util.js

/**
 * --------------------------------------------------------------------------
 * Bootstrap (v4.0.0-beta.2): util.js
 * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
 * --------------------------------------------------------------------------
 */
var Util = function ($) {
  /**
   * ------------------------------------------------------------------------
   * Private TransitionEnd Helpers
   * ------------------------------------------------------------------------
   */
  var transition = false;
  var MAX_UID = 1000000;
  var TransitionEndEvent = {
    WebkitTransition: 'webkitTransitionEnd',
    transition: 'transitionend' // shoutout AngusCroll (https://goo.gl/pxwQGp)

  };

  function toType(obj) {
    return {}.toString.call(obj).match(/\s([a-zA-Z]+)/)[1].toLowerCase();
  }

  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); // eslint-disable-line prefer-rest-params
        }

        return undefined; // eslint-disable-line no-undefined
      }
    };
  }

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

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

    for (var name in TransitionEndEvent) {
      if (typeof 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;
    });
    setTimeout(function () {
      if (!called) {
        Util.triggerTransitionEnd(_this);
      }
    }, duration);
    return this;
  }