Prototypical inheritance

inheritance.js

function MyObject() {}

MyObject.prototype.doSomething = function() {
    console.log('MyObject.doSomething()');
}

// -----

var parent = MyObject;

function MyExtendedObject() {
    parent.apply(this, arguments);
}

MyExtendedObject.prototype = Object.create(parent.prototype);

MyExtendedObject.prototype.doSomething = function() {
    parent.prototype.doSomething.apply(this, arguments);
    console.log('MyExtendedObject.doSomething()');
}

// -----

var parent = MyObject;

function AnotherExtendedObject() {
    parent.apply(this, arguments);
}

AnotherExtendedObject.prototype = Object.create(parent.prototype);

AnotherExtendedObject.prototype.doSomething = function() {
    console.log('AnotherExtendedObject.doSomething()');
}