How can I emit the result to the consumer from a different function. When I try the following nothin...

# coroutines

[MRSasko]

How can I emit the result to the consumer from a different function.
When I try the following nothing happens?

fun fetchInfo(): Flow<State<SportInfo>> =
    flow {
      val result = memoryInfoResult
      if (result != null) {
        emit(result)
      } else {
        fetchSportInfo()
        .onEach { result ->
          when (result) {
            is Data -> {
              memoryInfoResult = result
              emit(result)
            }
            is Error, is Loading -> {
              emit(result)
            }
          }
        }
      }
    }

[Nick Allen]

Replace onEach with collect . onEach is not a terminating operator (not one that actually runs the flow).

[Nick Allen]

Also, this code is setup so if you have a cached result, you will never return anything else (updates are in an else).

[Nick Allen]

And remember that Flow is cold. So if you have 5 collectors, then they are all updating memoryInfoResult. Usually for something with shared data, I prefer a SharedFlow. Should be able to just tack .shareIn(someScope, SharingStarted.WhileSubscribed()) at the end which will run the flow only once for any number of subscribers at a time.

[MRSasko]

thanx @Nick Allen. It helped to replace onEach with collect. I also had to change the flow builder to channelFlow , and replace emit with send .

I only have one collector right now. But I might add more at some point.

[MRSasko]

Why is the channelFlow necessary in this example?

[Nick Allen]

not sure, I wouldn't expect it to be needed from collect, channelFlow is needed any time you are dealing with multiple coroutine contexts which takes extra overhead to deal with correctly. flow is optimized for cases where you don't need that overhead.