util.js

/**
 * --------------------------------------------------------------------------
 * Bootstrap (v4.0.0-alpha): util.js
 * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
 * --------------------------------------------------------------------------
 */

'use strict';

var Util = (function ($) {

  /**
   * ------------------------------------------------------------------------
   * Private TransitionEnd Helpers
   * ------------------------------------------------------------------------
   */

  var transition = false;

  var TransitionEndEvent = {
    WebkitTransition: 'webkitTransitionEnd',
    MozTransition: 'transitionend',
    OTransition: 'oTransitionEnd otransitionend',
    transition: 'transitionend'
  };

  // shoutout AngusCroll (https://goo.gl/pxwQGp)
  function toType(obj) {
    return ({}).toString.call(obj).match(/\s([a-zA-Z]+)/)[1].toLowerCase();
  }

  function isElement(obj) {
    return (obj[0] || obj).nodeType;
  }

  function getSpecialTransitionEndEvent() {
    return {
      bindType: transition.end,
      delegateType: transition.end,
      handle: function handle(event) {
        if ($(event.target).is(this)) {
          return event.handleObj.handler.apply(this, arguments);
        }
      }
    };
  }

  function transitionEndTest() {
    if (window.QUnit) {
      return false;
    }

    var el = document.createElement('bootstrap');

    for (var _name in TransitionEndEvent) {
      if (el.style[_name] !== undefined) {
        return { end: TransitionEndEvent[_name] };
      }
    }

    return false;
  }

  function transitionEndEmulator(duration) {
    var _this = this;

    var called = false;

    $(this).one(Util.TRANSITION_END, function () {
      called = true;