How do I make

Flow.transformLatest()

complete when upstream completes?

upstream
  .transformLatest { state ->
    emitAll(dataForState(state))
  }

say upstream is

currentState
  .takeWhile { state -> isCloseNowState(state) }

This would be easy if I had control of it, I could use

transformWhile

, what if I don't? How do I cancel

dataForState

when upstream completes? Actually, this is challenging even when I use

transformWhile()

cause it is not cancelling the previous one I'd need a

transformLatestWhile

I believe there is a

transformWhile

.

Sure, what if the

observeState
  .takeWhile { state -> isStopState(state) }

comes from upstream / a function I've no control in?

Oh nvm, I think just understood the problem.

In other words, how do I tell

transformLatest

to stop when upstream completes?

You can use

onCompletion

and emit a cancellation token.

I did something like this

upstream
  .map { it as MyState? }
  .onComplete { emit(null) }
  .transformLatest { state ->
    if (state != null) {
      emitAll(dataForState(state)
    }
  }

if I had a nullable emission I could have build a wrapper and did the same

Nice