Is the only way to make a step in a flow concurrent by using flatMapMerge? I have a transform step t...

# coroutines

[dave08]

Is the only way to make a step in a flow concurrent by using flatMapMerge? I have a transform step that can be made concurrent (it uses network requests), can I just use a withContext on it?

[Dennis Schröder]

If I understand your querstion right, my answer is:

There is a async-version of

flow::map
flow::filter
flow::onEach

flow::transform
and others ... https://kotlinlang.org/docs/reference/coroutines/flow.html#terminal-flow-operators

[dave08]

The only one of those that has a concurrency parameter is flatMapMerge... which I think collects each flow it receives in another coroutine... but I was wondering if I could avoid that... I think this question was asked before a few times... there might have been some updates since though...?

[Dennis Schröder]

https://kotlinlang.org/docs/reference/coroutines/flow.html#flowon-operator

[Dennis Schröder]

Maybe this helps you

.flowOn(Dispatchers.Default)

[dave08]

That seems to create only one coroutine running on one other thread for the whole chain of operations before the collect. Whereas to have EACH one of the transforms run on a different coroutine, it wouldn't be sufficient as far as I understand...

[Dennis Schröder]

Haven´t read it yet, but might help you

https://medium.com/@elizarov/execution-context-of-kotlin-flows-b8c151c9309b

[dave08]

Thanks for reminding me about that article 🙂 ...