gistfile1.js

Array.prototype.map2 = function(f) {
  return fold([], SynLib.append.combine(f));
}

Function.prototype.combine = function(g) {
    return function() { this(g(arguments)) };
}

var SynLib = {
  append: function(array, x) {
    array.push(x);
    return array;
  }
}