https://aac.ca/misc/jquery.once.js?v=1.2

1
2/**
3 * jQuery Once Plugin v1.2
4 * http://plugins.jquery.com/project/once
5 *
6 * Dual licensed under the MIT and GPL licenses:
7 *   http://www.opensource.org/licenses/mit-license.php
8 *   http://www.gnu.org/licenses/gpl.html
9 */
10
11(function ($) {
12  var cache = {}, uuid = 0;
13
14  /**
15   * Filters elements by whether they have not yet been processed.
16   *
17   * @param id
18   *   (Optional) If this is a string, then it will be used as the CSS class
19   *   name that is applied to the elements for determining whether it has
20   *   already been processed. The elements will get a class in the form of
21   *   "id-processed".
22   *
23   *   If the id parameter is a function, it will be passed off to the fn
24   *   parameter and the id will become a unique identifier, represented as a
25   *   number.
26   *
27   *   When the id is neither a string or a function, it becomes a unique
28   *   identifier, depicted as a number. The element's class will then be
29   *   represented in the form of "jquery-once-#-processed".
30   *
31   *   Take note that the id must be valid for usage as an element's class name.
32   * @param fn
33   *   (Optional) If given, this function will be called for each element that
34   *   has not yet been processed. The function's return value follows the same
35   *   logic as $.each(). Returning true will continue to the next matched
36   *   element in the set, while returning false will entirely break the
37   *   iteration.
38   */
39  $.fn.once = function (id, fn) {
40    if (typeof id != 'string') {
41      // Generate a numeric ID if the id passed can't be used as a CSS class.
42      if (!(id in cache)) {
43        cache[id] = ++uuid;
44      }
45      // When the fn parameter is not passed, we interpret it from the id.
46      if (!fn) {
47        fn = id;
48      }
49      id = 'jquery-once-' + cache[id];
50    }
51    // Remove elements from the set that have already been processed.
52    var name = id + '-processed';
53    var elements = this.not('.' + name).addClass(name);
54
55    return $.isFunction(fn) ? elements.each(fn) : elements;
56  };
57
58  /**
59   * Filters elements that have been processed once already.
60   *
61   * @param id
62   *   A required string representing the name of the class which should be used
63   *   when filtering the elements. This only filters elements that have already
64   *   been processed by the once function. The id should be the same id that
65   *   was originally passed to the once() function.
66   * @param fn
67   *   (Optional) If given, this function will be called for each element that
68   *   has not yet been processed. The function's return value follows the same
69   *   logic as $.each(). Returning true will continue to the next matched
70   *   element in the set, while returning false will entirely break the
71   *   iteration.
72   */
73  $.fn.removeOnce = function (id, fn) {
74    var name = id + '-processed';
75    var elements = this.filter('.' + name).removeClass(name);
76
77    return $.isFunction(fn) ? elements.each(fn) : elements;
78  };
79})(jQuery);