 'b' : ''" t-ref="child"/>
+          </div>
+          <span t-name="Child" class="c" t-att-class="state.d ? 'd' : ''"/>
+        </templates>`);
+
+    class Child extends Component {
+      state = useState({ d: true });
+    }
+    class ParentWidget extends Component {
+      static components = { Child };
+      state = useState({ b: true });
+      child = useRef("child");
+    }
+    const widget = new ParentWidget();
+    await widget.mount(fixture);
+
+    const span = fixture.querySelector("span")!;
+    expect(span.className).toBe("c d a b");
+
+    widget.state.b = false;
+    await nextTick();
+    expect(span.className).toBe("c d a");
+
+    (widget.child.comp as Child).state.d = false;
+    await nextTick();
+    expect(span.className).toBe("c a");
+
+    widget.state.b = true;
+    await nextTick();
+    expect(span.className).toBe("c a b");
+
+    (widget.child.comp as Child).state.d = true;
+    await nextTick();
+    expect(span.className).toBe("c a b d");
+    expect(env.qweb.templates.ParentWidget.fn.toString()).toMatchSnapshot();
+    expect(env.qweb.templates.Child.fn.toString()).toMatchSnapshot();
+  });
+
+  test("class on components do not interfere with user defined classes", async () => {
+    env.qweb.addTemplates(`
+        <templates>
+          <div t-name="App" t-att-class="{ c: state.c }" />
+        </templates>`);
+
+    class App extends Component {
+      state = useState({ c: true });
+      mounted() {
+        this.el!.classList.add("user");
+      }
+    }
+
+    const widget = new App();
+    await widget.mount(fixture);
+
+    expect(fixture.innerHTML).toBe('<div class="c user"></div>');
+
+    widget.state.c = false;
+    await nextTick();
+
+    expect(fixture.innerHTML).toBe('<div class="user"></div>');
+  });
+
+  test("style is properly added on widget root el", async () => {
+    env.qweb.addTemplate(
+      "ParentWidget",
+      `
+          <div>
+              <t t-component="child" style="font-weight: bold;"/>
+          </div>`
+    );
+
+    class SomeComponent extends Component {
+      static template = xml`<div/>`;
+    }
+
+    class ParentWidget extends Component {
+      static components = { child: SomeComponent };
+    }
+    const widget = new ParentWidget();
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe(`<div><div style="font-weight: bold;"></div></div>`);
+  });
+
+  test("dynamic t-att-style is properly added and updated on widget root el", async () => {
+    env.qweb.addTemplate(
+      "ParentWidget",
+      `
+          <div>
+              <t t-component="child" t-att-style="state.style"/>
+          </div>`
+    );
+
+    class SomeComponent extends Component {
+      static template = xml`<div/>`;
+    }
+
+    class ParentWidget extends Component {
+      static components = { child: SomeComponent };
+      state = useState({ style: "font-size: 20px" });
+    }
+    const widget = new ParentWidget();
+    await widget.mount(fixture);
+
+    expect(env.qweb.templates.ParentWidget.fn.toString()).toMatchSnapshot();
+
+    expect(fixture.innerHTML).toBe(`<div><div style="font-size: 20px;"></div></div>`);
+
+    widget.state.style = "font-size: 30px";
+    await nextTick();
+
+    expect(fixture.innerHTML).toBe(`<div><div style="font-size: 30px;"></div></div>`);
+  });
+
+  test("error in subcomponent with class", async () => {
+    class Child extends Component {
+      static template = xml`<div t-esc="this.will.crash"/>`;
+    }
+    class ParentWidget extends Component {
+      static template = xml`<div><Child class="a"/></div>`;
+      static components = { Child };
+    }
+    const widget = new ParentWidget();
+    let error;
+    try {
+      await widget.mount(fixture);
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe("Cannot read property 'crash' of undefined");
+    expect(fixture.innerHTML).toBe("");
+  });
+});

tests/component/error_handling.test.ts

@@ -0,0 +1,523 @@
+import { Component, Env } from "../../src/component/component";
+import { useState } from "../../src/hooks";
+import { xml } from "../../src/tags";
+import { makeTestEnv, makeTestFixture, nextTick } from "../helpers";
+
+//------------------------------------------------------------------------------
+// Setup and helpers
+//------------------------------------------------------------------------------
+
+// We create before each test:
+// - fixture: a div, appended to the DOM, intended to be the target of dom
+//   manipulations.  Note that it is removed after each test.
+// - env: a WEnv, necessary to create new components
+
+let fixture: HTMLElement;
+let env: Env;
+
+beforeEach(() => {
+  fixture = makeTestFixture();
+  env = makeTestEnv();
+  Component.env = env;
+});
+
+afterEach(() => {
+  fixture.remove();
+});
+
+describe("component error handling (catchError)", () => {
+  /**
+   * This test suite requires often to wait for 3 ticks. Here is why:
+   * - First tick is to let the app render and crash.
+   * - When we crash, we call the catchError handler in a setTimeout (because we
+   *   need to wait for the previous rendering to be completely stopped). So, we
+   *   need to wait for the second tick.
+   * - Then, when the handler changes the state, we need to wait for the interface
+   *   to be rerendered.
+   *  */
+
+  test("can catch an error in a component render function", async () => {
+    const consoleError = console.error;
+    console.error = jest.fn();
+    const handler = jest.fn();
+    env.qweb.on("error", null, handler);
+    class ErrorComponent extends Component {
+      static template = xml`<div>hey<t t-esc="props.flag and state.this.will.crash"/></div>`;
+    }
+    class ErrorBoundary extends Component {
+      static template = xml`
+          <div>
+            <t t-if="state.error">Error handled</t>
+            <t t-else=""><t t-slot="default" /></t>
+          </div>`;
+      state = useState({ error: false });
+
+      catchError() {
+        this.state.error = true;
+      }
+    }
+    class App extends Component {
+      static template = xml`
+          <div>
+            <ErrorBoundary><ErrorComponent flag="state.flag"/></ErrorBoundary>
+          </div>`;
+      state = useState({ flag: false });
+      static components = { ErrorBoundary, ErrorComponent };
+    }
+    const app = new App();
+    await app.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><div><div>heyfalse</div></div></div>");
+    app.state.flag = true;
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div><div>Error handled</div></div>");
+
+    expect(console.error).toBeCalledTimes(0);
+    console.error = consoleError;
+    expect(handler).toBeCalledTimes(1);
+  });
+
+  test("no component catching error lead to full app destruction", async () => {
+    expect.assertions(6);
+    const handler = jest.fn();
+    env.qweb.on("error", null, handler);
+    const consoleError = console.error;
+    console.error = jest.fn();
+
+    class ErrorComponent extends Component {
+      static template = xml`<div>hey<t t-esc="props.flag and state.this.will.crash"/></div>`;
+    }
+
+    class App extends Component {
+      static template = xml`<div><ErrorComponent flag="state.flag"/></div>`;
+      static components = { ErrorComponent };
+      state = useState({ flag: false });
+      async render() {
+        try {
+          await super.render();
+        } catch (e) {
+          expect(e.message).toBe("Cannot read property 'this' of undefined");
+        }
+      }
+    }
+    const app = new App();
+    await app.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><div>heyfalse</div></div>");
+    app.state.flag = true;
+    await nextTick();
+    expect(fixture.innerHTML).toBe("");
+
+    expect(console.error).toBeCalledTimes(0);
+    console.error = consoleError;
+    expect(app.__owl__.isDestroyed).toBe(true);
+    expect(handler).toBeCalledTimes(1);
+  });
+
+  test("can catch an error in the initial call of a component render function (parent mounted)", async () => {
+    const handler = jest.fn();
+    env.qweb.on("error", null, handler);
+    const consoleError = console.error;
+    console.error = jest.fn();
+    class ErrorComponent extends Component {
+      static template = xml`<div>hey<t t-esc="state.this.will.crash"/></div>`;
+    }
+    class ErrorBoundary extends Component {
+      static template = xml`
+          <div>
+            <t t-if="state.error">Error handled</t>
+            <t t-else=""><t t-slot="default" /></t>
+          </div>`;
+      state = useState({ error: false });
+
+      catchError() {
+        this.state.error = true;
+      }
+    }
+    class App extends Component {
+      static template = xml`
+          <div>
+              <ErrorBoundary><ErrorComponent /></ErrorBoundary>
+          </div>`;
+      static components = { ErrorBoundary, ErrorComponent };
+    }
+    const app = new App();
+    await app.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><div>Error handled</div></div>");
+
+    expect(console.error).toBeCalledTimes(0);
+    console.error = consoleError;
+    expect(handler).toBeCalledTimes(1);
+  });
+
+  test("can catch an error in the initial call of a component render function (parent updated)", async () => {
+    const handler = jest.fn();
+    env.qweb.on("error", null, handler);
+    const consoleError = console.error;
+    console.error = jest.fn();
+    class ErrorComponent extends Component {
+      static template = xml`<div>hey<t t-esc="state.this.will.crash"/></div>`;
+    }
+    class ErrorBoundary extends Component {
+      static template = xml`
+          <div>
+            <t t-if="state.error">Error handled</t>
+            <t t-else=""><t t-slot="default" /></t>
+          </div>`;
+      state = useState({ error: false });
+
+      catchError() {
+        this.state.error = true;
+      }
+    }
+    class App extends Component {
+      static template = xml`
+          <div>
+              <ErrorBoundary t-if="state.flag"><ErrorComponent /></ErrorBoundary>
+          </div>`;
+      state = useState({ flag: false });
+      static components = { ErrorBoundary, ErrorComponent };
+    }
+    const app = new App();
+    await app.mount(fixture);
+    app.state.flag = true;
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div><div>Error handled</div></div>");
+
+    expect(console.error).toBeCalledTimes(0);
+    console.error = consoleError;
+    expect(handler).toBeCalledTimes(1);
+  });
+
+  test("can catch an error in the constructor call of a component render function", async () => {
+    const handler = jest.fn();
+    env.qweb.on("error", null, handler);
+    const consoleError = console.error;
+    console.error = jest.fn();
+    env.qweb.addTemplates(`
+        <templates>
+          <div t-name="ErrorBoundary">
+              <t t-if="state.error">Error handled</t>
+              <t t-else=""><t t-slot="default" /></t>
+          </div>
+          <div t-name="ErrorComponent">Some text</div>
+          <div t-name="App">
+              <ErrorBoundary><ErrorComponent /></ErrorBoundary>
+          </div>
+        </templates>`);
+    class ErrorComponent extends Component {
+      constructor(parent) {
+        super(parent);
+        throw new Error("NOOOOO");
+      }
+    }
+    class ErrorBoundary extends Component {
+      state = useState({ error: false });
+
+      catchError() {
+        this.state.error = true;
+      }
+    }
+    class App extends Component {
+      static components = { ErrorBoundary, ErrorComponent };
+    }
+    const app = new App();
+    await app.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><div>Error handled</div></div>");
+
+    expect(console.error).toBeCalledTimes(0);
+    console.error = consoleError;
+    expect(handler).toBeCalledTimes(1);
+  });
+
+  test("can catch an error in the willStart call", async () => {
+    const consoleError = console.error;
+    console.error = jest.fn();
+    class ErrorComponent extends Component {
+      static template = xml`<div t-name="ErrorComponent">Some text</div>`;
+      async willStart() {
+        // we wait a little bit to be in a different stack frame
+        await nextTick();
+        throw new Error("NOOOOO");
+      }
+    }
+    class ErrorBoundary extends Component {
+      static template = xml`
+          <div>
+            <t t-if="state.error">Error handled</t>
+            <t t-else=""><t t-slot="default" /></t>
+          </div>`;
+      state = useState({ error: false });
+
+      catchError() {
+        this.state.error = true;
+      }
+    }
+    class App extends Component {
+      static template = xml`<div><ErrorBoundary><ErrorComponent /></ErrorBoundary></div>`;
+      static components = { ErrorBoundary, ErrorComponent };
+    }
+    const app = new App();
+    await app.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><div>Error handled</div></div>");
+
+    expect(console.error).toBeCalledTimes(0);
+    console.error = consoleError;
+  });
+
+  test.skip("can catch an error in the mounted call", async () => {
+    // we do not catch error in mounted anymore
+    console.error = jest.fn();
+    env.qweb.addTemplates(`
+        <templates>
+          <div t-name="ErrorBoundary">
+              <t t-if="state.error">Error handled</t>
+              <t t-else=""><t t-slot="default" /></t>
+          </div>
+          <div t-name="ErrorComponent">Some text</div>
+          <div t-name="App">
+              <ErrorBoundary><ErrorComponent /></ErrorBoundary>
+          </div>
+        </templates>`);
+    class ErrorComponent extends Component {
+      mounted() {
+        throw new Error("NOOOOO");
+      }
+    }
+    class ErrorBoundary extends Component {
+      state = useState({ error: false });
+
+      catchError() {
+        this.state.error = true;
+      }
+    }
+    class App extends Component {
+      static components = { ErrorBoundary, ErrorComponent };
+    }
+    const app = new App();
+    await app.mount(fixture);
+    await nextTick();
+    await nextTick();
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div><div>Error handled</div></div>");
+  });
+
+  test.skip("can catch an error in the willPatch call", async () => {
+    // we do not catch error in willPatch anymore
+    const consoleError = console.error;
+    console.error = jest.fn();
+    class ErrorComponent extends Component {
+      static template = xml`<div><t t-esc="props.message"/></div>`;
+      willPatch() {
+        throw new Error("NOOOOO");
+      }
+    }
+    class ErrorBoundary extends Component {
+      static template = xml`
+          <div>
+            <t t-if="state.error">Error handled</t>
+            <t t-else=""><t t-slot="default" /></t>
+          </div>`;
+      state = useState({ error: false });
+
+      catchError() {
+        this.state.error = true;
+      }
+    }
+    class App extends Component {
+      static template = xml`
+          <div>
+              <span><t t-esc="state.message"/></span>
+            <ErrorBoundary><ErrorComponent message="state.message" /></ErrorBoundary>
+          </div>`;
+      state = useState({ message: "abc" });
+      static components = { ErrorBoundary, ErrorComponent };
+    }
+    const app = new App();
+    await app.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><span>abc</span><div><div>abc</div></div></div>");
+    app.state.message = "def";
+    await nextTick();
+    await nextTick();
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div><span>def</span><div>Error handled</div></div>");
+    expect(console.error).toHaveBeenCalledTimes(1);
+    console.error = consoleError;
+  });
+
+  test("a rendering error will reject the mount promise", async () => {
+    const consoleError = console.error;
+    console.error = jest.fn(() => {});
+    // we do not catch error in willPatch anymore
+    class App extends Component {
+      static template = xml`<div><t t-esc="this.will.crash"/></div>`;
+    }
+
+    const app = new App();
+    let error;
+    try {
+      await app.mount(fixture);
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe("Cannot read property 'crash' of undefined");
+
+    expect(console.error).toBeCalledTimes(0);
+    console.error = consoleError;
+  });
+
+  test("an error in mounted call will reject the mount promise", async () => {
+    const consoleError = console.error;
+    console.error = jest.fn(() => {});
+
+    class App extends Component {
+      static template = xml`<div>abc</div>`;
+      mounted() {
+        throw new Error("boom");
+      }
+    }
+
+    const app = new App();
+    let error;
+    try {
+      await app.mount(fixture);
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe("boom");
+    expect(fixture.innerHTML).toBe("");
+
+    expect(console.error).toBeCalledTimes(0);
+    console.error = consoleError;
+  });
+
+  test("an error in willPatch call will reject the render promise", async () => {
+    const consoleError = console.error;
+    console.error = jest.fn(() => {});
+
+    class App extends Component {
+      static template = xml`<div><t t-esc="val"/></div>`;
+      val = 3;
+      willPatch() {
+        throw new Error("boom");
+      }
+    }
+
+    const app = new App();
+    await app.mount(fixture);
+    app.val = 4;
+    let error;
+    try {
+      await app.render();
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe("boom");
+    expect(fixture.innerHTML).toBe("");
+
+    expect(console.error).toBeCalledTimes(0);
+    console.error = consoleError;
+  });
+
+  test("an error in patched call will reject the render promise", async () => {
+    const consoleError = console.error;
+    console.error = jest.fn(() => {});
+
+    class App extends Component {
+      static template = xml`<div><t t-esc="val"/></div>`;
+      val = 3;
+      patched() {
+        throw new Error("boom");
+      }
+    }
+
+    const app = new App();
+    await app.mount(fixture);
+    app.val = 4;
+    let error;
+    try {
+      await app.render();
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe("boom");
+    expect(fixture.innerHTML).toBe("");
+
+    expect(console.error).toBeCalledTimes(0);
+    console.error = consoleError;
+  });
+
+  test("a rendering error in a sub component will reject the mount promise", async () => {
+    const consoleError = console.error;
+    console.error = jest.fn(() => {});
+    // we do not catch error in willPatch anymore
+    class Child extends Component {
+      static template = xml`<div><t t-esc="this.will.crash"/></div>`;
+    }
+    class App extends Component {
+      static template = xml`<div><Child/></div>`;
+      static components = { Child };
+    }
+
+    const app = new App();
+    let error;
+    try {
+      await app.mount(fixture);
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe("Cannot read property 'crash' of undefined");
+
+    expect(console.error).toBeCalledTimes(0);
+    console.error = consoleError;
+  });
+
+  test("a rendering error will reject the render promise", async () => {
+    const consoleError = console.error;
+    console.error = jest.fn(() => {});
+    // we do not catch error in willPatch anymore
+    class App extends Component {
+      static template = xml`<div><t t-if="flag" t-esc="this.will.crash"/></div>`;
+      flag = false;
+    }
+
+    const app = new App();
+    await app.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div></div>");
+    app.flag = true;
+    let error;
+    try {
+      await app.render();
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe("Cannot read property 'crash' of undefined");
+
+    expect(console.error).toBeCalledTimes(0);
+    console.error = consoleError;
+  });
+
+  test("a rendering error will reject the render promise (with sub components)", async () => {
+    class Child extends Component {
+      static template = xml`<span></span>`;
+    }
+    class Parent extends Component {
+      static template = xml`<div><Child/><t t-esc="x.y"/></div>`;
+      static components = { Child };
+    }
+
+    let error;
+    try {
+      const parent = new Parent();
+      await parent.mount(fixture);
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe("Cannot read property 'y' of undefined");
+  });
+});

tests/component/props_validation.test.ts

@@ -25,7 +25,7 @@ afterEach(() => {
   QWeb.dev = dev;
 });
 
-class Widget extends Component<any, any> {}
+class Widget extends Component {}
 
 //------------------------------------------------------------------------------
 // Tests
@@ -96,7 +96,7 @@ describe("props validation", () => {
     ];
 
     let props;
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><TestWidget p="p"/></div>`;
       get p() {
         return props.p;
@@ -153,14 +153,14 @@ describe("props validation", () => {
     ];
 
     let props;
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><TestWidget p="p"/></div>`;
       get p() {
         return props.p;
       }
     }
     for (let test of Tests) {
-      let TestWidget = class extends Component<any, any> {
+      let TestWidget = class extends Component {
         static props = { p: { type: test.type } };
         static template = xml`<div>hey</div>`;
       };
@@ -200,11 +200,11 @@ describe("props validation", () => {
   });
 
   test("can validate a prop with multiple types", async () => {
-    class TestWidget extends Component<any, any> {
+    class TestWidget extends Component {
       static template = xml`<div>hey</div>`;
       static props = { p: [String, Boolean] };
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><TestWidget p="p"/></div>`;
       static components = { TestWidget };
       get p() {
@@ -244,11 +244,11 @@ describe("props validation", () => {
   });
 
   test("can validate an optional props", async () => {
-    class TestWidget extends Component<any, any> {
+    class TestWidget extends Component {
       static template = xml`<div>hey</div>`;
       static props = { p: { type: String, optional: true } };
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><TestWidget p="p"/></div>`;
       static components = { TestWidget };
       get p() {
@@ -288,11 +288,11 @@ describe("props validation", () => {
   });
 
   test("can validate an array with given primitive type", async () => {
-    class TestWidget extends Component<any, any> {
+    class TestWidget extends Component {
       static template = xml`<div>hey</div>`;
       static props = { p: { type: Array, element: String } };
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><TestWidget p="p"/></div>`;
       static components = { TestWidget };
       get p() {
@@ -340,11 +340,11 @@ describe("props validation", () => {
   });
 
   test("can validate an array with multiple sub element types", async () => {
-    class TestWidget extends Component<any, any> {
+    class TestWidget extends Component {
       static template = xml`<div>hey</div>`;
       static props = { p: { type: Array, element: [String, Boolean] } };
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><TestWidget p="p"/></div>`;
       static components = { TestWidget };
       get p() {
@@ -393,13 +393,13 @@ describe("props validation", () => {
   });
 
   test("can validate an object with simple shape", async () => {
-    class TestWidget extends Component<any, any> {
+    class TestWidget extends Component {
       static template = xml`<div>hey</div>`;
       static props = {
         p: { type: Object, shape: { id: Number, url: String } }
       };
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><TestWidget p="p"/></div>`;
       static components = { TestWidget };
       get p() {
@@ -451,7 +451,7 @@ describe("props validation", () => {
   });
 
   test("can validate recursively complicated prop def", async () => {
-    class TestWidget extends Component<any, any> {
+    class TestWidget extends Component {
       static template = xml`<div>hey</div>`;
       static props = {
         p: {
@@ -463,7 +463,7 @@ describe("props validation", () => {
         }
       };
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><TestWidget p="p"/></div>`;
       static components = { TestWidget };
       get p() {
@@ -503,7 +503,7 @@ describe("props validation", () => {
   });
 
   test("can validate optional attributes in nested sub props", () => {
-    class TestComponent extends Component<any, any> {
+    class TestComponent extends Component {
       static props = {
         myprop: {
           type: Array,
@@ -536,7 +536,7 @@ describe("props validation", () => {
   });
 
   test("can validate with a custom validator", () => {
-    class TestComponent extends Component<any, any> {
+    class TestComponent extends Component {
       static props = {
         size: {
           validate: e => ["small", "medium", "large"].includes(e)
@@ -562,7 +562,7 @@ describe("props validation", () => {
 
   test("can validate with a custom validator, and a type", () => {
     const validator = jest.fn(n => 0 <= n && n <= 10);
-    class TestComponent extends Component<any, any> {
+    class TestComponent extends Component {
       static props = {
         n: {
           type: Number,
@@ -738,7 +738,7 @@ describe("props validation", () => {
 
   test("props are validated whenever component is updated", async () => {
     let error;
-    class TestWidget extends Component<any, any> {
+    class TestWidget extends Component {
       static props = { p: { type: Number } };
       static template = xml`<div><t t-esc="props.p"/></div>`;
 
