I'm certainly attracted to getting more experience of FP / a lisp in production (as opposed to a lisp in my text editor). However,

> Previously working with TypeScript has made me miss types and appreciate the runtime checks of spec.

This seems like a huge deal. Javascript has got to the point where it has nice static typing via typescript, and various new type-check-time language constructs associated with the typing, and enums, and really nice tooling for it all. Coming from Python I've been really enjoying typescript, since the tooling works slightly better (and doesn't suffer from Django's typing dead-ends). So, I am not all sure that I would be prepared to throw away static typing in exchange for lisp.