Has anyone ran into use cases for overloads of `Flow` operat

Question

Has anyone ran into use cases for overloads of `Flow` operators for `StateFlow` that preserve the `value` property I filed an issue for `map` here curious if people have other use cases or use cases for other operators or opinions about this proposal <https github com Kotlin kotlinx coroutines issues 2081>

streetsofboston · Answer

Why hot hold a second reference a reference to the original StateFlow Or collect the result Flow again causing the current state to be collected I can imagine something like this for `map` but it wouldn t work for `filter` for example

streetsofboston · Answer

I think the same is true for Rx Calling `map` a Processor Subject returns an `Observable` or `Flowable`

Zach Klippenstein (he/him) [MOD] · Answer

Yea the number of operations this makes sense for is pretty small

Zach Klippenstein (he/him) [MOD] · Answer

The difference from Rx is that `Subject` isn t a read only type and isn t suitable for exposing as such

Zach Klippenstein (he/him) [MOD] · Answer

gt Why hot hold a second reference a reference to the original StateFlow I m not sure what you mean For my use case the underlying `StateFlow` is completely hidden as an implementation detail of a class and only the more limited state subset is exposed

streetsofboston · Answer

The class wrapping hiding the StateFlow could expose a property getting its StateFlow s `value`

Zach Klippenstein (he/him) [MOD] · Answer

Doesn t that defeat the purpose of having `StateFlow` as a separate read only type in the first place

streetsofboston · Answer

I am playing the devil s advocate here I can see the usefulness but it seems very very limited to me

Zach Klippenstein (he/him) [MOD] · Answer

I appreciate it it also seems limited to me so I m trying to play devils advocate on myself sweat smile

Zach Klippenstein (he/him) [MOD] · Answer

I can also do something like this but it feels verbose and over complicated for a simple map ```totalState map it partialState stateIn scope initialValue = totalState value partialState ```

Zach Klippenstein (he/him) [MOD] · Answer

It was just pointed out that this is a duplicate issue and the original was closed with the rationale Any chain of operators on a state flow can be materialized into another StateFlow using stateIn operator so that answers that <https github com Kotlin kotlinx coroutines issues 2008 issuecomment 632614208>

bezrukov · Answer

will not it a bit misleading since StateFlow provides distinctUntilChanged behavior I mean let s say stateFlow contains 0 1 2 3 4 5 `stateFlow map it 2 ` will produce 0 1 2 which most likely unexpected there

Zach Klippenstein (he/him) [MOD] · Answer

That seems like reasonable behavior In my view using `StateFlow` implies that the values being emitted represent state and two states that are equivalent are not interesting