More examples of javascript inheritance patterns

inheritance.js

// There does not appear to be a clear winner here. #3 is ideal but too verbose.
// So, I think it is convenient to use a combination of all of these.

// establish a namespace
Ext.ns('MYCO.controls'); // for class definitions
Ext.ns('MYCO.mypage'); // for instances

// [1] Singleton object with functions (when only 1 object is necesary)
MYCO.mypage.mySimpleCar = {
  doors : 4,
  drive: function() { console.log('simple car driving'); }
};
MYCO.mypage.mySimpleCar.drive();

// [2] But, you cannot have multiple instances of that object...
// so instead use this.
MYCO.mypage.mySimpleCar = function(){
  return {
    doors : 4,
    drive: function() { console.log('simple car driving'); }
  };
};
new MYCO.mypage.mySimpleCar().drive();

// [3] Inheritable Class Definition - if you need inheritance
MYCO.controls.BaseCar = function() {};

// add methods to the base class using prototype
MYCO.controls.BaseCar.prototype.doors = 4;
MYCO.controls.BaseCar.prototype.drive = function() { console.log('Car with ' + this.doors + ' doors driving.') };

new MYCO.controls.BaseCar().drive(); // should have 4 doors.

MYCO.controls.SportsCar = function() {
  this.doors = this.doors / 2; // OK to override prototype
};

// set the base class
MYCO.controls.SportsCar.prototype = new MYCO.controls.BaseCar; // kinda weird to have to use 'new' here

// create an instance
MYCO.mypage.myCar = new MYCO.controls.SportsCar();
MYCO.mypage.myCar.drive(); // should have 2 doors

// [3a] with Ext, use...
MYCO.controls.Limo = Ext.extend(MYCO.controls.BaseCar, {
    constructor: function() { 
      this.doors *= 2;
    },
    driveFaster: function() { console.log('driving faster with ' + this.doors + ' doors'); }
});

new MYCO.controls.Limo().drive();
new MYCO.controls.Limo().driveFaster();

// [2b] (A fancier version of 2) 
// When creating a page controller (where no inheritance is expected and you only need one instance), this pattern works nicely
MYCO.mycontroller = function() {
  // private instance variables
  var foo = 33;

  // pseudo static initializer
  var staticInitializer = function() { // do some code here, will run only once
  }();

  // private method
  function foobar() { // do something
  }

  // public api
  return {
      publicMethod: function() {  // do something
      },

      publicVariable: 42,

      publicMethod2: function() { // do something
      }
  }
}(); // <- note function is executed to create object