Does JavaScript have classes?

A friend and I had an argument last week. He stated there were no such things as classes in JavaScript.

I said there was as you can say var object = new Object()

He says "as there is no word class used. It's not a class."

Who is right?

As a note; For future you needing a succinct Classy JS implement:

https://github.com/tnhu/jsface

Edit: July 2017

JavaScript classes introduced in ECMAScript 2015 are primarily syntactical sugar over JavaScript's existing prototype-based inheritance. The class syntax is not introducing a new object-oriented inheritance model to JavaScript. JavaScript classes provide a much simpler and clearer syntax to create objects and deal with inheritance.

- Mozilla ES6 Classes: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Classes

Solution 1:

Technically, the statement "JavaScript has no classes" is correct.

Although JavaScript is object-oriented language, it isn't a class-based language—it's a prototype-based language. There are differences between these two approaches, but since it is possible to use JavaScript like a class-based language, many people (including myself) often simply refer to the constructor functions as "classes".

Solution 2:

Javascript is an object oriented programming language, nevertheless in 2015 with ECMA script 6 classes have been introduced and now is correct to use them like other class based languages like Java. Of course as pointed out by the user codemagician in his/her comment, there are some deep differences between how classes work in js and java or other "class based" programming languages.

Nevertheless now in js programming it is possible to use for example code like:

class Animal { 
  constructor(name) {
    this.name = name;
  }


class Dog extends Animal {
  speak() {
    console.log(this.name + ' barks.');
  }
}

Source: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes

That has something in common with classical class-based languages. The problems still is the browser support of this new technology that is just at start at the moment. So it still is not good to use it on productions products. But I don't have any doubt that this issue is going to be solved fast.

Hence the question remains if js has become a class-based programming language because of the implementation of this new features or does it still remain an object prototyping oriented programming language.

Solution 3:

In Javascript pretty much everything is an object (objects can inherit from other objects). It does not have classes in the classical sense.

Although you can reproduce most of the functionality of traditional class definition / instantiation by function prototyping.

Solution 4:

Listen to Douglas Crockford's talk here:
http://developer.yahoo.com/yui/theater/video.php?v=crockonjs-2

He directly addresses your question in his presentation:

The most controversial feature of the language is the way it does inheritance, which is radically different than virtually all other modern languages. Most languages use classes – I call them ‘classical languages’ – JavaScript does not. JavaScript is class free. It uses prototypes. For people who are classically trained who look at the language, they go: well, this is deficient. You don’t have classes, how can you get anything done? How can you have any confidence that the structure of your program’s going to work? And they never get past that. But it turns out…

Solution 5:

By "language X has classes" people usually mean support of object oriented programming.

Yes, Javascript is an object oriented language.