<@UHAJKUSTU> Is there any simple solution for logg...

# decompose

[electrolobzik]

@Arkadii Ivanov Is there any simple solution for logging navigation changes in the component tree? Since we don’t have any centralised router which could make this logging, I am looking in direction of making a copy of DefaultStackNavigation but I really don’t like this solution much. Also it doesn’t cover slot navigation and has a lot of other cons.

[Arkadii Ivanov]

Currently, I don't see any solution that could be applied globally. You can create a logging wrapper for childFactory, but that needs to be applied in every place.

[Arkadii Ivanov]

Or wrap StackNavigation, but same cons here.

[electrolobzik]

It would be cool to have the flexibility of current implementation plus features of centralised event-based things like MVI in one place.

[electrolobzik]

😃

[electrolobzik]

Indeed the navigation part of the component being in fact stateful can be implemented in theory as a MVI-like state machine with all it’s features like middleware and logging

[electrolobzik]

Thanks for the feedback!

[Arkadii Ivanov]

It would be possible if the children extension function would be part of the ComponentContext interface. In this case one could create a custom component context and wrap the children call. I will think about it, but currently this looks overcomplicated.

[electrolobzik]

Maybe it’s possible to add a parameter to childStack method which will allow to pass a lambda for logging stack changes?

[electrolobzik]

but this still is not a global setting

[Arkadii Ivanov]

Maybe it’s possible to add a parameter to childStack method which will allow to pass a lambda for logging stack changes?

This is essentially equivalent to creating a custom wrapper for StackNavigation. This could be as simple as

val nav = LoggingStackNavigation<Config>()

[electrolobzik]

by “wrapper” do you mean creating another variant of DefaultStackNavigation?

[Arkadii Ivanov]

Or

val nav = StackNavigation<Config>()
val stack = childStack(source = nav.logged(), ...)

[Arkadii Ivanov]

Yeah, create a custom implementation that delegates to the standard StackNavigation.

[electrolobzik]

yeah, I was originally thinking in that direction. This may help if replace navigation with the wrapper everywhere. thanks!

[Arkadii Ivanov]

This is what I came up with.

class LoggingStackNavigation<C : Any>(
    private val delegate: StackNavigation<C> = StackNavigation(),
) : StackNavigation<C>, StackNavigationSource<C> by delegate {
    override fun navigate(
        transformer: (stack: List<C>) -> List<C>,
        onComplete: (newStack: List<C>, oldStack: List<C>) -> Unit,
    ) {
        delegate.navigate(transformer) { newStack, oldStack ->
            println("Stack changed to $newStack. Old stack: $oldStack.")
            onComplete(newStack, oldStack)
        }
    }
}