monsters.js

var Class = require('../lib/class').Class;

var Monster = Class.extend(

{
  count : 0
},

{
  init : function(name)
  {

    this.name = name;

    this.health = 10;

    this.Class.count++;
  },
  eat : function(smallChildren)
  {
    this.health += smallChildren;
  },
  fight : function()
  {
    this.health -= 2;
  }
});

var hydra = new Monster('hydra');
var dragon = new Monster('dragon');

console.log("Monster name: " + hydra.name); // -> hydra
console.log("Total monsters: " + Monster.count); // -> 2

hydra.eat(2);
console.log("Hydra health: " + hydra.health); // -> 12

dragon.fight();
console.log("Dragon health: " + dragon.health); // -> 8

var SeaMonster = Monster.extend({
  eat : function(smallChildren)
  {
    this._super(smallChildren / 2);
  },
  fight : function()
  {
    this.health -= 1;
  }
});

var lochNess = new SeaMonster('Loch Ness');

lochNess.eat(4);
console.log("Loch Ness ate. Health: " + lochNess.health); // -> 12

lochNess.fight();
console.log("Loch Ness fought. Health: " + lochNess.health); // -> 11