Function.create for inheritance

gistfile1.js

var Person = Function.create(null, {
  constructor: function (name) {
    this.name = name;
  },
  say: function (message) {
    return this.name + ' says: ' + message;
  }
});

var Pirate = Person.extend({
  constructor: function (name) {
    Pirate.superclass.constructor('Capt\'n ' + name);
  },
  say: function (message) {
    return Pirate.superclass.say(message) + ' Arr!!';
  }
});

var blackbeard = new Pirate('Blackbeard');
console.log(blackbeard.say('Ahoy, me mateys!')); // Capt'n Blackbeard says: Ahoy, me mateys! Arr!!

main.js

(function () {
  
  function getOwnPropertyDescriptors(obj) {
    var descriptors = {};
    for (var prop in obj) {
      if (obj.hasOwnProperty(prop)) {
        descriptors[prop] = Object.getOwnPropertyDescriptor(obj, prop);
      }
    }
    return descriptors;
  } 
  
  Function.create = function (superclass, proto) {
    var constructor = proto.constructor;
    if (!constructor) {
      constructor = proto.constructor = function () {};
    }
    
    constructor.prototype = Object.create(superclass ? superclass.prototype : {}, getOwnPropertyDescriptors(proto));
    
    if (superclass) {
    	constructor.superclass = superclass.prototype;
    }
    
    return constructor;
  };
  
  Function.prototype.extend = function (proto) {
    return Function.create(this, proto);
  };
  
}());