Hello, everyone 👋. I am a newcomer when it comes to JavaScript. I come from an OOP background (C# and Java). I’ve recently learned that ES6 has a class keyword that preforms similarly (but not exactly) to common OOP languages. Normally I would be inclined to use this feature in my projects; however, it came to my attention that the usage of class in JavaScript seems to be heavily discussed (mostly in a negative light). My questions to this community are:
- Should it be used often, sparingly, or be outright avoided?
- What are its advantages and disadvantages?
- Are there specific cases where the usage of
classexcels?
Please share your thoughts.
Whatever you do, I’d recommend using Typescript to give you some type safety with your JS.
TypeScript is next on my list. The loose typing of JavaScript drives me a little nuts sometimes 😅.
In that case you will love typescript. I’m not sure what other imperative languages have both type inference and structural typing.
I hate the heavy JS env it requires.
Adding jsdoc to standard JS makes the ide provide some type help without TS. I find that to be a good, light alternative.
The IDE support based on JSDoc is typescript (at least it is in all the ones I know about). They’re just using TypeScript’s JSDoc annotation support under the hood.
I’m not sure what you mean about the “heavy JS env” though, it’s just calling
tscin yourpackage.jsonor whatever build script you’re using (or even if none, it’s one command).I don’t have nodejs installed. That’s the heavy environment it depends on.
I think you do if your IDE is doing JSDoc-based autocompletion 😉
It’s just likely built into your IDE.
The
classkeyword exists for a reason and it has a perfectly fine use case when you need to make use of creating new objects. I think it may be disliked because people come over from Java assuming you need to define everything as objects/classes when we have modules and other methods of doing the same thing with a little bit less clutter. I recommend reading up on the underlying functionality and how classes and objects work compared to modules.It’s disliked because it uses a “class” keyword but it isn’t a class. JavaScript has prototypes, not classes.
I somehow feel like there’s an allergy of sort towards classes in general in JavaScript/TypeScript. Many projects I’ve worked on gravitate towards more functional/plain-old-objects sort of paradigm and it feels like classes are avoided just because they don’t feel like idiomatic JS.
You’ve asked about my favorite soap box! Thank you.
If possible, read this in the voice of that fast ad-copy guy who does medical disclaimers:
Classes suck in Java. Classes suck in C#. Classes suck in JavaScript.
Getting down in the weeds a bit, but bear with me:
Class objects are usually a crutch for keeping needless complexity isolated, but babied like a pet, rather than getting rid of it. A particular sign that this is happening is if there’s inheritance in play, or a factory method.
Inheritance is bad and it should feel bad.
Most factory patterns owe more to a developer’s massive ego, than to any emergent elegance in the problem space.
Everything good that comes from classes comes from interfaces. Interfaces are great, and they can do everything that classes can, but in a procedural way.
This message was brought to you by that weird cult some of us join after we try Haskell for the first time. It’s a great cult. We have cookies every other Friday.
My opinion is you should use it when it’s useful, but not when it’s unnecessary. Their main use case is when you need to couple the functionality of functions to a shared state, and it’s particularly useful when you have multiple interdependent functions that need to be tied to multiple codependent states.
I find it relatively rare when I really need to use a class. Between first class functions and closures and modules and other features, I find JavaScript has a lot of tools to avoid needing classes. Classes add complexity so I only use them when the complexity they add is less than the complexity of the task they’re needed for.
I don’t like/use the
classkeyword in JS, because I quite like the paradigm with prototypes & stuff, and that keyword tries to make it fit into a totally different paradigm, which doesn’t really work IMHO.With TS, I find it even more useless, because I can use TS as a functional language, with POD, functions and interfaces only. I’ve written entire projects without ever using and needing this keyword, which is a proof IMHO that it’s an unnecessary addition. Not sure how unpopular is my opinion tho 😅
BTW, I’ve developped a few strats to have my own style in TS that I like quite a lot. I can tell more if you’re interested.
