Why there is no ```public open fun <S> then(onFulfilled: ((T) -> Promise<S>)?): Promi...

# javascript

[Edoardo Luppi]

Why there is no

public open fun <S> then(onFulfilled: ((T) -> Promise<S>)?): Promise<S>

in KotlinJS Promise class?

How do I workaround this limitation?

[Artem Kobzar]

https://pl.kotl.in/gVSAGk72P

[Artem Kobzar]

There is a method inside Kotlin/JS Promise class

[Edoardo Luppi]

@Artem Kobzar ahhh, you mean that one?

[Edoardo Luppi]

otherwise I'm not understanding

[turansky]

WA:

// One more then
.then { it }

[turansky]

There is related issue on YouTrack

[Edoardo Luppi]

@turansky thanks! I had settled for:

val jsPromise = promise.then {
  val thenResult = thenFn(it) as JsZDeferred<S>
  thenResult.promise.unsafeCast<S>()
}

Note the unsafe cast, so it doesn't complain

[turansky]

We had extension thenKT***() to detect all places after issue fix

[Edoardo Luppi]

That's a good idea, I'll wrap it too

[Edoardo Luppi]

@turansky ticket is https://youtrack.jetbrains.com/issue/KT-19672 btw, just found it

[turansky]

Looks like Promise declaration can be updated 🙂

[turansky]

It works fine on playground

[Edoardo Luppi]

@turansky worth mentioning in the ticket itself?

[turansky]

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