OLD | NEW |
---|---|
(Empty) | |
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. | |
4 | |
5 /** @fileoverview | |
arv (Not doing code reviews)
2011/03/10 19:25:59
@fileoverview EventTracker ...
Rick Byers
2011/03/11 02:44:33
Done.
| |
6 * EventTracker is a simple class that manages the addition and removal of | |
7 * DOM event listeners. In particular, it keeps track of all listeners that | |
8 * have been added and makes it easy to remove some or all of them without | |
9 * requiring all the information again. This is particularly handy when | |
10 * the listener is a generated function such as a lambda or the result of | |
11 * calling Function.bind. The goal of this class is to make it easier to | |
12 * avoid memory leaks caused by DOM<->JS cycles - removing event listeners | |
13 * breakes the DOM->JS part of the cycle. | |
14 */ | |
15 | |
16 /** @constructor | |
17 * Create an EventTracker to track a set of events. | |
arv (Not doing code reviews)
2011/03/10 19:25:59
/**
* Description
* @constructor
*/
Rick Byers
2011/03/11 02:44:33
Done.
| |
18 * EventTracker instances are typically tied 1:1 with other objects or | |
19 * DOM elements whose listeners should be removed when the object is disposed | |
20 * or the corresponding elements are removed from the DOM. | |
21 */ | |
22 function EventTracker() { | |
23 /** | |
24 * @type {Array.<EventTracker.Entry>} | |
25 * @private | |
26 */ | |
27 this.listeners_ = []; | |
28 } | |
29 | |
30 /** | |
31 * The type of the internal tracking entry. | |
32 * @typedef {{node: !Node, | |
33 * eventType: string, | |
34 * listener: Function, | |
35 * capture: boolean}} | |
36 */ | |
37 EventTracker.Entry; | |
38 | |
39 /** | |
40 * Add an event listener - replacement for Node.addEventListener. | |
41 * @param {!Node} node The DOM node to add a listener to. | |
42 * @param {string} eventType The type of event to subscribe to. | |
43 * @param {Function} listener The listener to add. | |
44 * @param {boolean} capture Whether to invoke during the capture phase. | |
45 */ | |
46 EventTracker.prototype.add = function(node, eventType, listener, capture) | |
arv (Not doing code reviews)
2011/03/10 19:25:59
Use the following syntax instead:
EventTracker.pr
Rick Byers
2011/03/11 02:44:33
I like it, thanks! Done. Does it not matter that
arv (Not doing code reviews)
2011/03/11 20:08:46
No. constructor is not reliable anyway.
function
| |
47 { | |
arv (Not doing code reviews)
2011/03/10 19:25:59
{ before new line
Rick Byers
2011/03/11 02:44:33
Done.
| |
48 var h = {node: node, | |
arv (Not doing code reviews)
2011/03/10 19:25:59
var h = {
eventType: ...
...
};
Rick Byers
2011/03/11 02:44:33
Done.
| |
49 eventType: eventType, | |
50 listener: listener, | |
51 capture: capture}; | |
52 this.listeners_.push(h); | |
53 node.addEventListener(eventType, listener, capture); | |
54 }; | |
55 | |
56 /** | |
57 * Remove any specified event listeners added with this EventTracker. | |
58 * @param {!Node} node The DOM node to remove a listener from. | |
59 * @param {string} eventType The type of event to remove. | |
60 */ | |
61 EventTracker.prototype.remove = function(node, eventType) | |
62 { | |
63 this.listeners_ = this.listeners_.filter(function(h) { | |
64 if (h.node == node && h.eventType == eventType) { | |
65 EventTracker.removeEventListener_(h); | |
66 return false; | |
67 } | |
68 return true; | |
69 }); | |
70 }; | |
71 | |
72 /** | |
73 * Remove all event listeners added with this EventTracker. | |
74 */ | |
75 EventTracker.prototype.removeAll = function() | |
76 { | |
77 this.listeners_.forEach(EventTracker.removeEventListener_); | |
78 this.listeners_ = []; | |
79 }; | |
80 | |
81 /** | |
82 * Remove a single event listener given it's tracker entry. It's up to the | |
83 * caller to ensure the entry is removed from listeners_. | |
84 * @param {EventTracker.Entry} h The entry describing the listener to remove. | |
85 * @private | |
Rick Byers
2011/03/11 02:44:33
Note that this is a static method (doesn't access
arv (Not doing code reviews)
2011/03/11 20:08:46
Yes, looks perfect
| |
86 */ | |
87 EventTracker.removeEventListener_ = function(h) | |
88 { | |
89 h.node.removeEventListener(h.eventType, h.listener, h.capture); | |
90 }; | |
91 | |
92 | |
arv (Not doing code reviews)
2011/03/10 19:25:59
remove empty lines
Rick Byers
2011/03/11 02:44:33
Done.
| |
93 | |
94 | |
95 | |
OLD | NEW |