Hi @haukeh, I'm sorry for the delay.

I think java.lang.Optional is available on bot Scala.js and Scala Native. As far as I know they both use the scala re-implementation of the JDK, which contains Optional (https://github.com/scala-js/scala-js/blob/main/javalib/src/main/scala/java/util/Optional.scala).

Hi @lrytz, thanks for the info! When I first tried adding it to the default source root, some JS tests failed with errors like:

[error] Referring to non-existent method static java.util.OptionalDouble.of(double)java.util.OptionalDouble

Which made me - having literally no idea about scala-js - just assume Optional in general is not available. But now, after taking a closer look, it seems that it's only the primitive Optional wrappers like OptionalDouble etc. that are not available in JS.

So I guess a way to solve this would be creating a "lightweight" version of OptionConverters in the js and native source folders, which only contains the Option[T] stuff?

Ok, so I just found out that java.util.Optional is available in Scala-Native on the main branch, but it has not been released yet. (https://github.com/scala-native/scala-native/blob/main/javalib/src/main/scala/java/util/Optional.scala)

So for now I opted to create a slim variant of OptionConverters for JS only. Let me know what you think.

I just found out that java.util.Optional is available in Scala-Native on the main branch, but it has not been released yet

cc @WojciechMazur -- is that possibly changing soon?

Otherwise I'm happy to go with the current solution. Thank you @haukeh!

@lrytz There should be a new release of Scala Native introducing j.u.Optional later this week or at the beginning of the next one. I'm currently on mini-vacations and cut off from my workstation.
The implementation of Optional is exactly the same as on the Scala.js so it should work just fine

Hi @lrytz, sorry for the delay. As the new version of scala-native has been released in the meantime, I went ahead and updated it and added OptionConverters also for native.

I opted to create a "shared" source root for js and native, as the implementation is exactly the same. While this feels a little weird for one single class, It felt even worse to just plain copy the class. If anyone knows of a better or more elegant way to do this (with sbt-crossproject etc.) I'd be more than happy to improve on this.