I have state I want to share between `onStart` and `onCompletion` of a `Flow`. (Basically open a res...

# coroutines

[Dominaezzz]

I have state I want to share between onStart and onCompletion of a Flow. (Basically open a resource in onStart and close it in onCompletion) What's the most idiomatic way besides reinventing the wheel?

[gildor]

But it's how flow works by default, just use flow {} block

[elizarov]

➕ Do this:

fun <T> Flow<T>.myOperator() = flow {
    try {
         openResource()
         emitAll(this@myOperator)
    } finally {
         closeResource()
    }
}

[bnn]

@elizarov Is it the case when it comes to channelFlow ?

[bnn]

(I asked this question because usually I use channelFlow to wrap callback based api, creating callback object inside channelFlow {} block and closing it in awaitClose {})

[bnn]

👆 is something like this
https://github.com/bananaumai/android-suburi/blob/master/sensor-and-coroutines/app/src/main/java/dev/bananaumai/android/suburi/sensor_and_coroutines/MainActivity.kt#L90

[gildor]

For callbacks yes, use channelFlow/callbackFlow, but this question not about callbacks, as I understand, awaitClose tho of course useful, but actual implementation depends on what is happening after onStart

[bnn]

Yeah, actually it depends. thanks @gildor