I want to send the user a push notification with cloud functions on Firebase if someone commented to a topic on his iOS Device. This code below works fine if I put the content of the notification manually.

const functions = require('firebase-functions');
const admin = require('firebase-admin');

admin.initializeApp();

   exports.Push = functions.database.ref('/placeID/{pushId}/')
   .onCreate((snapshot, context) => {
 

      var topic = 'weather';
      const payload = {
          notification: {
              title: 'User Max',
              body: 'Hi how are you?',
              badge: '1',
              sound: 'default'
          }
     };
  
     admin.messaging().sendToTopic(topic,payload);

   })

In the next step I want to get the content of the comment the person has sent. Kinda get the value of the snapshot. I tried it like this and get no error in the Logs Explorer from Google. But also no Push Notification anymore.

const functions = require('firebase-functions');
const admin = require('firebase-admin');

admin.initializeApp();

   exports.Push = functions.database.ref('/placeID/{autogeneratedplaceID}/')
   .onCreate((snapshot, context) => {
 
      var username = snapshot.child("userName").val()
      var usercomment = snapshot.child("userComment").val()

      var topic = 'weather';
      const payload = {
          notification: {
              title: username,
              body: usercomment,
              badge: '1',
              sound: 'default'
          }
     };
     admin.messaging().sendToTopic(topic,payload);
   })

What is wrong here? I also found a video on Youtube with the exact solution. But this is for android and it did not really help me. Youtube

This is how my firebase realtime database structure looks like.