create-react-native-library/templates/expo-library/example/index.js

CLI to scaffold React Native libraries

import { registerRootComponent } from 'expo';

import App from './src/App';

// registerRootComponent calls AppRegistry.registerComponent('main', () => App);
// It also ensures that whether you load the app in Expo Go or in a native build,
// the environment is set up appropriately
registerRootComponent(App);