What is the proper / idiomatic way to update a sta...

# compose

[Tolriq]

What is the proper / idiomatic way to update a state in a class derived from another state without causing recomposition? Currently using something ugly like

val value by remember { 
derivedStateOf { 
       otherstate.value = state.value + calculation
       otherstate.value
 } }
Wrapper { value }

With wrapper being a simple composable to avoid inlining and so only have it's content recomposed. If I do not read the value somewhere the derivedStateOf is not updated. I'm probably missing something obvious.

[Adam Powell]

Why are you modifying otherstate.value here instead of defining this as

val value by remember {
  derivedStateOf { state.value + calculation }
}

?

[Tolriq]

Because it's a state in a class that I use to have that state used upstream and downstream it's actually updated in the middle of the hierarchy and use before and after.

[Tolriq]

I've actually solved that by extracting the calculation to another composable and wrapped the call to that composable that read the state as a param.

[Tolriq]

The main pain point currently is that reading a state in a composable will recompose the whole composable and not just the function that use it as parameter. (I guess this is normal as hard to know the side effects probably)

[Tolriq]

And once everything recompose and performance issues arise it's really hard / impossible to find out what is causing the issue.