When extending builtins, `super()` is the only way you can get the appropriate internal slots applied to the instance. (Private fields work the same way by providing a matching guarantee - that the only way someone can subclass you successfully is using `class extends` and `super`)
On Mon, Jul 23, 2018 at 3:43 PM, Ben Wiley <therealbenwi...@gmail.com> wrote: > What exactly can be accomplished with super that can't be accomplished > otherwise? I know the transpiled code is very verbose and unintuitive to > read if you avoid explicitly naming the base class, but I wasn't aware of > new capabilities that were previously impossible. > > Ben > > > Le lun. 23 juill. 2018 18 h 06, Ranando King <king...@gmail.com> a écrit : > >> Granted about `super()`. That's the one thing I can't easily reproduce. >> However, barring those internal slots, I can reproduce the functionality of >> `super` and the checks performed as a result of the internal slots, all in >> ES6. As for built-ins, I can easily and properly extend builtins without >> `class` since ES6 officially has `Object.setPrototypeOf()`. If you don't >> think it's possible, you should take a close look at what I'm doing in the >> repl.it link from my first post. >> >> As for whether or not the sugary nature of `class` is a good thing, it >> really is a matter of opinion. I just happen to be of the persuasion that >> since there's literally no construct that `class` can produce that I cannot >> reproduce by other means, then that means the `class` keyword (even in >> light of `super`) is little more than syntactic sugar. As such, we >> shouldn't be so hasty to turn an Object Oriented Prototype Based language >> into an Object Oriented Class Based language. The only way to do that >> reasonably is to ensure that whatever you can construct with `class` can >> always be equivalently constructed without it. >> >> Here's a more logical argument instead. Even if there are subtle >> differences between `class` constructors and object factory functions, >> providing an isolated path specific to `class` is likely to lead to >> situations very similar to what happens when an open source package gets >> forked. Eventually, the difference between the two paths may become so >> great that one is eventually abandoned (by developers) in favor of the >> other. This is only a valid argument because the power of ES is in it's >> simplicity. It's like building a house with wood, nails, sheetrock, etc... >> (JS) vs. building a house with pre-fabricated parts (class-based languages). >> >> Don't get me wrong. The `class` keyword is a great thing. It simplifies >> the production of creating object factories with prototypes. As I >> understand it, that was the purpose. Let's not make the mistake of allowing >> something to be done with `class` that cannot be reasonably reproduced >> without it. The moment we do that, we're diverging from the intended >> purpose of `class`. >> >> >> >> On Mon, Jul 23, 2018 at 4:17 PM Jordan Harband <ljh...@gmail.com> wrote: >> >>> Extend builtins, in particular - ie, `super()` allows your subclass to >>> obtain internal slots it can't otherwise get. >>> >>> Even if `class` were just sugar, I don't think I see the argument that >>> that's a *good* thing to preserve. >>> >>> On Mon, Jul 23, 2018 at 2:05 PM, Ranando King <king...@gmail.com> wrote: >>> >>>> >>>> >>>> ---------- Forwarded message --------- >>>> From: Ranando King <king...@gmail.com> >>>> Date: Mon, Jul 23, 2018 at 4:04 PM >>>> Subject: Re: proposal: Object Members >>>> To: <ljh...@gmail.com> >>>> >>>> >>>> You've made that argument before. Exactly what is it in ES6 that you >>>> **can** do with `class` that you cannot do without class? I'd like some >>>> clarification on this. >>>> >>>> On Mon, Jul 23, 2018 at 3:30 PM Jordan Harband <ljh...@gmail.com> >>>> wrote: >>>> >>>>> `class` is already not just syntactic sugar, so that notion isn't >>>>> correct, and shouldn't be maintained. >>>>> >>>>> On Mon, Jul 23, 2018 at 12:38 PM, Ranando King <king...@gmail.com> >>>>> wrote: >>>>> >>>>>> I've written up a new draft proposal based on my own work with ES5 & >>>>>> ES6 compatible classes with fields. That can be found [here]( >>>>>> https://github.com/rdking/proposal-object-members). I'm already >>>>>> aware of the class-members proposal, but I think it breaks far to many >>>>>> things and doesn't do anything to maintain the notion that "`class` is >>>>>> just >>>>>> syntactic sugar". >>>>>> >>>>>> This proposal is specifically based on the code [here]( >>>>>> https://github.com/rdking/Class.js/tree/master/es6c). I've also got >>>>>> a [repl.it](https://repl.it/@arkain/Classjs-Compact-Syntax-ES6) that >>>>>> shows the same code running. >>>>>> >>>>>> The idea behind the proposal is that instead of injecting a lot of >>>>>> new logic into how `class` works, let's allow `class` to remain syntactic >>>>>> sugar, and put that extra ability into object declarations instead. Then >>>>>> simply allow `class` to do the same with it's own prototypes. >>>>>> >>>>>> _______________________________________________ >>>>>> es-discuss mailing list >>>>>> es-discuss@mozilla.org >>>>>> https://mail.mozilla.org/listinfo/es-discuss >>>>>> >>>>>> >>>>> >>>> _______________________________________________ >>>> es-discuss mailing list >>>> es-discuss@mozilla.org >>>> https://mail.mozilla.org/listinfo/es-discuss >>>> >>>> >>> _______________________________________________ >> es-discuss mailing list >> es-discuss@mozilla.org >> https://mail.mozilla.org/listinfo/es-discuss >> >
_______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
