react native 的js 文件从哪里获取

 /**
   * Loading JavaScript code - uncomment the one you want.
   *
   * OPTION 1
   * Load from development server. Start the server from the repository root:
   *
   * $ npm start
   *
   * To run on device, change `localhost` to the IP address of your computer
   * (you can get this by typing `ifconfig` into the terminal and selecting the
   * `inet` value under `en0:`) and make sure your computer and iOS device are
   * on the same Wi-Fi network.
   */

  jsCodeLocation = [NSURL URLWithString:@"http://localhost:8081/index.ios.bundle?platform=ios&dev=true"];

  /**
   * OPTION 2
   * Load from pre-bundled file on disk. To re-generate the static bundle
   * from the root of your project directory, run
   *
   * $ react-native bundle --minify
   *
   * see http://facebook.github.io/react-native/docs/runningondevice.html
   */

//   jsCodeLocation = [[NSBundle mainBundle] URLForResource:@"main" withExtension:@"jsbundle"];

　　翻译下就是：

（1）通过本地的npm start 直接运行，需要编译，首次运行会比较慢

（2）获取jsbundle 的文件，直接运行。发布模式，也可以通过js 在线更新了。