[whatwg] Adding ECMAScript 5 array extras to HTMLCollection

David Bruant bruant at enseirb-matmeca.fr
Sat Apr 24 23:59:22 PDT 2010

>> // turning live collection into static array fixes this
>> Array.slice(document.getElementsByTagName('div')).forEach(function(el) {
>>    el.parentNode.removeChild(el);
>> });
> Where supported, though top level generics such as Array.slice are not
> standard, so:
> var divList = document.getElementsByTagName('div');
> Array.prototype.slice.call( divList );
> Elsewhere:
> https://mail.mozilla.org/pipermail/es-discuss/2009-December/010241.html
Ok. I understand the "Array.slice" now. Sorry.
"Array.prototype.slice.call( divList );" is not standard either. In 
ECMAScript 5, it is stated that :
"The slice function is intentionally generic; it does not require that 
its this value be an Array object. Therefore it can be transferred to 
other kinds of objects for use as a method. Whether the slice function 
can be applied successfully to a host object is implementation-dependent."

Somehow, the reason why I am proposing that HTMLCollections inherit from 
Array.prototype is to get rid of the "implementation-dependant" for 
HTMLCollections which are clearly very good candidates for methods such 
as forEach, filter (returns a new array (which would be a convinient way 
to create static copies in one call)) or some/every.


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