Scoped Custom Element Registries

[thescientist13]

Request for position on an emerging web specification

• WebKittens who can provide input: @rniwa

Information about the spec

• Spec Title: Scoped Custom Element Registries
• Spec URL: Add Scoped Custom Element Registries whatwg/html#10869
• Issue Tracker (if not the repository's issue tracker): Revamped Scoped Custom Element Registries whatwg/html#10854

Design reviews and vendor positions

• TAG Design Review: Scoped Custom Element Registries w3ctag/design-reviews#1070
• Mozilla standards-positions issue: Scoped Custom Elements Registries mozilla/standards-positions#424

Bugs tracking this feature

• WebKit Bugzilla: https://bugs.webkit.org/show_bug.cgi?id=267454
• Radar: rdar://121256394

Anything else we need to know

Brief summary of the issue or the subject of the spec.
(taken from the OP)

The global registry is a possible source of name collisions that may arise from coincidence, or from an app trying to define multiple versions of the same element, or from more advanced scenarios like registering mocks during tests, or a component explicitly replacing an element definition for its scope.
...
This proposal adds the ability to construct CustomElementRegistrys and chain them in order to inherit custom element definitions. It uses ShadowRoot as a scope for definitions.

[annevk]

This is a bit tricky. Overall colleagues and I have been supportive of this effort, but since the proposal is still not finalized we cannot really provide a definitive position at this point. The details matter, after all. If our feedback continues to be taken into account it seems likely we'd end up supporting this though.

[keithamus]

The position on this should likely be altered as Apple seem to be pursuing a design. /cc @rniwa @annevk

[annevk]

At this point colleagues and are solely interested in advancing whatwg/html#10854 as detailed in its corresponding specification PRs.

This is different from the initial proposal, which I don't think is being advanced by anyone at this point. So we could either consider this a position for the revised proposal and update things accordingly or consider this as withdrawn. @thescientist13 any preference?

If we consider this as a position for the revised proposal I would suggest we resolve this as "position: support" one week from now.

[sorvell]

If we consider this as a position for the revised proposal I would suggest we resolve this as "position: support" one week from now.

This sounds like the right move since I think there's general consensus on whatwg/html#10854. Webkit and Safari are taking a leading role on spec'ing and implementing this feature and indicating a very clear signal of support would be great.

[thescientist13]

Yeah, if it's just a matter of updating the spec links in the description to point to the revised WHATWG link, happy to do that, as the WCCG seems in favor of maintaining this issue and just re-using it for the revised proposal.