1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 /** @fileoverview EventTracker is a simple class that manages the addition and
6 * removal of DOM event listeners. In particular, it keeps track of all
7 * listeners that have been added and makes it easy to remove some or all of
8 * them without requiring all the information again. This is particularly
9 * handy when the listener is a generated function such as a lambda or the
10 * result of calling Function.bind.
13 // Use an anonymous function to enable strict mode just for this file (which
14 // will be concatenated with other files when embedded in Chrome)
15 var EventTracker = (function() {
19 * Create an EventTracker to track a set of events.
20 * EventTracker instances are typically tied 1:1 with other objects or
21 * DOM elements whose listeners should be removed when the object is disposed
22 * or the corresponding elements are removed from the DOM.
25 function EventTracker() {
27 * @type {Array.<EventTracker.Entry>}
34 * The type of the internal tracking entry.
35 * @typedef {{node: !Node,
42 EventTracker.prototype = {
44 * Add an event listener - replacement for Node.addEventListener.
45 * @param {!Node} node The DOM node to add a listener to.
46 * @param {string} eventType The type of event to subscribe to.
47 * @param {Function} listener The listener to add.
48 * @param {boolean} capture Whether to invoke during the capture phase.
50 add: function(node, eventType, listener, capture) {
57 this.listeners_.push(h);
58 node.addEventListener(eventType, listener, capture);
62 * Remove any specified event listeners added with this EventTracker.
63 * @param {!Node} node The DOM node to remove a listener from.
64 * @param {?string} eventType The type of event to remove.
66 remove: function(node, eventType) {
67 this.listeners_ = this.listeners_.filter(function(h) {
68 if (h.node == node && (!eventType || (h.eventType == eventType))) {
69 EventTracker.removeEventListener_(h);
77 * Remove all event listeners added with this EventTracker.
79 removeAll: function() {
80 this.listeners_.forEach(EventTracker.removeEventListener_);
86 * Remove a single event listener given it's tracker entry. It's up to the
87 * caller to ensure the entry is removed from listeners_.
88 * @param {EventTracker.Entry} h The entry describing the listener to remove.
91 EventTracker.removeEventListener_ = function(h) {
92 h.node.removeEventListener(h.eventType, h.listener, h.capture);