Is there something wrong with the design of this method It s both a `suspend fun` but also returns a Flow And the first line can t be caught like this because it s not inside the Flow ```suspend fun getChatUserFlow uid String Flow lt ChatUser gt val results = userCollection whereEqualTo FieldPath documentId uid get await return if results isEmpty results documents 0 reference asFlow lt ChatUser gt else flowOf null ```

Thanks that s a useful rule of thumb +1

Is there something wrong with the design of this method It s kotlinlang #coroutines

12/05/2020, 2:16 PM

Is there something wrong with the design of this method? It's both a

suspend fun

but also returns a Flow. And the first line can't be caught like this because it's not inside the Flow.

suspend fun getChatUserFlow(uid: String): Flow<ChatUser?> {
        val results = userCollection.whereEqualTo(FieldPath.documentId(), uid).get().await()
        return if (!results.isEmpty) {
            results.documents[0].reference.asFlow<ChatUser>()
        } else {
            flowOf(null)
        }
    }

Here is my new approach, I guess this makes more sense:

fun getChatUserFlow(uid: String): Flow<ChatUser?> =
        userCollection.whereEqualTo(FieldPath.documentId(), uid).asFlow<ChatUser>().flatMapLatest { result ->
            if (!result.isEmpty()) {
                userCollection.document(result[0].uid!!).asFlow()
            } else {
                flowOf(null)
            }
        }

12/06/2020, 12:24 AM

Yes, combining Flow with suspend function is usually not what you need

12/06/2020, 7:23 AM

Thanks, that's a useful rule of thumb 👍