'use strict';
 
 if (typeof Promise === 'undefined') {
   // Rejection tracking prevents a common issue where React gets into an
   // inconsistent state due to an error, but it gets swallowed by a Promise,
   // and the user has no idea what causes React's erratic future behavior.
   require('promise/lib/rejection-tracking').enable();
   window.Promise = require('promise/lib/es6-extensions.js');
 }
 
 // fetch() polyfill for making API calls.
 require('whatwg-fetch');
 
 // Object.assign() is commonly used with React.
 // It will use the native implementation if it's present and isn't buggy.
 Object.assign = require('object-assign');
 
 // In tests, polyfill requestAnimationFrame since jsdom doesn't provide it yet.
 // We don't polyfill it in the browser--this is user's responsibility.
 if (process.env.NODE_ENV === 'test') {
   require('raf').polyfill(global);
 }