[IMP] blockdom: t-on supports synthetic and native event handler

Synthetic handler is a sort of event delegation that allows placing
only one listener on the document to improve performance. It is an opt-in option.

Native listener places the listener on the node itself.

src/blockdom/block_compiler.ts

@@ -396,12 +396,12 @@ function updateCtx(ctx: BlockCtx, tree: IntermediateTree) {
         });
         break;
       case "handler": {
-        const setupHandler = createEventHandler(info.event!);
+        const { setup, update } = createEventHandler(info.event!);
         ctx.locations.push({
           idx: info.idx,
           refIdx: info.refIdx!,
-          setData: setupHandler,
-          updateData: setupHandler,
+          setData: setup,
+          updateData: update,
         });
         break;
       }

src/blockdom/config.ts

@@ -1,3 +1,13 @@
+export function filterOutModifiersFromData(dataList: any[]): { modifiers: string[], data: any[]} {
+  dataList = dataList.slice();
+  const modifiers = [];
+  let elm;
+  while ((elm = dataList[0]) && typeof elm === "string") {
+    modifiers.push(dataList.shift());
+  }
+  return { modifiers, data: dataList };
+}
+
 export const config = {
   // whether or not blockdom should normalize DOM whenever a block is created.
   // Normalizing dom mean removing empty text nodes (or containing only spaces)
@@ -10,6 +20,7 @@ export const config = {
     if (typeof data === "function") {
       data(ev);
     } else if (Array.isArray(data)) {
+      data = filterOutModifiersFromData(data).data;
       data[0](data[1], ev);
     }
   },

src/blockdom/events.ts

@@ -1,21 +1,61 @@
 import { config } from "./config";
 
-export function createEventHandler(event: string) {
-  setupSyntheticEvent(event);
-  const key = `__event__${event}`;
-  return function setupHandler(this: HTMLElement, data: any) {
-    (this as any)[key] = data;
-  };
+type EventHandlerSetter = (this: HTMLElement, data: any) => void;
+
+interface EventHandlerCreator {
+  setup: EventHandlerSetter;
+  update: EventHandlerSetter;
 }
 
-function nativeToSyntheticEvent(event: Event, name: string) {
-  const eventKey = `__event__${name}`;
+export function createEventHandler(rawEvent: string): EventHandlerCreator {
+  const eventName = rawEvent.split(".")[0];
+  if (rawEvent.includes(".synthetic")) {
+    return createSyntheticHandler(eventName);
+  } else {
+    return createElementHandler(eventName);
+  }
+}
+
+// Native listener
+function createElementHandler(evName: string): EventHandlerCreator {
+  let eventKey = `__event__${evName}`;
+  function listener(ev: Event) {
+    const currentTarget = ev.currentTarget;
+    if (!currentTarget || !document.contains(currentTarget as HTMLElement)) return;
+    const data = (currentTarget as any)[eventKey];
+    if (!data) return;
+    config.mainEventHandler(data, ev);
+  }
+
+  function setup(this: HTMLElement, data: any) {
+    (this as any)[eventKey] = data;
+    this.addEventListener(evName, listener);
+  }
+
+  function update(this: HTMLElement, data: any) {
+    (this as any)[eventKey] = data;
+  }
+
+  return { setup, update };
+}
+
+// Synthetic handler: a form of event delegation that allows placing only one
+// listener per event type.
+function createSyntheticHandler(evName: string): EventHandlerCreator {
+  let eventKey = `__event__synthetic_${evName}`;
+  setupSyntheticEvent(evName, eventKey);
+  function setup(this: HTMLElement, data: any) {
+    (this as any)[eventKey] = data;
+  }
+  return { setup, update: setup };
+}
+
+function nativeToSyntheticEvent(eventKey: string, event: Event) {
   let dom = event.target;
   while (dom !== null) {
     const data = (dom as any)[eventKey];
     if (data) {
       config.mainEventHandler(data, event);
-      return;
     }
     dom = (dom as any).parentNode;
   }
@@ -23,10 +63,10 @@ function nativeToSyntheticEvent(event: Event, name: string) {
 
 const CONFIGURED_SYNTHETIC_EVENTS: { [event: string]: boolean } = {};
 
