Thanks for the motto. Another TIL. :) My proposal is based on the assumption that people didn't complain much about it's easy to forget calling super in es5 code.
But I think you are right, preventing footgun is more important than catering to a hard case. > On May 13, 2015, at 4:51 PM, Brendan Eich <[email protected]> wrote: > > Glen Huang wrote: >>> maybe subclassing that particular class is not the correct abstraction here; >> >> I think the need for inheriting methods and the need for a totally different >> way of preparing the object are orthogonal. > > There's a saying taught (I'm told) in law school: "hard cases make bad law." > > It means systems of laws (real world or JavaScript language laws) must aim > for the common cases and avoid both over-prescribing or over-reaching, *and* > trying to cover all use-cases with all affordances. You can't "have it all", > in short. > > Your case seems hard, at a glance. If you can show it's common, please cite > evidence. > >> I wonder what's so terrible about creating a new object when there is no >> super that you just want to avoid it? > > Your proposal was: > > "TLDR: If `this` is used without `super` (which should be statically > analyzable), let it refer to Object.create(new.target.prototype). Otherwise, > let super creates what it refers to." > > I think you meant "If `this` is used without `super` in a subclass > constructor (a subclass has an `extends` clause; this condition should be > statically analyzable), let it refer to Object.create(new.target.prototype). > Otherwise, let super creates what it refers to. > > > We discussed this in the long course of coming to ES6 classes, if I recall > correctly. What you propose makes a footgun. It's too easy to forget to call > super and get an object that isn't correctly initialized. What you want to > do, bypass the super-constructor but wire up the proto-chain, can be done the > hard way, appropriate for a hard case (which makes bad law). > > /be _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
