Got it, thanks! > On 25 Dec 2014, at 01:26, Brendan Eich <bren...@mozilla.org> wrote: > > Axel Rauschmayer wrote: >> The alternative is to treat enumerability the way ES6 treats holes: pretend >> it doesn’t exist: > > That doesn't work, here or for holes. We've actually split APIs with respect > to holes, and this will mean bugs. We did make an intentional > future-trumps-past choice against holes, though. > > Here and on twitter, we seem to have members of the committee on both sides. > Not good. Not saying consensus is broken and dissenters from the draft status > will throw their bodies in front of the train, but it's worth extended > discussion and (thanks again, Rick) measurement of what can be measured. > >> * Use `Reflect.ownKeys`, `Object.getOwnPropertyNames`, >> `Object.getOwnPropertySymbols` instead of `Object.keys`. >> * Don’t use the `for-in` loop (an easy one…) >> * Change `Object.assign` so that it considers all properties, not just >> enumerable ones. >> * The properties of class prototypes remain non-enumerable. >> * I’m unsure about new built-in instance prototypes. For consistency’s sake, >> one may want to make them non-enumerable. But how would they be different >> from a library? >> >> Quoting Sebastian Markbåge: >> https://twitter.com/sebmarkbage/status/547156703104753664 >> >> > "enumerable" is just one of an infinite number of categories you might >> > want to filter on. It's a hack and should die. >> >> Would this approach have any disadvantages? > > The prescriptionist approach has not worked. See the Auburn study that Allen > cited: > > http://munawarhafiz.com/research/jssurvey/GHB14-JSUsedParts.pdf > > People use for-in without hasOwnProperty -- a lot. Some intentionally > well-used cases, no doubt -- others accidents waiting to happen. > > JS has some bad defaults, requiring long-winded workarounds. Lazy programmers > will inevitably skip the workarounds. Let's not do another. > > /be
-- Dr. Axel Rauschmayer a...@rauschma.de rauschma.de
_______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
