How could you create `sharedFlow` builder with the...

# coroutines

[hfhbd]

How could you create sharedFlow builder with the same signature like the cold flow builder: fun<T> sharedFlow(block: suspend FlowCollector<T>): SharedFlow<T>? It always requires a CoroutineScope...

[ephemient]

what would it mean to create a shared flow without a scope? if it didn't, and you ran

sharedFlow.collect() // in scope 1
sharedFlow.collect() // in scope 2 in parallel

then cancelled one of the scopes, in what scope should the single shared producer be running?

[hfhbd]

I don't understand your problem. Currently, you could do this:

fun<T> sharedFlow(block: MutableSharedFlow<T>.() -> Unit): SharedFlow<T> = MutableSharedFlow<Int>().apply(block)

val sf = sharedFlow {
    tryEmit(42)
}

But would like to use emit (and FlowCollector) instead.

[ephemient]

if sf were a plain flow, then tryEmit runs as a child within the scope of each collector

[ephemient]

but since it's a SharedFlow, there should be a single coroutine running tryEmit regardless of how many parallel collectors there are

[ephemient]

how should that work? if you pick the first collector, what do you do when it's cancelled?

[hfhbd]

Oh, after canceling the first collector, the SharedFlow should still emit the values, no matter how many collectors are actually subscribing.

[ephemient]

so… how would that even work? you can't re-parent the running coroutine

[hfhbd]

I want to have one SharedFlow acting as producer and multiple consumer... But yeah, after reading it again, the producer needs its own scope to run independently.

[Orhan Tozan]

@hfhbd you looking for produce { } ?

[hfhbd]

Not really, produce returns a channel, I want to get a SharedFlow.

[Orhan Tozan]

Why do you want to get a SharedFlow?

[hfhbd]

Because I want to migrate from BroadcastChannel to ShareFlow.

[Orhan Tozan]

What is your code trying to do?

[hfhbd]

It listens a hot event source and should broadcast these values to each subscriber, if present.

[Orhan Tozan]

Yes, you can do produce { ... }.receiveAsFlow()

[hfhbd]

Yeah, but why? I am currently using broadcast and want to migrate it to SharedFlow. Why should I use produce?

[Orhan Tozan]

Why do you want to migrate to SharedFlow if produce does what you want?
I could help you better if you could share your code piece🙂