memoize.coffee

_ = require "lodash"

memoize = (f) ->
  cache = {}
  memoizer = ->
    args = Array.prototype.slice.call(arguments)
    if _.has(cache, args) then cache[args] else cache[args] = f.apply this, args
  return memoizer

fib = (n) ->
  if n in [0, 1] then n else fib(n - 1) + fib(n - 2)

fib = memoize(fib)

console.log (fib 40)