TypeScript is a joy to program in. I was on a project where we had the opportunity to turn on all the strict checks (no use of any, no implicit nulls, etc.), and it was super enjoyable and efficient to program in.

You have algebraic types (well, 99%), union types, and concise ways of expressing tree types.

I would imagine it is more pleasant than Swift or Go, though I haven't used either of those very much.