Say I've got a class `Foo` (which I don't control)...

# coroutines

[bbaldino]

Say I've got a class Foo (which I don't control) which exposes a field incoming: ReceiveChannel<String>, and I have a custom type data class MyType(val str: String) and I want to add an extension field to Foo to expose a field incomingMyType: ReceiveChannel<MyType>. What's the best way to wrap the existing channel and map it to produce instances of MyType containing the String values? I have something equivalent to the code below working, but wondering if there's any better way. Maybe something with Flow?

val Foo.incomingMyType: ReceiveChannel<MyType>
    get() = produce {
        for (str in incoming) {
            send(MyType(str))
        }
    }

[Adam Powell]

Expose a Flow as your extension instead:

val Foo.incomingMyType: Flow<MyType> get() = incoming.receiveAsFlow()
    .map { MyType(it) }

[bbaldino]

Is receiveAsFlow pretty new? I don't seem to have it

[bbaldino]

I'm on kotlinx-coroutines-core 1.3.3 looks like

[bbaldino]

Looks like it might be in 1.4...I'm doing this in ktor which is still on coroutines 1.3

[bbaldino]

But good to know...is there a better way than mine in the meantime? (Until I get receiveAsFlow?)

[octylFractal]

it's not in 1.4, it's def. in 1.3, but maybe a later version

[Adam Powell]

it's been in for a while: https://github.com/Kotlin/kotlinx.coroutines/pull/1731

[octylFractal]

since dec 2019 according to commits

[Adam Powell]

you can declare a dependency on a newer kotlinx-coroutines-core version and ktor will happily still use it

[bbaldino]

Thanks, yeah looks like I was off by one (1.3.3 vs 1.3.4). Explicitly depending on 1.3.4 got it.

[Orhan Tozan]

Why not use the latest stable version and use 1.3.7?