polyfills.js

// @remove-on-eject-begin
/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */
// @remove-on-eject-end

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');