I was originally planning not to expose FFI to users (only the standard library would use it), but I think I've come around on it. It undercuts some of the guarantees I want Bagel to provide, but you could say the same about unsafe blocks in Rust and those haven't stopped its safety-checking from being useful.

However going the other way - calling Bagel from JS/TS - has been on the roadmap from day one and should work pretty seamlessly. Bagel already compiles to TS in fact, including type info.