React native – implemented Firebase Cloud Messaging & Notifee.
I’m trying to cover all the possible notification-scenarios but having issues with some of the cases.
I do receive the notifications to my physical devices (both platforms) and most of the logics work as should.

Here is my current code:

import { PermissionsAndroid } from 'react-native';
import messaging, { FirebaseMessagingTypes } from '@react-native-firebase/messaging';
import notifee, { AndroidImportance, EventType } from '@notifee/react-native';
import { logger } from '../managers/loggingManager';
import { markNotificationAsRead } from '../apiControllers/authApi';
import { androidVersion, isIOS } from './platformUtil';

// MARK: - Create Listeners
export const initNotificationHandling = async () => {
  /** App on FOREGROUND --> display notification */
  messaging().onMessage(async remoteMessage => {
    displayForegroundNotification(remoteMessage);
  });

  /** App on FOREGROUND --> user tapped the notification
   * or
   * App on QUIT in *iOS* --> user tapped the notification to open app */
  notifee.onForegroundEvent(({ type, detail }) => {
    if (type === EventType.PRESS) {
      logger.object('FOREGROUND Notification PRESSED', detail.notification);
    }
  });

  /** App opened from BACKGROUND in *Android* */
  messaging().onNotificationOpenedApp(remoteMessage => {
    logger.object('ANDROID was opened from BACKGROUND', remoteMessage);
  });

  // vvvvvvv NOT WORKING BLOCK vvvvvvv
  const initialNotification = await notifee.getInitialNotification();
  if (initialNotification) {
    logger.object('Notification caused application to open', initialNotification.notification);
    logger.object('Press action used to open the app', initialNotification.pressAction);
  }

  /** App on QUIT --> user taps "mark as read" on notification */
  notifee.onBackgroundEvent(async ({ type, detail }) => {
    const { notification, pressAction } = detail;
    if (!notification || !pressAction) return;
    if (type === EventType.ACTION_PRESS && pressAction.id === 'mark-as-read' && notification.id) {
      await markNotificationAsRead(notification.id);
      await notifee.cancelNotification(notification.id);
    }
  });
};


// MARK: - Display Notification
const displayForegroundNotification = async (
  remoteMessage: FirebaseMessagingTypes.RemoteMessage
) => {
  logger.object('FOREGROUND Notification received', remoteMessage.notification);

  // mandatory for Android
  const channelId = await notifee.createChannel({
    id: 'General',
    name: 'General Notifications',
    importance: AndroidImportance.HIGH,
  });

  try {
    await notifee.displayNotification({
      title: remoteMessage.notification?.title,
      body: remoteMessage.notification?.body,
      android: { channelId, importance: AndroidImportance.HIGH },
    });
  } catch (error) {
    logger.error(`Error displaying FOREGROUND Notification: ${error}`);
  }
};

The entire initNotificationHandling function is called first thing on my appInit logic.

What I still can’t figure out –

1. App was QUIT in Android and opened from tapping notification – how do i access the notification? My current code doesn’t work – the await notifee.getInitialNotification() always returns null.
2. What do i need messaging().setBackgroundMessageHandler() for? From my understanding its functionality is already covered in my other code.
3. How do I make my notification have the option to marked as read? So I can test if the network request is actually being sent and that code is indeed working.

I assume I did implement FCM correctly as I am getting the FCM token and am receiving notification to my devices via Postman. I did request permissions in both platforms as documented.

I’ve read the entire Firebase Cloud Messaging documentation as well as Notifee’s documentation.
Tried a bunch of online guides on Medium.
Also ChatGPT wasn’t helpful.