OO utilities

namespace.js

if (typeof(Name) === 'undefined') {
  (function(global) {
    "use strict";

    function defineNamespace(object, namespace) {
      var privates = Object.create(object), 
        base = object.valueOf;

      Object.defineProperty(object, 'valueOf', { 
        value: function valueOf(value) {
          if (value !== namespace || this !== object) {
            return base.apply(this, arguments);
          } else {
            return privates;
          }
      });

      return privates;
    }

    function Name() {
      var namespace = {};

      return function name(object) {
        var privates = object.valueOf(namespace);
        return privates !== object ? privates : defineNamespace(object, namespace);
      };
    }

    return global.Name = Name;
  })(this);
}

new.js

var beget = function (proto) {
  var args = [].slice.call(arguments, 1);
  var o = Object.create(proto);
  o.constructor.apply(o, args); 
  return o;
}

SomeKlass.js

var SomeKlass = (function () {
  var privates = Name();

  return {
    public_method: public_method,
    public_prop: 42,
    constructor: constructor
  };

  function public_method() {
    return local_utility();
  }

  function constructor() {
    privates(this).secret = secret;
  }

  function local_utility(_) {
    return privates(this).secret;
  }
});

use someklass.js

var instance = beget(SomeKlass, 42);
console.log(instance.public_method() === instance.public_prop);