Source: lib/util/fake_event.js

  1. /**
  2.  * @license
  3.  * Copyright 2016 Google Inc.
  4.  *
  5.  * Licensed under the Apache License, Version 2.0 (the "License");
  6.  * you may not use this file except in compliance with the License.
  7.  * You may obtain a copy of the License at
  8.  *
  9.  *     http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software
  12.  * distributed under the License is distributed on an "AS IS" BASIS,
  13.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14.  * See the License for the specific language governing permissions and
  15.  * limitations under the License.
  16.  */
  18. goog.provide('shaka.util.FakeEvent');
  22. /**
  23.  * Create an Event work-alike object based on the provided dictionary.
  24.  * The event should contain all of the same properties from the dict.
  25.  *
  26.  * @param {string} type
  27.  * @param {Object=} opt_dict
  28.  * @constructor
  29.  * @extends {Event}
  30.  */
  31. shaka.util.FakeEvent = function(type, opt_dict) {
  32.   // Take properties from dict if present.
  33.   let dict = opt_dict || {};
  34.   for (let key in dict) {
  35.     this[key] = dict[key];
  36.   }
  39.   // The properties below cannot be set by the dict.  They are all provided for
  40.   // compatibility with native events.
  42.   /** @const {boolean} */
  43.   this.bubbles = false;
  45.   /** @type {boolean} */
  46.   this.cancelable = false;
  48.   /** @type {boolean} */
  49.   this.defaultPrevented = false;
  51.   /**
  52.    * According to MDN, Chrome uses high-res timers instead of epoch time.
  53.    * Follow suit so that timeStamps on FakeEvents use the same base as
  54.    * on native Events.
  55.    * @const {number}
  56.    * @see https://developer.mozilla.org/en-US/docs/Web/API/Event/timeStamp
  57.    */
  58.   this.timeStamp = window.performance && window.performance.now ?
  59.       window.performance.now() : Date.now();
  61.   /** @const {string} */
  62.   this.type = type;
  64.   /** @const {boolean} */
  65.   this.isTrusted = false;
  67.   /** @type {EventTarget} */
  68.   this.currentTarget = null;
  70.   /** @type {EventTarget} */
  71.   this.target = null;
  74.   /**
  75.    * Non-standard property read by FakeEventTarget to stop processing listeners.
  76.    * @type {boolean}
  77.    */
  78.   this.stopped = false;
  79. };
  82. /**
  83.  * Prevents the default action of the event.  Has no effect if the event isn't
  84.  * cancellable.
  85.  * @override
  86.  */
  87. shaka.util.FakeEvent.prototype.preventDefault = function() {
  88.   if (this.cancelable) {
  89.     this.defaultPrevented = true;
  90.   }
  91. };
  94. /**
  95.  * Stops processing event listeners for this event.  Provided for compatibility
  96.  * with native Events.
  97.  * @override
  98.  */
  99. shaka.util.FakeEvent.prototype.stopImmediatePropagation = function() {
  100.   this.stopped = true;
  101. };
  104. /**
  105.  * Does nothing, since FakeEvents do not bubble.  Provided for compatibility
  106.  * with native Events.
  107.  * @override
  108.  */
  109. shaka.util.FakeEvent.prototype.stopPropagation = function() {};