What is the most idiomatic way of having a `Mutabl...

# coroutines

[ursus]

What is the most idiomatic way of having a MutableSharedFlow (that acts as a trigger to refresh stuff), that has a default value (so syncs get triggered right away on start)?

I find manually throwing in `trigger.emit(Unit)`after everyone is subscriber a bit awkwards

Unless there is an API I'm not aware of, probably the best would be to have own subclass right? Like this maybe?

class TriggerFlow : Flow<Unit> {
    private val _trigger = MutableSharedFlow<Unit>(
        replay = 1
    )
    
    init {
        _trigger.tryEmit(Unit)
    }
    
    suspend fun trigger() {
        _trigger.emit(Unit)
    }
    
    override suspend fun collect(collector: FlowCollector<Unit>) {
        _trigger.collect(collector)
    }
}

How does this look? Is the tryEmit in init cool?

[streetsofboston]

You can emit values in a (MutableShared)Flow's onStart callback.

[ursus]

but that's subscription local, no? i.e. I have to do it on every callsite (?)

[streetsofboston]

createOrGetMySharedFlow().onStart { emit(Unit) }..... collect { ... } should work, I think

[streetsofboston]

This would add an onStart for each collect call

[ursus]

yea, which makes me think that populating the replay buffer would be clear, no?

[streetsofboston]

I think so, yes. But I'd need to try/test that 😁