How can I use Firebase Functions to send FCM to user?

Question

Firebase currently rolled out Firebase Functions to add server side code

Firebase Functions

I was wondering if there could be a way to call FCM notifications through those functions when there is some change in database.

Answer 1

Firebase SDK for Cloud Functions includes the Firebase Admin SDK, you can find an example that we made here Send Firebase Cloud Messaging notifications for new followers

In brief:

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

exports.foo = functions.database.ref('/bar').onWrite(event => {
  const tokens = ...;
  const payload = ...;
  return admin.messaging().sendToDevice(tokens, payload);  
})