Quick Javascript Inheritance

Sometimes its best to keep things quick.

Object.create(Person.prototype) is pretty simple, but what if we want an inheriting object to overwrite some properties as well as methods? By creating a new object from another’s prototype, you are only inheriting methods, unless you just don’t care and put all your data in an object’s prototype.

Of course there are more complex methods of achieving inheritance in javascript, but a lot of those require the use of an api that abstracts from bare bones javascript. Bare bones is good.

So lets keep things simple, quick, and a little dirty. Use $.extend directly onto the created instance to create an inheritance chain. If jQuery is not your cup of tea, _.extend, or any generic object extending function will work.

function Person(options) {
    $.extend(this, Person.defaults, options);

Person.defaults = {
    name: '',
    age: 0

Person.prototype.makeImmortal = function () {
    this.age = Infinity;

function Guy(options) {
    $.extend(this, new Person(options), Guy.defaults, options);

Guy.defaults = {
    gender: 'male'

Guy.prototype.sayName = function () {
    return this.name;

var person = new Person();
> Person {name: "", age: 0, makeImmortal: function}

var guy = new Guy();
> Guy {name: "", age: 0, makeImmortal: function, gender: "male", sayName: function}

Is new Guy() instanceof Person === true? Of course not. Did I say it was quick and dirty? Yes.