/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

"use strict";

/**
 * Create a debouncing function wrapper to only call the target function after a certain
 * amount of time has passed without it being called.
 *
 * @param {Function} func
 *         The function to debounce
 * @param {number} wait
 *         The wait period
 * @param {Object} scope
 *         The scope to use for func
 * @return {Function} The debounced function, which has a `cancel` method that the
 *                    consumer can call to cancel any pending setTimeout callback.
 */
exports.debounce = function(func, wait, scope) {
  let timer = null;

  function clearTimer(resetTimer = false) {
    if (timer) {
      clearTimeout(timer);
    }
    if (resetTimer) {
      timer = null;
    }
  }

  const debouncedFunction = function() {
    clearTimer();

    const args = arguments;
    timer = setTimeout(function() {
      timer = null;
      func.apply(scope, args);
    }, wait);
  };

  debouncedFunction.cancel = clearTimer.bind(null, true);

  return debouncedFunction;
};