Question for the author, why not fully adopt TypeScript? Ie have TypeSpec be a well-defined, limited subset of TypeScript? At first glance, it seems to me that a model maps to an interface, an op is a function, and an enum is a string literal union.

I understand that you can’t express everything that way, eg annotations, but you could get pretty far with putting those in JSDoc comments, no? I could see a big practical benefit to TS code being able to read an API spec directly without another conversion step, so I’m curious why you chose not to go with that.