Node JS FCM token not sending notification to user

Question

I'm trying to send a notification based on the user FCM token, I have used the firebase function to successfully send a notification if there are any changes to the firebase database for that particular user. But currently, the node.JS function does not provide any logs messages/notification sent to the user. Please do help me in resolving these issues.

//import firebase functions modules
const functions = require('firebase-functions');
//import admin module
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);


// Listens for new messages added to messages/:pushId
exports.pushNotification = functions.database.ref('/Notification/{receiver_id}/push_id/{job_id}').onWrite((data, context) => {

  const receiver_id = context.params.receiver_id;
  const job_id = context.params.job_id;
  console.log('Start');
  console.log('receiverID : ' + receiver_id);
  console.log('jobID : ' + job_id);

  const DeviceToken = admin.database().ref(`/User/${receiver_id}/fcmtoken`).once('value');

    return DeviceToken.then(result => 
    {
        const token_id = result.val();
        console.log(token_id);
        const payload = 
        {
            notification:
            {
                title: "New Job Request",
                body: `JobID ` + job_id,
                tag: collapseKey,
                icon: "default",
                color: '#18d821',
                sound: 'default',
            }
        };

        return admin.messaging().sendToDevice(token_id, payload)
        .then(response => 
            {
                console.log('This was a notification feature.');
                return null;

            })
            .catch(function(error) {
                console.log('Error sending message:', error);
            });
    });
});

It's not displaying any log messages or any notification.

Answer 1

You are using the incorrect promise. The sendToDevice may be abort when the triggger function finish because it isn't waiting for that promise.

exports.pushNotification = functions.database.ref('/Notification/{receiver_id}/push_id/{job_id}').onWrite((data, context) => {

  const receiver_id = context.params.receiver_id;
  const job_id = context.params.job_id;
  console.log('Start');
  console.log('receiverID : ' + receiver_id);
  console.log('jobID : ' + job_id);

  const DeviceToken = admin.database().ref(`/User/${receiver_id}/fcmtoken`).once('value');

  return DeviceToken.then(result => 
    {
        const token_id = result.val();
        console.log(token_id);
        const payload = 
        {
            notification:
            {
                title: "New Job Request",
                body: `JobID ` + job_id,
                tag: collapseKey,
                icon: "default",
                color: '#18d821',
                sound: 'default',
            }
        }; 
        return admin.messaging().sendToDevice(token_id, payload) 
    })
    .then(response => {
        console.log('This was a notification feature.');
        return null; 
    })
    .catch(function(error) {
        console.log('Error sending message:', error);
    });                
});