[REF] qweb: revamp event management

Closes #111

doc/qweb.md

@@ -357,61 +357,81 @@ will result in :
 ### `t-on` directive
 
 In a component's template, it is useful to be able to register handlers on some
-elements to some specific events. This
-is what makes a template _alive_. There are two different use cases.
+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
+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)
 
-   ```xml
-   <button t-on-click="someMethod">Do something</button>
-   ```
 
-   This will be roughly translated in javascript like this:
+A _pure_ DOM event is directly triggered by a user interaction (e.g. a `click`).
 
-   ```js
-   button.addEventListener("click", widget.someMethod.bind(widget));
-   ```
+```xml
+<button t-on-click="someMethod">Do something</button>
+```
 
-   The suffix (`click` in this example) is simply the name of the actual DOM
-   event.
+This will be roughly translated in javascript like this:
 
-   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.
+```js
+button.addEventListener("click", widget.someMethod.bind(widget));
+```
 
-   | 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 |
+The suffix (`click` in this example) is simply the name of the actual DOM
+event.
 
-   ```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.
+A _business_ DOM event is triggered by a call to `trigger` on a component.
 
-2. Register an event handler on a component. This will not capture a DOM event,
-   but rather a _business_ event:
+```xml
+<t t-widget="MyWidget" t-on-menu-loaded="someMethod"/>
+```
 
-   ```xml
-   <t t-widget="MyWidget" t-on-menuLoaded="someMethod"/>
-   ```
+```js
+ class MyWidget {
+     someWhere() {
+         const payload = ...;
+         this.trigger('menu-loaded', payload);
+     }
+ }
+ ```
+The call to `trigger` generates a [_CustomEvent_](https://developer.mozilla.org/docs/Web/Guide/Events/Creating_and_triggering_events)
+of type `menu-loaded` and dispatches it on the component's DOM element
+(`this.el`). The event bubbles and is cancelable. The parent widget 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 MyWidget {
-       someWhere() {
-           const payload = ...;
-           this.trigger('menuLoaded', payload);
-       }
-   }
-   ```
+```js
+ class ParentWidget {
+     someMethod(ev) {
+         const payload = ev.detail;
+         ...
+     }
+ }
+ ```
 
-   Here, the parent widget will receive the payload in its `someMethod` handler,
-   whenever the event is triggered.
+By convention, we use KebabCase for the name of _business_ events.
+
+
+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.
 
 The `t-on` directive also allows to prebind some arguments. For example,
 

extras/playground/app.js

@@ -242,20 +242,20 @@ class App extends owl.Component {
     });
   }
   updateCode(ev) {
-    this.state[ev.type] = ev.value;
+    this.state[ev.detail.type] = ev.detail.value;
   }
   toggleLayout() {
     this.state.splitLayout = !this.state.splitLayout;
   }
   updatePanelHeight(ev) {
-    if (!ev.delta) {
+    if (!ev.detail.delta) {
       return;
     }
     let height = this.state.topPanelHeight;
     if (!height) {
       height = document.getElementsByClassName("tabbed-editor")[0].clientHeight;
     }
-    this.state.topPanelHeight = height + ev.delta;
+    this.state.topPanelHeight = height + ev.detail.delta;
   }
 
   async downloadCode() {

src/component.ts

@@ -1,4 +1,3 @@
-import { EventBus } from "./event_bus";
 import { Observer } from "./observer";
 import { QWeb, CompiledTemplate } from "./qweb_core";
 import { h, patch, VNode } from "./vdom";
@@ -67,11 +66,7 @@ const TEMPLATE_MAP: { [key: number]: { [name: string]: string } } = {};
 //------------------------------------------------------------------------------
 let nextId = 1;
 
-export class Component<
-  T extends Env,
-  Props extends {},
-  State extends {}
-> extends EventBus {
+export class Component<T extends Env, Props extends {}, State extends {}> {
   readonly __owl__: Meta<Env, Props>;
   template?: string;
 
@@ -119,8 +114,6 @@ export class Component<
    * the t-widget directive in a template)
    */
   constructor(parent: Component<T, any, any> | T, props?: Props) {
-    super();
-
     const defaultProps = (<any>this.constructor).defaultProps;
     if (defaultProps) {
       props = this._applyDefaultProps(props, defaultProps);
@@ -355,6 +348,23 @@ export class Component<
     this.__owl__.observer!.set(target, key, value);
   }
 
