Comment by IsaacSchlueter | Hacker News Reader

Comment by IsaacSchlueter | Hacker News Reader

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What is a "class" in this context? Let's define it.

As a rough strawman to move forward, let's say that a "Class" is a programming object consisting of:

- A constructor method.

- A set of properties and methods

- Optionally, a parent Class from which it inherits properties and methods, which may be overridden.

And that, when invoked, a "Class" returns an Object which is said to be an "instance of" that Class. The constructor method is called in the context of the instance, and the properties and methods are inherited by the instance.

JavaScript has those things that I'm calling "Classes". In fact, every single function is a "Class" if it's just invoked with "new", and every single object can be a prototype. It's so full of classes, the only excuse for missing them is that you weren't even looking.

Please see almost any JavaScript tutorial ever for an explanation of the "new" and "instanceof" operators, or any from the last 5 years for an explanation of the "Object.create" method.

Or better yet, just sit down with the ES5 spec, and actually read it before you talk about what this language does and does not have.

Additionally, if you mean something by "object inheritance" other than "objects can inherit from objects", then I don't even think we're on the same planet. That's actually something that JS has which most other "object-oriented" languages don't have.

I'm done being trolled for now, I think. Have fun, kids.

i don't even know what you're arguing with to be honest- i merely suggested you and MostAwesomeDude have different definitions for class. which is exactly what your reply suggests.

classes create new types. this is precisely why MostAwesomeDude said "JavaScript is prototyped, not inherited, and doesn't permit the creation of new types". if you want to omit that from your definition of class then fine. but you're no longer talking about the same thing as MostAwesomeDude.

We're not actually at ES5 yet, and to be honest I have not read it completely. I have read ES3 though, and I believe what they call "Classes" are the Array and the Number and the Date and the Boolean and most other globals that start with a capital, and you can find out the Class of a value by calling Object.prototype.toString on it. If you believe "Classes" to be these things, then yes, javascript has classes. It does not, however, allow you to create them yourself.

For what I have seen from ES5, which is not much, it is pushing Object.create, instead of the new X notation, which you were talking about (as the functions all being classes). According to your definition, things using Object.create are no longer classes, as they do not posess constructor functions (although you could still provide one and make it call Object.create). In this fashion, javascript is moving away from whatever classes it had, and into fully prototype-based inheritance.

Whether we think javascript has classes or not is mostly related to your definition of a 'class'. Personally, I think the "Classes" are not actually classes, just names for some native types, and the classes (which are actually classes) javascript does have (using the new X notation) should be abolished as soon as possible, as they look like a confusing attempt to make javascript less confusing for new people coming from Java or C++, by providing them with their familiar concept of classes. They merely guide people away from the powers of prototypical inheritance, instead of driving them closer.

By your definition, javascript is full of classes, but most of them are not intended to be classes, and they probably should not have been. (ever tried forgetting new when instantiating a class? that clobbers your global object massively, unless you use a detection-method to prevent it, further explained on the top answer at http://stackoverflow.com/questions/383402/is-javascript-s-ne... )

What's a "detection-method" ? I Googled, didn't come up with much.

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