Typescript. We try not to be type/pl theory fanatics. Choose your tools well. Haskell is great since the core of our product is an interpreter/compiler with multiple stages. But I don't wanna use it everywhere.

Personally I'd be using JS (or TS) + jQuery. Almost no dependencies, but a lot more manual. No one would be happy on the team if we did this of course. And it can be impractical