It's not Haskell, but you can write great functional programming code with Javascript. I think it is very ergonomic for FP. Remember that Javascript is the world's most misunderstood programming language =))
As much as I appreciate the FP features of Python, I much prefer a language that enforces immutability. Constraints like that make the code easier to understand, reduces the number of possible bugs.
At this stage in my life, when I'm beginning to give up on immutability being taken seriously, I'd almost settle for proper immutable collections being provided alongside the mutable ones.
I really just want to combine Sets and Maps the way I combine numbers and strings.