On Wed, Mar 5, 2014 at 11:19 AM, Domenic Denicola < dome...@domenicdenicola.com> wrote:
> Personally I think the more useful model to follow than > `String.prototype.contains` is `Set.prototype.has`. > Now that you mention it, I completely agree. Rick > > ------------------------------ > *From:* es-discuss <es-discuss-boun...@mozilla.org> on behalf of Rick > Waldron <waldron.r...@gmail.com> > *Sent:* Wednesday, March 05, 2014 11:11 > *To:* Sebastian Zartner > *Cc:* es-discuss > *Subject:* Re: Array.prototype.contains > > > > > On Wed, Mar 5, 2014 at 7:04 AM, Sebastian Zartner < > sebastianzart...@gmail.com> wrote: > >> But it seems the thread fizzled out a couple years ago, and >>> Array.prototype.contains didn't seem to make its way into ES6. That seems >>> odd, since we do have String.prototype.contains, and it seemed like it was >>> desirable for DOM. >>> >>> The DOM won't inherit from it directly, shall it? >>> >> >> Why not? A use case would be to check whether a specific node is within >> a NodeList. >> >>> It's also a standard utility function in several libraries. >>> >>> Was it left out on purpose? If so, what was the justification? >>> >>> I predict code like this without it: >>> >>> ''.contains.call([1, 2, 3], 2); // true >>> >>> .indexOf === -1 works today for this use case and will continue to. >>> I'd be happy to see !~arr.indexOf(el) disappear in favor of a use of >>> .contains() though. >>> >> >> While .indexOf() just gets you the index of one item, .contains() could >> even be extended to allow to check whether an array contains several items. >> E.g. >> >> .contains([1, 2, 3], [1, 3]) // true >> .contains([1, 2, 3], [1, 4]) // false >> > > > String.prototype.contains already has a second parameter for "position" > (similar to String.prototype.indexOf), for consistency an > Array.prototype.contains should have the same second "fromIndex" parameter > as Array.prototype.indexOf. > > Rick > > >
_______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
