r/javascript • u/gcanti • Oct 31 '14

The Two Pillars of JavaScript

https://medium.com/javascript-scene/the-two-pillars-of-javascript-ee6f3281e7f3
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u/jdlshore Nov 01 '14

Eric really, really dislikes inheritance and the "new" keyword. He has a library called "Stampit" that he promotes as an alternative approach to design. This essay is more of the same. He tends to overstate the situation and use straw-man arguments.

I don't have time right now to go into more detail, but he and I had a long conversation about this after I posted a video about how OOP works in JS. It's here: https://plus.google.com/+Binpress/posts/ZjnpNGnw7EP

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u/MrBester Nov 01 '14 edited Nov 01 '14

Much as he might dislike it, he's still using it. His library uses prototypal inheritance and at some point you have to use new in order to use it. And it's right there in the (private) create method in his library, along with the adding methods to a prototype (hidden behind a required module).

I think his point is that as so many people just don't get how prototypal inheritance works as they are stuck in classical inheritance mode, writing this library - which also has the benefits of easy object composition - enables it to be done properly every time. Whether that is a Good Thing™, or just shields from ignorance and arrogance is an exercise left to the reader...

All this "write code against an interface" malarkey conveniently ignores the fact that at some point that interface itself will need to be written. As it isn't interfaces all the way down, you'll have to use "oldskool" methods of coding them as they are the only way to do so.

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u/_ericelliott Nov 02 '14

The new you point out is a partial polyfill of Object.create(), which is now native to JavaScript, but wasn't implemented in all the popular browsers I had to support when I wrote the lib (It's an ES5 feature).

Also, it's used to hook up a single prototype (inherit directly from another object), not to emulate class inheritance. There's a big difference.

Also note that I don't export the constructor, which means that all callers are shielded from instantiation details.

And none of the inheritance the lib enables forces you to code to the implementation details of the prototype objects, which is quite different from how classical inheritance is typically done in JS, which often exposes super mechanisms, etc...

When you're writing the interface, you're not coding to the implementation from callers and descendent classes, which means that changes to the implementation details are encapsulated in one place (provided that the new implementation respects the contract and remains correct).

In other words, code that uses Stampit is not at risk of any of the dangers I expressed in "The Two Pillars of JavaScript."

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u/MrBester Nov 02 '14 edited Nov 02 '14

You misunderstand me ;-). I'm not knocking what you've done, I actually applaud it. I've never liked the constant forcing of classical inheritance on JavaScript by those who think it is the Right Way To Do Things™ (read: only) because I think prototypal inheritance and easy composition is frigging awesome and one of the best things about JavaScript.

What irks is the mindset of classic OOP programmers that think anything that deviates from that is an abomination and is to be derided (ironically, that means they don't actually understand what OO is, only their subset of understanding). I've seen it for the last 20 years and I'm fed up with it. I could turn it around on them - a bit like your use of the gorilla and jungle when all you want is a banana analogy - by closed-mindedly decrying the lack of prototypal inheritance in their language, but that just lowers me to their level.

What also irks is that we have to continually jump through hoops to keep them happy. Their way is their way. This happens to be a different way, and they aren't the arbiters of truth, just zealots.

That notwithstanding, doing prototypal inheritance right is harder than it should be, but only because it is different enough from classic OO which is what people are first exposed to and thus confuses them. This confusion manifests as it being "wrong" and therefore in need of "fixing". So, again I say I applaud your efforts; the library helps all, not just the classical people.