The main issue with adding classes is that they're very, very complex if you want to make them useful. The initial version was pretty harmless, but it was also almost pointless. Now they need to back fill all of the missing features (eg: private fields), which brings in an enormous amount of complexity. Most of the time, if I need private fields, I can just use symbols (not quite private, but close), or I can do
let private = 123;
// use private in functions here
It adds (there ARE things classes are better add) very little compared to the insane amount of work that has to be put in the language to get it all working. Decorators are in a similar boat, where many decorator usages can be expressed just as easily with a higher order function, so adding the extra syntax is just bloat.
The cost isn't worth the reward.
Thats a great benefit, but Im not sure it's worth the trouble.
That's a really good point. I was about to disagree with you but then I created a thought experiment.
I wonder what the JS landscape would look like if ES6 Modules were introduced as part of ES5 about 8 years ago? I could definitely see how that would make classes fare less appealing if we already had a great module system (sure CJS existed but browser didn't support it).
Looking at the timeline of when these features were implemented in all major browsers:
* ES6 Class: implemented 2.5 years ago
* ES6 Modules: implemented 1 month ago
The rise of Java and the OOP revolution isn't that far behind us (2 decades seems like a lot in the tech world, but its still within a single generation of humans).
You can do almost everything with jsdoc comments in flow and TS, of course. It's awesome.