Hey, I believe that the documentation for `derived...

# compose

[Lukasz Burcon]

Hey, I believe that the documentation for derivedStateOf is misleading, and it that SideEffect should be declared in remember using no keys to really benefit from its caching mechanism.

Here’s a documentation using keys with remember with derivedStateOf:

<https://developer.android.com/jetpack/compose/side-effects#derivedstateof>

And here’s a documentation that doesn’t use keys in remembers:
<https://developer.android.com/reference/kotlin/androidx/compose/runtime/package-summary#derivedStateOf(kotlin.Function0)>

Any thoughts on that?

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

I don’t see what either of these examples have to do with SideEffect

[Lukasz Burcon]

Nah, i just used name Side effect in the meaning of derivedStateOf to avoid duplication in the initial message ;)

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

So you’re thinking it would make sense to turn highPriorityKeywords into a state (eg using rememberUpdatedState) and then get rid of the remember keys around derivedStateOf?

[Lukasz Burcon]

Just the other way round - having remember using no keys, as derivedStateOf knows when to reevaluate itself. That would make perfect sense for me

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

That’s what I meant - but you can’t do that without turning the highPriorityKeywords argument into a state otherwise the derivedStateOf lambda would just capture the initial value and never update if the caller passed a different list in

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

Passing todoTasks as a key shouldn’t actually change behavior in this case, I believe, because that list is always the same object. So even if the contents of the list change, it shouldn’t invalidate the remember, and the derivedStateOf will handle the update itself as you’d probably want.

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

Which means that if you stored highPriorityKeywords in a state and got rid of the keys, it wouldn’t save you anything when highPriorityKeywords changed since the only for that to happen would mean that the function was already being reexecuted.