Let's say I have this flow ```fun loadUsersByRegion(regions: List<String>): Flow<List<Us...

# android

[pers]

Let's say I have this flow

fun loadUsersByRegion(regions: List<String>): Flow<List<User>>

I want to call fetchInfo on each item without nesting map....

fun fetchInfo(user: User): Info

is there any better?

.flatMapConcat { users ->
            flow {
                val usersInfo = users.map { user -> fetchInfo(user) }
                emit(usersInfo)
            }
        }

[Chris Fillmore]

Why does loadUsersByRegion return a flow? It could suspend and return a List of Users

[pers]

it is roomdb

[gildor]

Direct replacement would be:

.flatMapConcat { users ->
 flowOf(users.map { fetchInfo(it) })
}

So at least there is no need to explicitly call emit

[gildor]

But not sure about your usage of flatMapConcat for this, looks that I would prefer to use flatMapLatest, to cancel previus fetchInfo if update list of users already loaded, so it wouldn't create situation when a buch of updates of loadUsersByRegion() running one by one and slowdown actual emit of Info (because concat waits for every item)
Still not very efficient, concidering that we request it again for any change in list of users, even if only one record is changes

If fetchInfo is DB call, I feel that it must be done on DB level, if network, I would think about caching info for users instead