@@ -750,7 +750,7 @@ describe("props validation", () => {
         }
       }
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><TestWidget p="state.p"/></div>`;
       static components = { TestWidget };
       state: any = useState({ p: 1 });
@@ -767,12 +767,12 @@ describe("props validation", () => {
   });
 
   test("default values are applied before validating props at update", async () => {
-    class TestWidget extends Component<any, any> {
+    class TestWidget extends Component {
       static props = { p: { type: Number } };
       static template = xml`<div><t t-esc="props.p"/></div>`;
       static defaultProps = { p: 4 };
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><TestWidget p="state.p"/></div>`;
       static components = { TestWidget };
       state: any = useState({ p: 1 });
@@ -790,11 +790,11 @@ describe("props validation", () => {
 
 describe("default props", () => {
   test("can set default values", async () => {
-    class TestWidget extends Component<any, any> {
+    class TestWidget extends Component {
       static defaultProps = { p: 4 };
       static template = xml`<div><t t-esc="props.p"/></div>`;
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><TestWidget /></div>`;
       static components = { TestWidget };
     }

tests/component/slots.test.ts

@@ -0,0 +1,876 @@
+import { Component, Env } from "../../src/component/component";
+import { QWeb } from "../../src/qweb/qweb";
+import { xml } from "../../src/tags";
+import { useState, useRef } from "../../src/hooks";
+import { makeTestFixture, makeTestEnv, nextTick } from "../helpers";
+
+//------------------------------------------------------------------------------
+// Setup and helpers
+//------------------------------------------------------------------------------
+
+// We create before each test:
+// - fixture: a div, appended to the DOM, intended to be the target of dom
+//   manipulations.  Note that it is removed after each test.
+// - env: a WEnv, necessary to create new components
+
+let fixture: HTMLElement;
+let env: Env;
+
+beforeEach(() => {
+  fixture = makeTestFixture();
+  env = makeTestEnv();
+  Component.env = env;
+});
+
+afterEach(() => {
+  fixture.remove();
+});
+
+function children(w: Component): Component[] {
+  const childrenMap = w.__owl__.children;
+  return Object.keys(childrenMap).map(id => childrenMap[id]);
+}
+
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+
+describe("t-slot directive", () => {
+  test("can define and call slots", async () => {
+    env.qweb.addTemplates(`
+          <templates>
+            <div t-name="Parent">
+               <Dialog>
+                  <t t-set="header"><span>header</span></t>
+                  <t t-set="footer"><span>footer</span></t>
+               </Dialog>
+            </div>
+            <div t-name="Dialog">
+              <div><t t-slot="header"/></div>
+              <div><t t-slot="footer"/></div>
+            </div>
+          </templates>
+      `);
+    class Dialog extends Component {}
+    class Parent extends Component {
+      static components = { Dialog };
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe(
+      "<div><div><div><span>header</span></div><div><span>footer</span></div></div></div>"
+    );
+    expect(env.qweb.templates.Parent.fn.toString()).toMatchSnapshot();
+    expect(env.qweb.templates.Dialog.fn.toString()).toMatchSnapshot();
+    expect(QWeb.slots["1_header"].toString()).toMatchSnapshot();
+    expect(QWeb.slots["1_footer"].toString()).toMatchSnapshot();
+  });
+
+  test("named slots can define a default content", async () => {
+    class Dialog extends Component {
+      static template = xml`
+          <span>
+            <t t-slot="header">default content</t>
+          </span>`;
+    }
+    class Parent extends Component {
+      static template = xml`<div><Dialog/></div>`;
+      static components = { Dialog };
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe("<div><span>default content</span></div>");
+    expect(env.qweb.templates[Dialog.template].fn.toString()).toMatchSnapshot();
+  });
+
+  test("dafault slots can define a default content", async () => {
+    class Dialog extends Component {
+      static template = xml`
+          <span>
+            <t t-slot="default">default content</t>
+          </span>`;
+    }
+    class Parent extends Component {
+      static template = xml`<div><Dialog/></div>`;
+      static components = { Dialog };
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe("<div><span>default content</span></div>");
+    expect(env.qweb.templates[Dialog.template].fn.toString()).toMatchSnapshot();
+  });
+
+  test("default content is not rendered if slot is provided", async () => {
+    class Dialog extends Component {
+      static template = xml`
+          <span>
+            <t t-slot="default">default content</t>
+          </span>`;
+    }
+    class Parent extends Component {
+      static template = xml`<div><Dialog>hey</Dialog></div>`;
+      static components = { Dialog };
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe("<div><span>hey</span></div>");
+  });
+
+  test("default content is not rendered if named slot is provided", async () => {
+    class Dialog extends Component {
+      static template = xml`
+          <span>
+            <t t-slot="header">default content</t>
+          </span>`;
+    }
+    class Parent extends Component {
+      static template = xml`<div><Dialog><t t-set="header">hey</t></Dialog></div>`;
+      static components = { Dialog };
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe("<div><span>hey</span></div>");
+  });
+
+  test("slots are rendered with proper context", async () => {
+    env.qweb.addTemplates(`
+          <templates>
+            <div t-name="Parent">
+              <span class="counter"><t t-esc="state.val"/></span>
+              <Dialog>
+                <t t-set="footer"><button t-on-click="doSomething">do something</button></t>
+              </Dialog>
+            </div>
+            <span t-name="Dialog"><t t-slot="footer"/></span>
+          </templates>
+      `);
+    class Dialog extends Component {}
+    class Parent extends Component {
+      static components = { Dialog };
+      state = useState({ val: 0 });
+      doSomething() {
+        this.state.val++;
+      }
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe(
+      '<div><span class="counter">0</span><span><button>do something</button></span></div>'
+    );
+
+    fixture.querySelector("button")!.click();
+    await nextTick();
+
+    expect(fixture.innerHTML).toBe(
+      '<div><span class="counter">1</span><span><button>do something</button></span></div>'
+    );
+    expect(QWeb.slots["1_footer"].toString()).toMatchSnapshot();
+  });
+
+  test("slots are rendered with proper context, part 2", async () => {
+    env.qweb.addTemplates(`
+          <templates>
+              <a t-name="Link" t-att-href="props.to">
+                  <t t-slot="default"/>
+              </a>
+              <div t-name="App">
+                  <u><li t-foreach="state.users" t-as="user" t-key="user.id">
+                      <Link to="'/user/' + user.id">User <t t-esc="user.name"/></Link>
+                  </li></u>
+              </div>
+          </templates>
+      `);
+    class Link extends Component {}
+
+    class App extends Component {
+      state = useState({
+        users: [
+          { id: 1, name: "Aaron" },
+          { id: 2, name: "David" }
+        ]
+      });
+      static components = { Link };
+    }
+
+    const app = new App();
+    await app.mount(fixture);
+
+    expect(fixture.innerHTML).toBe(
+      '<div><u><li><a href="/user/1">User Aaron</a></li><li><a href="/user/2">User David</a></li></u></div>'
+    );
+    expect(env.qweb.templates.Link.fn.toString()).toMatchSnapshot();
+    expect(env.qweb.templates.App.fn.toString()).toMatchSnapshot();
+
+    // test updateprops here
+    app.state.users[1].name = "Mathieu";
+    await nextTick();
+    expect(fixture.innerHTML).toBe(
+      '<div><u><li><a href="/user/1">User Aaron</a></li><li><a href="/user/2">User Mathieu</a></li></u></div>'
+    );
+    expect(QWeb.slots["1_default"].toString()).toMatchSnapshot();
+  });
+
+  test("slots are rendered with proper context, part 3", async () => {
+    env.qweb.addTemplates(`
+          <templates>
+              <a t-name="Link" t-att-href="props.to">
+                  <t t-slot="default"/>
+              </a>
+              <div t-name="App">
+                  <u><li t-foreach="state.users" t-as="user" t-key="user.id" >
+                      <t t-set="userdescr" t-value="'User ' + user.name"/>
+                      <Link to="'/user/' + user.id"><t t-esc="userdescr"/></Link>
+                  </li></u>
+              </div>
+          </templates>
+      `);
+    class Link extends Component {}
+
+    class App extends Component {
+      state = useState({
+        users: [
+          { id: 1, name: "Aaron" },
+          { id: 2, name: "David" }
+        ]
+      });
+      static components = { Link };
+    }
+
+    const app = new App();
+    await app.mount(fixture);
+
+    expect(fixture.innerHTML).toBe(
+      '<div><u><li><a href="/user/1">User Aaron</a></li><li><a href="/user/2">User David</a></li></u></div>'
+    );
+    expect(env.qweb.templates.Link.fn.toString()).toMatchSnapshot();
+    expect(env.qweb.templates.App.fn.toString()).toMatchSnapshot();
+
+    // test updateprops here
+    app.state.users[1].name = "Mathieu";
+    await nextTick();
+    expect(fixture.innerHTML).toBe(
+      '<div><u><li><a href="/user/1">User Aaron</a></li><li><a href="/user/2">User Mathieu</a></li></u></div>'
+    );
+    expect(QWeb.slots["1_default"].toString()).toMatchSnapshot();
+  });
+
+  test("slots are rendered with proper context, part 4", async () => {
+    env.qweb.addTemplates(`
+          <templates>
+              <a t-name="Link" t-att-href="props.to">
+                  <t t-slot="default"/>
+              </a>
+              <div t-name="App">
+                  <t t-set="userdescr" t-value="'User ' + state.user.name"/>
+                  <Link to="'/user/' + state.user.id"><t t-esc="userdescr"/></Link>
+              </div>
+          </templates>
+      `);
+    class Link extends Component {}
+
+    class App extends Component {
+      state = useState({ user: { id: 1, name: "Aaron" } });
+      static components = { Link };
+    }
+
+    const app = new App();
+    await app.mount(fixture);
+
+    expect(fixture.innerHTML).toBe('<div><a href="/user/1">User Aaron</a></div>');
+
+    expect(env.qweb.templates.App.fn.toString()).toMatchSnapshot();
+
+    // test updateprops here
+    app.state.user.name = "David";
+    await nextTick();
+    expect(fixture.innerHTML).toBe('<div><a href="/user/1">User David</a></div>');
+    expect(QWeb.slots["1_default"].toString()).toMatchSnapshot();
+  });
+
+  test("refs are properly bound in slots", async () => {
+    class Dialog extends Component {
+      static template = xml`<span><t t-slot="footer"/></span>`;
+    }
+    class Parent extends Component {
+      static template = xml`
+            <div>
+              <span class="counter"><t t-esc="state.val"/></span>
+              <Dialog>
+                <t t-set="footer"><button t-ref="myButton" t-on-click="doSomething">do something</button></t>
+              </Dialog>
+            </div>
+          `;
+      static components = { Dialog };
+      state = useState({ val: 0 });
+      button = useRef("myButton");
+      doSomething() {
+        this.state.val++;
+      }
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe(
+      '<div><span class="counter">0</span><span><button>do something</button></span></div>'
+    );
+
+    parent.button.el!.click();
+    await nextTick();
+
+    expect(fixture.innerHTML).toBe(
+      '<div><span class="counter">1</span><span><button>do something</button></span></div>'
+    );
+    expect(QWeb.slots["1_footer"].toString()).toMatchSnapshot();
+  });
+
+  test("content is the default slot", async () => {
+    env.qweb.addTemplates(`
+          <templates>
+            <div t-name="Parent">
+               <Dialog>
+                  <span>sts rocks</span>
+               </Dialog>
+            </div>
+            <div t-name="Dialog"><t t-slot="default"/></div>
+          </templates>
+      `);
+    class Dialog extends Component {}
+    class Parent extends Component {
+      static components = { Dialog };
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe("<div><div><span>sts rocks</span></div></div>");
+    expect(QWeb.slots["1_default"].toString()).toMatchSnapshot();
+  });
+
+  test("default slot work with text nodes", async () => {
+    env.qweb.addTemplates(`
+          <templates>
+            <div t-name="Parent">
+               <Dialog>sts rocks</Dialog>
+            </div>
+            <div t-name="Dialog"><t t-slot="default"/></div>
+          </templates>
+      `);
+    class Dialog extends Component {}
+    class Parent extends Component {
+      static components = { Dialog };
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe("<div><div>sts rocks</div></div>");
+    expect(QWeb.slots["1_default"].toString()).toMatchSnapshot();
+  });
+
+  test("multiple roots are allowed in a named slot", async () => {
+    env.qweb.addTemplates(`
+          <templates>
+            <div t-name="Parent">
+               <Dialog>
+                  <t t-set="content">
+                      <span>sts</span>
+                      <span>rocks</span>
+                  </t>
+               </Dialog>
+            </div>
+            <div t-name="Dialog"><t t-slot="content"/></div>
+          </templates>
+      `);
+    class Dialog extends Component {}
+    class Parent extends Component {
+      static components = { Dialog };
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe("<div><div><span>sts</span><span>rocks</span></div></div>");
+    expect(QWeb.slots["1_content"].toString()).toMatchSnapshot();
+  });
+
+  test("multiple roots are allowed in a default slot", async () => {
+    env.qweb.addTemplates(`
+          <templates>
+            <div t-name="Parent">
+               <Dialog>
+                  <span>sts</span>
+                  <span>rocks</span>
+               </Dialog>
+            </div>
+            <div t-name="Dialog"><t t-slot="default"/></div>
+          </templates>
+      `);
+    class Dialog extends Component {}
+    class Parent extends Component {
+      static components = { Dialog };
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe("<div><div><span>sts</span><span>rocks</span></div></div>");
+    expect(QWeb.slots["1_default"].toString()).toMatchSnapshot();
+  });
+
+  test("missing slots are ignored", async () => {
+    env.qweb.addTemplates(`
+          <templates>
+            <div t-name="Parent">
+              <Dialog/>
+            </div>
+            <span t-name="Dialog">
+              <t t-slot="default"/>
+              <span>some content</span>
+              <t t-slot="footer"/>
+            </span>
+          </templates>
+      `);
+    class Dialog extends Component {}
+    class Parent extends Component {
+      static components = { Dialog };
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe("<div><span><span>some content</span></span></div>");
+  });
+
+  test("t-debug on a t-set (defining a slot)", async () => {
+    const consoleLog = console.log;
+    console.log = jest.fn();
+
+    env.qweb.addTemplates(`
+          <templates>
+            <div t-name="Parent">
+              <Dialog><t t-set="content" t-debug="">abc</t></Dialog>
+            </div>
+            <span t-name="Dialog">
+              <t t-slot="content"/>
+            </span>
+          </templates>
+      `);
+    class Dialog extends Component {}
+    class Parent extends Component {
+      static components = { Dialog };
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+    expect(console.log).toHaveBeenCalledTimes(0);
+    console.log = consoleLog;
+  });
+
+  test("slot preserves properly parented relationship", async () => {
+    env.qweb.addTemplates(`
+          <templates>
+            <div t-name="Parent">
+               <Child>
+                  <GrandChild/>
+               </Child>
+            </div>
+            <div t-name="Child"><t t-slot="default"/></div>
+            <div t-name="GrandChild">Grand Child</div>
+          </templates>
+      `);
+    class Child extends Component {}
+    class GrandChild extends Component {}
+    class Parent extends Component {
+      static components = { Child, GrandChild };
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe("<div><div><div>Grand Child</div></div></div>");
+
+    const parentChildren = children(parent);
+    expect(parentChildren.length).toBe(1);
+    expect(parentChildren[0]).toBeInstanceOf(Child);
+
+    const childrenChildren = children(parentChildren[0]);
+    expect(childrenChildren.length).toBe(1);
+    expect(childrenChildren[0]).toBeInstanceOf(GrandChild);
+  });
+
+  test("nested slots: evaluation context and parented relationship", async () => {
+    let slot;
+    class Slot extends Component {
+      static template = xml`<span t-esc="props.val"/>`;
+      constructor(parent, props) {
+        super(parent, props);
+        slot = this;
+      }
+    }
+    class GrandChild extends Component {
+      static template = xml`<div><t t-slot="default"/></div>`;
+    }
+    class Child extends Component {
+      static components = { GrandChild };
+      static template = xml`
+          <GrandChild>
+            <t t-slot="default"/>
+          </GrandChild>`;
+    }
+    class Parent extends Component {
+      static components = { Child, Slot };
+      static template = xml`<Child><Slot val="state.val"/></Child>`;
+      state = useState({ val: 3 });
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe("<div><span>3</span></div>");
+    expect(slot.__owl__.parent).toBeInstanceOf(GrandChild);
+  });
+
+  test("slot are properly rendered if inner props are changed", async () => {
+    env.qweb.addTemplates(`
+      <templates>
+          <div t-name="SomeComponent">
+              SC:<t t-esc="props.val"/>
+          </div>
+  
+  
+          <div t-name="GenericComponent">
+              <t t-slot="default" />
+          </div>
+  
+          <div t-name="App">
+              <button t-on-click="inc">Inc[<t t-esc="state.val"/>]</button>
+              <GenericComponent>
+                  <SomeComponent val="state.val"/>
+              </GenericComponent>
+          </div>
+      </templates>
+      `);
+    class SomeComponent extends Component {}
+    class GenericComponent extends Component {}
+    class App extends Component {
+      static components = { GenericComponent, SomeComponent };
+      state = useState({ val: 4 });
+
+      inc() {
+        this.state.val++;
+      }
+    }
+    const app = new App();
+    await app.mount(fixture);
+
+    expect(fixture.innerHTML).toBe("<div><button>Inc[4]</button><div><div> SC:4</div></div></div>");
+    (<any>fixture.querySelector("button")).click();
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div><button>Inc[5]</button><div><div> SC:5</div></div></div>");
+  });
+
+  test("slots and wrapper components", async () => {
+    class Link extends Component {
+      static template = xml`
+          <a href="abc">
+              <t t-slot="default"/>
+          </a>`;
+    }
+
+    class A extends Component {
+      static template = xml`<Link>hey</Link>`;
+      static components = { Link: Link };
+    }
+
+    const a = new A();
+    await a.mount(fixture);
+
+    expect(fixture.innerHTML).toBe(`<a href="abc">hey</a>`);
+  });
+
+  test("template can just return a slot", async () => {
+    class Child extends Component {
+      static template = xml`<span><t t-esc="props.value"/></span>`;
+    }
+    class SlotComponent extends Component {
+      static template = xml`<t t-slot="default"/>`;
+    }
+
+    class Parent extends Component {
+      static template = xml`
+          <div>
+              <SlotComponent><Child value="state.value"/></SlotComponent>
+          </div>`;
+      static components = { SlotComponent, Child };
+      state = useState({ value: 3 });
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><span>3</span></div>");
+
+    expect(QWeb.TEMPLATES[SlotComponent.template].fn.toString()).toMatchSnapshot();
+
+    parent.state.value = 5;
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div><span>5</span></div>");
+  });
+
+  test("multiple slots containing components", async () => {
+    class C extends Component {
+      static template = xml`<span><t t-esc="props.val"/></span>`;
+    }
+    class B extends Component {
+      static template = xml`<div><t t-slot="s1"/><t t-slot="s2"/></div>`;
+    }
+    class A extends Component {
+      static template = xml`
+          <B>
+            <t t-set="s1"><C val="1"/></t>
+            <t t-set="s2"><C val="2"/></t>
+          </B>`;
+      static components = { B, C };
+    }
+
+    const a = new A();
+    await a.mount(fixture);
+
+    expect(fixture.innerHTML).toBe(`<div><span>1</span><span>2</span></div>`);
+  });
+
+  test("slots in t-foreach and re-rendering", async () => {
+    class Child extends Component {
+      static template = xml`<span><t t-esc="state.val"/><t t-slot="default"/></span>`;
+      state = useState({ val: "A" });
+      mounted() {
+        this.state.val = "B";
+      }
+    }
+    class Parent extends Component {
+      static components = { Child };
+      static template = xml`
+          <div>
+            <t t-foreach="Array(2)" t-as="n" t-key="n_index">
+              <Child><t t-esc="n_index"/></Child>
+            </t>
+          </div>`;
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><span>A0</span><span>A1</span></div>");
+
+    await nextTick(); // wait for the changes triggered in mounted to be applied
+    expect(fixture.innerHTML).toBe("<div><span>B0</span><span>B1</span></div>");
+  });
+
+  test("slots in t-foreach with t-set and re-rendering", async () => {
+    class Child extends Component {
+      static template = xml`
+          <span>
+            <t t-esc="state.val"/>
+            <t t-slot="default"/>
+          </span>`;
+      state = useState({ val: "A" });
+      mounted() {
+        this.state.val = "B";
+      }
+    }
+    class ParentWidget extends Component {
+      static components = { Child };
+      static template = xml`
+          <div>
+            <t t-foreach="Array(2)" t-as="n" t-key="n_index">
+              <t t-set="dummy" t-value="n_index"/>
+              <Child><t t-esc="dummy"/></Child>
+            </t>
+          </div>`;
+    }
+
+    const widget = new ParentWidget();
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><span>A0</span><span>A1</span></div>");
+
+    await nextTick(); // wait for changes triggered in mounted to be applied
+    expect(fixture.innerHTML).toBe("<div><span>B0</span><span>B1</span></div>");
+  });
+
+  test("nested slots in same template", async () => {
+    let child, child2, child3;
+    class Child extends Component {
+      static template = xml`
+          <span id="c1">
+            <div>
+              <t t-slot="default"/>
+            </div>
+          </span>`;
+      constructor(parent, props) {
+        super(parent, props);
+        child = this;
+      }
+    }
+    class Child2 extends Component {
+      static template = xml`
+          <span id="c2">
+            <t t-slot="default"/>
+          </span>`;
+      constructor(parent, props) {
+        super(parent, props);
+        child2 = this;
+      }
+    }
+    class Child3 extends Component {
+      static template = xml`
+          <span>Child 3</span>`;
+      constructor(parent, props) {
+        super(parent, props);
+        child3 = this;
+      }
+    }
+    class Parent extends Component {
+      static components = { Child, Child2, Child3 };
+      static template = xml`
+          <span id="parent">
+            <Child>
+              <Child2>
+                <Child3/>
+              </Child2>
+            </Child>
+          </span>`;
+    }
+
+    const widget = new Parent();
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe(
+      '<span id="parent"><span id="c1"><div><span id="c2"><span>Child 3</span></span></div></span></span>'
+    );
+
+    expect(child3.__owl__.parent).toStrictEqual(child2);
+    expect(child2.__owl__.parent).toStrictEqual(child);
+    expect(child.__owl__.parent).toStrictEqual(widget);
+  });
+
+  test("t-slot nested within another slot", async () => {
+    let portal, modal, child3;
+    class Child3 extends Component {
+      static template = xml`
+          <span>Child 3</span>`;
+      constructor(parent, props) {
+        super(parent, props);
+        child3 = this;
+      }
+    }
+    class Modal extends Component {
+      static template = xml`
+          <span id="modal">
+            <t t-slot="default"/>
+          </span>`;
+      constructor(parent, props) {
+        super(parent, props);
+        modal = this;
+      }
+    }
+    class Portal extends Component {
+      static template = xml`
+          <span id="portal">
+            <t t-slot="default"/>
+          </span>`;
+      constructor(parent, props) {
+        super(parent, props);
+        portal = this;
+      }
+    }
+    class Dialog extends Component {
+      static components = { Modal, Portal };
+      static template = xml`
+          <span id="c2">
+            <Modal>
+              <Portal>
+                <t t-slot="default"/>
+              </Portal>
+             </Modal>
+          </span>`;
+    }
+    class Parent extends Component {
+      static components = { Child3, Dialog };
+      static template = xml`
+          <span id="c1">
+            <Dialog>
+              <Child3/>
+            </Dialog>
+          </span>`;
+    }
+
+    const widget = new Parent();
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe(
+      '<span id="c1"><span id="c2"><span id="modal"><span id="portal"><span>Child 3</span></span></span></span></span>'
+    );
+
+    expect(child3.__owl__.parent).toStrictEqual(portal);
+    expect(portal.__owl__.parent).toStrictEqual(modal);
+  });
+
+  test("t-slot supports many instances", async () => {
+    let child3;
+    class Child3 extends Component {
+      static template = xml`
+          <span>Child 3</span>`;
+      constructor(parent, props) {
+        super(parent, props);
+        child3 = this;
+      }
+    }
+    class Dialog extends Component {
+      static template = xml`
+          <span id="c2">
+            <t t-slot="default"/>
+          </span>`;
+    }
+    class Parent extends Component {
+      static components = { Child3, Dialog };
+      static template = xml`
+          <span id="c1">
+            <Dialog>
+              <Child3 val="state.lol"/>
+            </Dialog>
+          </span>`;
+      state = { lol: "k" };
+    }
+
+    const widget = new Parent();
+    await widget.mount(fixture);
+    expect(child3.props.val).toBe("k");
+
+    const widget_1 = new Parent();
+    widget_1.state.lol = "m";
+    await widget_1.mount(fixture);
+    expect(child3.props.val).toBe("m");
+  });
+
+  test("slots in slots, with vars", async () => {
+    class B extends Component {
+      static template = xml`<span><t t-slot="default"/></span>`;
+    }
+    class A extends Component {
+      static template = xml`
+          <div>
+            <B>
+              <t t-slot="default"/>
+            </B>
+          </div>`;
+      static components = { B };
+    }
+    class Parent extends Component {
+      static template = xml`
+          <div>
+            <t t-set="test" t-value="state.name"/>
+            <A>
+              <p>hey<t t-esc="test"/></p>
+            </A>
+          </div>`;
+      static components = { A };
+      state = { name: "aaron" };
+    }
+
+    const parent = new Parent();
+    await parent.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><div><span><p>heyaaron</p></span></div></div>");
+  });
+});

