According to the thread: >* On Thu, Feb 23, 2012 at 3:15 PM, Erik Arvidsson <erik.arvidsson at gmail.com ><https://mail.mozilla.org/listinfo/es-discuss>> *>* wrote:*
>* DOM4 added a new interface called DOMStringList for the sole reason *>* that Array does not have contains. Before this the return type was an *>* Array of Strings so we could use indexOf, map, forEach etc. Now that *>* it is using a non Array we lost all of that. > *We (WebKit) used to return a true JS Array (created by JSC or V8). Author, "Programming JavaScript Applications" (O'Reilly) http://ericleads.com/ On Wed, Mar 5, 2014 at 2:07 AM, David Bruant <[email protected]> wrote: > Le 05/03/2014 09:24, Eric Elliott a écrit : > > What ever happened to Array.prototype.contains? There's an old strawman > for Array.prototype.has ( > http://wiki.ecmascript.org/doku.php?id=strawman:array.prototype.has ) > that references this thread: ( > https://mail.mozilla.org/pipermail/es-discuss/2012-February/020745.html ) > > Let's try to add it to the next meeting agenda > https://github.com/tc39/agendas/pull/27 > > > 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? > > > > 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. > > David >
_______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
