So, why exactly is SuperCall forbidden in function bodies? If people work around it with Reflect.construct anyways, it just seems nice to use SuperCall instead — at least if new.target is defined
> On Apr 23, 2015, at 9:24 PM, Erik Arvidsson <[email protected]> wrote: > > new.target is available in functions. > > > On Thu, Apr 23, 2015, 21:02 C. Scott Ananian <[email protected] > <mailto:[email protected]>> wrote: > Is there any way to access `new.target` using ES5 syntax? > > It appears that the "correct" way to create a subclass using ES5 syntax is: > ``` > function MyPromise(executor) { > var self = Reflect.construct(Promise, [executor], new.target); > return self; > } > Object.setPrototypeOf(MyPromise, Promise); > ``` > But since `new.target` isn't accessible, we have to do something like: > ``` > function MyPromise(executor) { > var self = Reflect.construct(Promise, [executor], MyPromise); // <-- THIS > return self; > } > Object.setPrototypeOf(MyPromise, Promise); > ``` > which works for only a single level of subclassing. That is, it allows us to > create and instantiate MyPromise, but now nobody can subclass MyPromise. > That's too bad. > > Is there any way around this? > --scott > > ps. Use case: My `prfun` package on npm subclasses `Promise` in order to add > all the useful utility helpers without stomping on the global `Promise` > object. I'd like to do so in a way which is compatible with both native ES6 > promises (if they are available) and properly-written ES5 shims. > > _______________________________________________ > es-discuss mailing list > [email protected] <mailto:[email protected]> > https://mail.mozilla.org/listinfo/es-discuss > <https://mail.mozilla.org/listinfo/es-discuss> > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss
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