Module pattern along with prototypal inheritance...

modulepattern-prototype.js

namespace('MINE');  

MINE.parent = (function() { 
    // private funcs and vars here

    // Public API - constructor
    var Parent = function (coords) {
       // ...do constructor stuff here
    };

    // Public API - prototype
    Parent.prototype = {
       constructor: Parent,
       func1:  function ()    { ... },
       func2:  function ()    { ... }
    }

    return Parent;
 }());
 
 MINE.child = (function () {

  var Child = function (coords) {
    Parent.call(this, arguments);    
  }

  Child.prototype = Object.create(Parent.prototype);

  Child.prototype.constructor = Child;
  Child.prototype.func2 = function () { ... };

  return Child;

}());