node_modules/prop-types/index.js

/**
 * 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.
 */

if (process.env.NODE_ENV !== 'production') {
  var ReactIs = require('react-is');

  // By explicitly using `prop-types` you are opting into new development behavior.
  // http://fb.me/prop-types-in-prod
  var throwOnDirectAccess = true;
  module.exports = require('./factoryWithTypeCheckers')(ReactIs.isElement, throwOnDirectAccess);
} else {
  // By explicitly using `prop-types` you are opting into new production behavior.
  // http://fb.me/prop-types-in-prod
  module.exports = require('./factoryWithThrowingShims')();
}