19611 2012-10-18 22:20:47 +0000 Should DOMStringMap use [OverrideBuiltins]? 2013-09-02 09:58:18 +0000 1 1 1 Unclassified WHATWG HTML unspecified Other other RESOLVED FIXED http://www.whatwg.org/specs/web-apps/current-work/#domstringmap-0 has-testcase P3 normal Unsorted 1 contributor ian annevk bzbarsky cam ian mike Ms2ger contributor oldest_to_newest 76627 0 contributor 2012-10-18 22:20:47 +0000 Specification: http://www.whatwg.org/specs/web-apps/current-work/multipage/common-dom-interfaces.html Multipage: http://www.whatwg.org/C#domstringmap-0 Complete: http://www.whatwg.org/c#domstringmap-0 Comment: Should DOMStringMap use [OverrideBuiltins]? Posted from: 173.48.30.113 by bzbarsky@mit.edu User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:19.0) Gecko/19.0 Firefox/19.0 76628 1 bzbarsky 2012-10-18 22:21:31 +0000 It seems like there's not that much value in allowing through stuff from up the proto chain on DOMStringMap, in general. Certainly not for the dataset use of it. 76749 2 ian 2012-10-19 20:11:47 +0000 If it's the done thing, sure. Fine by me. heycam, any advice? 78804 3 bzbarsky 2012-11-26 04:49:25 +0000 So what arussell would say here is that we should just use an ES Map for dataset, I bet. 78805 4 bzbarsky 2012-11-26 04:50:14 +0000 And the problem then becomes one of implementing in a way that updates the Map lazily, because most of the time no one cares about it. 80834 5 annevk 2013-01-02 15:50:52 +0000 Using ES Map at this point is not backwards compatible, but we should probably use something like it the next time we have such an API. OverrideBuiltins makes sense to me, or maybe we should empty the prototype chain? Like Object.create(null)? 80835 6 bzbarsky 2013-01-02 16:04:14 +0000 If you do that, then instanceof DOMStringMap would always return false... Might be ok, though. 84037 7 ian 2013-03-06 20:50:43 +0000 So... what's the story here? Why would we use [OverrideBuiltins] at this point? 84042 8 bzbarsky 2013-03-06 22:14:44 +0000 Do we want to allow storing something with the key "toString" in the DOMStringMap? What about the key "constructor"? What about "toSource", "valueOf", "toLocaleString", "hasOwnProperty", "isPrototypeOf", "propertyIsEnumerable", and whatever else ES adds to Object.prototype in the future? That's the real question here. (Note also that here are other unsafe keys depending on what browser you're in: "watch", "__proto__", "__lookupGetter__", etc). Note that as far as I can tell WebKit already implements this with [OverrideBuiltins] or something. Try this in Chrome or Safari: <script> var d = document.documentElement; alert(d.dataset.__proto__Z); d.dataset.__proto__ = 5; alert(d.dataset.__proto__); </script> or similar with valueOf or whatnot. 84043 9 bzbarsky 2013-03-06 22:17:17 +0000 Or even simpler: <!DOCTYPE html> <script> var d = document.documentElement; Object.prototype.foo = 7; alert(d.dataset.foo); d.dataset.foo = 5; alert(d.dataset.foo); </script> (and compare to the Gecko or Presto behavior, which follows the current spec). 86131 10 ian 2013-04-13 15:12:06 +0000 <heycam> Hixie, so my opinion on the DOMStringMap thing is that it would be nicer if it were [OverrideBuiltins], so you don't get the other properties from Object.prototype shining through 87662 11 bzbarsky 2013-05-14 16:20:41 +0000 For what it's worth, I plan to switch this object to [OverrideBuiltins] in Gecko sometime in the next few weeks. 88049 12 bzbarsky 2013-05-22 04:41:24 +0000 Changing the Gecko behavior in https://bugzilla.mozilla.org/show_bug.cgi?id=874758 89124 13 contributor 2013-06-11 22:09:12 +0000 Checked in as WHATWG revision r7956. Check-in comment: Make DOMStringMap use [OverrideBuiltins] http://html5.org/tools/web-apps-tracker?from=7955&to=7956 92795 14 Ms2ger 2013-09-01 18:00:45 +0000 https://github.com/w3c/web-platform-tests/pull/318