React v0之后.49，你不需要 index.ios.js 和 index.android.js 。您只需要 index.js ：

After React v0.49, you don't need index.ios.js and index.android.js. You only need the index.js:

import {AppRegistry} from 'react-native';
import App from './app/App';

AppRegistry.registerComponent('appMobile', () => App);

（用你的名字替换 appMobile app）

(replace appMobile with the name of your app)

资料来源：（ https://github.com/facebook/react-native/releases/tag/v0.49.0 ）

从现在开始，新项目只有一个入口点（index.js）

New projects have a single entry-point (index.js) from now on