Sorry if I'm bothering, but I sometimes encounter ...

# javascript

[Hildebrandt Tobias]

Sorry if I'm bothering, but I sometimes encounter these "double types".
For example TanStack Table has the Updater which is defined like this:

sealed external interface Updater<T> /* T | ((old: T) -> T) */

inline fun <T> Updater(
    source: T,
): Updater<T> =
    unsafeSpecialCast(source)

inline fun <T> Updater(
    noinline source: (old: T) -> T,
): Updater<T> =
    unsafeSpecialCast(source)

I know I can create these using functionalUpdate() but how do I consume them?
Currently I do

this.onSortingChange = { newSorting ->
    setSorting(newSorting.unsafeCast<SortingState>())
}

but it feels kind of wrong.
What is correct way to consume such an Updater ?

[Erik van Velzen]

this.onSortingChange = Updater<SortingState> { newSorting ->
    setSorting(newSorting)
}

Does this work?

[Hildebrandt Tobias]

Sadly, no:

[Hildebrandt Tobias]

The compiler suggestion 😅

[Hildebrandt Tobias]

Okay this works, but it still doesn't look right this mimics the doc though (https://tanstack.com/table/v8/docs/guide/pagination):

useReactTable<T>(
    options = jso {
        val (pagination, setPagination) = states.pagination // StateInstance<PaginationState>
        
        this.state = jso<TableState> {
            this.pagination = pagination
        }
        
        this.onPaginationChange = unsafeSpecialCast(setPagination) 
    }
)

[turansky]

We have invalid declaration for Updater in fact

[turansky]

If you use Kotlin Wrappers and you need unsafeCast or asDynamic :
1. Probably you need it without reason, please check one more time
2. It can be typization error in wrappers (current case)

[turansky]

@Hildebrandt Tobias could you please report the problem, I will fix it 😎

[Hildebrandt Tobias]

In YouTrack or Kotlin-Wrapper Issues?

[turansky]

Kotlin Wrappers please

[Hildebrandt Tobias]

Will do

[Hildebrandt Tobias]

https://github.com/JetBrains/kotlin-wrappers/issues/2779

[turansky]

Fix released in Kotlin Wrappers 2025.5.0 😎