EventTarget-constructible.any.js

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This WPT test may be referenced by the following Test IDs:
- /dom/events/EventTarget-constructible.any.html - WPT Dashboard Interop Dashboard
- /dom/events/EventTarget-constructible.any.worker.html - WPT Dashboard Interop Dashboard

"use strict";

test(() => {

  const target = new EventTarget();

  const event = new Event("foo", { bubbles: true, cancelable: false });

  let callCount = 0;

  function listener(e) {

    assert_equals(e, event);

    ++callCount;

  target.addEventListener("foo", listener);

  target.dispatchEvent(event);

  assert_equals(callCount, 1);

  target.dispatchEvent(event);

  assert_equals(callCount, 2);

  target.removeEventListener("foo", listener);

  target.dispatchEvent(event);

  assert_equals(callCount, 2);

}, "A constructed EventTarget can be used as expected");

test(() => {

  const target = new EventTarget();

  const event = new Event("foo");

  function listener(e) {

    assert_equals(e, event);

    assert_equals(e.target, target);

    assert_equals(e.currentTarget, target);

    assert_array_equals(e.composedPath(), [target]);

  target.addEventListener("foo", listener, { once: true });

  target.dispatchEvent(event);

  assert_equals(event.target, target);

  assert_equals(event.currentTarget, null);

  assert_array_equals(event.composedPath(), []);

}, "A constructed EventTarget implements dispatch correctly");

test(() => {

  class NicerEventTarget extends EventTarget {

    on(...args) {

      this.addEventListener(...args);

    off(...args) {

      this.removeEventListener(...args);

    dispatch(type, detail) {

      this.dispatchEvent(new CustomEvent(type, { detail }));

  const target = new NicerEventTarget();

  const event = new Event("foo", { bubbles: true, cancelable: false });

  const detail = "some data";

  let callCount = 0;

  function listener(e) {

    assert_equals(e.detail, detail);

    ++callCount;

  target.on("foo", listener);

  target.dispatch("foo", detail);

  assert_equals(callCount, 1);

  target.dispatch("foo", detail);

  assert_equals(callCount, 2);

  target.off("foo", listener);

  target.dispatch("foo", detail);

  assert_equals(callCount, 2);

}, "EventTarget can be subclassed");