tests/component/styles.test.ts

@@ -0,0 +1,170 @@
+import { Component, Env } from "../../src/component/component";
+import { processSheet } from "../../src/component/styles";
+import { xml, css } from "../../src/tags";
+import { makeTestFixture, makeTestEnv } from "../helpers";
+
+//------------------------------------------------------------------------------
+// Setup and helpers
+//------------------------------------------------------------------------------
+
+// We create before each test:
+// - fixture: a div, appended to the DOM, intended to be the target of dom
+//   manipulations.  Note that it is removed after each test.
+// - env: an Env, necessary to create new components
+
+let fixture: HTMLElement;
+let env: Env;
+
+beforeEach(() => {
+  fixture = makeTestFixture();
+  env = makeTestEnv();
+  Component.env = env;
+  document.head.innerHTML = "";
+});
+
+afterEach(() => {
+  fixture.remove();
+});
+
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+
+describe("styles and component", () => {
+  test("can define an inline stylesheet", async () => {
+    class App extends Component {
+      static template = xml`<div class="app">text</div>`;
+      static style = css`
+        .app {
+          color: red;
+        }
+      `;
+    }
+    expect(document.head.innerHTML).toBe("");
+    const app = new App();
+
+    expect(document.head.innerHTML).toBe(`<style component=\"App\">.app {
+  color: red;
+}</style>`);
+
+    await app.mount(fixture);
+    const style = getComputedStyle(app.el!);
+    expect(style.color).toBe("red");
+    expect(fixture.innerHTML).toBe('<div class="app">text</div>');
+  });
+
+  test("inherited components properly apply css", async () => {
+    class App extends Component {
+      static template = xml`<div class="app">text</div>`;
+      static style = css`
+        .app {
+          color: red;
+        }
+      `;
+    }
+    class SubApp extends App {
+      static style = css`
+        .app {
+          font-weight: bold;
+        }
+      `;
+    }
+    expect(document.head.innerHTML).toBe("");
+    const app = new SubApp();
+
+    expect(document.head.innerHTML).toBe(`<style component=\"SubApp\">.app {
+  font-weight: bold;
+}</style><style component=\"App\">.app {
+  color: red;
+}</style>`);
+
+    await app.mount(fixture);
+    const style = getComputedStyle(app.el!);
+    expect(style.color).toBe("red");
+    expect(style.fontWeight).toBe("bold");
+    expect(fixture.innerHTML).toBe('<div class="app">text</div>');
+  });
+
+  test("get a meaningful error message if css helper is missing", async () => {
+    class App extends Component {
+      static template = xml`<div class="app">text</div>`;
+      static style = `.app {color: red;}`;
+    }
+    let error;
+    try {
+      new App();
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe(
+      "Invalid css stylesheet for component 'App'. Did you forget to use the 'css' tag helper?"
+    );
+  });
+
+  test("inline stylesheets are processed", async () => {
+    class App extends Component {
+      static template = xml`<div class="app">text</div>`;
+      static style = css`
+        .app {
+          color: red;
+          .some-class {
+            font-weight: bold;
+            width: 40px;
+          }
+
+          display: block;
+        }
+      `;
+    }
+    new App();
+
+    expect(document.head.querySelector("style")!.innerHTML).toBe(`.app {
+  color: red;
+}
+.app .some-class {
+  font-weight: bold;
+  width: 40px;
+}
+.app {
+  display: block;
+}`);
+  });
+
+  test("properly handle rules with commas", async () => {
+    const sheet = processSheet(`.parent-a, .parent-b {
+      .child-a, .child-b {
+        color: red;
+      }
+    }`);
+
+    expect(sheet)
+      .toBe(`.parent-a .child-a, .parent-a .child-b, .parent-b .child-a, .parent-b .child-b {
+  color: red;
+}`);
+  });
+
+  test("handle & selector", async () => {
+    let sheet = processSheet(`.btn {
+      &.danger {
+        color: red;
+      }
+    }`);
+
+    expect(sheet).toBe(`.btn.danger {
+  color: red;
+}`);
+
+    sheet = processSheet(`.some-class {
+      &.btn {
+        .other-class ~ & {
+          color: red;
+        }
+      }
+    }`);
+
+    expect(sheet).toBe(`.other-class ~ .some-class.btn {
+  color: red;
+}`);
+  });
+});

tests/component/un_mounting.test.ts

@@ -0,0 +1,473 @@
+import { Component, Env } from "../../src/component/component";
+import { useState } from "../../src/hooks";
+import { xml } from "../../src/tags";
+import { makeDeferred, makeTestEnv, makeTestFixture, nextTick, nextMicroTick } from "../helpers";
+
+//------------------------------------------------------------------------------
+// Setup and helpers
+//------------------------------------------------------------------------------
+
+// We create before each test:
+// - fixture: a div, appended to the DOM, intended to be the target of dom
+//   manipulations.  Note that it is removed after each test.
+// - env: a WEnv, necessary to create new components
+
+let fixture: HTMLElement;
+let env: Env;
+
+beforeEach(() => {
+  fixture = makeTestFixture();
+  env = makeTestEnv();
+  Component.env = env;
+});
+
+afterEach(() => {
+  fixture.remove();
+});
+
+describe("mount targets", () => {
+  test("can attach a component to an existing node (if same tagname)", async () => {
+    class App extends Component {
+      static template = xml`<div>app</div>`;
+    }
+    const div = document.createElement("div");
+    fixture.appendChild(div);
+
+    const app = new App();
+    await app.mount(div, { position: "self" });
+    expect(fixture.innerHTML).toBe("<div>app</div>");
+  });
+
+  test("cannot attach a component to an existing node (if not same tagname)", async () => {
+    class App extends Component {
+      static template = xml`<span>app</span>`;
+    }
+    const div = document.createElement("div");
+    fixture.appendChild(div);
+
+    const app = new App();
+    let error;
+    try {
+      await app.mount(div, { position: "self" });
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe("Cannot attach 'App' to target node (not same tag name)");
+  });
+
+  test("can mount a component (with position='first-child')", async () => {
+    class App extends Component {
+      static template = xml`<div>app</div>`;
+    }
+    const span = document.createElement("span");
+    fixture.appendChild(span);
+
+    const app = new App();
+    await app.mount(fixture, { position: "first-child" });
+    expect(fixture.innerHTML).toBe("<div>app</div><span></span>");
+  });
+
+  test("can mount a component (with position='last-child')", async () => {
+    class App extends Component {
+      static template = xml`<div>app</div>`;
+    }
+    const span = document.createElement("span");
+    fixture.appendChild(span);
+
+    const app = new App();
+    await app.mount(fixture, { position: "last-child" });
+    expect(fixture.innerHTML).toBe("<span></span><div>app</div>");
+  });
+
+  test("default mount option is 'last-child'", async () => {
+    class App extends Component {
+      static template = xml`<div>app</div>`;
+    }
+    const span = document.createElement("span");
+    fixture.appendChild(span);
+
+    const app = new App();
+    await app.mount(fixture);
+    expect(fixture.innerHTML).toBe("<span></span><div>app</div>");
+  });
+});
+
+describe("unmounting and remounting", () => {
+  test("widget can be unmounted and remounted", async () => {
+    const steps: string[] = [];
+    class MyWidget extends Component {
+      static template = xml`<div>Hey</div>`;
+      async willStart() {
+        steps.push("willstart");
+      }
+      mounted() {
+        steps.push("mounted");
+      }
+      willUnmount() {
+        steps.push("willunmount");
+      }
+      patched() {
+        throw new Error("patched should not be called");
+      }
+    }
+
+    const w = new MyWidget();
+    await w.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div>Hey</div>");
+    expect(steps).toEqual(["willstart", "mounted"]);
+
+    w.unmount();
+    expect(fixture.innerHTML).toBe("");
+    expect(steps).toEqual(["willstart", "mounted", "willunmount"]);
+
+    await w.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div>Hey</div>");
+    expect(steps).toEqual(["willstart", "mounted", "willunmount", "mounted"]);
+  });
+
+  test("widget can be mounted twice without ill effect", async () => {
+    const steps: string[] = [];
+    class MyWidget extends Component {
+      static template = xml`<div>Hey</div>`;
+      async willStart() {
+        steps.push("willstart");
+      }
+      mounted() {
+        steps.push("mounted");
+      }
+      willUnmount() {
+        steps.push("willunmount");
+      }
+    }
+
+    const w = new MyWidget();
+    await w.mount(fixture);
+    await w.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div>Hey</div>");
+    expect(steps).toEqual(["willstart", "mounted"]);
+  });
+
+  test("state changes in willUnmount do not trigger rerender", async () => {
+    const steps: string[] = [];
+
+    class Child extends Component {
+      static template = xml`
+          <span><t t-esc="props.val"/><t t-esc="state.n"/></span>
+        `;
+      state = useState({ n: 2 });
+      __render(f) {
+        steps.push("render");
+        return super.__render(f);
+      }
+      willPatch() {
+        steps.push("willPatch");
+      }
+      patched() {
+        steps.push("patched");
+      }
+
+      willUnmount() {
+        steps.push("willUnmount");
+        this.state.n = 3;
+      }
+    }
+    class Parent extends Component {
+      static template = xml`
+          <div>
+            <Child t-if="state.flag" val="state.val"/>
+          </div>
+        `;
+      static components = { Child };
+      state = useState({ val: 1, flag: true });
+    }
+
+    const widget = new Parent();
+    await widget.mount(fixture);
+    expect(steps).toEqual(["render"]);
+    expect(fixture.innerHTML).toBe("<div><span>12</span></div>");
+    widget.state.flag = false;
+    await nextTick();
+    // we make sure here that no call to __render is done
+    expect(steps).toEqual(["render", "willUnmount"]);
+  });
+
+  test("state changes in willUnmount will be applied on remount", async () => {
+    class TestWidget extends Component {
+      static template = xml`
+          <div><t t-esc="state.val"/></div>
+        `;
+      state = useState({ val: 1 });
+      willUnmount() {
+        this.state.val = 3;
+      }
+    }
+
+    const widget = new TestWidget();
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div>1</div>");
+    widget.unmount();
+    expect(fixture.innerHTML).toBe("");
+    await nextTick(); // wait for changes to be detected before remounting
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div>3</div>");
+    // we want to make sure that there are no remaining tasks left at this point.
+    expect(Component.scheduler.tasks.length).toBe(0);
+  });
+
+  test("sub component is still active after being unmounted and remounted", async () => {
+    class Child extends Component {
+      static template = xml`
+          <p t-on-click="state.value++">
+            <t t-esc="state.value"/>
+          </p>`;
+
+      state = useState({ value: 1 });
+    }
+
+    class Parent extends Component {
+      static components = { Child };
+      static template = xml`<div><Child/></div>`;
+    }
+
+    const w = new Parent();
+    await w.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><p>1</p></div>");
+
+    fixture.querySelector("p")!.click();
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div><p>2</p></div>");
+    w.unmount();
+    await nextTick();
+    await w.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><p>2</p></div>");
+    fixture.querySelector("p")!.click();
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div><p>3</p></div>");
+  });
+
+  test("change state just before mounting component", async () => {
+    const steps: number[] = [];
+    class TestWidget extends Component {
+      static template = xml`
+          <div><t t-esc="state.val"/></div>
+        `;
+      state = useState({ val: 1 });
+      __render(f) {
+        steps.push(this.state.val);
+        return super.__render(f);
+      }
+    }
+    TestWidget.prototype.__render = jest.fn(TestWidget.prototype.__render);
+
+    const widget = new TestWidget();
+    widget.state.val = 2;
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div>2</div>");
+    expect(TestWidget.prototype.__render).toHaveBeenCalledTimes(1);
+
+    // unmount and re-mount, as in this case, willStart won't be called, so it's
+    // slightly different
+    widget.unmount();
+    widget.state.val = 3;
+    await widget.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div>3</div>");
+    expect(TestWidget.prototype.__render).toHaveBeenCalledTimes(2);
+    expect(steps).toEqual([2, 3]);
+  });
+
+  test("change state while mounting component", async () => {
+    const steps: number[] = [];
+    class TestWidget extends Component {
+      static template = xml`
+          <div><t t-esc="state.val"/></div>
+        `;
+      state = useState({ val: 1 });
+      __render(f) {
+        steps.push(this.state.val);
+        return super.__render(f);
+      }
+    }
+    TestWidget.prototype.__render = jest.fn(TestWidget.prototype.__render);
+    TestWidget.prototype.__patch = jest.fn(TestWidget.prototype.__patch);
+
+    const widget = new TestWidget();
+    let prom = widget.mount(fixture);
+    widget.state.val = 2;
+    await prom;
+    expect(fixture.innerHTML).toBe("<div>2</div>");
+    expect(TestWidget.prototype.__render).toHaveBeenCalledTimes(1);
+
+    // unmount and re-mount, as in this case, willStart won't be called, so it's
+    // slightly different
+    widget.unmount();
+    prom = widget.mount(fixture);
+    widget.state.val = 3;
+    await prom;
+    expect(fixture.innerHTML).toBe("<div>3</div>");
+    expect(TestWidget.prototype.__render).toHaveBeenCalledTimes(3);
+    expect(TestWidget.prototype.__patch).toHaveBeenCalledTimes(2);
+    expect(steps).toEqual([2, 2, 3]);
+  });
+
+  test("change state while component is unmounted", async () => {
+    let child;
+    class Child extends Component {
+      static template = xml`<span t-esc="state.val"/>`;
+      state = useState({
+        val: "C1"
+      });
+      constructor(parent, props) {
+        super(parent, props);
+        child = this;
+      }
+    }
+
+    class Parent extends Component {
+      static components = { Child };
+      static template = xml`<div><t t-esc="state.val"/><Child/></div>`;
+      state = useState({ val: "P1" });
+    }
+
+    const parent = new Parent();
+    await parent.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div>P1<span>C1</span></div>");
+
+    parent.unmount();
+    expect(fixture.innerHTML).toBe("");
+
+    parent.state.val = "P2";
+    child.state.val = "C2";
+
+    await parent.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div>P2<span>C2</span></div>");
+  });
+
+  test("unmount component during a re-rendering", async () => {
+    const def = makeDeferred();
+    class Child extends Component {
+      static template = xml`<span><t t-esc="props.val"/></span>`;
+      willUpdateProps() {
+        return def;
+      }
+    }
+    Child.prototype.__render = jest.fn(Child.prototype.__render);
+
+    class Parent extends Component {
+      static template = xml`<div><Child val="state.val"/></div>`;
+      static components = { Child };
+      state = useState({ val: 1 });
+    }
+
+    const parent = new Parent();
+    await parent.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div><span>1</span></div>");
+    expect(Child.prototype.__render).toBeCalledTimes(1);
+
+    parent.state.val = 2;
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div><span>1</span></div>");
+
+    parent.unmount();
+    expect(fixture.innerHTML).toBe("");
+
+    def.resolve();
+    await nextTick();
+    expect(fixture.innerHTML).toBe("");
+    expect(Child.prototype.__render).toBeCalledTimes(1);
+  });
+
+  test("widget can be mounted on different target", async () => {
+    class MyWidget extends Component {
+      static template = xml`<div>Hey</div>`;
+      patched() {
+        throw new Error("patched should not be called");
+      }
+    }
+    const div = document.createElement("div");
+    const span = document.createElement("span");
+    fixture.appendChild(div);
+    fixture.appendChild(span);
+    const w = new MyWidget();
+    await w.mount(div);
+
+    expect(fixture.innerHTML).toBe("<div><div>Hey</div></div><span></span>");
+
+    await w.mount(span);
+    expect(fixture.innerHTML).toBe("<div></div><span><div>Hey</div></span>");
+  });
+
+  test("widget can be mounted on different target, another situation", async () => {
+    const def = makeDeferred();
+    const steps: string[] = [];
+
+    class MyWidget extends Component {
+      static template = xml`<div>Hey</div>`;
+      async willStart() {
+        return def;
+      }
+      patched() {
+        throw new Error("patched should not be called");
+      }
+    }
+    const div = document.createElement("div");
+    const span = document.createElement("span");
+    fixture.appendChild(div);
+    fixture.appendChild(span);
+    const w = new MyWidget();
+
+    w.mount(div).catch(() => steps.push("1 catch"));
+
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div></div><span></span>");
+
+    w.mount(span).then(() => steps.push("2 resolved"));
+
+    // we wait two microticks because this is the number of internal promises
+    // that need to be resolved/rejected, and because we want to prove here
+    // that the first mount operation is cancelled immediately, and not after
+    // one full tick.
+    await nextMicroTick();
+    await nextMicroTick();
+    expect(steps).toEqual(["1 catch"]);
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div></div><span></span>");
+
+    def.resolve();
+    await nextTick();
+    expect(steps).toEqual(["1 catch", "2 resolved"]);
+    expect(fixture.innerHTML).toBe("<div></div><span><div>Hey</div></span>");
+  });
+
+  test("widget can be mounted on same target, another situation", async () => {
+    const def = makeDeferred();
+    const steps: string[] = [];
+
+    class MyWidget extends Component {
+      static template = xml`<div>Hey</div>`;
+      async willStart() {
+        return def;
+      }
+      patched() {
+        throw new Error("patched should not be called");
+      }
+    }
+    const w = new MyWidget();
+
+    w.mount(fixture).then(() => steps.push("1 resolved"));
+
+    await nextTick();
+    expect(fixture.innerHTML).toBe("");
+
+    w.mount(fixture).then(() => steps.push("2 resolved"));
+
+    await nextTick();
+    expect(steps).toEqual([]);
+    expect(fixture.innerHTML).toBe("");
+
+    def.resolve();
+    await nextTick();
+    expect(steps).toEqual(["1 resolved", "2 resolved"]);
+    expect(fixture.innerHTML).toBe("<div>Hey</div>");
+  });
+});

tests/context.test.ts

@@ -32,7 +32,7 @@ describe("Context", () => {
   test("very simple use, with initial value", async () => {
     const testContext = new Context({ value: 123 });
 
-    class Test extends Component<any, any> {
+    class Test extends Component {
       static template = xml`<div><t t-esc="contextObj.value"/></div>`;
       contextObj = useContext(testContext);
     }
@@ -44,7 +44,7 @@ describe("Context", () => {
   test("useContext hook is reactive, for one component", async () => {
     const testContext = new Context({ value: 123 });
 
-    class Test extends Component<any, any> {
+    class Test extends Component {
       static template = xml`<div><t t-esc="contextObj.value"/></div>`;
       contextObj = useContext(testContext);
     }
@@ -59,11 +59,11 @@ describe("Context", () => {
   test("two components can subscribe to same context", async () => {
     const testContext = new Context({ value: 123 });
 
-    class Child extends Component<any, any> {
+    class Child extends Component {
       static template = xml`<span><t t-esc="contextObj.value"/></span>`;
       contextObj = useContext(testContext);
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><Child /><Child /></div>`;
       static components = { Child };
     }
@@ -80,7 +80,7 @@ describe("Context", () => {
     const def = makeDeferred();
     const steps: string[] = [];
 
-    class Child extends Component<any, any> {
+    class Child extends Component {
       static template = xml`<span><t t-esc="contextObj.value"/></span>`;
       contextObj = useContext(testContext);
       async render() {
@@ -90,7 +90,7 @@ describe("Context", () => {
       }
     }
 
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><Child /><Child /></div>`;
       static components = { Child };
     }
@@ -111,13 +111,13 @@ describe("Context", () => {
     const def = makeDeferred();
     const steps: string[] = [];
 
-    class SlowComp extends Component<any, any> {
+    class SlowComp extends Component {
       static template = xml`<p><t t-esc="props.value"/></p>`;
       willUpdateProps() {
         return def;
       }
     }
-    class Child extends Component<any, any> {
+    class Child extends Component {
       static template = xml`<span><SlowComp value="contextObj.value"/></span>`;
       static components = { SlowComp };
       contextObj = useContext(testContext);
@@ -128,12 +128,12 @@ describe("Context", () => {
       }
     }
 
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><Child /><Child /></div>`;
       static components = { Child };
     }
 
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`<div><Child /><Parent /></div>`;
       static components = { Child, Parent };
     }
@@ -166,7 +166,7 @@ describe("Context", () => {
     const testContext = new Context({ a: 1, b: 2 });
     const steps: string[] = [];
 
-    class Child extends Component<any, any> {
+    class Child extends Component {
       static template = xml`<span><t t-esc="contextObj1.a"/><t t-esc="contextObj2.b"/></span>`;
       contextObj1 = useContext(testContext);
       contextObj2 = useContext(testContext);
@@ -175,7 +175,7 @@ describe("Context", () => {
         return super.__render(fiber);
       }
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><Child /></div>`;
       static components = { Child };
     }
@@ -193,7 +193,7 @@ describe("Context", () => {
     const testContext = new Context({ a: 123, b: 321 });
     const steps: string[] = [];
 
-    class Child extends Component<any, any> {
+    class Child extends Component {
       static template = xml`<span><t t-esc="contextObj.a"/></span>`;
       contextObj = useContext(testContext);
       __render(fiber) {
@@ -201,7 +201,7 @@ describe("Context", () => {
         return super.__render(fiber);
       }
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><Child /><t t-esc="contextObj.b"/></div>`;
       static components = { Child };
       contextObj = useContext(testContext);
@@ -227,7 +227,7 @@ describe("Context", () => {
     const testContext = new Context({ a: 123 });
     const steps: string[] = [];
 
-    class Child extends Component<any, any> {
+    class Child extends Component {
       static template = xml`<span><t t-esc="contextObj.a"/></span>`;
       contextObj = useContext(testContext);
       __render(fiber) {
@@ -235,7 +235,7 @@ describe("Context", () => {
         return super.__render(fiber);
       }
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><Child t-if="state.flag"/></div>`;
       static components = { Child };
       state = useState({ flag: true });
@@ -263,14 +263,14 @@ describe("Context", () => {
   test("destroyed component before being mounted is inactive", async () => {
     const testContext = new Context({ a: 123 });
 
