Parasitic Combination Inheritance

parasitic-combination-inheritance.js

function obj(o) {
  function F() {}
  F.prototype = o;
  return new F();
}
 
function inheritPrototype(sub, sup) {
  var p = obj(sup.prototype);
  p.constructor = sub;
  sub.prototype = p;
}
 
function Animal(name) {
  this.name = name;
  this.children = [];
}
 
Animal.prototype.alertName = function() {
  alert(this.name);
}; 
 
Animal.prototype.alertChildren = function() {
  alert(this.children);
}; 
 
function Dog(name, master) {
  Animal.call(this, name); // inherit properties
  this.master = master;
}
 
inheritPrototype(Dog, Animal); // inherit prototype
 
Dog.prototype.alertMaster = function() {
  alert(this.master);
};
 
var d1 = new Dog("white", "walter");
var d2 = new Dog("black", "bob");
d1.children.push("w1");
d2.children.push(["b1", "b2"]);
 
d1.alertName();
d1.alertChildren();
d2.alertMaster();
d2.alertChildren();