https://sdfcu.org/core/misc/debounce.js?v=10.6.15

1/**
2 * @file
3 * Adapted from underscore.js with the addition Drupal namespace.
4 */
5
6/**
7 * Limits the invocations of a function in a given time frame.
8 *
9 * The debounce function wrapper should be used sparingly. One clear use case
10 * is limiting the invocation of a callback attached to the window resize event.
11 *
12 * Before using the debounce function wrapper, consider first whether the
13 * callback could be attached to an event that fires less frequently or if the
14 * function can be written in such a way that it is only invoked under specific
15 * conditions.
16 *
17 * @param {function} func
18 *   The function to be invoked.
19 * @param {number} wait
20 *   The time period within which the callback function should only be
21 *   invoked once. For example if the wait period is 250ms, then the callback
22 *   will only be called at most 4 times per second.
23 * @param {boolean} immediate
24 *   Whether we wait at the beginning or end to execute the function.
25 *
26 * @return {function}
27 *   The debounced function.
28 */
29Drupal.debounce = function (func, wait, immediate) {
30  let timeout;
31  let result;
32  return function (...args) {
33    const context = this;
34    const later = function () {
35      timeout = null;
36      if (!immediate) {
37        result = func.apply(context, args);
38      }
39    };
40    const callNow = immediate && !timeout;
41    clearTimeout(timeout);
42    timeout = setTimeout(later, wait);
43    if (callNow) {
44      result = func.apply(context, args);
45    }
46    return result;
47  };
48};