@dalias @swordgeek @theearthisapringle @alwayscurious The latter has been done better by Self among other languages.

There are ways to structure it, but most importantly JS JIT usually discards type info instead of keeping it in the native dynamic code, because otherwise the performance wins are more marginal. That's the wrong thing to do. It's a dynamic language, it should act like it.

@hayley would be able to give more concrete and relevant examples.