index.js

// import { registerRootComponent } from 'expo';
import React from 'react';
import { AppRegistry } from 'react-native';

import messaging from '@react-native-firebase/messaging';
import Notify from 'src/singletons/Notify';

import App from './App';

// Register background handler
messaging().setBackgroundMessageHandler(async remoteMessage => {
  return new Promise(async (resolve, reject) => {
    //console.log('Message handled in the background!', remoteMessage);
    await Notify.instance.handleIncomingPushAppInBG(remoteMessage);

    resolve(true);
  });
});

function HeadlessCheck({ isHeadless }) {
  if (isHeadless) {
    // App has been launched in the background by iOS, ignore
    return null;
  }

  return <App />;
}

AppRegistry.registerComponent('main', () => HeadlessCheck);

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