text: /**
   * Copyright (c) 2013-present, Facebook, Inc.
   *
   * This source code is licensed under the MIT license found in the
   * LICENSE file in the root directory of this source tree.
   *
   * @providesModule getVendorPrefixedEventName
   */
  
  'use strict';
  
  var ExecutionEnvironment = require('ExecutionEnvironment');
  
  /**
   * Generate a mapping of standard vendor prefixes using the defined style property and event name.
   *
   * @param {string} styleProp
   * @param {string} eventName
   * @returns {object}
   */
  function makePrefixMap(styleProp, eventName) {
    var prefixes = {};
  
    prefixes[styleProp.toLowerCase()] = eventName.toLowerCase();
    prefixes['Webkit' + styleProp] = 'webkit' + eventName;
    prefixes['Moz' + styleProp] = 'moz' + eventName;
    prefixes['ms' + styleProp] = 'MS' + eventName;
    prefixes['O' + styleProp] = 'o' + eventName.toLowerCase();
  
    return prefixes;
  }
  
  /**
   * A list of event names to a configurable list of vendor prefixes.
   */
  var vendorPrefixes = {
    animationend: makePrefixMap('Animation', 'AnimationEnd'),
    animationiteration: makePrefixMap('Animation', 'AnimationIteration'),
    animationstart: makePrefixMap('Animation', 'AnimationStart'),
    transitionend: makePrefixMap('Transition', 'TransitionEnd'),
  };
  
  /**
   * Event names that have already been detected and prefixed (if applicable).
   */
  var prefixedEventNames = {};
  
  /**
   * Element to check for prefixes on.
   */
  var style = {};
  
  /**
   * Bootstrap if a DOM exists.
   */
  if (ExecutionEnvironment.canUseDOM) {
    style = document.createElement('div').style;
  
    // On some platforms, in particular some releases of Android 4.x,
    // the un-prefixed "animation" and "transition" properties are defined on the
    // style object but the events that fire will still be prefixed, so we need
    // to check if the un-prefixed events are usable, and if not remove them from the map.
    if (!('AnimationEvent' in window)) {
      delete vendorPrefixes.animationend.animation;
      delete vendorPrefixes.animationiteration.animation;
      delete vendorPrefixes.animationstart.animation;
    }
  
    // Same as above
    if (!('TransitionEvent' in window)) {
      delete vendorPrefixes.transitionend.transition;
    }
  }
  
  /**
   * Attempts to determine the correct vendor prefixed event name.
   *
   * @param {string} eventName
   * @returns {string}
   */
  function getVendorPrefixedEventName(eventName) {
    if (prefixedEventNames[eventName]) {
      return prefixedEventNames[eventName];
    } else if (!vendorPrefixes[eventName]) {
      return eventName;
    }
  
    var prefixMap = vendorPrefixes[eventName];
  
    for (var styleProp in prefixMap) {
      if (prefixMap.hasOwnProperty(styleProp) && styleProp in style) {
        return (prefixedEventNames[eventName] = prefixMap[styleProp]);
      }
    }
  
    return '';
  }
  
  module.exports = getVendorPrefixedEventName;
  