-    class Child extends Component<any, any> {
+    class Child extends Component {
       static template = xml`<span><t t-esc="contextObj.a"/></span>`;
       contextObj = useContext(testContext);
       willStart() {
         return makeDeferred();
       }
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><Child t-if="state.flag"/></div>`;
       static components = { Child };
       state = useState({ flag: true });
@@ -293,7 +293,7 @@ describe("Context", () => {
     const testContext = new Context({ x: { n: 1 }, key: "x" });
     const def = makeDeferred();
     let stateC;
-    class ComponentC extends Component<any, any> {
+    class ComponentC extends Component {
       static template = xml`<span><t t-esc="context[props.key].n"/><t t-esc="state.x"/></span>`;
       context = useContext(testContext);
       state = useState({ x: "a" });
@@ -303,7 +303,7 @@ describe("Context", () => {
         stateC = this.state;
       }
     }
-    class ComponentB extends Component<any, any> {
+    class ComponentB extends Component {
       static components = { ComponentC };
       static template = xml`<p><ComponentC key="props.key"/></p>`;
 
@@ -311,7 +311,7 @@ describe("Context", () => {
         return def;
       }
     }
-    class ComponentA extends Component<any, any> {
+    class ComponentA extends Component {
       static components = { ComponentB };
       static template = xml`<div><ComponentB key="context.key"/></div>`;
       context = useContext(testContext);

tests/helpers.ts

@@ -1,4 +1,4 @@
-import { Env } from "../src/component/component";
+import { Env, Component } from "../src/component/component";
 import { scheduler } from "../src/component/scheduler";
 import { EvalContext, QWeb } from "../src/qweb/qweb";
 import { CompilationContext } from "../src/qweb/compilation_context";
@@ -25,6 +25,7 @@ beforeEach(() => {
   slots = Object.assign({}, QWeb.slots);
   nextId = QWeb.nextId;
   TEMPLATES = Object.assign({}, QWeb.TEMPLATES);
+  Component.scheduler.tasks = [];
 });
 
 afterEach(() => {
@@ -32,6 +33,7 @@ afterEach(() => {
   QWeb.slots = slots;
   QWeb.nextId = nextId;
   QWeb.TEMPLATES = TEMPLATES;
+  Component.scheduler.tasks = [];
 });
 
 // helpers
@@ -87,6 +89,11 @@ export function renderToDOM(
   context: EvalContext = {},
   extra?: any
 ): HTMLElement | Text {
+  if (!context.__owl__) {
+    // we add `__owl__` to better simulate a component as context.  This is
+    // particularly important for event handlers added with the `t-on` directive.
+    context.__owl__ = { isMounted: true };
+  }
   const vnode = qweb.render(template, context, extra);
 
   // we snapshot here the compiled code. This is useful to prevent unwanted code
@@ -116,11 +123,8 @@ export function renderToString(
   context: EvalContext = {},
   extra?: any
 ): string {
-  const node = renderToDOM(qweb, t, context, extra);
-  const result = node instanceof Text ? node.textContent! : node.outerHTML;
-  if (result !== qweb.renderToString(t, context, extra)) {
-    throw new Error("HTML string returned by renderToString helper does not match QWeb render");
-  }
+  const result = qweb.renderToString(t, context, extra);
+  expect(qweb.templates[t].fn.toString()).toMatchSnapshot();
   return result;
 }
 

tests/hooks.test.ts

@@ -9,7 +9,8 @@ import {
   onWillPatch,
   onWillStart,
   onWillUpdateProps,
-  useSubEnv
+  useSubEnv,
+  useExternalListener
 } from "../src/hooks";
 import { xml } from "../src/tags";
 
@@ -41,7 +42,7 @@ afterEach(() => {
 
 describe("hooks", () => {
   test("can use a state hook", async () => {
-    class Counter extends Component<any, any> {
+    class Counter extends Component {
       static template = xml`<div><t t-esc="counter.value"/></div>`;
       counter = useState({ value: 42 });
     }
@@ -63,7 +64,7 @@ describe("hooks", () => {
         steps.push("willunmount");
       });
     }
-    class MyComponent extends Component<any, any> {
+    class MyComponent extends Component {
       static template = xml`<div>hey</div>`;
       constructor() {
         super();
@@ -91,7 +92,7 @@ describe("hooks", () => {
         steps.push("willunmount");
       });
     }
-    class MyComponent extends Component<any, any> {
+    class MyComponent extends Component {
       static template = xml`<div>hey</div>`;
       constructor(parent, props) {
         super(parent, props);
@@ -99,7 +100,7 @@ describe("hooks", () => {
       }
     }
 
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><MyComponent t-if="state.flag"/></div>`;
       static components = { MyComponent };
       state = useState({ flag: true });
@@ -125,7 +126,7 @@ describe("hooks", () => {
         steps.push("hook:willunmount");
       });
     }
-    class MyComponent extends Component<any, any> {
+    class MyComponent extends Component {
       static template = xml`<div>hey</div>`;
       constructor() {
         super();
@@ -156,7 +157,7 @@ describe("hooks", () => {
         steps.push("hook:willunmount");
       });
     }
-    class MyComponent extends Component<any, any> {
+    class MyComponent extends Component {
       static template = xml`<div>hey</div>`;
       constructor(parent, props) {
         super(parent, props);
@@ -170,7 +171,7 @@ describe("hooks", () => {
       }
     }
 
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><MyComponent t-if="state.flag"/></div>`;
       static components = { MyComponent };
       state = useState({ flag: true });
@@ -196,7 +197,7 @@ describe("hooks", () => {
         steps.push("hook:willunmount" + i);
       });
     }
-    class MyComponent extends Component<any, any> {
+    class MyComponent extends Component {
       static template = xml`<div>hey</div>`;
       constructor() {
         super();
@@ -218,7 +219,7 @@ describe("hooks", () => {
   });
 
   test("useRef hook", async () => {
-    class Counter extends Component<any, any> {
+    class Counter extends Component {
       static template = xml`<div><button t-ref="button"><t t-esc="value"/></button></div>`;
       button = useRef("button");
       value = 0;
@@ -240,7 +241,7 @@ describe("hooks", () => {
 
   test("useRef hook is null if ref is removed ", async () => {
     expect.assertions(4);
-    class TestRef extends Component<any, any> {
+    class TestRef extends Component {
       static template = xml`<div><span t-if="state.flag" t-ref="span">owl</span></div>`;
       spanRef = useRef("span");
       state = useState({ flag: true });
@@ -260,10 +261,10 @@ describe("hooks", () => {
   });
 
   test("t-refs on widget are components", async () => {
-    class WidgetB extends Component<any, any> {
+    class WidgetB extends Component {
       static template = xml`<div>b</div>`;
     }
-    class WidgetC extends Component<any, any> {
+    class WidgetC extends Component {
       static template = xml`<div class="outer-div">Hello<WidgetB t-ref="mywidgetb" /></div>`;
       static components = { WidgetB };
       ref = useRef("mywidgetb");
@@ -279,11 +280,11 @@ describe("hooks", () => {
 
   test("t-refs are bound at proper timing", async () => {
     expect.assertions(2);
-    class Widget extends Component<any, any> {
+    class Widget extends Component {
       static template = xml`<div>widget</div>`;
     }
 
-    class ParentWidget extends Component<any, any> {
+    class ParentWidget extends Component {
       static template = xml`
         <div>
           <t t-foreach="state.list" t-as="elem" t-ref="child" t-key="elem" t-component="Widget"/>
@@ -308,10 +309,10 @@ describe("hooks", () => {
 
   test("t-refs are bound at proper timing (2)", async () => {
     expect.assertions(10);
-    class Widget extends Component<any, any> {
+    class Widget extends Component {
       static template = xml`<div>widget</div>`;
     }
-    class ParentWidget extends Component<any, any> {
+    class ParentWidget extends Component {
       static template = xml`
         <div>
           <t t-if="state.child1" t-ref="child1" t-component="Widget"/>
@@ -368,7 +369,7 @@ describe("hooks", () => {
       });
     }
 
-    class MyComponent extends Component<any, any> {
+    class MyComponent extends Component {
       static template = xml`<div><t t-if="state.flag">hey</t></div>`;
       state = useState({ flag: true });
 
@@ -402,7 +403,7 @@ describe("hooks", () => {
         steps.push("hook:willPatch");
       });
     }
-    class MyComponent extends Component<any, any> {
+    class MyComponent extends Component {
       static template = xml`<div><t t-if="state.flag">hey</t></div>`;
       state = useState({ flag: true });
 
@@ -436,7 +437,7 @@ describe("hooks", () => {
         steps.push("hook:willPatch" + i);
       });
     }
-    class MyComponent extends Component<any, any> {
+    class MyComponent extends Component {
       static template = xml`<div>hey<t t-esc="state.value"/></div>`;
       state = useState({ value: 1 });
       constructor() {
@@ -472,7 +473,7 @@ describe("hooks", () => {
     }
 
     test("simple input", async () => {
-      class SomeComponent extends Component<any, any> {
+      class SomeComponent extends Component {
         static template = xml`
             <div>
                 <input t-ref="input1"/>
@@ -493,7 +494,7 @@ describe("hooks", () => {
     });
 
     test("input in a t-if", async () => {
-      class SomeComponent extends Component<any, any> {
+      class SomeComponent extends Component {
         static template = xml`
             <div>
                 <input t-ref="input1"/>
@@ -520,7 +521,7 @@ describe("hooks", () => {
   });
 
   test("can use sub env", async () => {
-    class TestComponent extends Component<any, any> {
+    class TestComponent extends Component {
       static template = xml`<div><t t-esc="env.val"/></div>`;
       constructor() {
         super();
@@ -535,7 +536,7 @@ describe("hooks", () => {
   });
 
   test("parent and child env", async () => {
-    class Child extends Component<any, any> {
+    class Child extends Component {
       static template = xml`<div><t t-esc="env.val"/></div>`;
       constructor(parent, props) {
         super(parent, props);
@@ -543,7 +544,7 @@ describe("hooks", () => {
       }
     }
 
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><t t-esc="env.val"/><Child/></div>`;
       static components = { Child };
       constructor() {
@@ -567,14 +568,14 @@ describe("hooks", () => {
         steps.push("onWillUpdateProps");
       });
     }
-    class MyComponent extends Component<any, any> {
+    class MyComponent extends Component {
       static template = xml`<span><t t-esc="props.value"/></span>`;
       constructor(parent, props) {
         super(parent, props);
         useMyHook();
       }
     }
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`<div><MyComponent value="state.value"/></div>`;
       static components = { MyComponent };
       state = useState({ value: 1 });
@@ -592,4 +593,39 @@ describe("hooks", () => {
     expect(fixture.innerHTML).toBe("<div><span>2</span></div>");
     expect(steps).toEqual(["onWillStart", "onWillUpdateProps"]);
   });
+
+  test("useExternalListener", async () => {
+    let n = 0;
+
+    class MyComponent extends Component {
+      static template = xml`<span><t t-esc="props.value"/></span>`;
+      constructor(parent, props) {
+        super(parent, props);
+        useExternalListener(window as any, "click", this.increment);
+      }
+      increment() {
+        n++;
+      }
+    }
+    class App extends Component {
+      static template = xml`<div><MyComponent t-if="state.flag"/></div>`;
+      static components = { MyComponent };
+      state = useState({ flag: false });
+    }
+
+    const app = new App();
+    await app.mount(fixture);
+
+    expect(n).toBe(0);
+    window.dispatchEvent(new Event("click"));
+    expect(n).toBe(0);
+    app.state.flag = true;
+    await nextTick();
+    window.dispatchEvent(new Event("click"));
+    expect(n).toBe(1);
+    app.state.flag = false;
+    await nextTick();
+    window.dispatchEvent(new Event("click"));
+    expect(n).toBe(1);
+  });
 });

tests/misc/async_root.test.ts

@@ -27,7 +27,7 @@ afterEach(() => {
 describe("Asyncroot", () => {
   test("delayed component with AsyncRoot component", async () => {
     let def;
-    class Child extends Component<any, any> {
+    class Child extends Component {
       static template = xml`<span><t t-esc="props.val"/></span>`;
     }
     class AsyncChild extends Child {
@@ -35,7 +35,7 @@ describe("Asyncroot", () => {
         return def;
       }
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`
           <div>
             <button t-on-click="updateApp">Update App State</button>
@@ -74,7 +74,7 @@ describe("Asyncroot", () => {
 
   test("fast component with AsyncRoot", async () => {
     let def;
-    class Child extends Component<any, any> {
+    class Child extends Component {
       static template = xml`<span><t t-esc="props.val"/></span>`;
     }
     class AsyncChild extends Child {
@@ -83,7 +83,7 @@ describe("Asyncroot", () => {
       }
     }
 
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`
           <div>
             <button t-on-click="updateApp">Update App State</button>
@@ -122,7 +122,7 @@ describe("Asyncroot", () => {
 
   test("asyncroot component: mixed re-renderings", async () => {
     let def;
-    class Child extends Component<any, any> {
+    class Child extends Component {
       static template = xml`
         <span t-on-click="increment">
           <t t-esc="state.val"/>/<t t-esc="props.val"/>
@@ -138,7 +138,7 @@ describe("Asyncroot", () => {
         return def;
       }
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`
         <div>
           <button t-on-click="updateApp">Update App State</button>

