Javascript memoize decorator functor

memoize.js

function memoize(fn) {
  var invocationCache = {};
  return function() {
    var args = Array.prototype.slice.call(arguments);
    var cachedValue = invocationCache[args];
    if (cachedValue !== undefined) {
      return cachedValue;
    }
    var result = fn.apply(null, arguments);
    invocationCache[args] = result;
    return result;
  };
}