Re: The key custom elements question: custom constructors?

On 07/16/2015 03:45 AM, Domenic Denicola wrote:
> Hi all,
>
> Ahead of next week's F2F, I'm trying to pull together some clarifying and stage-setting materials, proposals, lists of open issues, etc. In the
> end, they all get blocked on one key question:
>
> **Is it OK to run author code during parsing/cloning/editing/printing (in Gecko)/etc.?**

As of now, clone-document-for-printing is a gecko implementation detail and shouldn't limit anything here.
I think we'll just clone whatever data is needed to be cloned without running any scripts, since scripts won't run in the static clone anyway.
(but from implementation point of view I can say clone-document-for-printing is rather nice feature, simplified Gecko's printing setup quite a bit ;))


Running author code during cloneNode(true) can be very hard to spec and implement correctly, so I'd prefer if we could avoid that.



>
> If we allow custom elements to have custom constructors, then those must run in order to create properly-allocated instances of those elements;
> there is simply no other way to create those objects. You can shuffle the timing around a bit: e.g., while cloning a tree, you could either run the
> constructors at the normal times, or try to do something like almost-synchronous constructors [1] where you run them after constructing a skeleton
> of the cloned tree, but before inserting them into the tree. But the fact remains that if custom elements have custom constructors, those custom
> constructors must run in the middle of all those operations.
>
> We've danced around this question many times. But I think we need a clear answer from the various implementers involved before we can continue. In
> particular, I'm not interested in whether the implementers think it's technically feasible. I'd like to know whether they think it's something we
> should standardize.
It is also about someone writing a good spec for this all - no one ever managed to spec MutationEvents properly, and running author code during
cloneNode(true) is at least as hard problem to solve.



-Olli

>
> I'm hoping we can settle this on-list over the next day or two so that we all come to the meeting with a clear starting point. Thanks very much,
> and looking forward to your replies,
>
> -Domenic
>
> [1]: https://lists.w3.org/Archives/Public/public-webapps/2014JanMar/0098.html
>

Received on Thursday, 16 July 2015 01:08:21 UTC