text: /**
   * 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.
   *
   * @flow
   */
  
  export type MessageHandler = (message: Object) => mixed;
  
  export default class Bridge {
    _messageHandler: ?MessageHandler;
  
    setMessageHandler(handler: MessageHandler) {
      this._messageHandler = handler;
      return this;
    }
  
    postMessage(msg: string | Object) {
      throw new Error('Subclasses of Bridge should implement their own postMessage()');
    }
  }
  