Is it possible to have `@JsExport` annotations on classes in `commonMain` and target `js` & `wa...

# webassembly

[phteven]

Is it possible to have @JsExport annotations on classes in commonMain and target js & wasmJs ?
I get the error this error: This annotation is not applicable to target 'standalone object'. Applicable targets: function

Currently I have js as a target in my project as I export a npm package for a react app.
In long term I want to switch to compose wasm. Is there any workaround to get this working?

[Artem Kobzar]

Unfortunately, no. js has a richer export model (and it only expands), and in the same time right now it's impossible in wasmJs to export nothing but top-level functions.

[phteven]

Do you have any recommendation how to use @JsExport only for js target and not for wasmJs?
Only way I see is to duplicate my modules and use one for wasm and one for js 😕

[Artem Kobzar]

It depends on your use case.
You mentioned that it's a plan to use compose, and what you can do, it's (right now) use only JS and export logic with the @JsExport (to not duplicate code).
Incrementally migrate/add some of the Compose components as multiplatform and export them to (to use it in the mentioned react app)
You can migrate the project in a long term incrementally and use the compose multiplatform with JS and as soon as you export only @Composable functions you can switch to wasmJs

[Artem Kobzar]

I have a demo project of how share logic on different levels of abstraction with Kotlin/JS but with VueJs. However, there should be not a big difference for a react application

[Artem Kobzar]

https://github.com/JSMonk/make-friends-with-kotlin-devs

[Artem Kobzar]

Each branch - different level of shared abstractions

[andylamax]

I think it is time we split these two functionalities.

kotlin.js.JsExport should be different from kotlin.wasm.JsExport and they should all be accessible from commonMain

[phteven]

Thank you for the information. I will take a look at the project!

[Robert Jaros]

Have you tried using expect/actual to declare @JsExport in common ?

[Robert Jaros]

Haven't tried this but it works with @JsModule in my project.

[andylamax]

I am currently defining this using expect/actual but you can tell it is obviously a work around