1 files changed, 219 insertions, 0 deletions
diff --git a/javascript/videojs/src/js/event-target.js b/javascript/videojs/src/js/event-target.js
new file mode 100644
index 0000000..68a0e97
--- /dev/null
+++ b/javascript/videojs/src/js/event-target.js
@@ -0,0 +1,219 @@
+/**
+ * @file src/js/event-target.js
+ */
+import * as Events from './utils/events.js';
+import window from 'global/window';
+
+let EVENT_MAP;
+
+/**
+ * `EventTarget` is a class that can have the same API as the DOM `EventTarget`. It
+ * adds shorthand functions that wrap around lengthy functions. For example:
+ * the `on` function is a wrapper around `addEventListener`.
+ *
+ * @see [EventTarget Spec]{@link https://www.w3.org/TR/DOM-Level-2-Events/events.html#Events-EventTarget}
+ * @class EventTarget
+ */
+class EventTarget {
+  /**
+   * Adds an `event listener` to an instance of an `EventTarget`. An `event listener` is a
+   * function that will get called when an event with a certain name gets triggered.
+   *
+   * @param {string|string[]} type
+   *        An event name or an array of event names.
+   *
+   * @param {Function} fn
+   *        The function to call with `EventTarget`s
+   */
+  on(type, fn) {
+    // Remove the addEventListener alias before calling Events.on
+    // so we don't get into an infinite type loop
+    const ael = this.addEventListener;
+
+    this.addEventListener = () => { };
+    Events.on(this, type, fn);
+    this.addEventListener = ael;
+  }
+  /**
+   * Removes an `event listener` for a specific event from an instance of `EventTarget`.
+   * This makes it so that the `event listener` will no longer get called when the
+   * named event happens.
+   *
+   * @param {string|string[]} type
+   *        An event name or an array of event names.
+   *
+   * @param {Function} fn
+   *        The function to remove.
+   */
+  off(type, fn) {
+    Events.off(this, type, fn);
+  }
+  /**
+   * This function will add an `event listener` that gets triggered only once. After the
+   * first trigger it will get removed. This is like adding an `event listener`
+   * with {@link EventTarget#on} that calls {@link EventTarget#off} on itself.
+   *
+   * @param {string|string[]} type
+   *        An event name or an array of event names.
+   *
+   * @param {Function} fn
+   *        The function to be called once for each event name.
+   */
+  one(type, fn) {
+    // Remove the addEventListener aliasing Events.on
+    // so we don't get into an infinite type loop
+    const ael = this.addEventListener;
+
+    this.addEventListener = () => { };
+    Events.one(this, type, fn);
+    this.addEventListener = ael;
+  }
+  /**
+   * This function will add an `event listener` that gets triggered only once and is
+   * removed from all events. This is like adding an array of `event listener`s
+   * with {@link EventTarget#on} that calls {@link EventTarget#off} on all events the
+   * first time it is triggered.
+   *
+   * @param {string|string[]} type
+   *        An event name or an array of event names.
+   *
+   * @param {Function} fn
+   *        The function to be called once for each event name.
+   */
+  any(type, fn) {
+    // Remove the addEventListener aliasing Events.on
+    // so we don't get into an infinite type loop
+    const ael = this.addEventListener;
+
+    this.addEventListener = () => { };
+    Events.any(this, type, fn);
+    this.addEventListener = ael;
+  }
+  /**
+   * This function causes an event to happen. This will then cause any `event listeners`
+   * that are waiting for that event, to get called. If there are no `event listeners`
+   * for an event then nothing will happen.
+   *
+   * If the name of the `Event` that is being triggered is in `EventTarget.allowedEvents_`.
+   * Trigger will also call the `on` + `uppercaseEventName` function.
+   *
+   * Example:
+   * 'click' is in `EventTarget.allowedEvents_`, so, trigger will attempt to call
+   * `onClick` if it exists.
+   *
+   * @param {string|EventTarget~Event|Object} event
+   *        The name of the event, an `Event`, or an object with a key of type set to
+   *        an event name.
+   */
+  trigger(event) {
+    const type = event.type || event;
+
+    // deprecation
+    // In a future version we should default target to `this`
+    // similar to how we default the target to `elem` in
+    // `Events.trigger`. Right now the default `target` will be
+    // `document` due to the `Event.fixEvent` call.
+    if (typeof event === 'string') {
+      event = { type };
+    }
+    event = Events.fixEvent(event);
+
+    if (this.allowedEvents_[type] && this['on' + type]) {
+      this['on' + type](event);
+    }
+
+    Events.trigger(this, event);
+  }
+  queueTrigger(event) {
+    // only set up EVENT_MAP if it'll be used
+    if (!EVENT_MAP) {
+      EVENT_MAP = new Map();
+    }
+
+    const type = event.type || event;
+    let map = EVENT_MAP.get(this);
+
+    if (!map) {
+      map = new Map();
+      EVENT_MAP.set(this, map);
+    }
+
+    const oldTimeout = map.get(type);
+
+    map.delete(type);
+    window.clearTimeout(oldTimeout);
+
+    const timeout = window.setTimeout(() => {
+      map.delete(type);
+      // if we cleared out all timeouts for the current target, delete its map
+      if (map.size === 0) {
+        map = null;
+        EVENT_MAP.delete(this);
+      }
+
+      this.trigger(event);
+    }, 0);
+
+    map.set(type, timeout);
+  }
+}
+
+/**
+ * A Custom DOM event.
+ *
+ * @typedef {CustomEvent} Event
+ * @see [Properties]{@link https://developer.mozilla.org/en-US/docs/Web/API/CustomEvent}
+ */
+
+/**
+ * All event listeners should follow the following format.
+ *
+ * @callback EventListener
+ * @this {EventTarget}
+ *
+ * @param {Event} event
+ *        the event that triggered this function
+ *
+ * @param {Object} [hash]
+ *        hash of data sent during the event
+ */
+
+/**
+ * An object containing event names as keys and booleans as values.
+ *
+ * > NOTE: If an event name is set to a true value here {@link EventTarget#trigger}
+ *         will have extra functionality. See that function for more information.
+ *
+ * @property EventTarget.prototype.allowedEvents_
+ * @protected
+ */
+EventTarget.prototype.allowedEvents_ = {};
+
+/**
+ * An alias of {@link EventTarget#on}. Allows `EventTarget` to mimic
+ * the standard DOM API.
+ *
+ * @function
+ * @see {@link EventTarget#on}
+ */
+EventTarget.prototype.addEventListener = EventTarget.prototype.on;
+
+/**
+ * An alias of {@link EventTarget#off}. Allows `EventTarget` to mimic
+ * the standard DOM API.
+ *
+ * @function
+ * @see {@link EventTarget#off}
+ */
+EventTarget.prototype.removeEventListener = EventTarget.prototype.off;
+
+/**
+ * An alias of {@link EventTarget#trigger}. Allows `EventTarget` to mimic
+ * the standard DOM API.
+ *
+ * @function
+ * @see {@link EventTarget#trigger}
+ */
+EventTarget.prototype.dispatchEvent = EventTarget.prototype.trigger;
+
+export default EventTarget;