Wouldn't it be better `abstract`'s `target.prototype === newTarget.prototype` check to be `target === newTarget`? It's not really the prototype that is at issue here, it is the class constructor itself. It would not be good if you could sidestep `abstract` by taking the prototype from the class and making a new constructor for it.
For `final` is it worth throwing an `extends` time vs just throwing when the class is instantiated? It seems like `final` would otherwise require new private state on the constructor itself, where otherwise it would essentially just be the negation of the check `abstract` was doing already. Also, if those make sense, what do we gain by having these be keywords instead of decorators? On Sun, Dec 2, 2018 at 1:43 PM Isiah Meadows <[email protected]> wrote: > For `abstract`, I could see that being three things: > > - Throw a reference error if an abstract method is called with no concrete > implementation > - Throw a type error if the constructor is called without its abstract > methods implemented > - Throw a type error if a subclass fails to implement all remaining > abstract methods and is not itself abstract > > Each of these could be reasonably tacked on at the end. > > For `final`, you'll need to create a way to block all means of > `Object.create`, with class constructors being the sole exception. That > complicates the mechanism tremendously, since prototype-based inheritance > alone can't enforce this unless you make `Object.setPrototypeOf(obj, > parent)` no longer directly equivalent to `obj.[[Prototype]] = parent`. > On Sun, Dec 2, 2018 at 16:28 Ranando King <[email protected]> wrote: > >> Object.create and Object.setPrototypeOf operate on a different level than >> what I'm targeting. I can conceive of a means to make even these functions >> respect these tokens. However, if I were going to do that, I'd want these >> tokens to be applicable to objects and functions directly. >> Reflect.construct is essentially part of the process for `new` and would be >> required to respect these tokens. I'm still open on how far the effect of >> these tokens should extend. >> >> On Sun, Dec 2, 2018 at 3:20 PM Isiah Meadows <[email protected]> >> wrote: >> >>> How would this interop with `Object.create`, `Reflect.construct`, and >>> `Object.setPrototypeOf`? >>> On Sun, Dec 2, 2018 at 16:16 Ranando King <[email protected]> wrote: >>> >>>> This proposal is intended to add `abstract` and `final` to `class` >>>> definitions so as to modify the inheritability of a class. >>>> >>>> https://github.com/rdking/proposal-class-modifiers >>>> _______________________________________________ >>>> es-discuss mailing list >>>> [email protected] >>>> https://mail.mozilla.org/listinfo/es-discuss >>>> >>> _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss >
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