https://www.nargs.org/core/misc/jquery.once.js?348a8fb4

1/**
2 * jQuery Once Plugin 1.2.6
3 * http://github.com/robloach/jquery-once
4 *
5 * Dual licensed under the MIT and GPL licenses:
6 *   http://www.opensource.org/licenses/mit-license.php
7 *   http://www.gnu.org/licenses/gpl.html
8 *
9 * This library changed its function signature in its 2.x branch. This is a
10 * forked version that is jQuery 3.x compatible.
11 *
12 * See https://github.com/backdrop/backdrop-issues/issues/6195
13 */
14
15(function (factory) {
16  "use strict";
17  if (typeof exports === 'object') {
18    factory(require('jquery'));
19  } else if (typeof define === 'function' && define.amd) {
20    define(['jquery'], factory);
21  } else {
22    factory(jQuery);
23  }
24}(function ($) {
25  "use strict";
26  var cache = {}, uuid = 0;
27
28  /**
29   * Filters elements by whether they have not yet been processed.
30   *
31   * @param id
32   *   (Optional) If this is a string, then it will be used as the CSS class
33   *   name that is applied to the elements for determining whether it has
34   *   already been processed. The elements will get a class in the form of
35   *   "id-processed".
36   *
37   *   If the id parameter is a function, it will be passed off to the fn
38   *   parameter and the id will become a unique identifier, represented as a
39   *   number.
40   *
41   *   When the id is neither a string or a function, it becomes a unique
42   *   identifier, depicted as a number. The element's class will then be
43   *   represented in the form of "jquery-once-#-processed".
44   *
45   *   Take note that the id must be valid for usage as an element's class name.
46   * @param fn
47   *   (Optional) If given, this function will be called for each element that
48   *   has not yet been processed. The function's return value follows the same
49   *   logic as $.each(). Returning true will continue to the next matched
50   *   element in the set, while returning false will entirely break the
51   *   iteration.
52   *
53   * @api public
54   */
55  $.fn.once = function (id, fn) {
56    if (typeof id !== 'string') {
57      // Generate a numeric ID if the id passed can't be used as a CSS class.
58      if (!(id in cache)) {
59        cache[id] = ++uuid;
60      }
61      // When the fn parameter is not passed, we interpret it from the id.
62      if (!fn) {
63        fn = id;
64      }
65      id = 'jquery-once-' + cache[id];
66    }
67    // Remove elements from the set that have already been processed.
68    var name = id + '-processed';
69    var elements = this.not('.' + name).addClass(name);
70
71    return typeof fn == 'function' ? elements.each(fn) : elements;
72  };
73
74  /**
75   * Filters elements that have been processed once already.
76   *
77   * @param id
78   *   A required string representing the name of the class which should be used
79   *   when filtering the elements. This only filters elements that have already
80   *   been processed by the once function. The id should be the same id that
81   *   was originally passed to the once() function.
82   * @param fn
83   *   (Optional) If given, this function will be called for each element that
84   *   has not yet been processed. The function's return value follows the same
85   *   logic as $.each(). Returning true will continue to the next matched
86   *   element in the set, while returning false will entirely break the
87   *   iteration.
88   *
89   * @api public
90   */
91  $.fn.removeOnce = function (id, fn) {
92    var name = id + '-processed';
93    var elements = this.filter('.' + name).removeClass(name);
94
95    return typeof fn == 'function' ? elements.each(fn) : elements;
96  };
97}));