Basic javascript prototypal inheritance example demonstrating instantiation, inheritance and superclasses calls

prototype.js

function Animal(name) {
  this.name = name;
}
Animal.prototype.breathe = function(animal) {
  console.log('animal breathe : ' + this.name);
};
Animal.prototype.die = function() {
  console.log('animal die : ' + this.name);
};



function Human() {
  // apply the super constructor to this
  Animal.apply(this, arguments);
}
// by default, inherit all super properties & methods
Human.prototype = new Animal();
// override some method
Human.prototype.breathe = function(human) {
    console.log('human breathe', this.name);
    Object.getPrototypeOf(Human.prototype).breathe.call(this);
    // call the parent. equivalent to :
    // Animal.prototype.breathe.call(this);
};


function SuperHero() {
  // apply the super constructor to this
  Human.apply(this, arguments);
}
// by default, inherit all super properties & methods
SuperHero.prototype = new Human();
SuperHero.prototype.breathe = function(superhero) {
    console.log('superhero breathe', this.name);
    Object.getPrototypeOf(SuperHero.prototype).breathe.call(this);  
    // equivalent to :
    // Human.prototype.breathe.call(this);
};
// override a method
SuperHero.prototype.die = function() {
      console.log('No luck, SuperHero never dies :)', this.name);
};


console.log('-----');

console.log('create animal');
var a = new Animal('popy');
console.log(a, a.name);
a.breathe();

console.log('-----');

console.log('create human');
var b = new Human('jul');
console.log(b, b.name);
b.breathe();

console.log('-----');

console.log('create SuperHero');
var c = new SuperHero('ironman');
console.log(c, c.name);
c.breathe();

console.log('-----');

a.die();
b.die();
c.die();

 Object.getPrototypeOf(Human.prototype).breathe.call(this);

I'd stay with

Animal.prototype.breathe.apply(this, arguments)

for maximum compatibility.

Human.prototype = new Animal();

as this.name is set, we can see unwanted behaviour :

var inherit = Object.create || function(object){
  function F(){}
  F.prototype = object
  return new F()
}

and

Human.prototype = inherit(Animal.prototype)

thanks a ton !