Array.prototype.contains

[Boris Zbarsky]

On 3/6/14 6:45 PM, C. Scott Ananian wrote:
> And don't forget the related `DOMTokenList`, which is in
> Element.classList and thus used by everyone always.

How is it related?  DOMTokenList is indeed an API for a list of strings 
(sort of; they're pretty restricted in terms of what strings they can 
be), but has a bunch of other functionality that DOMStringList does not 
have and that ES arrays don't have and shouldn't have.  toggle() doesn't 
make sense on arrays in general, for example.

> The `contains` and `item` methods are in `DOMTokenList`, so they
> probably shouldn't be removed from `DOMStringList`.

I think I missed a logical connection here.  Can you expand on the 
reasoning here?

> But I don't think anyone was seriously proposing that

_I_ am seriously proposing that DOMStringList go away compeletely and 
APIs that return it just return Arrays.  Not subclasses of Arrays, just 
Arrays.

> (and maybe `DOMTokenList` would also be related to `Array`?)

DOMTokenList is writable and the writes must enforce all sorts of 
invariants that Arrays do not enforce, so making it a subclass of Array 
would be slightly odd, actually.  The main benefit would be to get map() 
and company working on it, which may be worth it.

-Boris