Those definitely help, but the proposed erasableSyntaxOnly flag would disallow all features that can't be erased. So it would prevent you from using features like class parameter properties [1], enums, namespaces, and I'm assuming experimental decorators also.

It would essentially help you produce TypeScript that's compatible with the --experimental-strip-types flag (and ts-blank-space), rather than the --experimental-transform-types flag, which is nice because (as someone else in this thread pointed out), Node 23 enables the --experimental-strip-types flag by default: https://nodejs.org/en/blog/release/v23.6.0#unflagging---expe...

[1] https://www.typescriptlang.org/docs/handbook/2/classes.html#...

Also worth noting that the eslint rules for what `erasableSyntaxOnly` might be are already well established, for those looking to do it today.