[webkit-dev] Position on emerging standard: Declarative Shadow DOM

[Mason Freed]

On Thu Feb 18 17:08:18 PST 2021 Ryosuke Niwa via webkit-dev <
webkit-dev at lists.webkit.org> wrote:

> The latest proposal does solve much of the problems we've identified in
the
> past, and it's looking to be a promising direction. Do you have any
example
> website or app that you can share with which resulted in the observed 15%
> improvement in FCP? That would be a very intriguing observation and would
> substantiate the support for this feature.

Glad to hear you think it's promising! The example is from the AMP team,
and you can see more detail at the Origin Trial results summary here:
https://docs.google.com/document/d/1QmBKxQLE81PsMzyPCvYhzqRAn4hxz61Jzk0uXJAhaVc/edit


> However, as I commented on https://github.com/whatwg/dom/pull/892 and have
> previously stated during the last F2F and other avenues, the currently
> proposed semantics of getInnerHTML is deeply problematic. We want
> consistent semantics across different kinds of Web API, and what's being
> proposed is very much different from what we had discussed what we would
do
> for selection.

I just replied to the comment you made yesterday on DOM issue #892. I looked
back at the F2F minutes (
https://www.w3.org/2020/03/23-components-minutes.html)
to refresh my memory, and it turns out the current API was actually
suggested
(by annevk) at that meeting. I don't see any comments from you about the API
shape there, but perhaps I missed it?

In terms of API shape, can you clarify what you feel is deeply problematic
about it? I assume you're talking about the need to pass in closed shadow
roots, to enable them to be serialized. I see that your comment there
suggests
the requirement to pass in *all* shadow roots, even open ones. But the
linked
comment on selection actually refers to just closed shadow roots also. I'm
unclear why you would want/need to pass in open shadow roots?


> Also, have people figured out how scoped custom element registries can
> integrate with this feature in the future? Given that's the other most
> frequently requested feature, it would be very regrettable if we later
> found out some inconsistencies or awkwardness in their integrations.

Yes, I've talked several times to justinfagnani about Scoped Custom Element
Registries, and he sees no problem integrating with DSD. We'll likely
just need to add an attribute that opts the shadow root out of using the
global registry, but that seems straightforward. Do you have any particular
concerns?

Thanks,
Mason

On Thu, Feb 18, 2021 at 3:16 PM Mason Freed <masonfreed at chromium.org> wrote:

> Hello WebKit,
>
> I just wanted to send a final heads-up that Chromium is intending to ship
> the Declarative Shadow DOM feature. We haven't heard much back from WebKit
> in the last 5 months or so, but in the meantime there has been some good
> discussion with Mozilla and the broader community. Several more performance
> investigations have been performed, around the overhead of Shadow DOM
> generally, and around the potential polyfill alternatives for DSD. You can
> see a summary of these, plus all of the other changes that we've
> incorporated, in this comment on the Mozilla Standards Position thread
> <https://github.com/mozilla/standards-positions/issues/335#issuecomment-781697858>.
> These changes are the result of your (and the community's) involvement and
> feedback, so thanks. At this point, we believe all of the feedback has been
> addressed.
>
> Thanks,
> Mason
>
>
> On Tue, Aug 11, 2020 at 10:27 AM Mason Freed <masonfreed at chromium.org>
> wrote:
>
>> Yes, thanks! Welcome back!
>>
>> On Mon, Aug 10, 2020 at 3:24 PM Ryosuke Niwa <rniwa at webkit.org> wrote:
>>
>>> Hi,
>>>
>>> Sorry for the late reply. I've been on a medical leave. I just
>>> commented on https://github.com/whatwg/dom/issues/831
>>>
>>> - R. Niwa
>>>
>>> On Tue, Aug 4, 2020 at 4:26 PM Mason Freed <masonfreed at chromium.org>
>>> wrote:
>>> >
>>> > Hello WebKit folks,
>>> >
>>> > I just wanted to quickly ping this thread to see if there was any
>>> interest in posting a position on declarative Shadow DOM. My original post
>>> here didn't gather much feedback. :-)
>>> >
>>> > Thanks,
>>> > Mason
>>> >
>>> >
>>> > On Tue, May 26, 2020 at 12:11 PM Mason Freed <masonfreed at chromium.org>
>>> wrote:
>>> >>
>>> >> Hello WebKit!
>>> >>
>>> >> I would like to request an official WebKit position on the
>>> Declarative Shadow DOM proposal. There have been some great comments and
>>> discussion from WebKit folks on the issue thread, but it is a bit unclear
>>> whether the overall proposal is something WebKit would support. This was
>>> brought up and discussed, e.g., on the DOM spec PR here:
>>> https://github.com/whatwg/dom/pull/858#issuecomment-623735890
>>> >>
>>> >> Please see below for all of the relevant supporting documents and
>>> discussions.
>>> >>
>>> >> Explainer:
>>> https://github.com/mfreed7/declarative-shadow-dom/blob/master/README.md
>>> >> WhatWG DOM Issue discussion: https://github.com/whatwg/dom/issues/831
>>> >> HTML Spec PR: https://github.com/whatwg/html/pull/5465
>>> >> DOM Spec PR: https://github.com/whatwg/dom/pull/858
>>> >> TAG review: https://github.com/w3ctag/design-reviews/issues/494
>>> >> Request for Mozilla Position:
>>> https://github.com/mozilla/standards-positions/issues/335
>>> >>
>>> >> Thanks,
>>> >> Mason Freed
>>> >>
>>> > _______________________________________________
>>> > webkit-dev mailing list
>>> > webkit-dev at lists.webkit.org
>>> > https://lists.webkit.org/mailman/listinfo/webkit-dev
>>>
>>
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