zlacker

Yeah that's kinda the point; you get all that, unless you don't run the build-step/in-editor dev process. And the only reason to make that step optional, is to not run it, which is a worse experience.

So I'm not necessarily saying it's a bad thing, it's just that I don't see the point. And given that there's the major downside of having to go through the standards process, both now and in the future, which will likely involve breaking changes and making it harder to update, I don't see it happening. (Edit: I should add that I do think the "types as comments" proposal makes sense. I do see the advantage of being able to run TS code without a build step. It's just the part where we'd throw an error in the user's face that I don't see providing value to anyone.)

I do think TC39 is progressive enough to be OK with changes to JS if those would allow TS to have more effective type checking (as long as they're backwards compatible, of course, which would also be the case if TS got incorporated into JS), so I don't think it's necessary for that.

Performance improvements enabled by optimisations would be nice, but I believe I heard that no major gains would be expected there, especially compared to something like WASM.