I am making a chat application where I am trying to send push notifications to when one user sends a message to the other user.

I am using firebase cloud functions with JavaScript and in the firebase functions log I can see that it's able to get the user who sends the message and the user who receives the message. But for some reason It's showing me that the token is empty.

Even though I have a token and I am able to print it in the log(The screenshot of firebase cloud functions log where you can see that token is being printed and I have partially marked over it).

For more reference I am also attaching the screenshot of my two collections in firebase -

1. All the users collection where the push token is being saved.(The structure is users>uid>{user_info}).

2. The chat collection screenshot where you can see the structure of chats.(The structure here is chatroom>chatid>chats>{chat_documents}).

My index.js file in functions folder for firebase is below-

const functions = require('firebase-functions')
const admin = require('firebase-admin')
admin.initializeApp()

exports.sendNotification = functions.firestore
  .document('chatroom/{chatId}/chats/{message}')
  .onCreate((snap) => {
    console.log('----------------start function--------------------')

    const doc = snap.data()
    console.log(doc)

    const idFrom = doc.idFrom
    const idTo = doc.idTo
    const contentMessage = doc.mesaage

    console.log(`Starting to push token`)
    // Get push token user to (receive)
    admin
      .firestore()
      .collection('users')
      .where('uid', '==', idTo)
      .get()
      .then(querySnapshot => {
        querySnapshot.forEach(userTo => {
          console.log(`Found user to: ${userTo.data().name}`)
          console.log(`Found user to: ${userTo.data().pushtoken}`)
          try {
            // Get info of the user who is sending the message
            admin
              .firestore()
              .collection('users')
              .where('uid', '==', idFrom)
              .get()
              .then(querySnapshot2 => {
                querySnapshot2.forEach(userFrom => {
                  console.log(`Found user from: ${userFrom.data().name}`)
                  const payload = {
                    notification: {
                      title: `"${userFrom.data().name}"`,
                      body: contentMessage,
                      badge: '1',
                      sound: 'default'
                    }
                  }
                  // Lets push to the target device
                  admin
                    .messaging()
                    .sendToDevice(payload,userTo.data().pushtoken)
                    .then(response => {
                      console.log('Successfully sent message:', response)
                    })
                    .catch(error => {
                      console.log('Error sending message:', error)
                    })
                })
              })
          } catch(e){
            console.log('Can not find pushToken target user')
          }
        })
      })
    return null
  })

What might be the problem here as I am not able to figure it out? Your help would be really appreciated. Also kindly let me know if you want any more information regarding the same.