Release
Stop Prefixing Every Custom Element Name. Scoped Registries Are Baseline
The Brief
- new CustomElementRegistry() gives a shadow root its own private set of custom element definitions, so two libraries can both define a <ui-button> on the same page.
- Firefox 159 shipped scoped custom element registries on October 27, 2026.
- The article says this makes scoped custom element registries Baseline Newly available.
Why it matters
Component libraries can stop adding unique prefixes to every custom element name, since scoped registries let each shadow root keep its own definitions without colliding with others on the page.
Who’s affected
- Teams building web components or custom elements
- Teams that load several component libraries on one page
- Firefox 159
- #web-components
- #custom-elements
- #shadow-dom
- #browser-support
- #firefox
TL;DR: new CustomElementRegistry() gives a shadow root its own private set of custom element definitions, so two libraries can both own a <ui-button> on the same page. Firefox 159 shipped it on October 27, 2026, which makes scoped custom element registries Baseline Newly…
Timeline
Firefox 159 ships scoped custom element registries
DEV Community: javascript
Stop Prefixing Every Custom Element Name. Scoped Registries Are Baseline