Javascript (node.js): Herencia

BasicClassDefinition.js (Animal)

// Constructor

function Animal(age) {

  // always initialize all instance properties
  this.hasEnergy=true;
  this.hasAge=true;
  this.Age=age;

}

// class methods

Animal.prototype.getOld = function() {
 this.Age++;
 console.log(this.Age);
};
module.exports = Animal;

Clase B: (Dog)

//Import animal definition
var Animal = require("../1.2.1 Class Definition/BasicClassDefinition");

//Import util required for inheritance
var util = require("util");

//class creation
function Dog(age)
{
 //call to Animal base constructor passing params
  Animal.call(this, age);
}

//Tell to engine that Dog inherits from Animal
util.inherits(Dog, Animal);
//create a new instance of dog
var dogInstance = new Dog(50);
//call getOld defined on base class 10 times
for(i=0;i<10;i++)
{
 //call inherited method
 dogInstance.getOld();
}