Everyone using jQuery is benefitting from functional programming. Querying, traversing, and filtering are based on `each` and `map`. It turns what was formerly looping and saving values as temporary/instance variables into declarative, collection-based compositions of functions.

Beyond that, Michael Fogus — big in the Clojure + Clojurescript community — has Functional Javascript which explores functional concepts using Underscore: http://www.amazon.com/Functional-JavaScript-Introducing-Prog...

Marijn Haverbeke — a big Lisp hacker and the creator of Codemirror — has a nice chapter in (the free!) Eloquent Javascript as well: http://eloquentjavascript.net/chapter6.html

You should also check out how Javascript supports functional programming in languages that compile to Javascript such as LiveScript or Elm.

http://livescript.net/ http://elm-lang.org/

I highly recommend "Functional JavaScript" by Michael Fogus (creator of Lemonad), http://www.amazon.com/Functional-JavaScript-Introducing-Prog...