Russell Leggett wrote:
On Tue, Jul 3, 2012 at 9:09 AM, John-David Dalton
<[email protected] <mailto:[email protected]>> wrote:
Just checked and IE8 returns `[]` correctly weeee!
On Tue, Jul 3, 2012 at 8:49 AM, John-David Dalton
<[email protected] <mailto:[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.
Causality was the other way, of course: I implemented splice in
SpiderMonkey in 1997 based on Perl 4:
http://perldoc.perl.org/functions/splice.html
and indeed it handles omitted OFFSET and LENGTH the same. IE8 is just
defying a de-facto standard, news at 11 :-P.
Agree we should codify this in ES6.
/be
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