Deleted Firestore documents still being retrieved

Question

I have deleted some documents through a batch delete from a trigger in Cloud Functions. The console shows them as being deleted, however, my app still retrieves the docs! Th

Answer 1

Probably you have the problem, that the app uses the cache and loads as well some documents from it. One thing you could try is to disable the offline persistence.

If you're using Android with Real-Time Database you could try this:

FirebaseDatabase.getInstance().setPersistenceEnabled(true);

iOS + Real-Time Database

Database.database().isPersistenceEnabled = true

If you're using FireStore then use the following:

Android:

FirebaseFirestoreSettings settings = new FirebaseFirestoreSettings.Builder()
        .setPersistenceEnabled(false)
        .build();
db.setFirestoreSettings(settings);

iOS:

let settings = FirestoreSettings()
settings.isPersistenceEnabled = false

// Any additional options
// ...

// Enable offline data persistence
let db = Firestore.firestore()
db.settings = settings

Answer 2

Documents remain fetchable for a while after deletion. Their existence status rely on the DocumentSnapshot property - 'exists' and can be read and filtered in the pipe with snapshotChanges() method for docs and collections. See the example below:

...
.snapshotChanges()
      .pipe(
        map((actions: DocumentChangeAction<T>[]) => {
          return actions
            .filter((a: DocumentChangeAction<T>) => a.payload.doc.exists)
            .map((a: DocumentChangeAction<T>) => {
              const data: T = {...a.payload.doc.data() as {}} as T;
              data['id'] = a.payload.doc.id;
              return data;
            });
        })
      );