When targeting Scala.js and/or Scala Native, it would be nice to have the exit code of the process set correctly, as it is with the JVM.

I believe Scala native already supports using System.exit, java.lang.System is listed here: https://scala-native.org/en/stable/lib/javalib.html , and here is a corresponding test where it is used https://github.com/scala-native/scala-native/blob/main/scripted-tests/run/system-exit/src/main/scala/Exit.scala

For nodejs, and this api https://nodejs.org/api/process.html#processexitcode_1, we can gracefully set an exit code. From the docs:

A number which will be the process exit code, when the process either exits gracefully, or is exited via process.exit without specifying a code.

I've built + run these changes locally to confirm, but I'd be happy to set up a corresponding test suite with some guidance of similar tests that might already be in place.