tests/misc/portal.test.ts

@@ -0,0 +1,890 @@
+import { Portal } from "../../src/misc/portal";
+import { xml } from "../../src/tags";
+import { makeTestFixture, makeTestEnv, nextTick } from "../helpers";
+import { Component } from "../../src/component/component";
+import { useState } from "../../src/hooks";
+import { QWeb } from "../../src/qweb";
+
+//------------------------------------------------------------------------------
+// Setup and helpers
+//------------------------------------------------------------------------------
+
+// We create before each test:
+// - fixture: a div, appended to the DOM, intended to be the target of dom
+//   manipulations.  Note that it is removed after each test.
+// - outside: a div with id #outside appended into fixture, meant to be used as
+//   target by Portal component
+// - a test env, necessary to create components, that is set on Component
+
+let fixture: HTMLElement;
+let outside: HTMLElement;
+
+beforeEach(() => {
+  fixture = makeTestFixture();
+  outside = document.createElement("div");
+  outside.setAttribute("id", "outside");
+  fixture.appendChild(outside);
+
+  Component.env = makeTestEnv();
+});
+
+afterEach(() => {
+  fixture.remove();
+});
+
+describe("Portal: Props validation", () => {
+  test("target is mandatory", async () => {
+    const dev = QWeb.dev;
+    QWeb.dev = true;
+    class Parent extends Component {
+      static components = { Portal };
+      static template = xml`
+        <div>
+          <Portal>
+            <div>2</div>
+          </Portal>
+        </div>`;
+    }
+    let error;
+    try {
+      const parent = new Parent();
+      await parent.mount(fixture);
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe(`Missing props 'target' (component 'Portal')`);
+
+    QWeb.dev = dev;
+  });
+
+  test("target is not list", async () => {
+    const dev = QWeb.dev;
+    QWeb.dev = true;
+    class Parent extends Component {
+      static components = { Portal };
+      static template = xml`
+        <div>
+          <Portal target="['body']">
+            <div>2</div>
+          </Portal>
+        </div>`;
+    }
+    let error;
+    try {
+      const parent = new Parent();
+      await parent.mount(fixture);
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe(`Invalid Prop 'target' in component 'Portal'`);
+
+    QWeb.dev = dev;
+  });
+});
+
+describe("Portal: Basic use and DOM placement", () => {
+  test("basic use of portal", async () => {
+    const dev = QWeb.dev;
+    QWeb.dev = true;
+    class Parent extends Component {
+      static components = { Portal };
+      static template = xml`
+        <div>
+          <span>1</span>
+          <Portal target="'#outside'">
+            <div>2</div>
+          </Portal>
+        </div>`;
+    }
+    let error;
+    let parent;
+    try {
+      parent = new Parent();
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeUndefined();
+    await parent.mount(fixture);
+    expect(outside.innerHTML).toBe("<div>2</div>");
+    expect(parent.el!.outerHTML).toBe("<div><span>1</span><portal></portal></div>");
+    QWeb.dev = dev;
+  });
+
+  test("conditional use of Portal", async () => {
+    class Parent extends Component {
+      static components = { Portal };
+      static template = xml`
+        <div>
+          <span>1</span>
+          <Portal target="'#outside'" t-if="state.hasPortal">
+            <div>2</div>
+          </Portal>
+        </div>`;
+
+      state = useState({ hasPortal: false });
+    }
+
+    const parent = new Parent();
+    await parent.mount(fixture);
+    expect(outside.innerHTML).toBe("");
+    expect(parent.el!.outerHTML).toBe("<div><span>1</span></div>");
+
+    parent.state.hasPortal = true;
+    await nextTick();
+    expect(outside.innerHTML).toBe("<div>2</div>");
+    expect(parent.el!.outerHTML).toBe("<div><span>1</span><portal></portal></div>");
+
+    parent.state.hasPortal = false;
+    await nextTick();
+    expect(outside.innerHTML).toBe("");
+    expect(parent.el!.outerHTML).toBe("<div><span>1</span></div>");
+
+    parent.state.hasPortal = true;
+    await nextTick();
+    expect(outside.innerHTML).toBe("<div>2</div>");
+    expect(parent.el!.outerHTML).toBe("<div><span>1</span><portal></portal></div>");
+  });
+
+  test("conditional use of Portal (with sub Component)", async () => {
+    class Child extends Component {
+      static template = xml`<div><t t-esc="props.val"/></div>`;
+    }
+    class Parent extends Component {
+      static components = { Portal, Child };
+      static template = xml`
+        <div>
+          <span>1</span>
+          <Portal t-if="state.hasPortal" target="'#outside'">
+            <Child val="state.val"/>
+          </Portal>
+        </div>`;
+      state = useState({ hasPortal: false, val: 1 });
+    }
+
+    const parent = new Parent();
+    await parent.mount(fixture);
+    expect(outside.innerHTML).toBe("");
+    expect(parent.el!.outerHTML).toBe("<div><span>1</span></div>");
+
+    parent.state.hasPortal = true;
+    await nextTick();
+    expect(outside.innerHTML).toBe("<div>1</div>");
+    expect(parent.el!.outerHTML).toBe("<div><span>1</span><portal></portal></div>");
+
+    parent.state.hasPortal = false;
+    await nextTick();
+    expect(outside.innerHTML).toBe("");
+    expect(parent.el!.outerHTML).toBe("<div><span>1</span></div>");
+
+    parent.state.val = 2;
+    await nextTick();
+    expect(outside.innerHTML).toBe("");
+    expect(parent.el!.outerHTML).toBe("<div><span>1</span></div>");
+
+    parent.state.hasPortal = true;
+    await nextTick();
+    expect(outside.innerHTML).toBe("<div>2</div>");
+    expect(parent.el!.outerHTML).toBe("<div><span>1</span><portal></portal></div>");
+  });
+
+  test("with target in template (before portal)", async () => {
+    class Parent extends Component {
+      static components = { Portal };
+      static template = xml`
+        <div>
+          <div id="local-target"></div>
+          <span>1</span>
+          <Portal target="'#local-target'">
+            <p>2</p>
+          </Portal>
+        </div>`;
+    }
+
+    const parent = new Parent();
+    await parent.mount(fixture);
+    expect(parent.el!.innerHTML).toBe(
+      '<div id="local-target"><p>2</p></div><span>1</span><portal></portal>'
+    );
+  });
+
+  test("with target in template (after portal)", async () => {
+    class Parent extends Component {
+      static components = { Portal };
+      static template = xml`
+        <div>
+          <span>1</span>
+          <Portal target="'#local-target'">
+            <p>2</p>
+          </Portal>
+          <div id="local-target"></div>
+        </div>`;
+    }
+
+    const parent = new Parent();
+    await parent.mount(fixture);
+    expect(parent.el!.innerHTML).toBe(
+      '<span>1</span><portal></portal><div id="local-target"><p>2</p></div>'
+    );
+  });
+
+  test("portal with target not in dom", async () => {
+    const consoleError = console.error;
+    console.error = jest.fn(() => {});
+
+    class Parent extends Component {
+      static components = { Portal };
+      static template = xml`
+        <div>
+          <Portal target="'#does-not-exist'">
+            <div>2</div>
+          </Portal>
+        </div>`;
+    }
+
+    const parent = new Parent();
+    let error;
+    try {
+      await parent.mount(fixture);
+    } catch (e) {
+      error = e;
+    }
+
+    expect(error).toBeDefined();
+    expect(error.message).toBe('Could not find any match for "#does-not-exist"');
+    expect(console.error).toBeCalledTimes(0);
+    expect(fixture.innerHTML).toBe(`<div id="outside"></div>`);
+    console.error = consoleError;
+  });
+
+  test("portal with child and props", async () => {
+    const steps: string[] = [];
+    class Child extends Component {
+      static template = xml`<span><t t-esc="props.val"/></span>`;
+      mounted() {
+        steps.push("mounted");
+        expect(outside.innerHTML).toBe("<span>1</span>");
+      }
+      patched() {
+        steps.push("patched");
+        expect(outside.innerHTML).toBe("<span>2</span>");
+      }
+    }
+    class Parent extends Component {
+      static components = { Portal, Child };
+      static template = xml`
+        <div>
+          <Portal target="'#outside'">
+            <Child val="state.val"/>
+          </Portal>
+        </div>`;
+      state = useState({ val: 1 });
+    }
+
+    const parent = new Parent();
+    await parent.mount(fixture);
+    expect(outside.innerHTML).toBe("<span>1</span>");
+    expect(parent.el!.innerHTML).toBe("<portal></portal>");
+
+    parent.state.val = 2;
+    await nextTick();
+    expect(outside.innerHTML).toBe("<span>2</span>");
+    expect(parent.el!.innerHTML).toBe("<portal></portal>");
+    expect(steps).toEqual(["mounted", "patched"]);
+  });
+
+  test("portal with only text as content", async () => {
+    const consoleError = console.error;
+    console.error = jest.fn(() => {});
+
+    class Parent extends Component {
+      static components = { Portal };
+      static template = xml`
+        <div>
+          <Portal target="'#outside'">
+            <t t-esc="'only text'"/>
+          </Portal>
+        </div>`;
+    }
+
+    const parent = new Parent();
+    let error;
+    try {
+      await parent.mount(fixture);
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe("Portal must have exactly one non-text child (has 0)");
+    expect(console.error).toBeCalledTimes(0);
+    expect(fixture.innerHTML).toBe(`<div id="outside"></div>`);
+    console.error = consoleError;
+  });
+
+  test("portal with no content", async () => {
+    const consoleError = console.error;
+    console.error = jest.fn(() => {});
+
+    class Parent extends Component {
+      static components = { Portal };
+      static template = xml`
+        <div>
+          <Portal target="'#outside'">
+            <t t-if="false" t-esc="'ABC'"/>
+          </Portal>
+        </div>`;
+    }
+
+    const parent = new Parent();
+    let error;
+    try {
+      await parent.mount(fixture);
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe("Portal must have exactly one non-text child (has 0)");
+    expect(console.error).toBeCalledTimes(0);
+    expect(fixture.innerHTML).toBe(`<div id="outside"></div>`);
+    console.error = consoleError;
+  });
+
+  test("portal with many children", async () => {
+    const consoleError = console.error;
+    console.error = jest.fn(() => {});
+
+    class Parent extends Component {
+      static components = { Portal };
+      static template = xml`
+        <div>
+          <Portal target="'#outside'">
+            <div>1</div>
+            <p>2</p>
+          </Portal>
+        </div>`;
+    }
+    const parent = new Parent();
+    let error;
+    try {
+      await parent.mount(fixture);
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe("Portal must have exactly one non-text child (has 2)");
+    expect(console.error).toBeCalledTimes(0);
+    expect(fixture.innerHTML).toBe(`<div id="outside"></div>`);
+    console.error = consoleError;
+  });
+
+  test("portal with dynamic body", async () => {
+    class Parent extends Component {
+      static components = { Portal };
+      static template = xml`
+        <div>
+          <Portal target="'#outside'">
+            <span t-if="state.val" t-esc="state.val"/>
+            <div t-else=""/>
+          </Portal>
+        </div>`;
+      state = useState({ val: "ab" });
+    }
+
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(outside.innerHTML).toBe(`<span>ab</span>`);
+
+    parent.state.val = "";
+    await nextTick();
+    expect(outside.innerHTML).toBe(`<div></div>`);
+  });
+
+  test("portal could have dynamically no content", async () => {
+    const consoleError = console.error;
+    console.error = jest.fn(() => {});
+
+    class Parent extends Component {
+      static components = { Portal };
+      static template = xml`
+        <div>
+          <Portal target="'#outside'">
+            <span t-if="state.val" t-esc="state.val"/>
+          </Portal>
+        </div>`;
+      state = { val: "ab" };
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(outside.innerHTML).toBe(`<span>ab</span>`);
+
+    let error;
+    try {
+      parent.state.val = "";
+      await parent.render();
+    } catch (e) {
+      error = e;
+    }
+    expect(outside.innerHTML).toBe(``);
+
+    expect(error).toBeDefined();
+    expect(error.message).toBe("Portal must have exactly one non-text child (has 0)");
+
+    expect(console.error).toBeCalledTimes(0);
+    console.error = consoleError;
+  });
+
+  test("lifecycle hooks of portal sub component are properly called", async () => {
+    const steps: any[] = [];
+
+    class Child extends Component {
+      static template = xml`<span t-esc="props.val"/>`;
+      mounted() {
+        steps.push("child:mounted");
+      }
+      willPatch() {
+        steps.push("child:willPatch");
+      }
+      patched() {
+        steps.push("child:patched");
+      }
+      willUnmount() {
+        steps.push("child:willUnmount");
+      }
+    }
+    class Parent extends Component {
+      static components = { Portal, Child };
+      static template = xml`
+        <div>
+          <Portal t-if="state.hasChild" target="'#outside'">
+            <Child val="state.val"/>
+          </Portal>
+        </div>`;
+      state = useState({ hasChild: false, val: 1 });
+      mounted() {
+        steps.push("parent:mounted");
+      }
+      willPatch() {
+        steps.push("parent:willPatch");
+      }
+      patched() {
+        steps.push("parent:patched");
+      }
+      willUnmount() {
+        steps.push("parent:willUnmount");
+      }
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+    expect(steps).toEqual(["parent:mounted"]);
+
+    parent.state.hasChild = true;
+    await nextTick();
+    expect(steps).toEqual([
+      "parent:mounted",
+      "parent:willPatch",
+      "child:mounted",
+      "parent:patched"
+    ]);
+
+    parent.state.val = 2;
+    await nextTick();
+    expect(steps).toEqual([
+      "parent:mounted",
+      "parent:willPatch",
+      "child:mounted",
+      "parent:patched",
+      "parent:willPatch",
+      "child:willPatch",
+      "child:patched",
+      "parent:patched"
+    ]);
+
+    parent.state.hasChild = false;
+    await nextTick();
+    expect(steps).toEqual([
+      "parent:mounted",
+      "parent:willPatch",
+      "child:mounted",
+      "parent:patched",
+      "parent:willPatch",
+      "child:willPatch",
+      "child:patched",
+      "parent:patched",
+      "parent:willPatch",
+      "child:willUnmount",
+      "parent:patched"
+    ]);
+  });
+
+  test("portal destroys on crash", async () => {
+    class Child extends Component {
+      static template = xml`<span t-esc="props.error and this.will.crash" />`;
+      state = {};
+    }
+    class Parent extends Component {
+      static components = { Portal, Child };
+      static template = xml`
+        <div>
+          <Portal target="'#outside'" >
+            <Child error="state.error"/>
+          </Portal>
+        </div>`;
+      state = { error: false };
+    }
+
+    const parent = new Parent();
+    await parent.mount(fixture);
+    parent.state.error = true;
+
+    let error;
+    try {
+      await parent.render();
+    } catch (e) {
+      error = e;
+    }
+    expect(error).toBeDefined();
+    expect(error.message).toBe("Cannot read property 'crash' of undefined");
+  });
+
+  test("portal manual unmount", async () => {
+    class Parent extends Component {
+      static components = { Portal };
+      static template = xml`
+        <div>
+          <Portal target="'#outside'">
+            <span>gloria</span>
+          </Portal>
+        </div>`;
+    }
+
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(outside.innerHTML).toBe("<span>gloria</span>");
+    expect(parent.el!.innerHTML).toBe("<portal></portal>");
+
+    parent.unmount();
+    expect(outside.innerHTML).toBe("");
+    expect(parent.el!.innerHTML).toBe("<portal><span>gloria</span></portal>");
+
+    await parent.mount(fixture);
+    expect(outside.innerHTML).toBe("<span>gloria</span>");
+    expect(parent.el!.innerHTML).toBe("<portal></portal>");
+  });
+
+  test("portal manual unmount with subcomponent", async () => {
+    expect.assertions(9);
+    class Child extends Component {
+      static template = xml`<span>gloria</span>`;
+      mounted() {
+        expect(outside.contains(this.el)).toBeTruthy();
+      }
+      willUnmount() {
+        expect(outside.contains(this.el)).toBeTruthy();
+      }
+    }
+    class Parent extends Component {
+      static components = { Portal, Child };
+      static template = xml`
+        <div>
+          <Portal target="'#outside'">
+            <Child />
+          </Portal>
+        </div>`;
+    }
+
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(outside.innerHTML).toBe("<span>gloria</span>");
+    expect(parent.el!.innerHTML).toBe("<portal></portal>");
+
+    parent.unmount();
+    expect(outside.innerHTML).toBe("");
+    expect(parent.el!.innerHTML).toBe("<portal><span>gloria</span></portal>");
+
+    await parent.mount(fixture);
+    expect(outside.innerHTML).toBe("<span>gloria</span>");
+    expect(parent.el!.innerHTML).toBe("<portal></portal>");
+  });
+});
+
+describe("Portal: Events handling", () => {
+  test("events triggered on movable pure node are handled", async () => {
+    class Parent extends Component {
+      static components = { Portal };
+      static template = xml`
+        <div>
+          <Portal target="'#outside'">
+            <span id="trigger-me" t-on-custom="_onCustom" t-esc="state.val"/>
+          </Portal>
+        </div>`;
+      state = useState({ val: "ab" });
+
+      _onCustom() {
+        this.state.val = "triggered";
+      }
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(outside.innerHTML).toBe(`<span id="trigger-me">ab</span>`);
+    outside.querySelector("#trigger-me")!.dispatchEvent(new Event("custom"));
+    await nextTick();
+    expect(outside.innerHTML).toBe(`<span id="trigger-me">triggered</span>`);
+  });
+
+  test("events triggered on movable owl components are redirected", async () => {
+    let childInst: Component | null = null;
+    class Child extends Component {
+      static template = xml`
+         <span t-on-custom="_onCustom" t-esc="props.val"/>`;
+
+      constructor(parent, props) {
+        super(parent, props);
+        childInst = this;
+      }
+
+      _onCustom() {
+        this.trigger("custom-portal");
+      }
+    }
+    class Parent extends Component {
+      static components = { Portal, Child };
+      static template = xml`
+        <div t-on-custom-portal="_onCustomPortal">
+          <Portal target="'#outside'">
+            <Child val="state.val"/>
+          </Portal>
+        </div>`;
+      state = useState({ val: "ab" });
+
+      _onCustomPortal() {
+        this.state.val = "triggered";
+      }
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(outside.innerHTML).toBe(`<span>ab</span>`);
+    childInst!.trigger("custom");
+    await nextTick();
+    expect(outside.innerHTML).toBe(`<span>triggered</span>`);
+  });
+
+  test("events triggered on contained movable owl components are redirected", async () => {
+    const steps: string[] = [];
+    let childInst: Component | null = null;
+    class Child extends Component {
+      static template = xml`
+         <span t-on-custom="_onCustom"/>`;
+
+      constructor(parent, props) {
+        super(parent, props);
+        childInst = this;
+      }
+
+      _onCustom() {
+        this.trigger("custom-portal");
+      }
+    }
+    class Parent extends Component {
+      static components = { Portal, Child };
+      static template = xml`
+        <div t-on-custom="_handled" t-on-custom-portal="_handled">
+          <Portal target="'#outside'">
+            <div>
+              <Child/>
+            </div>
+          </Portal>
+        </div>`;
+
+      _handled(ev) {
+        steps.push(ev.type);
+      }
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    childInst!.trigger("custom");
+    await nextTick();
+
+    // This is expected because trigger is synchronous
+    expect(steps).toMatchObject(["custom-portal", "custom"]);
+  });
+
+  test("Dom events are not mapped", async () => {
+    let childInst: Component | null = null;
+    const steps: string[] = [];
+    class Child extends Component {
+      static template = xml`
+        <button>child</button>`;
+
+      constructor(parent, props) {
+        super(parent, props);
+        childInst = this;
+      }
+    }
+    class Parent extends Component {
+      static components = { Portal, Child };
+      static template = xml`
+        <div t-on-click="_handled">
+          <Portal target="'#outside'">
+            <Child />
+          </Portal>
+        </div>`;
+
+      _handled(ev) {
+        steps.push(ev.type as string);
+      }
+    }
+    const bodyListener = ev => {
+      steps.push(`body: ${ev.type}`);
+    };
+    document.body.addEventListener("click", bodyListener);
+
+    const parent = new Parent();
+    await parent.mount(fixture);
+    childInst!.el!.click();
+
+    expect(steps).toEqual(["body: click"]);
+    document.body.removeEventListener("click", bodyListener);
+  });
+
+  test("Nested portals event propagation", async () => {
+    const outside2 = document.createElement("div");
+    outside2.setAttribute("id", "outside2");
+    fixture.appendChild(outside2);
+
+    const steps: Array<string> = [];
+    let childInst: Component | null = null;
+    class Child2 extends Component {
+      static template = xml`<div>child2</div>`;
+      constructor(parent, props) {
+        super(parent, props);
+        childInst = this;
+      }
+    }
+    class Child extends Component {
+      static components = { Portal, Child2 };
+      static template = xml`
+        <Portal target="'#outside2'">
+          <Child2 />
+        </Portal>`;
+    }
+    class Parent extends Component {
+      static components = { Portal, Child };
+      static template = xml`
+        <div t-on-custom='_handled'>
+          <Portal target="'#outside'">
+            <Child/>
+          </Portal>
+        </div>`;
+
+      _handled(ev) {
+        steps.push(`${ev.type} from ${ev.originalComponent.constructor.name}`);
+      }
+    }
+
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    childInst!.trigger("custom");
+    expect(steps).toEqual(["custom from Child2"]);
+  });
+
+  test("portal's parent's env is not polluted", async () => {
+    class Child extends Component {
+      static template = xml`
+        <button>child</button>`;
+    }
+    class Parent extends Component {
+      static components = { Portal, Child };
+      static template = xml`
+        <div>
+          <Portal target="'#outside'">
+            <Child />
+          </Portal>
+        </div>`;
+    }
+    const parent = new Parent();
+    const parentEnv = Object.assign({}, parent.env);
+    await parent.mount(fixture);
+    expect(parentEnv).toStrictEqual(parent.env);
+  });
+
+  test("Portal composed with t-slot", async () => {
+    const steps: Array<string> = [];
+    let childInst: Component | null = null;
+    class Child2 extends Component {
+      static template = xml`<div>child2</div>`;
+      constructor(parent, props) {
+        super(parent, props);
+        childInst = this;
+      }
+    }
+    class Child extends Component {
+      static components = { Portal, Child2 };
+      static template = xml`
+        <Portal target="'#outside'">
+          <t t-slot="default"/>
+        </Portal>`;
+    }
+    class Parent extends Component {
+      static components = { Child, Child2 };
+      static template = xml`
+        <div t-on-custom='_handled'>
+          <Child>
+            <Child2/>
+          </Child>
+        </div>`;
+
+      _handled(ev) {
+        steps.push(ev.type as string);
+      }
+    }
+
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    childInst!.trigger("custom");
+    expect(steps).toEqual(["custom"]);
+  });
+});
+
+describe("Portal: UI/UX", () => {
+  test("focus is kept across re-renders", async () => {
+    class Child extends Component {
+      static template = xml`
+        <input id="target-me" t-att-placeholder="props.val"/>`;
+    }
+    class Parent extends Component {
+      static components = { Portal, Child };
+      static template = xml`
+        <div>
+          <Portal target="'#outside'">
+            <Child val="state.val"/>
+          </Portal>
+        </div>`;
+      state = useState({ val: "ab" });
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+    const input = document.querySelector("#target-me");
+    expect(input!.nodeName).toBe("INPUT");
+    expect((input as HTMLInputElement).placeholder).toBe("ab");
+
+    (input as HTMLInputElement).focus();
+    expect(document.activeElement === input).toBeTruthy();
+
+    parent.state.val = "bc";
+    await nextTick();
+    const inputReRendered = document.querySelector("#target-me");
+    expect(inputReRendered!.nodeName).toBe("INPUT");
+    expect((inputReRendered as HTMLInputElement).placeholder).toBe("bc");
+    expect(document.activeElement === inputReRendered).toBeTruthy();
+  });
+});

tests/qweb/qweb.test.ts

@@ -46,6 +46,26 @@ describe("static templates", () => {
     expect(renderToString(qweb, "test")).toBe("<div>word</div>");
   });
 
+  test("div with a class attribute", () => {
+    qweb.addTemplate("test", `<div class="abc">word</div>`);
+    expect(renderToString(qweb, "test")).toBe(`<div class="abc">word</div>`);
+  });
+
+  test("div with a class attribute with a quote", () => {
+    qweb.addTemplate("test", `<div class="a'bc">word</div>`);
+    expect(renderToString(qweb, "test")).toBe(`<div class="a'bc">word</div>`);
+  });
+
+  test("div with an arbitrary attribute with a quote", () => {
+    qweb.addTemplate("test", `<div abc="a'bc">word</div>`);
+    expect(renderToString(qweb, "test")).toBe(`<div abc="a'bc">word</div>`);
+  });
+
+  test("div with a empty class attribute", () => {
+    qweb.addTemplate("test", `<div class="">word</div>`);
+    expect(renderToString(qweb, "test")).toBe(`<div>word</div>`);
+  });
+
   test("div with a span child node", () => {
     qweb.addTemplate("test", "<div><span>word</span></div>");
     expect(renderToString(qweb, "test")).toBe("<div><span>word</span></div>");
@@ -55,6 +75,19 @@ describe("static templates", () => {
     qweb.addTemplate("test", "<div>hello <!-- comment-->owl</div>");
     expect(renderToString(qweb, "test")).toBe("<div>hello <!-- comment-->owl</div>");
   });
+
+  test("properly handle comments between t-if/t-else", () => {
+    qweb.addTemplate(
+      "test",
+      `
+      <div>
+        <span t-if="true">true</span>
+        <!-- comment-->
+        <span t-else="">owl</span>
+      </div>`
+    );
+    expect(renderToString(qweb, "test")).toBe("<div><span>true</span></div>");
+  });
 });
 
 describe("error handling", () => {
@@ -110,9 +143,11 @@ describe("t-esc", () => {
     expect(renderToString(qweb, "test", { var: "ok" })).toBe("<span>ok</span>");
   });
 
-  test.skip("escaping", () => {
+  test("escaping", () => {
     qweb.addTemplate("test", `<span><t t-esc="var"/></span>`);
-    expect(renderToString(qweb, "test", { var: "<ok>" })).toBe("<span>&lt;ok&gt;</span>");
+    expect(renderToString(qweb, "test", { var: "<ok>abc</ok>" })).toBe(
+      "<span>&amp;lt;ok&amp;gt;abc&amp;lt;/ok&amp;gt;</span>"
+    );
   });
 
   test("escaping on a node", () => {
@@ -129,6 +164,49 @@ describe("t-esc", () => {
     qweb.addTemplate("test", `<span t-esc="var">nope</span>`);
     expect(renderToString(qweb, "test")).toBe("<span>nope</span>");
   });
+
+  test("t-esc is escaped", () => {
+    qweb.addTemplate("test", `<div><t t-set="var"><p>escaped</p></t><t t-esc="var"/></div>`);
+    const domRendered = renderToDOM(qweb, "test");
+    expect(domRendered.textContent).toBe("<p>escaped</p>");
+  });
+
+  test("t-esc=0 is escaped", () => {
+    qweb.addTemplate("test", `<span><t t-esc="0"/></span>`);
+    qweb.addTemplate("testCaller", `<div><t t-call="test"><p>escaped</p></t></div>`);
+    const domRendered = renderToDOM(qweb, "testCaller") as HTMLElement;
+    expect(domRendered.querySelector("span")!.textContent).toBe("<p>escaped</p>");
+  });
+
+  test("div with falsy values", () => {
+    qweb.addTemplate(
+      "test",
+      `
+      <div>
+        <p t-esc="v1"/>
+        <p t-esc="v2"/>
+        <p t-esc="v3"/>
+        <p t-esc="v4"/>
+        <p t-esc="v5"/>
+      </div>`
+    );
+    const vals = {
+      v1: false,
+      v2: undefined,
+      v3: null,
+      v4: 0,
+      v5: ""
+    };
+    expect(renderToString(qweb, "test", vals)).toBe(
+      "<div><p>false</p><p></p><p></p><p>0</p><p></p></div>"
+    );
+  });
+
+  test("t-esc work with spread operator", () => {
+    qweb.addTemplate("test", `<span><t t-esc="[...state.list]"/></span>`);
+    const result = renderToString(qweb, "test", { state: { list: [1, 2] } });
+    expect(result).toBe("<span>1,2</span>");
+  });
 });
 
 describe("t-raw", () => {
@@ -235,6 +313,18 @@ describe("t-set", () => {
     );
   });
 
+  test("t-set with content and sub t-esc", () => {
+    qweb.addTemplate(
+      "test",
+      `<div>
+        <t t-set="setvar"><t t-esc="beep"/> boop</t>
+        <t t-esc="setvar"/>
+      </div>`
+    );
+
+    expect(renderToString(qweb, "test", { beep: "beep" })).toBe("<div>beep boop</div>");
+  });
+
   test("evaluate value expression, part 2", () => {
     qweb.addTemplate(
       "test",
@@ -268,6 +358,58 @@ describe("t-set", () => {
     expect(renderToString(qweb, "test", { flag: true })).toBe("<div>1</div>");
     expect(renderToString(qweb, "test", { flag: false })).toBe("<div>0</div>");
   });
+
+  test("t-set body is evaluated immediately", () => {
+    qweb.addTemplate(
+      "test",
+      `<div>
+        <t t-set="v1" t-value="'before'"/>
+        <t t-set="v2">
+          <span><t t-esc="v1"/></span>
+        </t>
+        <t t-set="v1" t-value="'after'"/>
+        <t t-raw="v2"/>
+      </div>`
+    );
+
+    expect(renderToString(qweb, "test")).toBe("<div><span>before</span></div>");
+  });
+
+  test("t-set with t-value (falsy) and body", () => {
+    qweb.addTemplate(
+      "test",
+      `<div>
+        <t t-set="v3" t-value="false"/>
+        <t t-set="v1" t-value="'before'"/>
+        <t t-set="v2" t-value="v3">
+          <span><t t-esc="v1"/></span>
+        </t>
+        <t t-set="v1" t-value="'after'"/>
+        <t t-set="v3" t-value="true"/>
+        <t t-raw="v2"/>
+      </div>`
+    );
+
+    expect(renderToString(qweb, "test")).toBe("<div><span>before</span></div>");
+  });
+
+  test("t-set with t-value (truthy) and body", () => {
+    qweb.addTemplate(
+      "test",
+      `<div>
+        <t t-set="v3" t-value="'Truthy'"/>
+        <t t-set="v1" t-value="'before'"/>
+        <t t-set="v2" t-value="v3">
+          <span><t t-esc="v1"/></span>
+        </t>
+        <t t-set="v1" t-value="'after'"/>
+        <t t-set="v3" t-value="false"/>
+        <t t-raw="v2"/>
+      </div>`
+    );
+
+    expect(renderToString(qweb, "test")).toBe("<div>Truthy</div>");
+  });
 });
 
 describe("t-if", () => {
@@ -355,7 +497,7 @@ describe("t-if", () => {
   });
 
   test("t-esc with t-elif", () => {
-    qweb.addTemplate("test", `<div><t t-if="false">abc</t><t t-else="1" t-esc="'x'"/></div>`);
+    qweb.addTemplate("test", `<div><t t-if="false">abc</t><t t-else="" t-esc="'x'"/></div>`);
     expect(renderToString(qweb, "test")).toBe("<div>x</div>");
   });
 
@@ -432,6 +574,18 @@ describe("attributes", () => {
     expect(result).toBe(`<div foo="bar"></div>`);
   });
 
+  test("dynamic class attribute", () => {
+    qweb.addTemplate("test", `<div t-att-class="c"/>`);
+    const result = renderToString(qweb, "test", { c: "abc" });
+    expect(result).toBe(`<div class="abc"></div>`);
+  });
+
+  test("dynamic empty class attribute", () => {
+    qweb.addTemplate("test", `<div t-att-class="c"/>`);
+    const result = renderToString(qweb, "test", { c: "" });
+    expect(result).toBe(`<div></div>`);
+  });
+
   test("dynamic attribute with a dash", () => {
     qweb.addTemplate("test", `<div t-att-data-action-id="id"/>`);
     const result = renderToString(qweb, "test", { id: 32 });
@@ -535,7 +689,7 @@ describe("attributes", () => {
     expect(result).toBe(`<div foo="a 0 is 1 of 2 ]"></div>`);
   });
 
-  test.skip("various escapes", () => {
+  test("various escapes", () => {
     // not needed??
     qweb.addTemplate(
       "test",
@@ -551,7 +705,7 @@ describe("attributes", () => {
       baz: 1,
       qux: { qux: "<>" }
     });
-    const expected = `<div foo="&lt;foo" bar="&lt;bar&gt;" baz="&lt;&quot;&lt;baz&gt;&quot;&gt;" qux="&lt;&gt;"></div>`;
+    const expected = '<div foo="<foo" bar="0" baz="<1>" qux="<>"></div>';
     expect(result).toBe(expected);
   });
 
