I have two listeners - one for the user's profile and one for the rooms the user is in; the uids of the rooms are stored in an array on the profile, i.e. the query for the second listener depends on data from the first.

It looks like this (simplified):

// profile listener
onSnapshot(profileRef, (snapshot) => setProfile(snapshot.doc.data())

// rooms listener
const roomsQuery = query(
  collection(db, "rooms")
  where("uid", "in", profile.roomsList)
)
onSnapshot(roomsQuery, (snapshot) => setRooms(snapshot.docs)

When the user is added to a new room, the profile updates with the new roomsList. But the rooms snapshot doesn't update - presumably because the query can't be updated dynamically.

Question

So, is there a way of updating the listener's query (i.e. keeping the same listener), or do I have to unsubscribe from the existing listener and re-subscribe with the new query every time profile is updated?

Versions

Using the new V9 of the Javascript sdk

CodePudding user response：

Firestore queries are immutable, so there's no way to change the condition once the query has been created. You'll indeed have to attach a listener to a new query to get the updates roomsList. If you enable offline persistence though, the overlapping documents between the queries will be read from the local cache.

Also see: How to constantly update query for Firebase Realtime Database with LiveData and ViewModel in Android