var nums = ki (take 6 (map (fn [x] (js x * 2)) (range 1000)));
npm install -g ki
ki -o main.out.js main.js
ki has lambdas, lexical scoping, namespaces, local bindings, recursion, persistent data structures, lazyness, data literals, keywords, multiple arity functions, backcall-style continuations, multimethods, atoms and macros. And source maps.