Is there a way to chain `onEach` with `MutableStateFlow` and return a `MutableStateFlow`? My use ca...

kevin.cianfarini

10/27/2020, 3:07 AM

Is there a way to chain

onEach

with

MutableStateFlow

and return a

MutableStateFlow

? My use case -- calling

SavedStateHandle.getLiveData(key: String)

will automatically save new emissions to that live data into the saved state. I would like something like this to be possible with StateFlow

Copy code

fun <T> SavedStateHandle.getStateFlow(key: String, defaultValue: T): MutableStateFlow<T> {
    return MutableStateFlow(this[key] ?: defaultValue).onEach {
        this[key] = it
    }
}

However,

onEach

returns a regular instance of

Flow

. Is this something that's been discussed? If not, I'm more than willing to open an issue.

Zach Klippenstein (he/him) [MOD]

10/27/2020, 4:17 PM

I asked about this sort of thing a few months ago, the response was “it’s harder than it looks” for transforming operators, but I don’t think that argument applies to side effect operators like