+  /**
+   * Emit a custom event of type 'eventType' with the given 'payload' on the
+   * component's el, if it exists. However, note that the event will only bubble
+   * up to the parent DOM nodes. Thus, it must be called between mounted() and
+   * willUnmount().
+   */
+  trigger(eventType: string, payload?: any) {
+    if (this.el) {
+      const ev = new CustomEvent(eventType, {
+        bubbles: true,
+        cancelable: true,
+        detail: payload
+      });
+      this.el.dispatchEvent(ev);
+    }
+  }
+
   //--------------------------------------------------------------------------
   // Private
   //--------------------------------------------------------------------------
@@ -375,7 +385,6 @@ export class Component<
       delete parent.__owl__.children[id];
       __owl__.parent = null;
     }
-    this.clear();
     __owl__.isDestroyed = true;
     delete __owl__.vnode;
   }

src/qweb_extensions.ts

@@ -437,7 +437,7 @@ QWeb.addDirective({
       tattStyle = attVar;
     }
     let updateClassCode = "";
-    if (classAttr || tattClass || styleAttr || tattStyle) {
+    if (classAttr || tattClass || styleAttr || tattStyle || events.length) {
       let classCode = "";
       if (classAttr) {
         classCode =
@@ -456,9 +456,14 @@ QWeb.addDirective({
           }`;
         updateClassCode = `let cl=w${widgetID}.el.classList;for (let k in ${attVar}) {if (${attVar}[k]) {cl.add(k)} else {cl.remove(k)}}`;
       }
+      let eventsCode = events
+        .map(function([eventName, handler]) {
+          return `vn.elm.addEventListener('${eventName}', owner['${handler}'].bind(owner));`;
+        })
+        .join("");
       const styleExpr = tattStyle || (styleAttr ? `'${styleAttr}'` : false);
-      const styleCode = styleExpr ? `vn.elm.style = ${styleExpr}` : "";
-      createHook = `vnode.data.hook = {create(_, vn){${classCode}${styleCode}}};`;
+      const styleCode = styleExpr ? `vn.elm.style = ${styleExpr};` : "";
+      createHook = `vnode.data.hook = {create(_, vn){${classCode}${styleCode}${eventsCode}}};`;
     }
 
     ctx.addLine(
@@ -493,9 +498,6 @@ QWeb.addDirective({
     ctx.addLine(
       `context.__owl__.cmap[${templateID}] = w${widgetID}.__owl__.id;`
     );
-    for (let [event, method] of events) {
-      ctx.addLine(`w${widgetID}.on('${event}', owner, owner['${method}'])`);
-    }
     ctx.addLine(`def${defID} = w${widgetID}._prepare();`);
     // hack: specify empty remove hook to prevent the node from being removed from the DOM
     // FIXME: click to re-add widget during remove transition -> leak

tests/__snapshots__/component.test.ts.snap

@@ -31,7 +31,7 @@ exports[`class and style attributes with t-widget dynamic t-att-style is properl
         w4 = new W4(owner, props4);
         context.__owl__.cmap[4] = w4.__owl__.id;
         def3 = w4._prepare();
-        def3 = def3.then(vnode=>{vnode.data.hook = {create(_, vn){vn.elm.style = _5}};let pvnode=h(vnode.sel, {key: 4, hook: {insert(vn) {let nvn=w4._mount(vnode, pvnode.elm);pvnode.elm=nvn.elm;},remove() {},destroy(vn) {w4.destroy();}}});c1[_2_index]=pvnode;w4.__owl__.pvnode = pvnode;});
+        def3 = def3.then(vnode=>{vnode.data.hook = {create(_, vn){vn.elm.style = _5;}};let pvnode=h(vnode.sel, {key: 4, hook: {insert(vn) {let nvn=w4._mount(vnode, pvnode.elm);pvnode.elm=nvn.elm;},remove() {},destroy(vn) {w4.destroy();}}});c1[_2_index]=pvnode;w4.__owl__.pvnode = pvnode;});
     } else {
         def3 = def3 || w4._updateProps(props4, extra.forceUpdate, extra.patchQueue);
         def3 = def3.then(()=>{if (w4.__owl__.isDestroyed) {return};w4.el.style=_5;let pvnode=w4.__owl__.pvnode;c1[_2_index]=pvnode;});

tests/component.test.ts

@@ -1450,28 +1450,30 @@ describe("class and style attributes with t-widget", () => {
 
 describe("other directives with t-widget", () => {
   test("t-on works as expected", async () => {
-    let n = 0;
-    env.qweb.addTemplate(
-      "ParentWidget",
-      `<div><t t-widget="child" t-on-customevent="someMethod"/></div>`
-    );
+    expect.assertions(4);
+    env.qweb.addTemplates(`
+      <templates>
+        <div t-name="ParentWidget"><t t-widget="child" t-on-custom-event="someMethod"/></div>
+      </templates>
+    `);
     class ParentWidget extends Widget {
       widgets = { child: Child };
-      someMethod(arg) {
-        expect(arg).toBe(43);
-        n++;
+      n = 0;
+      someMethod(ev) {
+        expect(ev.detail).toBe(43);
+        this.n++;
       }
     }
     class Child extends Widget {}
     const widget = new ParentWidget(env);
     await widget.mount(fixture);
     let child = children(widget)[0];
-    expect(n).toBe(0);
-    child.trigger("customevent", 43);
-    expect(n).toBe(1);
+    expect(widget.n).toBe(0);
+    child.trigger("custom-event", 43);
+    expect(widget.n).toBe(1);
     child.destroy();
-    child.trigger("customevent", 43);
-    expect(n).toBe(1);
+    child.trigger("custom-event", 43);
+    expect(widget.n).toBe(1);
   });
 
   test("t-if works with t-widget", async () => {