-function setupSyntheticEvent(name: string) {
-  if (CONFIGURED_SYNTHETIC_EVENTS[name]) {
+function setupSyntheticEvent(evName: string, eventKey: string) {
+  if (CONFIGURED_SYNTHETIC_EVENTS[eventKey]) {
     return;
   }
-  document.addEventListener(name, (event) => nativeToSyntheticEvent(event, name));
-  CONFIGURED_SYNTHETIC_EVENTS[name] = true;
+  document.addEventListener(evName, (event) => nativeToSyntheticEvent(eventKey, event));
+  CONFIGURED_SYNTHETIC_EVENTS[eventKey] = true;
 }

src/component/handler.ts

@@ -1,7 +1,10 @@
+import { filterOutModifiersFromData } from "../blockdom/config";
+
 export function mainEventHandler(data: any, ev: Event) {
   if (typeof data === "function") {
     data(ev);
   } else {
+    data = filterOutModifiersFromData(data).data;
     const ctx = data[0];
     const method = data[1];
     const args = data[2] || [];

tests/blockdom/block_event_handling.test.ts

@@ -106,3 +106,92 @@ test("two same block nodes with different handlers", async () => {
   (fixture.firstChild!.nextSibling as HTMLDivElement).click();
   expect(steps).toEqual(["1", "2"]);
 });
+
+test("two same block nodes with different handlers (synthetic)", async () => {
+  const block = createBlock('<div block-handler-0="click.synthetic"></div>');
+  let steps: string[] = [];
+  let handler1 = () => steps.push("1");
+  let handler2 = () => steps.push("2");
+  const tree = multi([block([handler1]), block([handler2])]);
+
+  mount(tree, fixture);
+  expect(fixture.innerHTML).toBe("<div></div><div></div>");
+
+  (fixture.firstChild as HTMLDivElement).click();
+  (fixture.firstChild!.nextSibling as HTMLDivElement).click();
+  expect(steps).toEqual(["1", "2"]);
+});
+
+test("synthetic and native handlers can cohabitate", async () => {
+  const block = createBlock('<div block-handler-0="click.synthetic"><div block-handler-1="click"/></div>');
+  let steps: string[] = [];
+  let handler1 = () => steps.push("1");;
+  let handler2 = () => steps.push("2");
+  const tree = block([handler1, handler2]);
+
+  mount(tree, fixture);
+  expect(fixture.innerHTML).toBe("<div><div></div></div>");
+
+  (fixture.firstChild!.firstChild as HTMLDivElement).click();
+  expect(steps).toEqual(["2", "1"]);
+  (fixture.firstChild as HTMLDivElement).click();
+  expect(steps).toEqual(["2", "1", "1"]);
+});
+
+test("synthetic and native handlers can cohabitate (2)", async () => {
+  const block = createBlock('<div block-handler-0="click"><div block-handler-1="click.synthetic"/></div>');
+  let steps: string[] = [];
+  let handler1 = () => steps.push("1");;
+  let handler2 = () => steps.push("2");
+  const tree = block([handler1, handler2]);
+
+  mount(tree, fixture);
+  expect(fixture.innerHTML).toBe("<div><div></div></div>");
+
+  (fixture.firstChild!.firstChild as HTMLDivElement).click();
+  expect(steps).toEqual(["1", "2"]);
+  (fixture.firstChild as HTMLDivElement).click();
+  expect(steps).toEqual(["1", "2", "1"]);
+});
+
+test("synthetic and native handlers can cohabitate (3)", async () => {
+  const parent = createBlock(`<div block-handler-0="click"><block-child-0/><block-child-1/></div>`)
+  const block = createBlock('<div block-handler-0="click"/>');
+  const blockSynth = createBlock('<div block-handler-0="click.synthetic"/>');
+  let steps: string[] = [];
+  const handler0 = () => steps.push("0");;
+  let handler1 = () => steps.push("1");;
+  let handler2 = () => steps.push("2");
+  const tree = parent([handler0], [block([handler1]), blockSynth([handler2])]);
+
+  mount(tree, fixture);
+  expect(fixture.innerHTML).toBe("<div><div></div><div></div></div>");
+
+  const children = fixture.children[0].children;
+
+  (children[0] as HTMLElement).click();
+  expect(steps).toEqual(["1", "0"]);
+  (children[1] as HTMLElement).click();
+  expect(steps).toEqual(["1", "0", "0", "2"]);
+});
+
+test("synthetic and native handlers can cohabitate (5)", async () => {
+  const parent = createBlock(`<div block-handler-0="click"><block-child-0/><block-child-1/></div>`)
+  const block = createBlock('<div block-handler-0="click"/>');
+  const blockSynth = createBlock('<div block-handler-0="click.synthetic"/>');
+  let steps: string[] = [];
+  const handler0 = (ev: Event) => { steps.push("0"); ev.stopPropagation();};
+  let handler1 = () => steps.push("1");;
+  let handler2 = () => steps.push("2");
+  const tree = parent([handler0], [block([handler1]), blockSynth([handler2])]);
+
+  mount(tree, fixture);
+  expect(fixture.innerHTML).toBe("<div><div></div><div></div></div>");
+
+  const children = fixture.children[0].children;
+
+  (children[0] as HTMLElement).click();
+  expect(steps).toEqual(["1", "0"]);
+  (children[1] as HTMLElement).click();
+  expect(steps).toEqual(["1", "0", "0"]);
+});