@@ -576,10 +730,19 @@ describe("attributes", () => {
 
 describe("t-call (template calling", () => {
   test("basic caller", () => {
+    qweb.addTemplate("_basic-callee", "<span>ok</span>");
+    qweb.addTemplate("caller", '<div><t t-call="_basic-callee"/></div>');
+    const expected = "<div><span>ok</span></div>";
+    expect(renderToString(qweb, "caller")).toBe(expected);
+    expect(qweb.subTemplates["_basic-callee"].toString()).toMatchSnapshot();
+  });
+
+  test("basic caller, no parent node", () => {
     qweb.addTemplate("_basic-callee", "<div>ok</div>");
     qweb.addTemplate("caller", '<t t-call="_basic-callee"/>');
     const expected = "<div>ok</div>";
     expect(renderToString(qweb, "caller")).toBe(expected);
+    expect(qweb.subTemplates["_basic-callee"].toString()).toMatchSnapshot();
   });
 
   test("t-call with t-if", () => {
@@ -587,6 +750,7 @@ describe("t-call (template calling", () => {
     qweb.addTemplate("caller", '<div><t t-if="flag" t-call="sub"/></div>');
     const expected = "<div><span>ok</span></div>";
     expect(renderToString(qweb, "caller", { flag: true })).toBe(expected);
+    expect(qweb.subTemplates["sub"].toString()).toMatchSnapshot();
   });
 
   test("t-call not allowed on a non t node", () => {
@@ -671,6 +835,7 @@ describe("t-call (template calling", () => {
     `);
     const expected = "<div><div><span>hey</span> <span>yay</span></div></div>";
     expect(renderToString(qweb, "main")).toBe(expected);
+    expect(qweb.subTemplates["SubTemplate"].toString()).toMatchSnapshot();
   });
 
   test("cascading t-call t-raw='0'", () => {
@@ -720,7 +885,7 @@ describe("t-call (template calling", () => {
     `);
     const expected = "<div><span>hey</span></div>";
     expect(renderToString(qweb, "recursive")).toBe(expected);
-    const recursiveFn = Object.values(qweb.recursiveFns)[0] as any;
+    const recursiveFn = Object.values(qweb.subTemplates)[0] as any;
     expect(recursiveFn.toString()).toMatchSnapshot();
   });
 
@@ -748,7 +913,7 @@ describe("t-call (template calling", () => {
     expect(renderToString(qweb, "Parent", { root }, { fiber: { vars: {}, scope: {} } })).toBe(
       expected
     );
-    const recursiveFn = Object.values(qweb.recursiveFns)[0] as any;
+    const recursiveFn = Object.values(qweb.subTemplates)[0] as any;
     expect(recursiveFn.toString()).toMatchSnapshot();
   });
 
@@ -775,7 +940,7 @@ describe("t-call (template calling", () => {
     const expected =
       "<div><div><p>a</p><div><p>b</p><div><p>d</p></div></div><div><p>c</p></div></div></div>";
     expect(renderToString(qweb, "Parent", { root }, { fiber: {} })).toBe(expected);
-    const recursiveFn = Object.values(qweb.recursiveFns)[0] as any;
+    const recursiveFn = Object.values(qweb.subTemplates)[0] as any;
     expect(recursiveFn.toString()).toMatchSnapshot();
   });
 
@@ -785,6 +950,68 @@ describe("t-call (template calling", () => {
     const expected = "<div><span>desk</span></div>";
     expect(trim(renderToString(qweb, "abcd"))).toBe(expected);
   });
+
+  test("t-call, conditional and t-set in t-call body", () => {
+    QWeb.registerTemplate("callee1", "<div>callee1</div>");
+    QWeb.registerTemplate("callee2", '<div>callee2 <t t-esc="v"/></div>');
+    QWeb.registerTemplate(
+      "caller",
+      `<div>
+        <t t-set="v1" t-value="'elif'"/>
+        <t t-if="v1 === 'if'" t-call="callee1" />
+        <t t-elif="v1 === 'elif'" t-call="callee2" >
+          <t t-set="v" t-value="'success'" />
+        </t>
+       </div>`
+    );
+    const rendered = renderToString(qweb, "caller");
+    expect(rendered).toBe(`<div><div>callee2 success</div></div>`);
+  });
+
+  test("t-call with t-set inside and outside", () => {
+    qweb.addTemplates(`
+      <templates>
+        <div t-name="main">
+          <t t-foreach="list" t-as="v">
+            <t t-set="val" t-value="v.val"/>
+            <t t-call="sub">
+              <t t-set="val3" t-value="val*3"/>
+            </t>
+          </t>
+        </div>
+        <t t-name="sub">
+          <span t-esc="val3"/>
+        </t>
+      </templates>
+    `);
+    const expected = "<div><span>3</span><span>6</span><span>9</span></div>";
+    const context = { list: [{ val: 1 }, { val: 2 }, { val: 3 }] };
+    expect(trim(renderToString(qweb, "main", context))).toBe(expected);
+  });
+
+  test("t-call with t-set inside and outside. 2", () => {
+    qweb.addTemplates(`
+      <templates>
+        <div t-name="main">
+          <t t-foreach="list" t-as="v">
+            <t t-set="val" t-value="v.val"/>
+            <t t-call="sub">
+              <t t-set="val3" t-value="val*3"/>
+            </t>
+          </t>
+        </div>
+        <t t-name="sub">
+          <span t-esc="val3"/>
+          <t t-esc="w"/>
+        </t>
+        <p t-name="wrapper"><t t-set="w" t-value="'fromwrapper'"/><t t-call="main"/></p>
+      </templates>
+    `);
+    const expected =
+      "<p><div><span>3</span>fromwrapper<span>6</span>fromwrapper<span>9</span>fromwrapper</div></p>";
+    const context = { list: [{ val: 1 }, { val: 2 }, { val: 3 }] };
+    expect(trim(renderToString(qweb, "wrapper", context))).toBe(expected);
+  });
 });
 
 describe("foreach", () => {
@@ -853,9 +1080,9 @@ describe("foreach", () => {
         <t t-foreach="[1]" t-as="item"><t t-esc="item"/></t>
       </div>`
     );
-    const context = {};
+    const context = { __owl__: {} };
     renderToString(qweb, "test", context);
-    expect(Object.keys(context).length).toBe(0);
+    expect(Object.keys(context)).toEqual(["__owl__"]);
   });
 
   test("t-foreach in t-forach", () => {
@@ -1133,6 +1360,69 @@ describe("t-on", () => {
     expect(owner.state.counter).toBe(2);
   });
 
+  test("t-on with inline statement, part 2", () => {
+    qweb.addTemplate("test", `<button t-on-click="state.flag = !state.flag">Toggle</button>`);
+    let owner = {
+      state: {
+        flag: true
+      }
+    };
+    const node = renderToDOM(qweb, "test", owner, { handlers: [] });
+    expect(owner.state.flag).toBe(true);
+    (<HTMLElement>node).click();
+    expect(owner.state.flag).toBe(false);
+    (<HTMLElement>node).click();
+    expect(owner.state.flag).toBe(true);
+  });
+
+  test("t-on with inline statement, part 3", () => {
+    qweb.addTemplate("test", `<button t-on-click="state.n = someFunction(3)">Toggle</button>`);
+    let owner = {
+      someFunction(n) {
+        return n + 1;
+      },
+      state: {
+        n: 11
+      }
+    };
+    const node = renderToDOM(qweb, "test", owner, { handlers: [] });
+    expect(owner.state.n).toBe(11);
+    (<HTMLElement>node).click();
+    expect(owner.state.n).toBe(4);
+  });
+
+  test("t-on with t-call", async () => {
+    expect.assertions(2);
+    qweb.addTemplate("sub", `<p t-on-click="update">lucas</p>`);
+    qweb.addTemplate("main", `<div><t t-call="sub"/></div>`);
+
+    let owner = {
+      update() {
+        expect(this).toBe(owner);
+      }
+    };
+
+    const node = renderToDOM(qweb, "main", owner, { handlers: [] });
+    (<HTMLElement>node).querySelector("p")!.click();
+  });
+
+  test("t-on, with arguments and t-call", async () => {
+    expect.assertions(3);
+    qweb.addTemplate("sub", `<p t-on-click="update(value)">lucas</p>`);
+    qweb.addTemplate("main", `<div><t t-call="sub"/></div>`);
+
+    let owner = {
+      update(val) {
+        expect(this).toBe(owner);
+        expect(val).toBe(444);
+      },
+      value: 444
+    };
+
+    const node = renderToDOM(qweb, "main", owner, { handlers: [] });
+    (<HTMLElement>node).querySelector("p")!.click();
+  });
+
   test("t-on with prevent and/or stop modifiers", async () => {
     expect.assertions(7);
     qweb.addTemplate(
@@ -1337,6 +1627,31 @@ describe("t-on", () => {
 
     expect(steps).toEqual(["onClick"]);
   });
+
+  test("t-on with .capture modifier", () => {
+    expect.assertions(2);
+    qweb.addTemplate(
+      "test",
+      `<div t-on-click.capture="onCapture">
+        <button t-on-click="doSomething">Button</button>
+      </div>`
+    );
+
+    const steps: string[] = [];
+    const owner = {
+      onCapture() {
+        steps.push("captured");
+      },
+      doSomething() {
+        steps.push("normal");
+      }
+    };
+    const node = renderToDOM(qweb, "test", owner, { handlers: [] });
+
+    const button = (<HTMLElement>node).getElementsByTagName("button")[0];
+    button.click();
+    expect(steps).toEqual(["captured", "normal"]);
+  });
 });
 
 describe("t-ref", () => {
@@ -1505,7 +1820,7 @@ describe("debugging", () => {
     console.log = jest.fn();
     qweb.addTemplate(
       "test",
-      `<div t-debug="1"><t t-if="true"><span t-debug="1">hey</span></t></div>`
+      `<div t-debug=""><t t-if="true"><span t-debug="">hey</span></t></div>`
     );
     qweb.render("test");
     expect(qweb.templates.test.fn.toString()).toMatchSnapshot();
@@ -1514,6 +1829,22 @@ describe("debugging", () => {
     console.log = consoleLog;
   });
 
+  test("t-debug on sub template", () => {
+    const consoleLog = console.log;
+    console.log = jest.fn();
+    qweb.addTemplates(`
+      <templates>
+      <p t-name="sub" t-debug="">coucou</p>
+      <div t-name="test">
+        <t t-call="sub"/>
+      </div>
+      </templates>`);
+    qweb.render("test");
+
+    expect(console.log).toHaveBeenCalledTimes(1);
+    console.log = consoleLog;
+  });
+
   test("t-log", () => {
     const consoleLog = console.log;
     console.log = jest.fn();

tests/qweb/qweb_expressions.test.ts

@@ -50,6 +50,18 @@ describe("tokenizer", () => {
       { type: "OPERATOR", value: "typeof " },
       { type: "SYMBOL", value: "a" }
     ]);
+
+    expect(tokenize("a...1")).toEqual([
+      { type: "SYMBOL", value: "a" },
+      { type: "OPERATOR", value: "..." },
+      { type: "VALUE", value: "1" }
+    ]);
+
+    expect(tokenize("a in b")).toEqual([
+      { type: "SYMBOL", value: "a" },
+      { type: "OPERATOR", value: "in " },
+      { type: "SYMBOL", value: "b" }
+    ]);
   });
 
   test("strings", () => {
@@ -92,7 +104,7 @@ describe("expression evaluation", () => {
 
   test("parenthesis", () => {
     expect(compileExpr("(1)", {})).toBe("(1)");
-    expect(compileExpr("a*(1 +3)", {})).toBe("context['a']*(1+3)");
+    expect(compileExpr("a*(1 +3)", {})).toBe("scope['a']*(1+3)");
   });
 
   test("objects and sub objects", () => {
@@ -100,8 +112,8 @@ describe("expression evaluation", () => {
   });
 
   test("replacing variables", () => {
-    expect(compileExpr("a", {})).toBe("context['a']");
-    expect(compileExpr("a", { a: { id: "_3", expr: "" } })).toBe("_3");
+    expect(compileExpr("a", {})).toBe("scope['a']");
+    expect(compileExpr("a", { a: { id: "_3", expr: "scope._3" } })).toBe("scope._3");
   });
 
   test("arrays and objects", () => {
@@ -111,56 +123,77 @@ describe("expression evaluation", () => {
   });
 
   test("dot operator", () => {
-    expect(compileExpr("a.b", {})).toBe("context['a'].b");
-    expect(compileExpr("a.b.c", {})).toBe("context['a'].b.c");
+    expect(compileExpr("a.b", {})).toBe("scope['a'].b");
+    expect(compileExpr("a.b.c", {})).toBe("scope['a'].b.c");
   });
 
   test("various unary operators", () => {
-    expect(compileExpr("!flag", {})).toBe("!context['flag']");
+    expect(compileExpr("!flag", {})).toBe("!scope['flag']");
     expect(compileExpr("-3", {})).toBe("-3");
-    expect(compileExpr("-a", {})).toBe("-context['a']");
-    expect(compileExpr("typeof a", {})).toBe("typeof context['a']");
+    expect(compileExpr("-a", {})).toBe("-scope['a']");
+    expect(compileExpr("typeof a", {})).toBe("typeof scope['a']");
   });
 
   test("various binary operators", () => {
-    expect(compileExpr("color == 'black'", {})).toBe("context['color']=='black'");
-    expect(compileExpr("a || b", {})).toBe("context['a']||context['b']");
-    expect(compileExpr("color === 'black'", {})).toBe("context['color']==='black'");
-    expect(compileExpr("'li_'+item", {})).toBe("'li_'+context['item']");
-    expect(compileExpr("state.val > 1", {})).toBe("context['state'].val>1");
+    expect(compileExpr("color == 'black'", {})).toBe("scope['color']=='black'");
+    expect(compileExpr("a || b", {})).toBe("scope['a']||scope['b']");
+    expect(compileExpr("color === 'black'", {})).toBe("scope['color']==='black'");
+    expect(compileExpr("'li_'+item", {})).toBe("'li_'+scope['item']");
+    expect(compileExpr("state.val > 1", {})).toBe("scope['state'].val>1");
+    expect(compileExpr("a in b", {})).toBe("scope['a']in scope['b']");
   });
 
   test("boolean operations", () => {
-    expect(compileExpr("a && b", {})).toBe("context['a']&&context['b']");
+    expect(compileExpr("a && b", {})).toBe("scope['a']&&scope['b']");
   });
 
   test("ternary operators", () => {
-    expect(compileExpr("a ? b: '2'", {})).toBe("context['a']?context['b']:'2'");
-    expect(compileExpr("a ? b: (c or '2') ", {})).toBe(
-      "context['a']?context['b']:(context['c']||'2')"
-    );
+    expect(compileExpr("a ? b: '2'", {})).toBe("scope['a']?scope['b']:'2'");
+    expect(compileExpr("a ? b: (c or '2') ", {})).toBe("scope['a']?scope['b']:(scope['c']||'2')");
     expect(compileExpr("a ? {test:c}: [1,u]", {})).toBe(
-      "context['a']?{test:context['c']}:[1,context['u']]"
+      "scope['a']?{test:scope['c']}:[1,scope['u']]"
     );
   });
 
   test("word replacement", () => {
-    expect(compileExpr("a or b", {})).toBe("context['a']||context['b']");
-    expect(compileExpr("a and b", {})).toBe("context['a']&&context['b']");
+    expect(compileExpr("a or b", {})).toBe("scope['a']||scope['b']");
+    expect(compileExpr("a and b", {})).toBe("scope['a']&&scope['b']");
   });
 
   test("function calls", () => {
-    expect(compileExpr("a()", {})).toBe("context['a']()");
-    expect(compileExpr("a(1)", {})).toBe("context['a'](1)");
-    expect(compileExpr("a(1,2)", {})).toBe("context['a'](1,2)");
-    expect(compileExpr("a(1,2,{a:[a]})", {})).toBe("context['a'](1,2,{a:[context['a']]})");
+    expect(compileExpr("a()", {})).toBe("scope['a']()");
+    expect(compileExpr("a(1)", {})).toBe("scope['a'](1)");
+    expect(compileExpr("a(1,2)", {})).toBe("scope['a'](1,2)");
+    expect(compileExpr("a(1,2,{a:[a]})", {})).toBe("scope['a'](1,2,{a:[scope['a']]})");
     expect(compileExpr("'x'.toUpperCase()", {})).toBe("'x'.toUpperCase()");
     expect(compileExpr("'x'.toUpperCase({a: 3})", {})).toBe("'x'.toUpperCase({a:3})");
-    expect(compileExpr("'x'.toUpperCase(a)", { a: { id: "_v5", expr: "" } })).toBe(
-      "'x'.toUpperCase(_v5)"
+    expect(compileExpr("'x'.toUpperCase(a)", { a: { id: "_v5", expr: "scope._v5" } })).toBe(
+      "'x'.toUpperCase(scope._v5)"
     );
-    expect(compileExpr("'x'.toUpperCase({b: a})", { a: { id: "_v5", expr: "" } })).toBe(
-      "'x'.toUpperCase({b:_v5})"
+    expect(compileExpr("'x'.toUpperCase({b: a})", { a: { id: "_v5", expr: "scope._v5" } })).toBe(
+      "'x'.toUpperCase({b:scope._v5})"
     );
   });
+
+  test("arrow functions", () => {
+    expect(compileExpr("list.map(e => e.val)", {})).toBe("scope['list'].map(e=>e.val)");
+    expect(compileExpr("list.map(e => a + e)", {})).toBe("scope['list'].map(e=>scope['a']+e)");
+    expect(compileExpr("list.map((e) => e)", {})).toBe("scope['list'].map((e)=>e)");
+    expect(compileExpr("list.map((elem, index) => elem + index)", {})).toBe(
+      "scope['list'].map((elem,index)=>elem+index)"
+    );
+  });
+
+  test("assignation", () => {
+    expect(compileExpr("a = b", {})).toBe("scope['a']=scope['b']");
+    expect(compileExpr("a += b", {})).toBe("scope['a']+=scope['b']");
+    expect(compileExpr("a -= b", {})).toBe("scope['a']-=scope['b']");
+    expect(compileExpr("a.b = !a.b", {})).toBe("scope['a'].b=!scope['a'].b");
+  });
+
+  test("spread operator", () => {
+    expect(compileExpr("[...state.list]", {})).toBe("[...scope['state'].list]");
+    expect(compileExpr("f(...state.list)", {})).toBe("scope['f'](...scope['state'].list)");
+    expect(compileExpr("f([...list])", {})).toBe("scope['f']([...scope['list']])");
+  });
 });

tests/router/__snapshots__/link.test.ts.snap

@@ -1,21 +1,22 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`Link component can render simple cases 1`] = `
-"function anonymous(context,extra
+"function anonymous(context, extra
 ) {
+    // Template name: \\"__template__1\\"
     let utils = this.constructor.utils;
-    let owner = context;
-    var h = this.h;
-    let _6 = utils.toObj({'router-link-active':context['isActive']});
-    var _7 = context['href'];
-    let c8 = [], p8 = {key:8,attrs:{href: _7},class:_6,on:{}};
-    var vn8 = h('a', p8, c8);
-    extra.handlers['click' + 8] = extra.handlers['click' + 8] || function (e) {const fn = context['navigate'];if (fn) { fn.call(owner, e); } else { context.navigate; }};
-    p8.on['click'] = extra.handlers['click' + 8];
-    const slot9 = this.constructor.slots[context.__owl__.slotId + '_' + 'default'];
-    if (slot9) {
-        slot9.call(this, context.__owl__.parent, Object.assign({}, extra, {parentNode: c8, vars: extra.vars, parent: extra.parent || owner}));
+    let scope = Object.create(context);
+    let h = this.h;
+    let _4 = utils.toObj({'router-link-active':scope['isActive']});
+    let _5 = scope['href'];
+    let c6 = [], p6 = {key:6,attrs:{href: _5},class:_4,on:{}};
+    let vn6 = h('a', p6, c6);
+    extra.handlers['click__7__'] = extra.handlers['click__7__'] || function (e) {if (!context.__owl__.isMounted){return}utils.getComponent(context)['navigate'](e);};
+    p6.on['click'] = extra.handlers['click__7__'];
+    const slot8 = this.constructor.slots[context.__owl__.slotId + '_' + 'default'];
+    if (slot8) {
+        slot8.call(this, context.__owl__.scope, Object.assign({}, extra, {parentNode: c6, parent: extra.parent || context}));
     }
-    return vn8;
+    return vn6;
 }"
 `;

tests/router/__snapshots__/route_component.test.ts.snap

@@ -1,44 +1,45 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`RouteComponent can render simple cases 1`] = `
-"function anonymous(context,extra
+"function anonymous(context, extra
 ) {
+    // Template name: \\"__template__1\\"
     let utils = this.constructor.utils;
     let QWeb = this.constructor;
     let parent = context;
-    let owner = context;
+    let scope = Object.create(context);
     let result;
-    var h = this.h;
-    if (context['routeComponent']) {
-        const nodeKey6 = context['env'].router.currentRouteName;
-        //COMPONENT
-        let k9 = \`__10__\` + nodeKey6;
-        let w8 = k9 in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap[k9]] : false;
-        let vn11 = {};
-        result = vn11;
-        let props8 = Object.assign({}, context['env'].router.currentParams);
-        if (w8 && w8.__owl__.currentFiber && !w8.__owl__.vnode) {
-            w8.destroy();
-            w8 = false;
+    let h = this.h;
+    if (scope['routeComponent']) {
+        {
+            let key0 = scope['env'].router.currentRouteName;
+            // Component 'routeComponent'
+            let k5 = \`__5__\${key0}__\`;
+            let w4 = k5 in parent.__owl__.cmap ? parent.__owl__.children[parent.__owl__.cmap[k5]] : false;
+            let vn6 = {};
+            result = vn6;
+            let props4 = Object.assign({}, scope['env'].router.currentParams);
+            if (w4 && w4.__owl__.currentFiber && !w4.__owl__.vnode) {
+                w4.destroy();
+                w4 = false;
+            }
+            if (w4) {
+                w4.__updateProps(props4, extra.fiber, undefined);
+                let pvnode = w4.__owl__.pvnode;
+                utils.defineProxy(vn6, pvnode);
+            } else {
+                let componentKey4 = \`routeComponent\`;
+                let W4 = context.constructor.components[componentKey4] || QWeb.components[componentKey4]|| scope['routeComponent'];
+                if (!W4) {throw new Error('Cannot find the definition of component \\"' + componentKey4 + '\\"')}
+                w4 = new W4(parent, props4);
+                parent.__owl__.cmap[k5] = w4.__owl__.id;
+                let fiber = w4.__prepare(extra.fiber, undefined, () => { const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
+                let pvnode = h('dummy', {key: k5, hook: {remove() {},destroy(vn) {w4.destroy();}}});
+                utils.defineProxy(vn6, pvnode);
+                w4.__owl__.pvnode = pvnode;
+            }
+            w4.__owl__.parentLastFiberId = extra.fiber.id;
         }
-        if (w8) {
-            w8.__updateProps(props8, extra.fiber, undefined, undefined);
-            let pvnode = w8.__owl__.pvnode;
-            utils.defineProxy(vn11, pvnode);
-        } else {
-            let componentKey8 = \`routeComponent\`;
-            let W8 = context.constructor.components[componentKey8] || QWeb.components[componentKey8]|| context['routeComponent'];
-            if (!W8) {throw new Error('Cannot find the definition of component \\"' + componentKey8 + '\\"')}
-            w8 = new W8(parent, props8);
-            parent.__owl__.cmap[k9] = w8.__owl__.id;
-            let def7 = w8.__prepare(extra.fiber, undefined, undefined);
-            let pvnode = h('dummy', {key: k9, hook: {remove() {},destroy(vn) {w8.destroy();}}});
-            const fiber = w8.__owl__.currentFiber;
-            def7.then(function () { if (fiber.isCompleted) { return; } const vnode = fiber.vnode; pvnode.sel = vnode.sel; });
-            utils.defineProxy(vn11, pvnode);
-            w8.__owl__.pvnode = pvnode;
-        }
-        w8.__owl__.parentLastFiberId = extra.fiber.id;
     }
     return result;
 }"

tests/router/link.test.ts

@@ -31,7 +31,7 @@ describe("Link component", () => {
             </div>
         </templates>
     `);
-    class App extends Component<any, any> {
+    class App extends Component {
       static components = { Link: Link };
     }
 
