Is it possible to get all documents in a Firestore Cloud Function?

Question

I want to update a value on all documents in a collection using cloud functions as they are dependent on the creation date, but looking through the Cloud Firestore Triggers

Answer 1

You'd typically use the Admin SDK for that in your Cloud Functions code. Once you have that, it's a matter of read the collection as usual. Check the node examples in the firebase documentation on reading all documents from a collection:

const admin = require('firebase-admin');

admin.initializeApp({
    credential: admin.credential.applicationDefault()
});

var db = admin.firestore();

var citiesRef = db.collection('cities');
var allCities = citiesRef.get()
    .then(snapshot => {
        snapshot.forEach(doc => {
            console.log(doc.id, '=>', doc.data());
        });
    })
    .catch(err => {
        console.log('Error getting documents', err);
    });

Answer 2

Its possible. if you want to get your document inside array. Without foreach.

const admin = require('firebase-admin');
admin.initializeApp({
    credential: admin.credential.applicationDefault()
});

const docRef = admin.firestore().collection('cities');
docRef.get()
.then(snapshot => {
    let arrayR = snapshot.docs.map(doc => {
       return doc.data();
    }); 
    res.json(arrayR);        
}).catch(function(error){
    console.log("got an error",error);        
})