I don't know if any of the "cool kids" believe Javascript is a functional language. Can one write code in a functional STYLE in Javascript? (can they write higher order functions, can they write functions with no side-effects, could they build monads) Sure, it's entirely possible - just like it is in Ruby, Python, and pretty much any decent language. I think what some of the push is, is to write javascript in more of a functional style as they feel it's more elegant. (I could be way off base though... I haven't been "cool" in years)