firebase Nodejs async cloud function not finishing execution - node.js

Question

I am building a firebase cloud function that when I change a value in my db, I get UIDs of all users in db then check a node called wishlists to see if the user has products in one of his wishlists. if the wishlists of the users do not have products the cloud function sends a notification to the user with a msg to fill his wishlist. The function works for one user but when I iterate the user's nodes and call the work that I do for one user, it finishes before completing all the work. I believe that the probléme comes from not handling properly the async functions. Any help is appreciated. Thanks!
const functions = require('firebase-functions');
const admin = require('firebase-admin');
const runtimeOpts = {
timeoutSeconds: 180,
memory: '1GB'
}
admin.initializeApp(functions.config().firebase);
exports.sendAdminNotificationForEmptyWishlists = functions.runWith(runtimeOpts)
.database.ref('/dev/fireNotifCloudFunc')
.onWrite(async () => {
// get all users uids
const ref = admin.database().ref().child('Influencers')
return ref.once("value")
.then(function(snapshot) {
snapshot.forEach( async function(child) {
await checkUserWishlists(child.key)
})
})
.catch(function(error){
console.log(error);
});
});
//check users wishlists
async function checkUserWishlists(uid){
var ref = admin.database().ref().child('Articles').child(uid)
ref.once("value")
.then(function(snapshot) {
if(snapshot.exists()){
const wishlistsNumber = snapshot.numChildren();
let wishlistCount = 0
let userHasProduct = false
var BreakException = {};
try {
snapshot.forEach(function(child) {
wishlistCount = wishlistCount + 1
//wishlist node
if(child.child("articles").exists()){
//user have not empty wishlist
userHasProduct = true
throw BreakException
}
});
}
catch(err){
if (err !== BreakException) throw err;
}
if((wishlistCount === wishlistsNumber) && !userHasProduct){
let fcmToken = (async () => {
fcmToken = await getUserFirestoreFCM(uid).then(()=>{
sendPushNotificationToUser(fcmToken,"emptyWishlists")
return fcmToken
})
.catch((error)=>{
console.log("error getting fcm token " + error);
})
})();
}
}
else{
console.log("user did not exist in articles node" );
return
}
})
.catch(function(error){
console.log(error);
});
}
async function getUserFirestoreFCM(uid){
let documentRef = admin.firestore().doc("users_table/" + uid);
documentRef.get().then(documentSnapshot => {
if (documentSnapshot.exists) {
console.log('Document exist')
return documentSnapshot.get('fcmToken')
}
else {
console.log('Document dosen\'t exist')
return
}
})
.catch(function(error){
console.log('error geting fcm token from firestore ' + error);
})
}
async function sendPushNotificationToUser(fcm,type){
//get fcm token
if(type === "emptyWishlists"){
//notification content
const payloadEmptyWishlists = {
notification: {
title: `Vos wishlists sont vides !`,
body: "Hello veuillez ajouter des produits dans vos wishlists pour joindre les
influenceurs dans le fil d'acceil, cheers ! ",
icon: "default",
sound: "default"
}
};
const options = {
priority: "high",
timeToLive: 60 * 60 * 24
};
//send notif
return admin.messaging().sendToDevice(fcm,
payloadEmptyWishlists,options).then(function(response){
console.log('Notification sent successfully:',response);
return
})
.catch(function(error){
console.log('Notification sent failed:',error);
});
}
}
this is a screeshot from the logs

Answer 1

I think you should not use async/await in forEach loop callaback. This generally is tricky. Searching for good explanation I have found this article. I think its very short and clear.
In this situation I don't think that you need this async/await, but I would have to implement it to be sure. Anyway, if it appear that you still need async there is workaround in mentioned article.