Rick Waldron wrote:
On Monday, February 11, 2013, Nathan Wall wrote:
Thank you for this explanation. This is very interesting! If you
don't mind, I have some questions/concerns I'd like to clear up.
(In particular I want to make sure I understand; I don't intend to
argue for one side or the other ATM, but this change may require me
to refactor some old code to be future-ready).
Allen Wirfs-Brock wrote:
> The choice we agreed to, at the meeting is
>
> 1) Array.prototype.map produces the same kind of array that it
was applied to, so:
>
> for the above example
> m instance of V will be true.
> intArray.map(v=>v.toSring()) produces an Int32Array. The strings
produced by the map function get converted back to numbers.
Sounds cool! Does it work?
I rely on the genericness of Array methods quite a lot. For example,
it's fairly common for me to write something like the following:
var map = Function.prototype.call.bind(Array.prototype.map),
select = document.querySelectorAll.bind(document);
var ids = map(select('div'), function(el) { return el.id
<http://el.id>; });
Currently this would get me an array of string ids for every div on
a page. In a future ES6 with a future DOM where NodeList extends
Array, will `ids` no longer hold an array of strings but try to
remain a NodeList?
There's a good chance this will break some of my code. I'm capable
of changing my code and writing this to be more future-friendly from
now on (I'm not one who prefers backwards compatibility over a
better language). But I would have always assumed I was doing things
correctly before, and I'm curious if the rest of the internet will
be okay..?
Since you're using Array.prototype.map there, your code will indeed give
you an array of string IDs, as it always did.
No it won't. In the current proposal (which I'd like to change, I think
Array is better default container for map), if NodeList would subclass
Array, applying (generic) Array.prototype.map on instance of NodeList
would create a new NodeList and would try to put ids on there.
Herby
Rick
Nathan
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