@@ -65,7 +65,7 @@ describe("Link component", () => {
             </div>
         </templates>
     `);
-    class App extends Component<any, any> {
+    class App extends Component {
       static components = { Link: Link };
     }
 

tests/router/route_component.test.ts

@@ -33,9 +33,9 @@ describe("RouteComponent", () => {
             <span t-name="Users">Users</span>
         </templates>
     `);
-    class About extends Component<any, any> {}
-    class Users extends Component<any, any> {}
-    class App extends Component<any, any> {
+    class About extends Component {}
+    class Users extends Component {}
+    class App extends Component {
       static components = { RouteComponent };
     }
 
@@ -65,8 +65,8 @@ describe("RouteComponent", () => {
             <span t-name="Book">Book <t t-esc="props.title"/></span>
         </templates>
     `);
-    class Book extends Component<any, any> {}
-    class App extends Component<any, any> {
+    class Book extends Component {}
+    class App extends Component {
       static components = { RouteComponent };
     }
 
@@ -87,12 +87,12 @@ describe("RouteComponent", () => {
             <span t-name="Book">Book <t t-esc="props.title"/>|<t t-esc="incVal"/></span>
         </templates>
     `);
-    class Book extends Component<any, any> {
+    class Book extends Component {
       get incVal() {
         return this.props.val + 1;
       }
     }
-    class App extends Component<any, any> {
+    class App extends Component {
       static components = { RouteComponent };
     }
 

tests/store_hooks.test.ts

@@ -29,7 +29,7 @@ describe("connecting a component to store", () => {
     };
     const store = new Store({ state, actions });
 
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`
             <div>
                 <span t-foreach="todos" t-key="todo.id" t-as="todo"><t t-esc="todo.msg"/></span>
@@ -49,20 +49,25 @@ describe("connecting a component to store", () => {
   });
 
   test("useStore can observe primitive types and call onUpdate", async () => {
-    const state = { isBoolean: false };
+    const state = { isBoolean: false, nullValue: null };
     const actions = {
       setTrue({ state }) {
         state.isBoolean = true;
+      },
+      setNotNull({ state }) {
+        state.nullValue = "ok";
       }
     };
     const store = new Store({ state, actions });
 
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`
             <div>
                 <span t-if="isBoolean">ok</span>
+                <span t-if="nullValue !== null">not null</span>
             </div>`;
       isBoolean: boolean;
+      nullValue: string;
       constructor() {
         super();
         this.isBoolean = useStore(state => state.isBoolean, {
@@ -70,6 +75,11 @@ describe("connecting a component to store", () => {
             this.isBoolean = isBoolean;
           }
         });
+        this.nullValue = useStore(state => state.nullValue, {
+          onUpdate: nullValue => {
+            this.nullValue = nullValue;
+          }
+        });
       }
     }
 
@@ -82,10 +92,46 @@ describe("connecting a component to store", () => {
     store.dispatch("setTrue");
     await nextTick();
     expect(fixture.innerHTML).toBe("<div><span>ok</span></div>");
+
+    store.dispatch("setNotNull");
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div><span>ok</span><span>not null</span></div>");
+  });
+
+  test("map works on the result of useStore when the resulting array changes for a bigger one", async () => {
+    const state = { smallerArray: [1], biggerArray: [2, 3], useSmallArray: true };
+    const store = new Store({ state });
+
+    class App extends Component {
+      static template = xml`<div t-esc="mapAdd"/>`;
+      storeProps = {
+        array: useStore(state => {
+          if (state.useSmallArray) {
+            return state.smallerArray;
+          }
+          return state.biggerArray;
+        })
+      };
+      get mapAdd() {
+        return this.storeProps.array.map(a => {
+          return a + 1;
+        });
+      }
+    }
+
+    (<any>env).store = store;
+    const app = new App();
+
+    await app.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div>2</div>");
+
+    store.state.useSmallArray = false;
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div>3,4</div>");
   });
 
   test("throw error if no store is found", async () => {
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`<div></div>`;
       todos = useStore(state => state.todos);
     }
@@ -105,7 +151,7 @@ describe("connecting a component to store", () => {
     const actions = {};
     const store = new Store({ state, actions });
 
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`<div/>`;
       storeState = useStore(state => state.a);
     }
@@ -128,7 +174,7 @@ describe("connecting a component to store", () => {
     };
     const store = new Store({ state, actions });
 
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`
             <div>
                 <span t-esc="a.value"/>
@@ -162,7 +208,7 @@ describe("connecting a component to store", () => {
     };
     const store = new Store({ state, actions });
 
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`
             <div>
                 <span t-foreach="todos" t-key="todo.id" t-as="todo"><t t-esc="todo.msg"/></span>
@@ -199,7 +245,7 @@ describe("connecting a component to store", () => {
     };
     const store = new Store({ state, actions });
 
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`<div><t t-esc="nbrTodos.value"/></div>`;
       nbrTodos = useStore(state => ({ value: state.todos.length }));
     }
@@ -227,7 +273,7 @@ describe("connecting a component to store", () => {
       }
     };
     const store = new Store({ state, actions });
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`<div><t t-esc="nbrTodos.value"/></div>`;
       nbrTodos = useStore(state => ({ value: state.todos.length }), { isEqual: shallowEqual });
     }
@@ -261,7 +307,7 @@ describe("connecting a component to store", () => {
     };
     const store = new Store({ state, actions });
 
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`
             <div>
                 <span t-foreach="todos" t-key="todo.id" t-as="todo"><t t-esc="todo.msg"/></span>
@@ -290,7 +336,7 @@ describe("connecting a component to store", () => {
     });
     (<any>env).store = store;
 
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`
           <div>
               <button t-on-click="dispatch('inc')">Inc</button>
@@ -319,14 +365,14 @@ describe("connecting a component to store", () => {
     };
     const store = new Store({ state, actions: {} });
 
-    class TodoItem extends Component<any, any> {
+    class TodoItem extends Component {
       static template = xml`<span><t t-esc="todo.text"/></span>`;
       todo = useStore((state, props) => {
         return state.todos.find(t => t.id === props.todoId);
       });
     }
 
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`<div><TodoItem todoId="state.currentId"/></div>`;
       static components = { TodoItem };
       state = useState({ currentId: 1 });
@@ -353,14 +399,14 @@ describe("connecting a component to store", () => {
     };
     const store = new Store({ state, actions });
 
-    class TodoItem extends Component<any, any> {
+    class TodoItem extends Component {
       static template = xml`<span><t t-esc="todo.text"/></span>`;
       todo = useStore((state, props) => {
         return state.todos.find(t => t.id === props.id);
       });
     }
 
-    class TodoList extends Component<any, any> {
+    class TodoList extends Component {
       static template = xml`
         <div>
           <TodoItem t-foreach="todos" t-as="todo" id="todo.id" t-key="todo.id"/>
@@ -398,7 +444,7 @@ describe("connecting a component to store", () => {
     };
     const store = new Store({ state, getters });
 
-    class TodoItem extends Component<any, any> {
+    class TodoItem extends Component {
       static template = xml`
         <div>
           <span><t t-esc="storeProps.activeTodoText"/></span>
@@ -414,7 +460,7 @@ describe("connecting a component to store", () => {
       });
     }
 
-    class TodoList extends Component<any, any> {
+    class TodoList extends Component {
       static components = { TodoItem };
       static template = xml`
         <div>
@@ -435,12 +481,12 @@ describe("connecting a component to store", () => {
   });
 
   test("connected component is updated when props are updated", async () => {
-    class Beer extends Component<any, any> {
+    class Beer extends Component {
       static template = xml`<span><t t-esc="beer.name"/></span>`;
       beer = useStore((state, props) => state.beers[props.id]);
     }
 
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`<div><Beer id="state.beerId"/></div>`;
       static components = { Beer };
       state = useState({ beerId: 1 });
@@ -460,7 +506,7 @@ describe("connecting a component to store", () => {
   });
 
   test("connected component is updated when store is changed", async () => {
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`
         <div>
             <span t-foreach="data.beers" t-as="beer" t-key="beer.name"><t t-esc="beer.name"/></span>
@@ -493,7 +539,7 @@ describe("connecting a component to store", () => {
   test("connected component is updated when mixing store and props changes", async () => {
     let counter = 0;
 
-    class Beer extends Component<any, any> {
+    class Beer extends Component {
       static template = xml`<span><t t-esc="beer.name"/></span>`;
       beer = useStore((state, props) => state.beers[props.id], {
         onUpdate: result => {
@@ -502,7 +548,7 @@ describe("connecting a component to store", () => {
       });
     }
 
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`<div><Beer id="state.beerId"/></div>`;
       static components = { Beer };
       state = useState({ beerId: 1 });
@@ -534,7 +580,7 @@ describe("connecting a component to store", () => {
   });
 
   test("connected component is properly cleaned up on destroy", async () => {
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`<div></div>`;
       state = useStore((state, props) => state);
     }
@@ -553,7 +599,7 @@ describe("connecting a component to store", () => {
   });
 
   test("connected component with undefined, null and string props", async () => {
-    class Beer extends Component<any, any> {
+    class Beer extends Component {
       static template = xml`
             <div t-name="Beer">
                 <span>taster:<t t-esc="data.taster"/></span>
@@ -567,7 +613,7 @@ describe("connecting a component to store", () => {
       }));
     }
 
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`<div><Beer id="state.beerId"/></div>`;
       static components = { Beer };
       state = useState({ beerId: 0 });
@@ -612,7 +658,7 @@ describe("connecting a component to store", () => {
   });
 
   test("connected component deeply reactive with undefined, null and string props", async () => {
-    class Beer extends Component<any, any> {
+    class Beer extends Component {
       static template = xml`
             <div>
                 <span>taster:<t t-esc="info.taster"/></span>
@@ -628,7 +674,7 @@ describe("connecting a component to store", () => {
       });
     }
 
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`<div><Beer id="state.beerId"/></div>`;
       static components = { Beer };
       state = useState({ beerId: 0 });
@@ -703,7 +749,7 @@ describe("connecting a component to store", () => {
         state.x.val = val;
       }
     };
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><t t-esc="x.val"/></div>`;
       x = useStore(state => {
         return Object.assign({}, state.x);
@@ -724,7 +770,7 @@ describe("connecting a component to store", () => {
   test("correct update order when parent/children are connected", async () => {
     const steps: string[] = [];
 
-    class Child extends Component<any, any> {
+    class Child extends Component {
       static template = xml`<span><t t-esc="state.msg"/></span>`;
 
       state = useStore((state, props) => {
@@ -732,7 +778,7 @@ describe("connecting a component to store", () => {
         return { msg: state.msg[props.key] };
       });
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><Child key="state.current"/></div>`;
       static components = { Child };
 
@@ -771,7 +817,7 @@ describe("connecting a component to store", () => {
     let def = makeDeferred();
     def.resolve();
 
-    class Child extends Component<any, any> {
+    class Child extends Component {
       static template = xml`<span><t t-esc="state.msg"/></span>`;
       state = useStore((s, props) => {
         steps.push("child");
@@ -779,7 +825,7 @@ describe("connecting a component to store", () => {
       });
     }
 
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`
             <div>
                 <Child t-if="state.flag" someId="state.someId"/>
@@ -839,7 +885,7 @@ describe("connecting a component to store", () => {
       actions
     });
 
-    class TodoItem extends Component<any, any> {
+    class TodoItem extends Component {
       static template = xml`
             <div class="todo">
                 <t t-esc="state.todo.title"/>
@@ -860,7 +906,7 @@ describe("connecting a component to store", () => {
         return super.__render(f);
       }
     }
-    class TodoApp extends Component<any, any> {
+    class TodoApp extends Component {
       static template = xml`
             <div class="todoapp">
                 <t t-foreach="Object.values(state.todos)" t-as="todo">
@@ -912,7 +958,7 @@ describe("connecting a component to store", () => {
       actions
     });
 
-    class TodoItem extends Component<any, any> {
+    class TodoItem extends Component {
       static template = xml`
             <div class="todo">
                 <t t-esc="state.todo.title"/>
@@ -934,7 +980,7 @@ describe("connecting a component to store", () => {
       }
     }
 
-    class TodoApp extends Component<any, any> {
+    class TodoApp extends Component {
       static template = xml`
             <div class="todoapp">
                 <t t-foreach="Object.values(state.todos)" t-as="todo">
@@ -978,7 +1024,7 @@ describe("connecting a component to store", () => {
   test("connected component willpatch/patch hooks are called on store updates", async () => {
     const steps: string[] = [];
 
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`<div><t t-esc="store.msg"/></div>`;
       store = useStore(s => ({ msg: s.msg }));
 
@@ -1013,12 +1059,12 @@ describe("connecting a component to store", () => {
   test("connected child components stop listening to store when destroyed", async () => {
     let steps: any = [];
 
-    class Child extends Component<any, any> {
+    class Child extends Component {
       static template = xml`<div><t t-esc="store.val"/></div>`;
       store = useStore(s => s);
     }
 
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><Child t-if="state.child" /></div>`;
       static components = { Child };
       state = useState({ child: true });
@@ -1051,14 +1097,14 @@ describe("connecting a component to store", () => {
   test("connected child component destroyed by dispatched action", async () => {
     let steps: any = [];
 
-    class Child extends Component<any, any> {
+    class Child extends Component {
       static template = xml`<div><t t-esc="store.val"/></div>`;
       store = useStore(s => {
         steps.push("child selector");
         return s;
       });
     }
-    class Parent extends Component<any, any> {
+    class Parent extends Component {
       static template = xml`<div><Child t-if="store.child" /></div>`;
       static components = { Child };
       store = useStore(s => {
@@ -1089,7 +1135,7 @@ describe("connecting a component to store", () => {
   });
 
   test("dispatch an action", async () => {
-    class App extends Component<any, any> {
+    class App extends Component {
       static template = xml`<div><t t-esc="store.counter"/></div>`;
       store = useStore(state => state);
       dispatch = useDispatch();
@@ -1157,7 +1203,7 @@ describe("various scenarios", () => {
     };
     const store = new Store({ actions, state });
 
-    class Attachment extends Component<any, any> {
+    class Attachment extends Component {
       static template = xml`
             <div>
                 <span>Attachment <t t-esc="props.id"/></span>
@@ -1167,7 +1213,7 @@ describe("various scenarios", () => {
       attachment = useStore((state, props) => ({ name: state.attachments[props.id].name }));
     }
 
-    class Message extends Component<any, any> {
+    class Message extends Component {
       static template = xml`
             <div>
                 <button t-on-click="doStuff">Do stuff</button>

tests/tooling/debug_script_1.test.ts

@@ -0,0 +1,57 @@
+/**
+ * We can only make one test per file, since the debug tool modify in place
+ * the owl object in a way that is difficult to undo.
+ */
+
+import { debugOwl } from "../../tools/debug";
+import * as owl from "../../src/index";
+
+import { Component, Env } from "../../src/component/component";
+import { xml } from "../../src/tags";
+import { useState } from "../../src/hooks";
+import { makeTestFixture, makeTestEnv, nextTick } from "../helpers";
+
+let fixture: HTMLElement = makeTestFixture();
+let env: Env = makeTestEnv();
+Component.env = env;
+
+debugOwl(owl, {});
+
+test("can log full lifecycle", async () => {
+  const steps: string[] = [];
+  const log = console.log;
+  console.log = arg => steps.push(arg);
+
+  class Child extends Component {
+    static template = xml`<div>child</div>`;
+  }
+
+  class Parent extends Component {
+    static template = xml`<div><Child t-if="state.flag"/></div>`;
+    static components = { Child };
+    state = useState({ flag: false });
+  }
+
+  const parent = new Parent(null, {});
+  await parent.mount(fixture);
+
+  parent.state.flag = true;
+  await nextTick();
+
+  expect(steps).toEqual([
+    "[OWL_DEBUG] Parent<id=1> constructor, props={}",
+    "[OWL_DEBUG] Parent<id=1> mount",
+    "[OWL_DEBUG] Parent<id=1> willStart",
+    "[OWL_DEBUG] Parent<id=1> rendering template",
+    "[OWL_DEBUG] Parent<id=1> mounted",
+    "[OWL_DEBUG] Parent<id=1> render",
+    "[OWL_DEBUG] Parent<id=1> rendering template",
+    "[OWL_DEBUG] Child<id=2> constructor, props={}",
+    "[OWL_DEBUG] Child<id=2> willStart",
+    "[OWL_DEBUG] Child<id=2> rendering template",
+    "[OWL_DEBUG] Parent<id=1> willPatch",
+    "[OWL_DEBUG] Child<id=2> mounted",
+    "[OWL_DEBUG] Parent<id=1> patched"
+  ]);
+  console.log = log;
+});

tests/tooling/debug_script_2.test.ts

@@ -0,0 +1,50 @@
+/**
+ * We can only make one test per file, since the debug tool modify in place
+ * the owl object in a way that is difficult to undo.
+ */
+
+import { debugOwl } from "../../tools/debug";
+import * as owl from "../../src/index";
+
+import { Component, Env } from "../../src/component/component";
+import { xml } from "../../src/tags";
+import { makeTestFixture, makeTestEnv } from "../helpers";
+
+let fixture: HTMLElement = makeTestFixture();
+let env: Env = makeTestEnv();
+Component.env = env;
+
+debugOwl(owl, { logScheduler: true });
+
+test("can log scheduler start and stop", async () => {
+  const steps: string[] = [];
+  const log = console.log;
+  console.log = arg => steps.push(arg);
+
+  class Child extends Component {
+    static template = xml`<div>child</div>`;
+  }
+
+  class Parent extends Component {
+    static template = xml`<div><Child /></div>`;
+    static components = { Child };
+  }
+
+  const parent = new Parent(null, {});
+  await parent.mount(fixture);
+
+  expect(steps).toEqual([
+    "[OWL_DEBUG] Parent<id=1> constructor, props={}",
+    "[OWL_DEBUG] Parent<id=1> mount",
+    "[OWL_DEBUG] Parent<id=1> willStart",
+    "[OWL_DEBUG] scheduler: start running tasks queue",
+    "[OWL_DEBUG] Parent<id=1> rendering template",
+    "[OWL_DEBUG] Child<id=2> constructor, props={}",
+    "[OWL_DEBUG] Child<id=2> willStart",
+    "[OWL_DEBUG] Child<id=2> rendering template",
+    "[OWL_DEBUG] Child<id=2> mounted",
+    "[OWL_DEBUG] Parent<id=1> mounted",
+    "[OWL_DEBUG] scheduler: stop running tasks queue"
+  ]);
+  console.log = log;
+});

tests/tooling/debug_script_3.test.ts

@@ -0,0 +1,46 @@
+/**
+ * We can only make one test per file, since the debug tool modify in place
+ * the owl object in a way that is difficult to undo.
+ */
+
+import { debugOwl } from "../../tools/debug";
+import * as owl from "../../src/index";
+
+import { Component, Env } from "../../src/component/component";
+import { xml } from "../../src/tags";
+import { makeTestFixture, makeTestEnv } from "../helpers";
+
+let fixture: HTMLElement = makeTestFixture();
+let env: Env = makeTestEnv();
+Component.env = env;
+
+debugOwl(owl, { logScheduler: true });
+
+test("log a specific message for render method calls if component is not mounted", async () => {
+  const steps: string[] = [];
+  const log = console.log;
+  console.log = arg => steps.push(arg);
+
+  class Parent extends Component {
+    static template = xml`<div><t t-esc="state.value"/></div>`;
+    state = owl.hooks.useState({ value: 1 });
+  }
+
+  const parent = new Parent(null, {});
+  await parent.mount(fixture);
+  parent.unmount();
+  parent.state.value = 2;
+
+  expect(steps).toEqual([
+    "[OWL_DEBUG] Parent<id=1> constructor, props={}",
+    "[OWL_DEBUG] Parent<id=1> mount",
+    "[OWL_DEBUG] Parent<id=1> willStart",
+    "[OWL_DEBUG] scheduler: start running tasks queue",
+    "[OWL_DEBUG] Parent<id=1> rendering template",
+    "[OWL_DEBUG] Parent<id=1> mounted",
+    "[OWL_DEBUG] scheduler: stop running tasks queue",
+    "[OWL_DEBUG] Parent<id=1> willUnmount",
+    "[OWL_DEBUG] Parent<id=1> render (warning: component is not mounted, this render has no effect)"
+  ]);
+  console.log = log;
+});

tests/tooling/debug_script_4.test.ts

@@ -0,0 +1,57 @@
+/**
+ * We can only make one test per file, since the debug tool modify in place
+ * the owl object in a way that is difficult to undo.
+ */
+
+import { debugOwl } from "../../tools/debug";
+import * as owl from "../../src/index";
+
+import { Component, Env } from "../../src/component/component";
+import { xml } from "../../src/tags";
+import { makeTestFixture, makeTestEnv } from "../helpers";
+
+let fixture: HTMLElement = makeTestFixture();
+let env: Env = makeTestEnv();
+Component.env = env;
+
+debugOwl(owl, { logScheduler: true });
+
+test("log a sub component with non stringifiable props", async () => {
+  const steps: string[] = [];
+  const log = console.log;
+  console.log = arg => steps.push(arg);
+
+  class Child extends Component {
+    static template = xml`<span><t t-esc="props.obj.val"/></span>`;
+  }
+
+  const circularObject: any = { val: 1 };
+  circularObject.circularObject = circularObject;
+
+  class Parent extends Component {
+    static template = xml`<div><Child obj="obj"/></div>`;
+    static components = { Child };
+    obj = circularObject;
+  }
+
+  const parent = new Parent(null, {});
+  await parent.mount(fixture);
+  parent.unmount();
+
+  expect(steps).toEqual([
+    "[OWL_DEBUG] Parent<id=1> constructor, props={}",
+    "[OWL_DEBUG] Parent<id=1> mount",
+    "[OWL_DEBUG] Parent<id=1> willStart",
+    "[OWL_DEBUG] scheduler: start running tasks queue",
+    "[OWL_DEBUG] Parent<id=1> rendering template",
+    "[OWL_DEBUG] Child<id=2> constructor, props=<JSON error>",
+    "[OWL_DEBUG] Child<id=2> willStart",
+    "[OWL_DEBUG] Child<id=2> rendering template",
+    "[OWL_DEBUG] Child<id=2> mounted",
+    "[OWL_DEBUG] Parent<id=1> mounted",
+    "[OWL_DEBUG] scheduler: stop running tasks queue",
+    "[OWL_DEBUG] Parent<id=1> willUnmount",
+    "[OWL_DEBUG] Child<id=2> willUnmount"
+  ]);
+  console.log = log;
+});

