For a channel what is the opposite of a flatMap, in other words how to take a channel of some array ...

# coroutines

[Luis Munoz]

For a channel what is the opposite of a flatMap, in other words how to take a channel of some array and start sending the values individually?

[bdawg.io]

Are you saying Channel<Array<T>> and flatten it to Channel<T>?

[Luis Munoz]

yes exactly

[Dennis]

I edited the example from https://kotlinlang.org/docs/reference/coroutines/channels.html#pipelines

fun <T> CoroutineScope.flatten(channel: ReceiveChannel<Array<T>>): ReceiveChannel<T> = produce {
    for (items in channel) {
        for(item in items) send(item)
    }
}

However there could be something already that i don't know...

[Luis Munoz]

cool thanks!

[bdawg.io]

If you're going to do other operators, you should consider using a Flow

val myChannel = channel
    .consumeAsFlow()
    .flatMapConcat { it.asFlow() }
    .filter { ... }
    .map { ... }
    .produceIn(myScope)

[Dennis]

very nice. Also https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.channels/flat-map.html suggests that it's deprecated in favor of flow