I haven't done a lot of Typescript, but I've done at least a couple of month's worth now, and every time I have to type "as" my inner Haskell programmer screams.
If I could add one feature to Typescript it would be something like "as" that actually validates the result against the type system and can fail. Unfortunately, that's way, way easier said than done. It's the bad type of keyword that has unbounded runtime cost because it would have to be a runtime comparison, and there are a lot of design questions about how to write it. However, I still petulantly want it even though I can hardly define it. "zod" is pretty good but you can see how trying to add that as a "keyword" is nightmare fuel for a language-level change.
If I could add one feature to Typescript it would be something like "as" that actually validates the result against the type system and can fail. Unfortunately, that's way, way easier said than done. It's the bad type of keyword that has unbounded runtime cost because it would have to be a runtime comparison, and there are a lot of design questions about how to write it. However, I still petulantly want it even though I can hardly define it. "zod" is pretty good but you can see how trying to add that as a "keyword" is nightmare fuel for a language-level change.