Error getting document ReferenceError: from_data is not defined - node.js

Question

Hi I'm stuck at the part where I get error when getting documents. I want to get the fields for users name.
This is the result i get from the console log: From user id: PGIfPp8wmnR1PB1XeiBfUgSnGO62From user: [object Promise] To user id [object Promise].
What am i doing wrong ?
index.js
'use strict'
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();
const db = admin.firestore();
exports.sendNotification = functions.firestore.document('users/{userID}/notifications/{notificationID}')
.onWrite((change, context) => {
const user_id = context.params.userID;
const notification_id = context.params.notificationID;
console.log('We have notification from: ' + user_id + ' The notification id is: ' + notification_id);
return db.collection('users').doc(user_id)
.collection('notifications').doc(notification_id).get().then(queryResult => {
if (!queryResult.exists) {
console.log('No documents');
}else{
console.log("Document data: " ,queryResult.data());
const from_user_id = queryResult.data().from;
const from_data = admin.firestore().collection('users').doc(from_user_id).get();
const to_data = admin.firestore().collection('users').doc(user_id).get();
console.log("From user id: " + from_user_id + "From user: " + from_data + " To user id " + to_data);
}
return Promise.all([from_data, to_data]).then(result => {
const from_name = result[0].data().name;
const to_name = result[1].data().name;
return console.log("FROM: " + from_name + " TO: " + to_name);
});
}).catch(err =>{
console.error('Error getting document', err);
})
});
Error i get
Error getting document ReferenceError: from_data is not defined
at db.collection.doc.collection.doc.get.then.queryResult (/user_code/index.js:31:37)
at process._tickDomainCallback (internal/process/next_tick.js:135:7)

Answer 1

In these two lines:
const from_data = admin.firestore().collection('users').doc(from_user_id).get();
const to_data = admin.firestore().collection('users').doc(user_id).get();
You're assinging values to promises that will resolve with document data. You haven't got actual document data yet. You need to use the promises returned by get() to find the actual data, just like you're doing earlier in your function.