Is there a way to use @JsExport annotations (or other annotations, specific to its own platform) in ...

# multiplatform

[Grantas33]

Is there a way to use @JsExport annotations (or other annotations, specific to its own platform) in common code?

[Justin]

If you figure this out (I’m told it is possible using version 1.4-M2 of Kotlin and the js plugin), I’d love to see what your build.gradle.kts looks like. I’m hoping to use that patterns to auto generate typescript defs for my nodeJs library target.

[Robert Jaros]

You can declare an annotation with expect and declare actual typealias in platform code.

[Robert Jaros]

But I had problems using Java annotations with parameters this way.

[russhwolf]

If the annotation has parameters then you need `expect`/`actual` for them as well. It’s doable, but it’s a bit of a pain because you can’t make use of @OptionalExpectation

[russhwolf]

For @JsExport in particular, it’s coming in 1.4-M2 and tracked here https://youtrack.jetbrains.com/issue/KT-35966

[Robert Jaros]

I've just tested the `expect`/`actual` for annotations with parameters and something had to be fixed in Kotlin in the last six months, because it works fine for me now. Even with @OptionalExpectation.

[Robert Jaros]

That's great - I can use spring data annotations in common code now.