Firestore update all documents in collections

Question

I have a firestore collections named users, each users have a generated id with a field score :

users 
    0e8X3VFL56rHBxxgkYOW
        score : 4
    3SeDjr         


        

Answer 1

For some strange reason the accepted answer ( thehamzarocks ) wasn't working for me, none of the documents were updated. Maybe there's a bug in AngularFire2. Anyway, I decided to loop over the docs array of the QuerySnapshot instead of using its forEach method, and add each update to a batch queue. Batching bulk operations is also more efficient than sending a new update request for each update operation.

resetScore(): Promise<void> {
  return this.usersCollectionRef.ref.get().then(resp => {
    console.log(resp.docs)
    let batch = this.afs.firestore.batch();

    resp.docs.forEach(userDocRef => {
      batch.update(userDocRef.ref, {'score': 0, 'leadsWithSalesWin': 0, 'leadsReported': 0});
    })
    batch.commit().catch(err => console.error(err));
  }).catch(error => console.error(error))
}

Answer 2

Batch updates are nice but bare in mind that they are limited to 500 document updates per transaction. If this reset isn't done often maybe simplest approach is:

async function resetScores() {
  const collection = await db
    .collection("users")
    .get()
  collection.forEach(doc=> {
    doc.ref
      .update({
        score: 0
      })
  })
}

Answer 3

You can get all the documents in the collection, get their id's and perform updates using those id's:

db.collection("cities").get().then(function(querySnapshot) {
    querySnapshot.forEach(function(doc) {
        doc.ref.update({
            capital: true
        });
    });
});

Answer 4

Firestore doesn't have the ability to bulk update documents without knowing their IDs. You will have to somehow know the document ID of each document to update (perform a query, or do batches of queries), and update each one individually.