devtools/shared/debounce.js

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 "use strict";
   6
   7 /**
   8  * Create a debouncing function wrapper to only call the target function after a certain
   9  * amount of time has passed without it being called.
  10  *
  11  * @param {Function} func
  12  *         The function to debounce
  13  * @param {number} wait
  14  *         The wait period
  15  * @param {Object} scope
  16  *         The scope to use for func
  17  * @return {Function} The debounced function, which has a `cancel` method that the
  18  *                    consumer can call to cancel any pending setTimeout callback.
  19  */
  20 exports.debounce = function (func, wait, scope) {
  21   let timer = null;
  22
  23   function clearTimer(resetTimer = false) {
  24     if (timer) {
  25       clearTimeout(timer);
  26     }
  27     if (resetTimer) {
  28       timer = null;
  29     }
  30   }
  31
  32   const debouncedFunction = function () {
  33     clearTimer();
  34
  35     const args = arguments;
  36     timer = setTimeout(function () {
  37       timer = null;
  38       func.apply(scope, args);
  39     }, wait);
  40   };
  41
  42   debouncedFunction.cancel = clearTimer.bind(null, true);
  43
  44   return debouncedFunction;
  45 };