tools/benchmarks/owl-0.10.0/app.js

@@ -1,173 +0,0 @@
-import {
-  buildData,
-  startMeasure,
-  stopMeasure,
-  formatNumber
-} from "../shared/utils.js";
-
-//------------------------------------------------------------------------------
-// Likes Counter Widget
-//------------------------------------------------------------------------------
-class Counter extends owl.Component {
-  state = { counter: 0 };
-  template = "Counter";
-
-  increment() {
-    this.state.counter++;
-  }
-}
-
-//------------------------------------------------------------------------------
-// Message Widget
-//------------------------------------------------------------------------------
-class Message extends owl.Component {
-  widgets = { Counter };
-  template = "Message";
-
-  shouldUpdate(nextProps) {
-    return nextProps !== this.props;
-  }
-  removeMessage() {
-    this.trigger("remove_message", {
-      id: this.props.id
-    });
-  }
-}
-
-//------------------------------------------------------------------------------
-// Root Widget
-//------------------------------------------------------------------------------
-class App extends owl.Component {
-  widgets = { Message };
-  state = { messages: [], multipleFlag: false, clearAfterFlag: false };
-  template = "App";
-
-  mounted() {
-    this.log(
-      `Benchmarking Owl v${owl._version} (build date: ${
-        owl._date
-      })`
-    );
-  }
-
-  benchmark(message, fn, callback) {
-    if (this.state.multipleFlag) {
-      const N = 20;
-      let n = N;
-      let total = 0;
-      let cb = info => {
-        let finalize = () => {
-          n--;
-          total += info.delta;
-          if (n === 0) {
-            const avg = total / N;
-            this.log(`Average: ${formatNumber(avg)}ms`, true);
-            if (callback) {
-              callback();
-            }
-          } else {
-            this._benchmark(message, fn, cb);
-          }
-        };
-
-        if (this.state.clearAfterFlag) {
-          this._benchmark(
-            "clear",
-            () => {
-              this.state.messages = [];
-            },
-            finalize,
-            false
-          );
-        } else {
-          finalize();
-        }
-      };
-      this._benchmark(message, fn, cb);
-    } else {
-      this._benchmark(message, fn, callback);
-    }
-  }
-
-  _benchmark(message, fn, cb, log = true) {
-    setTimeout(() => {
-      startMeasure(message);
-      fn();
-      stopMeasure(info => {
-        if (log) {
-          this.log(info.msg);
-        }
-        if (cb) {
-          cb(info);
-        }
-      });
-    }, 10);
-  }
-
-  addMessages(n) {
-    this.benchmark("add " + n, () => {
-      const newMessages = buildData(n);
-      this.state.messages.push.apply(this.state.messages, newMessages);
-    });
-  }
-
-  clear() {
-    this._benchmark("clear", () => {
-      this.state.messages = [];
-    });
-  }
-
-  updateSomeMessages() {
-    this.benchmark("update every 10th", () => {
-      const messages = this.state.messages;
-      for (let i = 0; i < this.state.messages.length; i += 10) {
-        const msg = Object.assign({}, messages[i]);
-        msg.author += "!!!";
-        this.set(messages, i, msg);
-      }
-    });
-  }
-
-  removeMessage(data) {
-    this.benchmark("remove message", () => {
-      const index = this.state.messages.findIndex(m => m.id === data.id);
-      this.state.messages.splice(index, 1);
-    });
-  }
-
-  log(str, isBold) {
-    const div = document.createElement("div");
-    if (isBold) {
-      div.classList.add("bold");
-    }
-    div.textContent = `> ${str}`;
-    this.refs.log.appendChild(div);
-    this.refs.log.scrollTop = this.refs.log.scrollHeight;
-  }
-
-  clearLog() {
-    this.refs.log.innerHTML = "";
-  }
-
-  toggleMultiple() {
-    this.state.multipleFlag = !this.state.multipleFlag;
-  }
-
-  toggleClear() {
-    this.state.clearAfterFlag = !this.state.clearAfterFlag;
-  }
-}
-
-//------------------------------------------------------------------------------
-// Application initialization
-//------------------------------------------------------------------------------
-async function start() {
-  const templates = await owl.utils.loadTemplates("templates.xml");
-  const env = {
-    qweb: new owl.QWeb(templates)
-  };
-  const app = new App(env);
-  app.mount(document.body);
-}
-
-start();

tools/benchmarks/owl-0.10.0/index.html

@@ -1,13 +0,0 @@
-<!DOCTYPE html>
-<html lang="en">
-<head>
-  <meta charset="UTF-8">
-  <title>OWL 0.10.0 Benchmark</title>
-  <link href="../shared/main.css" rel="stylesheet"/>
-  <script src='owl.js'></script>
-</head>
-<body>
-  <div id='main'></div>
-  <script src='app.js' type="module"></script>
-</body>
-</html>

tools/benchmarks/owl-0.10.0/templates.xml

@@ -1,50 +0,0 @@
-<templates>
-  <div t-name="App" class="main">
-      <div class="left-thing">
-        <div class="title">Actions</div>
-        <div class="panel">
-          <button t-on-click="addMessages(100)">Add 100 messages</button>
-          <button t-on-click="addMessages(1000)">Add 1k messages</button>
-          <button t-on-click="addMessages(10000)">Add 10k messages</button>
-          <button t-on-click="addMessages(30000)">Add 30k messages</button>
-          <button t-on-click="updateSomeMessages">Update every 10th messages</button>
-          <button t-on-click="clear">Clear</button>
-        </div>
-        <div class="flags">
-            <div>
-                <input type="checkbox" id="multipleflag" t-on-change="toggleMultiple" t-att-checked="state.multipleFlag"/>
-                <label for="multipleflag">Do it 20x</label>
-            </div>
-            <div>
-                <input type="checkbox" id="clearFlag" t-on-change="toggleClear"  t-att-checked="state.clearAfterFlag"/>
-                <label for="clearFlag">Clear after</label>
-            </div>
-        </div>
-        <div class="info">Number of messages: <t t-esc="state.messages.length"/></div>
-        <hr/>
-        <div class="title">Log <span class="clear-log" t-on-click="clearLog">(clear)</span></div>
-        <div class="log">
-            <div class="log-content" t-ref="'log'"/>
-        </div>
-      </div>
-      <div class="right-thing">
-          <div class="content" t-on-remove-message="removeMessage">
-              <t t-foreach="state.messages" t-as="message">
-                  <t t-widget="Message" t-key="message.id" t-props="message" t-on-remove_message="removeMessage"/>
-              </t>
-          </div>
-      </div>
-  </div>
-
-  <div t-name="Message" class="message">
-    <span class="author"><t t-esc="props.author"/></span>
-    <span class="msg"><t t-esc="props.msg"/></span>
-    <button class="remove" t-on-click="removeMessage">Remove</button>
-    <t t-widget="Counter"/>
-  </div>
-
-  <div t-name="Counter">
-    <button t-on-click="increment">Value: <t t-esc="state.counter"/></button>
-  </div>
-
-</templates>

tools/benchmarks/owl-0.12.0/app.js

@@ -1,170 +0,0 @@
-import {
-  buildData,
-  startMeasure,
-  stopMeasure,
-  formatNumber
-} from "../shared/utils.js";
-
-//------------------------------------------------------------------------------
-// Likes Counter Widget
-//------------------------------------------------------------------------------
-class Counter extends owl.Component {
-  state = { counter: 0 };
-
-  increment() {
-    this.state.counter++;
-  }
-}
-
-//------------------------------------------------------------------------------
-// Message Widget
-//------------------------------------------------------------------------------
-class Message extends owl.Component {
-  widgets = { Counter };
-
-  shouldUpdate(nextProps) {
-    return nextProps !== this.props;
-  }
-  removeMessage() {
-    this.trigger("remove_message", {
-      id: this.props.id
-    });
-  }
-}
-
-//------------------------------------------------------------------------------
-// Root Widget
-//------------------------------------------------------------------------------
-class App extends owl.Component {
-  widgets = { Message };
-  state = { messages: [], multipleFlag: false, clearAfterFlag: false };
-
-  mounted() {
-    this.log(
-      `Benchmarking Owl v${owl.__info__.version} (build date: ${
-        owl.__info__.date
-      })`
-    );
-  }
-
-  benchmark(message, fn, callback) {
-    if (this.state.multipleFlag) {
-      const N = 20;
-      let n = N;
-      let total = 0;
-      let cb = info => {
-        let finalize = () => {
-          n--;
-          total += info.delta;
-          if (n === 0) {
-            const avg = total / N;
-            this.log(`Average: ${formatNumber(avg)}ms`, true);
-            if (callback) {
-              callback();
-            }
-          } else {
-            this._benchmark(message, fn, cb);
-          }
-        };
-
-        if (this.state.clearAfterFlag) {
-          this._benchmark(
-            "clear",
-            () => {
-              this.state.messages = [];
-            },
-            finalize,
-            false
-          );
-        } else {
-          finalize();
-        }
-      };
-      this._benchmark(message, fn, cb);
-    } else {
-      this._benchmark(message, fn, callback);
-    }
-  }
-
-  _benchmark(message, fn, cb, log = true) {
-    setTimeout(() => {
-      startMeasure(message);
-      fn();
-      stopMeasure(info => {
-        if (log) {
-          this.log(info.msg);
-        }
-        if (cb) {
-          cb(info);
-        }
-      });
-    }, 10);
-  }
-
-  addMessages(n) {
-    this.benchmark("add " + n, () => {
-      const newMessages = buildData(n);
-      this.state.messages.push.apply(this.state.messages, newMessages);
-    });
-  }
-
-  clear() {
-    this.benchmark("clear", () => {
-      this.state.messages = [];
-    });
-  }
-
-  updateSomeMessages() {
-    this.benchmark("update every 10th", () => {
-      const messages = this.state.messages;
-      for (let i = 0; i < this.state.messages.length; i += 10) {
-        const msg = Object.assign({}, messages[i]);
-        msg.author += "!!!";
-        this.set(messages, i, msg);
-      }
-    });
-  }
-
-  removeMessage(data) {
-    this.benchmark("remove message", () => {
-      const index = this.state.messages.findIndex(m => m.id === data.id);
-      this.state.messages.splice(index, 1);
-    });
-  }
-
-  log(str, isBold) {
-    const div = document.createElement("div");
-    if (isBold) {
-      div.classList.add("bold");
-    }
-    div.textContent = `> ${str}`;
-    this.refs.log.appendChild(div);
-    this.refs.log.scrollTop = this.refs.log.scrollHeight;
-  }
-
-  clearLog() {
-    this.refs.log.innerHTML = "";
-  }
-
-  toggleMultiple() {
-    this.state.multipleFlag = !this.state.multipleFlag;
-  }
-
-  toggleClear() {
-    this.state.clearAfterFlag = !this.state.clearAfterFlag;
-  }
-}
-
-//------------------------------------------------------------------------------
-// Application initialization
-//------------------------------------------------------------------------------
-async function start() {
-  const templates = await owl.utils.loadTemplates("templates.xml");
-  const env = {
-    qweb: new owl.QWeb(templates)
-  };
-  const app = new App(env);
-  app.mount(document.body);
-}
-
-start();

tools/benchmarks/owl-0.12.0/templates.xml

@@ -1,50 +0,0 @@
-<templates>
-  <div t-name="App" class="main">
-      <div class="left-thing">
-        <div class="title">Actions</div>
-        <div class="panel">
-          <button t-on-click="addMessages(100)">Add 100 messages</button>
-          <button t-on-click="addMessages(1000)">Add 1k messages</button>
-          <button t-on-click="addMessages(10000)">Add 10k messages</button>
-          <button t-on-click="addMessages(30000)">Add 30k messages</button>
-          <button t-on-click="updateSomeMessages">Update every 10th messages</button>
-          <button t-on-click="clear">Clear</button>
-        </div>
-        <div class="flags">
-            <div>
-                <input type="checkbox" id="multipleflag" t-on-change="toggleMultiple" t-att-checked="state.multipleFlag"/>
-                <label for="multipleflag">Do it 20x</label>
-            </div>
-            <div>
-                <input type="checkbox" id="clearFlag" t-on-change="toggleClear"  t-att-checked="state.clearAfterFlag"/>
-                <label for="clearFlag">Clear after</label>
-            </div>
-        </div>
-        <div class="info">Number of messages: <t t-esc="state.messages.length"/></div>
-        <hr/>
-        <div class="title">Log <span class="clear-log" t-on-click="clearLog">(clear)</span></div>
-        <div class="log">
-            <div class="log-content" t-ref="log"/>
-        </div>
-      </div>
-      <div class="right-thing">
-          <div class="content" t-on-remove-message="removeMessage">
-              <t t-foreach="state.messages" t-as="message">
-                  <t t-widget="Message" t-key="message.id" t-props="message" t-on-remove_message="removeMessage"/>
-              </t>
-          </div>
-      </div>
-  </div>
-
-  <div t-name="Message" class="message">
-    <span class="author"><t t-esc="props.author"/></span>
-    <span class="msg"><t t-esc="props.msg"/></span>
-    <button class="remove" t-on-click="removeMessage">Remove</button>
-    <t t-widget="Counter"/>
-  </div>
-
-  <div t-name="Counter">
-    <button t-on-click="increment">Value: <t t-esc="state.counter"/></button>
-  </div>
-
-</templates>

tools/benchmarks/owl-0.16.0/index.html

@@ -1,13 +0,0 @@
-<!DOCTYPE html>
-<html lang="en">
-<head>
-  <meta charset="UTF-8">
-  <title>OWL 0.16.0 Benchmark</title>
-  <link href="../shared/main.css" rel="stylesheet"/>
-  <script src='owl.js'></script>
-</head>
-<body>
-  <div id='main'></div>
-  <script src='app.js' type="module"></script>
-</body>
-</html>

tools/benchmarks/owl-0.8.0/app.js

@@ -1,173 +0,0 @@
-import {
-  buildData,
-  startMeasure,
-  stopMeasure,
-  formatNumber
-} from "../shared/utils.js";
-
-//------------------------------------------------------------------------------
-// Likes Counter Widget
-//------------------------------------------------------------------------------
-class Counter extends owl.Component {
-  state = { counter: 0 };
-  template = "Counter";
-
-  increment() {
-    this.state.counter++;
-  }
-}
-
-//------------------------------------------------------------------------------
-// Message Widget
-//------------------------------------------------------------------------------
-class Message extends owl.Component {
-  widgets = { Counter };
-  template = "Message";
-
-  shouldUpdate(nextProps) {
-    return nextProps !== this.props;
-  }
-  removeMessage() {
-    this.trigger("remove_message", {
-      id: this.props.id
-    });
-  }
-}
-
-//------------------------------------------------------------------------------
-// Root Widget
-//------------------------------------------------------------------------------
-class App extends owl.Component {
-  widgets = { Message };
-  state = { messages: [], multipleFlag: false, clearAfterFlag: false };
-  template = "App";
-
-  mounted() {
-    this.log(
-      `Benchmarking Owl v${owl._version} (build date: ${
-        owl._date
-      })`
-    );
-  }
-
-  benchmark(message, fn, callback) {
-    if (this.state.multipleFlag) {
-      const N = 20;
-      let n = N;
-      let total = 0;
-      let cb = info => {
-        let finalize = () => {
-          n--;
-          total += info.delta;
-          if (n === 0) {
-            const avg = total / N;
-            this.log(`Average: ${formatNumber(avg)}ms`, true);
-            if (callback) {
-              callback();
-            }
-          } else {
-            this._benchmark(message, fn, cb);
-          }
-        };
-
-        if (this.state.clearAfterFlag) {
-          this._benchmark(
-            "clear",
-            () => {
-              this.state.messages = [];
-            },
-            finalize,
-            false
-          );
-        } else {
-          finalize();
-        }
-      };
-      this._benchmark(message, fn, cb);
-    } else {
-      this._benchmark(message, fn, callback);
-    }
-  }
-
-  _benchmark(message, fn, cb, log = true) {
-    setTimeout(() => {
-      startMeasure(message);
-      fn();
-      stopMeasure(info => {
-        if (log) {
-          this.log(info.msg);
-        }
-        if (cb) {
-          cb(info);
-        }
-      });
-    }, 10);
-  }
-
-  addMessages(n) {
-    this.benchmark("add " + n, () => {
-      const newMessages = buildData(n);
-      this.state.messages.push.apply(this.state.messages, newMessages);
-    });
-  }
-
-  clear() {
-    this._benchmark("clear", () => {
-      this.state.messages = [];
-    });
-  }
-
-  updateSomeMessages() {
-    this.benchmark("update every 10th", () => {
-      const messages = this.state.messages;
-      for (let i = 0; i < this.state.messages.length; i += 10) {
-        const msg = Object.assign({}, messages[i]);
-        msg.author += "!!!";
-        this.set(messages, i, msg);
-      }
-    });
-  }
-
-  removeMessage(data) {
-    this.benchmark("remove message", () => {
-      const index = this.state.messages.findIndex(m => m.id === data.id);
-      this.state.messages.splice(index, 1);
-    });
-  }
-
-  log(str, isBold) {
-    const div = document.createElement("div");
-    if (isBold) {
-      div.classList.add("bold");
-    }
-    div.textContent = `> ${str}`;
-    this.refs.log.appendChild(div);
-    this.refs.log.scrollTop = this.refs.log.scrollHeight;
-  }
-
-  clearLog() {
-    this.refs.log.innerHTML = "";
-  }
-
-  toggleMultiple() {
-    this.state.multipleFlag = !this.state.multipleFlag;
-  }
-
-  toggleClear() {
-    this.state.clearAfterFlag = !this.state.clearAfterFlag;
-  }
-}
-
-//------------------------------------------------------------------------------
-// Application initialization
-//------------------------------------------------------------------------------
-async function start() {
-  const templates = await owl.utils.loadTemplates("templates.xml");
-  const env = {
-    qweb: new owl.QWeb(templates)
-  };
-  const app = new App(env);
-  app.mount(document.body);
-}
-
-start();

tools/benchmarks/owl-0.8.0/index.html

@@ -1,13 +0,0 @@
-<!DOCTYPE html>
-<html lang="en">
-<head>
-  <meta charset="UTF-8">
-  <title>OWL 0.8.0 Benchmark</title>
-  <link href="../shared/main.css" rel="stylesheet"/>
-  <script src='owl-0.8.0.js'></script>
-</head>
-<body>
-  <div id='main'></div>
-  <script src='app.js' type="module"></script>
-</body>
-</html>

tools/benchmarks/owl-0.8.0/templates.xml

@@ -1,50 +0,0 @@
-<templates>
-  <div t-name="App" class="main">
-      <div class="left-thing">
-        <div class="title">Actions</div>
-        <div class="panel">
-          <button t-on-click="addMessages(100)">Add 100 messages</button>
-          <button t-on-click="addMessages(1000)">Add 1k messages</button>
-          <button t-on-click="addMessages(10000)">Add 10k messages</button>
-          <button t-on-click="addMessages(30000)">Add 30k messages</button>
-          <button t-on-click="updateSomeMessages">Update every 10th messages</button>
-          <button t-on-click="clear">Clear</button>
-        </div>
-        <div class="flags">
-            <div>
-                <input type="checkbox" id="multipleflag" t-on-change="toggleMultiple" t-att-checked="state.multipleFlag"/>
-                <label for="multipleflag">Do it 20x</label>
-            </div>
-            <div>
-                <input type="checkbox" id="clearFlag" t-on-change="toggleClear"  t-att-checked="state.clearAfterFlag"/>
-                <label for="clearFlag">Clear after</label>
-            </div>
-        </div>
-        <div class="info">Number of messages: <t t-esc="state.messages.length"/></div>
-        <hr/>
-        <div class="title">Log <span class="clear-log" t-on-click="clearLog">(clear)</span></div>
-        <div class="log">
-            <div class="log-content" t-ref="'log'"/>
-        </div>
-      </div>
-      <div class="right-thing">
-          <div class="content" t-on-remove-message="removeMessage">
-              <t t-foreach="state.messages" t-as="message">
-                  <t t-widget="Message" t-key="message.id" t-props="message" t-on-remove_message="removeMessage"/>
-              </t>
-          </div>
-      </div>
-  </div>
-
-  <div t-name="Message" class="message">
-    <span class="author"><t t-esc="props.author"/></span>
-    <span class="msg"><t t-esc="props.msg"/></span>
-    <button class="remove" t-on-click="removeMessage">Remove</button>
-    <t t-widget="Counter"/>
-  </div>
-
-  <div t-name="Counter">
-    <button t-on-click="increment">Value: <t t-esc="state.counter"/></button>
-  </div>
-
-</templates>

tools/benchmarks/owl-1.0.0-beta1/app.js

@@ -1,10 +1,11 @@
 import { buildData, startMeasure, stopMeasure, formatNumber } from "../shared/utils.js";
 
+const { useState, useRef } = owl.hooks;
 //------------------------------------------------------------------------------
 // Likes Counter Widget
 //------------------------------------------------------------------------------
 class Counter extends owl.Component {
-  state = { counter: 0 };
+  state = useState({ counter: 0 });
 
   increment() {
     this.state.counter++;
@@ -15,8 +16,6 @@ class Counter extends owl.Component {
 // Message Widget
 //------------------------------------------------------------------------------
 class Message extends owl.Component {
-  widgets = { Counter };
-
   shouldUpdate(nextProps) {
     return nextProps.message !== this.props.message;
   }
@@ -26,13 +25,14 @@ class Message extends owl.Component {
     });
   }
 }
+Message.components = { Counter };
 
 //------------------------------------------------------------------------------
 // Root Widget
 //------------------------------------------------------------------------------
 class App extends owl.Component {
-  widgets = { Message };
-  state = { messages: [], multipleFlag: false, clearAfterFlag: false };
+  state = useState({ messages: [], multipleFlag: false, clearAfterFlag: false });
+  logRef = useRef("log");
 
   mounted() {
     this.log(`Benchmarking Owl v${owl.__info__.version} (build date: ${owl.__info__.date})`);
@@ -108,10 +108,10 @@ class App extends owl.Component {
   updateSomeMessages() {
     this.benchmark("update every 10th", () => {
       const messages = this.state.messages;
-      for (let i = 0; i < this.state.messages.length; i += 10) {
+      for (let i = 0; i < messages.length; i += 10) {
         const msg = Object.assign({}, messages[i]);
         msg.author += "!!!";
-        this.set(messages, i, msg);
+        messages[i] = msg;
       }
     });
   }
@@ -129,32 +129,25 @@ class App extends owl.Component {
       div.classList.add("bold");
     }
     div.textContent = `> ${str}`;
-    this.refs.log.appendChild(div);
-    this.refs.log.scrollTop = this.refs.log.scrollHeight;
+    this.logRef.el.appendChild(div);
+    this.logRef.el.scrollTop = this.logRef.el.scrollHeight;
   }
 
   clearLog() {
-    this.refs.log.innerHTML = "";
-  }
-
-  toggleMultiple() {
-    this.state.multipleFlag = !this.state.multipleFlag;
-  }
-
-  toggleClear() {
-    this.state.clearAfterFlag = !this.state.clearAfterFlag;
+    this.logRef.el.innerHTML = "";
   }
 }
+App.components = { Message };
 
 //------------------------------------------------------------------------------
 // Application initialization
 //------------------------------------------------------------------------------
 async function start() {
-  const templates = await owl.utils.loadTemplates("templates.xml");
-  const env = {
-    qweb: new owl.QWeb(templates)
+  const templates = await owl.utils.loadFile("templates.xml");
+  App.env = {
+    qweb: new owl.QWeb({ templates })
   };
-  const app = new App(env);
+  const app = new App();
   app.mount(document.body);
 }
 

tools/benchmarks/owl-1.0.0-beta1/index.html

@@ -2,12 +2,11 @@
 <html lang="en">
 <head>
   <meta charset="UTF-8">
-  <title>OWL 0.12.0 Benchmark</title>
+  <title>OWL v1.0.0-beta1 Benchmark</title>
   <link href="../shared/main.css" rel="stylesheet"/>
   <script src='owl.js'></script>
 </head>
 <body>
-  <div id='main'></div>
   <script src='app.js' type="module"></script>
 </body>
 </html>