tests/components/event_handling.test.ts

@@ -33,7 +33,7 @@ describe("event handling", () => {
     expect(fixture.innerHTML).toBe("<span><div>simple vnode</div>2</span>");
   });
 
-  test.skip("support for callable expression in event handler", async () => {
+  test("support for callable expression in event handler", async () => {
     class Counter extends Component {
       static template = xml`
       <div><t t-esc="state.value"/><input type="text" t-on-input="obj.onInput"/></div>`;

tests/misc/portal.test.ts

@@ -432,7 +432,7 @@ describe("Portal", () => {
     expect(parent.env).toStrictEqual({});
   });
 
-  test.skip("Portal composed with t-slot", async () => {
+  test("Portal composed with t-slot", async () => {
     const steps: Array<string> = [];
     let childInst: Component | null = null;
     class Child2 extends Component {

tests/qweb/__snapshots__/event_handling.test.ts.snap

@@ -240,6 +240,38 @@ exports[`t-on receive event in first argument 1`] = `
 }"
 `;
 
+exports[`t-on t-on modifiers (native listener) basic support for native listener 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div class=\\"myClass\\" block-handler-0=\\"click\\"><button block-handler-1=\\"click\\">Button</button></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let d1 = [ctx, 'divClicked'];
+    let d2 = [ctx, 'btnClicked'];
+    return block1([d1, d2]);
+  }
+}"
+`;
+
+exports[`t-on t-on modifiers (synthetic listener) basic support for synthetic 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div block-handler-0=\\"click.synthetic\\"><button block-handler-1=\\"click.synthetic\\">Button</button></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let d1 = [ctx, 'divClicked'];
+    let d2 = [ctx, 'btnClicked'];
+    return block1([d1, d2]);
+  }
+}"
+`;
+
 exports[`t-on t-on with inline statement (function call) 1`] = `
 "function anonymous(bdom, helpers
 ) {

tests/qweb/event_handling.test.ts

@@ -301,4 +301,55 @@ describe("t-on", () => {
       "Missing event name with t-on directive"
     );
   });
+
+  describe("t-on modifiers (native listener)", () => {
+    test("basic support for native listener", () => {
+      const template = `<div class="myClass" t-on-click="divClicked">
+        <button t-on-click="btnClicked">Button</button>
+      </div>`;
+
+      const steps: string[] = [];
+
+      const owner = {
+        divClicked(ev: Event) {
+          expect(ev.currentTarget).toBe(div);
+          steps.push("divClicked");
+        },
+        btnClicked(ev: Event) {
+          expect(ev.currentTarget).toBe(button);
+          steps.push("btnClicked");
+        },
+      };
+      const node = mountToFixture(template, owner);
+      const div = node.querySelector(".myClass");
+      const button = (<HTMLElement>node).getElementsByTagName("button")[0];
+      button.click();
+      expect(steps).toEqual(["btnClicked", "divClicked"]);
+    });
+  });
+
+  describe("t-on modifiers (synthetic listener)", () => {
+    test("basic support for synthetic", () => {
+      const template = `<div t-on-click.synthetic="divClicked">
+        <button t-on-click.synthetic="btnClicked">Button</button>
+      </div>`;
+
+      const steps: string[] = [];
+
+      const owner = {
+        divClicked(ev: Event) {
+          expect(ev.currentTarget).toBe(document);
+          steps.push("divClicked");
+        },
+        btnClicked(ev: Event) {
+          expect(ev.currentTarget).toBe(document);
+          steps.push("btnClicked");
+        },
+      };
+      const node = mountToFixture(template, owner);
+      const button = (<HTMLElement>node).getElementsByTagName("button")[0];
+      button.click();
+      expect(steps).toEqual(["btnClicked", "divClicked"]);
+    });
+  });
 });