Map items of collection snapshot in Firebase Firestore

Question

Firebase Firestore Guides show how to iterate documents in a collection snapshot with forEach:

db.collection("cities").get().then(function(querySnapshot) {     querySnapshot.forEach(function(doc) {         console.log(doc.id, " => ", doc.data());     }); }); 

I imagined it would support map as well, but it doesn't. How can I map the snapshot?

Answer 1

The answer is:

querySnapshot.docs.map(function(doc) {   # do something }) 

The Reference page for Firestore reveals the docs property on the snapshot.

docs non-null Array of non-null firebase.firestore.DocumentSnapshot

An array of all the documents in the QuerySnapshot.

Answer 2

Got pretty sick and tired of Firestore returning stuff in their classes or whatever. Here's a helper that if you give it a db and collection it will return all the records in that collection as a promise that resolves an actual array.

const docsArr = (db, collection) => {   return db     .collection(collection)     .get()     .then(snapshot => snapshot.docs.map(x => x.data())) }  ;(async () => {   const arr = await docsArr(myDb, myCollection)   console.log(arr) })()