Ho to make this call async ```videosList forEachIndexed inde

Question

Ho to make this call async ```videosList forEachIndexed index video BaseVideo gt val userData = getUserData video calling suspend function listWithData index userData = userData ```

gildor · Answer

```val result List lt UserData gt = videosList map video gt async getUserData video awaitAll ```

gildor · Answer

But in this case you do not limit concurrency

Kulwinder Singh · Answer

gt But in this case you do not limit concurrency h

Kulwinder Singh · Answer

What does this mean please explain

gildor · Answer

it means that each item of videosList will start own coroutine

gildor · Answer

it may be fine

gildor · Answer

depends on what getUserData does

Kulwinder Singh · Answer

so does it effect perfomance

gildor · Answer

gildor · Answer

gildor · Answer

coroutine itself is cheap

Kulwinder Singh · Answer

getUserData just get Document from Firestore collection

gildor · Answer

don t know how it works so have no advices

gildor · Answer

just mention that it doesn t limit concurrency

gildor · Answer

if you want limit amount of concurrent coroutines you need working pool pattern implementation

gildor · Answer

I recommend you watch this talk from KotlinConf by Roman <https www youtube com watch v=a3agLJQ6vt8>

Kulwinder Singh · Answer

Yes thanks for link i will definitely check it out

gildor · Answer

Actually in your case you have also simple way to limit amount of parallel tasks just use chunked ```val result List lt UserData gt = videosList chunked PARALLEL COROUTINES AMOUNT flatMap videos gt videos map video gt async getUserData video awaitAll ```

Kulwinder Singh · Answer

But here i know in advance that how many items `videosList` is having it has only 5 items so i don t think i have to convert it to `chucked` i m paginating `RecyclerView` loading data 5 items each time

gildor · Answer

Then don t worry about concurrency

Kulwinder Singh · Answer

But still i think that what would happen if user scrolls list lot of time then there will be many `async` `coroutines` created so how much it will effect

gildor · Answer

as I said it depends on getUserData implementation

Kulwinder Singh · Answer

``` private suspend fun getUserData video BaseVideo UserDataAboutVideo return if currentUser = null val userDataDocument = firestore getUserDataAboutVideos currentUser uid document video videoId get await if userDataDocument exists userDataDocument toObject UserDataAboutVideo class java else null else null ```

Kulwinder Singh · Answer

await implementation is ```suspend fun lt T gt Task lt T gt await T return suspendCoroutine continuation gt this addOnCompleteListener result gt if result result = null amp amp result isSuccessful continuation resume result result else continuation resumeWithException result exception cause ```

gildor · Answer

I have no idea how Firestore is implemented and work with multiple parallel requests

Kulwinder Singh · Answer

ok No problem thanks for your all suggestions +1

Kulwinder Singh · Answer

your answers helped me alot

gildor · Answer

+1