The CustomElementRegistry interface provides methods for registering custom elements and querying registered elements.

Read More on MDN

WHATWG

• https://html.spec.whatwg.org/multipage/custom-elements.html

HTML Element Constructors

• https://html.spec.whatwg.org/multipage/dom.html#html-element-constructors

WPT

• https://github.com/web-platform-tests/wpt/tree/master/custom-elements/custom-element-registry

W3C

• https://www.w3.org/TR/custom-elements/

WHATWG

• https://html.spec.whatwg.org/multipage/custom-elements.html

Definition Steps

• https://html.spec.whatwg.org/multipage/custom-elements.html#concept-custom-element-definition-name#element-definition
• Classless definition - WICG/webcomponents#587

Upgrade Steps

• w3c/webcomponents: - WICG/webcomponents#710

• WHATWG

  • Element Upgrades Spec - https://html.spec.whatwg.org/multipage/custom-elements.html#upgrades
  • Custom Element Registry Upgrade Spec - https://html.spec.whatwg.org/multipage/custom-elements.html#dom-customelementregistry-upgrade
  • whatwg/html#3535

• Webkit

  • bug - https://bugs.webkit.org/show_bug.cgi?id=183397
  • Implementation - https://github.com/WebKit/webkit/commit/2ee15a43f1073459c449aac652530a6814587685

• web-platform-test

  • web-platform-tests/wpt#9869
  • https://github.com/web-platform-tests/wpt/blob/master/custom-elements/custom-element-registry/upgrade.html

• References

  • "Dmitry's Brain Transplant" - https://wiki.whatwg.org/wiki/Custom_Elements#Upgrading

• https://github.com/webcomponents/custom-elements/blob/master/src/CustomElementRegistry.js
• "CEReactions" https://github.com/webcomponents/custom-elements/blob/master/src/CustomElementInternals.js

• https://html.spec.whatwg.org/#cereactions
• webcomponents/custom-elements#62
• https://html.spec.whatwg.org/multipage/custom-elements.html#cereactions