Cloud functions onUpdate: Cannot read property 'forEach' of undefined

Question

Now I am trying to update the picture in my project. I could update the picture url in the cloud fire store. But also I want to delete the previous picture from the cloud storag

Answer 1

onUpdate is only looking at one document and it would appear from your screenshot of your doc that snap.before.data().sample is a string where your code is treating it like an object, or even a query snapshot?

Unless I've misunderstood, does this is correct your code?

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

const Firestore = admin.firestore;
const db = Firestore();



exports.onProductUpdate = functions.firestore.document('Product/{productId}').onUpdate(async(snap, context) => {
    const deletePost = snap.before.data().sample;
    const bucket = admin.storage().bucket();

    await bucket.file(deletePost).delete();

    return null;   // See https://firebase.google.com/docs/functions/terminate-functions
 
});