How to use

onMessage

function

in

Module

messaging().onMessage(async remoteMessage => {
   console.log('[FCMService] a new FCM message arrived!', remoteMessage);
   if (remoteMessage) {
    let notification = null;
    if (Platform.OS === 'ios') {
     notification = remoteMessage.data.notification;
    } else {
     notification = remoteMessage.notification;
    }
    onNotification(notification);
   }
  })

const unsubscribe = messaging().onMessage(async remoteMessage => {
  console.warn("message when app opening...", remoteMessage)
});