http://net.tutsplus.com/tutorials/javascript-ajax/closures-front-to-back/

cached-multi-args.coffee

# Cache a func with multiple args like Math.max(1, 2, 3)
Function::cached = ->
  cache = {}
  (args...) => # Note: could've used a regular `->` and keep the `self = @`
    argsKey = args.join()  
    if argsKey of cache 
      console.log "Hitting cache with #{argsKey}"
      return cache[argsKey]
    console.log "Cache miss..."
    return cache[argsKey] = @(args...)

Math.max = Math.max.cached()
Math.max 1, 2, 3     # cache miss
Math.max 3, 4, 5     # cache miss
Math.max 1, 2, 3     # cache hit
Math.max 1, 2, 3, 4  # cache miss
Math.max 1, 2, 3, 4  # cache hit

compiled.js

// Compiled by Coffeescript
var __slice = [].slice;
Function.prototype.cached = function() {
  var self = this;
  var cache = {};
  return function() {
    var args, argsKey;
    args = 1 <= arguments.length ? __slice.call(arguments, 0) : [];
    argsKey = args.join();
    if (argsKey in cache) {
      console.log("Hitting cache with " + argsKey);
      return cache[argsKey];
    }
    console.log("Cache miss...");
    return cache[argsKey] = _this.apply(null, args);
  };
};

Math.max = Math.max.cached();
Math.max(1, 2, 3);    // cache miss
Math.max(3, 4, 5);    // cache miss
Math.max(1, 2, 3);    // cache hit
Math.max(1, 2, 3, 4); // cache miss
Math.max(1, 2, 3, 4); // cache hit