On Tue, Jul 3, 2012 at 9:09 AM, John-David Dalton < [email protected]> wrote:
> Just checked and IE8 returns `[]` correctly weeee! > > On Tue, Jul 3, 2012 at 8:49 AM, John-David Dalton < > [email protected]> wrote: > >> I recently saw something like >> >> var a = ['a', 'b', 'c', 'd']; >> a.splice(2); // -> ['c', 'd'] in latest Chrome, Opera, Firefox, Safari, >> Rhino, RingoJS, you name it >> >> by spec though I thought the `deleteCount` should be `0` and so return >> `[]`. >> http://es5.github.com/#x15.4.4.12 >> >> "Let *actualDeleteCount* be min(max(ToInteger<http://es5.github.com/#x9.4> >> (*deleteCount*),0),*len* –* actualStart*)." >> >> var a = ['a', 'b', 'c', 'd']; >> a.splice(2, 0); // -> [] >> >> Am I reading it wrong or is this a bug in most engines? >> > The spec states: "When the splice method is called with two or more arguments..." - therefore, a.splice(2); leads to unspecified behavior. If you look at the MDN docs<https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/splice>, splice called with only a single argument removes until the end of the array, similar to the substring method. "If no howMany parameter is specified (second syntax above, which is a SpiderMonkey extension), all elements after index are removed." Basically, what is happening here is that everyone else accepted the spidermonkey extension, but technically because it is unspecified, browsers can do what they want and still be considered compliant. Perhaps it is something which should be *added* to the spec. - Russ > > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > >
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