[Sammi]

No the proposal is _not_ to include Typescript type checking in the browser. The proposal is to make the browser understand where the ts types are so it can _ignore_ them. So that you can write ts and have it be type checked on your machine, and them ship the ts and have it run on client machines _without_ any type checking running there. The browser will run the ts as though it was js.

So the types will actually be able to be anything. It can be a completely different type checking superset language than Typescript even! Nothing will be locked at the current level.

It's a frikkin magical proposal.

https://github.com/tc39/proposal-type-annotations

[_flux]

Here we can see concretely the benefits of TypeScript taking the strict stance of not generating any code, so basically stripping types will work.

Though, weren't there some exceptions to that?

It seems though the syntactical structures that are chosen to be ignored need to be listed in the proposal, making the support in browser non-trivial and still hindering the future extensions of TS and similar languages, because all future constructs would need to be supersets of this proposal—or whatever version is practically supported by current browsers. If a language brings up a new construct all the users of that construct need to revert back from shipping their source-code as is, increasing the cost of introducing such things in the future.

Personally I don't see great benefits in having straight up TS work as-is in the browsers as you still need to run type checking phase locally, but I do see that some would like to see that happen and that it would simplify some release processes.

It would not simplify the release process of folks that want to minify and obfuscate their sources, but it's probably fine to make that comparatively even harder ;).

[Sammi]

The benefit is that we can forgo any build or compile step, and just ship code as is. There will be no source maps error to worry about. We will be able to run and debug the exact code that we wrote and not some jumbled transpiled code. We can just have a local type checker that can help with correctness and inline suggestions in our ide.

When I say nothing will be locked down, then that does only mean the type checking itself will not be locked down. Indeed it will not be specified at all. Buuuuut the location of the types in the js syntaxt will 100% be locked down and specified. That's what the proposal is. So there will be limitations on coming up with novel ways to integrate type syntax with the js syntax. But you will of course still be able to make your own compiler if you want this.