Hmm, I don’t think either of those warrants any concern about “TS features making their way into JS” or “overlapping syntax”.
The first one is removing a TS feature that failed to make its way into JS, and the second is about explicitly carving out a space in the syntax so that you can use TS (or Flow!) in JS codebases without being locked into any particular tooling.
The first one is removing a TS feature that failed to make its way into JS, and the second is about explicitly carving out a space in the syntax so that you can use TS (or Flow!) in JS codebases without being locked into any particular tooling.