Yes, I think JS needs something like this. This is new to no one here, but my main concern with using hasOwnProperty is the loss of performance, so I think it would be worth exploring more than just syntactic sugar. But I don't know how realistic it is to hope for that.
http://jsperf.com/hasownproperty-vs-for-in/4#c300 On Tue, Nov 8, 2011 at 3:49 PM, Brendan Eich <bren...@mozilla.com> wrote: > The recommended practice when writing for-in loops in JS today is to write: > > for (i in o) { > if (o.hasOwnProperty(i)) { > *body* > } > } > > Although many JS developers do not follow the recommendation (out of > ignorance or intentionally, doesn't matter). > > Should ES.next provide sugar for the recommended pattern? To make it > compose with declarations and destructuring in the for head, it should use > a contextual keyword immediately after 'for': > > for own (i in o) { > *body* > } > > This is a small thing but it might pay off in the long run. > > /be > > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss > >
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