config/polyfills.js

// Copyright (c) 2017 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

(/* istanbul ignore next */ function() {
  /* istanbul ignore if */
  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');
}());