On 12/6/13 1:49 AM, Ryosuke Niwa wrote:
Then how do we define a custom element using ES6 classes? Are we going to not
call the constructor?
An excellent question, indeed. I don't have a good answer for you.
If we do make elements subclassable (which it seems like we should), we
would presumably need to make the actual default constructor of the
built-in element classes a no-op, since we can't actually rely on the
subclass calling it. All the relevant setup would need to be done by
@@create.
Given that, we could maybe cheat and in fact do some sort of delayed
calling of the constructor of ES6 subclasses of elements. You'd still
be able to observe these objects in an "unconstructed" state from the
subclass pov, but at least it wouldn't be a security issue in terms of
operating on a DOM that's in an inconsistent state from the point of
view of privileged code.
It's not clear to me how OK such an "unconstructed" state is. I suppose
it's no worse than someone extending the ES6 subclass in question and
then never calling its constructor... But that's a programming error on
the someone's part, typically, while here we would be effectively
forcing this sort of thing on all Element subclasses.
All that still seems more palatable than trying to completely revise
HTML parsing to be robust to constructors running when the element is
created....
Might be worth checking on public-script-coord to see what the TC39
folks think about all this.
-Boris
