I came across a sample application (Google's NowIn...

# coroutines

[Bradleycorn]

I came across a sample application (Google's NowInAndroid app), that has this bit of code to collect a StateFlow:

var uiState: InitializationState by mutableStateOf(Loading)

lifecycleScope.launch {
    lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
        viewModel.uiState
            .onEach { uiState = it }
            .collect()
    }
}

I'm curious if there's a particular reason why they use onEach to update the state value?
Why not use the collect method directly, like the example below?

var uiState: InitializationState by mutableStateOf(Loading)

lifecycleScope.launch {
    lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
        viewModel.uiState.collect { uiState = it }
    }
}

The only thing I can really think of is that they did it that way for "future proofing", in case they want to add additional functional method calls (map, filter, etc) to the flow.

[ephemient]

I haven't looked into the history here but I've seen other examples when code that was .launchIn(lifecycleScope) was modified to be wrapped in repeatOnLifecycle after that was introduced

[jw]

Yeah that may be true, but it would have been needless-bordering-on-incorrect even then as the subscription to the stateflow is pointless to keep alive longer than needed (as opposed to some kind of cold flow).

[jw]

unless they also did not have the lifecycleScope.launch as well...

[Alex Vanyo]

I would not read into .onEach { /* ... */ }.collect() vs .collect { /* ... */ } that much in either direction, I don’t think there’s a strong reason either way. They should be entirely equivalent, if you prefer one over the other, than use that.

I don’t really think “future-proofing” is really a consideration, it’s a one line change to swap to the other if needed for some reason in the future.

[Bradleycorn]

Thanks @Alex Vanyo that's what I was looking for ...
Was there a particular reason it was written the way that it was, or just "author's choice".
Sounds like it was author's choice.

[Alex Vanyo]

Author’s choice for sure