Hello team! When I'm trying to compile code like ...

# multiplatform

[genovich]

Hello team!

When I'm trying to compile code like interface X : () -> Unit in KMP, then it leads to Implementing a function interface is prohibited in JavaScript. I'm curious why?

On the other hand code like interface X: suspend () -> Unit is compiling, but leads to runtime exception (TypeError: %field_name% is not a function) in javascript when I'm trying to invoke such function, e.g.

interface X: suspend () -> Unit

suspend fun invoke(func: suspend () -> Unit) {
  func.invoke() // fails here
}

invoke(XImpl())

However, if I replace invoke(XImpl()) with function reference invoke(XImpl()::invoke then it is working as expected.

Thus I have two questions:
• Why are functional interfaces prohibited in JS?
• Is it possible to allow them or add a compile-time exception to suspend the inheritance of functions?
I'll be exceptionally grateful if you allow me to help you implement the fix.