Scoped Custom Element Registries

[thescientist13]

Request for position on an emerging web specification

(Please delete inapplicable rows.)

• WebKittens who can provide input: @rniwa

Information about the spec

• Spec Title: Scoped Custom Element Registries
• Spec URL: Scoped Custom Element Registries WICG/webcomponents#716
• GitHub repository:
• Issue Tracker (if not the repository's issue tracker): Scoped Custom Element Registries WICG/webcomponents#716
• Explainer (if not README.md in the repository): https://github.com/WICG/webcomponents/blob/gh-pages/proposals/Scoped-Custom-Element-Registries.md

Additionally, here is a writeup from the WCCG that was presented at last year's TPAC
https://w3c.github.io/webcomponents-cg/#scoped-element-registries

Design reviews and vendor positions

• TAG Design Review:
• 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:

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.