How to create OOP Class in Javascript

Question

I\'m hesitant to use just any tutorial because I know how those tutorials can end up being, teaching you bad ways to do things. I want to setup a class in Javascript, so th

Answer 1

There is no such thing as a class in JavaScript, instead everything in JavaScript is an object.

To create a new object you define a function that uses the this keyword in it (a “constructor function”), and then call it with the new operator:

function Foo (id) { // By convention, constructor functions start with a capital letter
    this.id = id;
}

var foo1 = new Foo(1);
var foo2 = new Foo(2);

However, these objects have no methods. To add methods, you need to define a prototype object on their constructor function:

Foo.prototype = {
    getId: function () {
        return this.id;
    }
}

This new getId function will be usable by all Foo objects. However, as was stated, there are no classes in JavaScript and as such there are other constructs you will use in order to produce different results.

I highly recommend the videos by Douglas Crockford in which he explains much of the javascript OO nature. The talks can be found here:

http://developer.yahoo.com/yui/theater/

Douglas Crockford — The JavaScript Programming Language

Douglas Crockford — Advanced JavaScript

Those will give you a basic understanding of the structure of javascript and should help the transition from classical to functional programming.