utils.js

'use strict';

var utils = module.exports = {};

utils.args = function (defval, names) {
  defval || (defval = {});
  names || (names = []);

  var map = {};

  names.forEach(function (val) {
    map[val.length] = val;
  });

  return function (args) {
    var newargs = Object.create(defval);
    var names = map[args.length];
    
    if (!names) {
      throw new Error('Wrong arguments');
    }

    names.forEach(function (name, index) {
      newargs[name] = args[index];
    });

    return newargs;
  };
};

utils.function = function (defval, names, fn) {
  var getArgs = utils.args(defval, names);
  return function () {
    return fn.call(this, getArgs(arguments));
  };
};

var fn = utils.function({hello: 'world', ghostisland: 'taiwan'}, [['hello', 'ghostisland'], ['ghostisland']], function (args) {
  console.log(args);
});

fn('taiwan', 'lol');
fn('lol');