Hi, how can I run concurrent coroutines and wait all are done (like Promise.all in JS) ? I see the m...

# coroutines

[mmaillot]

Hi, how can I run concurrent coroutines and wait all are done (like Promise.all in JS) ? I see the method with a map which create Deferred then call await() :

data.map {
                async(Bg) { it.httpGet().response() }
            }.map {
                it.await()
            }

Is it the good approach ?

[louiscad]

@mmaillot Yes, it is!

[mmaillot]

Good, thank you! Do you know how to write a race condition ? I mean await until the first coroutines is done.

[gildor]

Also there is a proposal to add extension function for such cases:
https://github.com/Kotlin/kotlinx.coroutines/issues/171
But for now you can write such function yourself

[gildor]

Race condition? What do you mean?
To wait when first coroutine is done just call await on first coroutine. But actually this code already does this

[mmaillot]

Like Promise.race in JS, I want to wait until one of my coroutine is complete (not nessary the first but the fastest)

[uhe]

you can use select together with Deferred.onAwait for that

[venkat]

Here’s a few PromiseJS like operations on lists of Deferreds: https://github.com/venkatperi/kotlin-coroutines-lib/blob/master/docs/com.vperi.kotlinx.coroutines.experimental/kotlin.collections.-iterable/index.md