Inheritance

// this is wrong because all Cat instances would inherit from a single instance of Animal
// which means that any members that were initialized in the Animal constructor
// would be inherited, possibly overriding what was in Animal.prototype.
// also, the constructor property if Cat instances would point to the wrong constructor.
function Animal(){}
function Cat(){}
Cat.prototype = new Animal();

var myAnimal = new Animal();
var myCat = new Cat();

WScript.Echo((myCat instanceof Cat).toString() +     ":true");
WScript.Echo((myCat instanceof Animal).toString() +  ":true");
WScript.Echo((myCat.constructor === Cat).toString()+ ":true");
WScript.Echo((myCat.constructor === Animal).toString() + ":false");
WScript.Echo((myAnimal instanceof Cat).toString() + ":false");
WScript.Echo((myAnimal instanceof Animal).toString() + ":true");
WScript.Echo((myAnimal.constructor === Animal).toString() + ":true");
WScript.Echo((myAnimal.constructor === Cat).toString() + ":false");

WScript.Echo("---------------------------------------")
WScript.Echo("---------------------------------------")


//this is wrong because both Cat and Animal refer to the exact same object
// this means that myAnimal is now both an instanceof Cat and an instanceof Animal
// also, myCat.constructor is Animal and not Cat
// and if I need to update the behavior of all Cats, I can't do so without also changing the
//behavior of all Animals as well since they both share the exact same object

function Animal(){}
Animal.prototype.foo = function(){
    return "Hola"
}
function Cat(){}
Cat.prototype = Animal.prototype;

var myAnimal = new Animal()
var myCat = new Cat();

WScript.Echo((myCat instanceof Cat).toString() +     ":true");
WScript.Echo((myCat instanceof Animal).toString() +  ":true");
WScript.Echo((myCat.constructor === Cat).toString()+ ":true");
WScript.Echo((myCat.constructor === Animal).toString() + ":false");
WScript.Echo("---------------------------------------")
WScript.Echo((myAnimal instanceof Cat).toString() + ":false");
WScript.Echo((myAnimal instanceof Animal).toString() + ":true");
WScript.Echo((myAnimal.constructor === Animal).toString() + ":true");
WScript.Echo((myAnimal.constructor === Cat).toString() + ":false");
WScript.Echo(myAnimal.foo() + ":Hola")
WScript.Echo(myCat.foo() + ":Hola")
Cat.prototype.foo = function(){
    return "Bueno"
}
WScript.Echo(myAnimal.foo() + ":Hola")
WScript.Echo(myCat.foo() + ":Bueno")


WScript.Echo("---------------------------------------")
WScript.Echo("---------------------------------------")

//The correct way

function Animal(){}
function Cat(){}
Cat.prototype = copy(Animal.prototype)
extend(Cat.prototype, {
    constructor : Cat,
    myExtendedMember : function(){
        return "foo"
    }
}