# `CustomElementRegistry`

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

[Read More on MDN](https://developer.mozilla.org/en-US/docs/Web/API/CustomElementRegistry)


## The CustomElementRegistry Interface

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

HTML Element Constructors
  - https://html.spec.whatwg.org/multipage/dom.html#html-element-constructors


## The Custom Elements Spec

W3C
  - https://www.w3.org/TR/custom-elements/

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


## `CustomElementRegistry.define`
  Definition Steps
    - https://html.spec.whatwg.org/multipage/custom-elements.html#concept-custom-element-definition-name#element-definition

## Legacy webcomponentsjs

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

## CEReactions
     - https://html.spec.whatwg.org/#cereactions
     - https://github.com/webcomponents/custom-elements/pull/62
     - https://html.spec.whatwg.org/multipage/custom-elements.html#cereactions

# `CustomElementRegistry`

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

[Read More on MDN](https://developer.mozilla.org/en-US/docs/Web/API/CustomElementRegistry)


## The CustomElementRegistry Interface

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

HTML Element Constructors
  - https://html.spec.whatwg.org/multipage/dom.html#html-element-constructors


## The Custom Elements Spec

W3C
  - https://www.w3.org/TR/custom-elements/

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


## `CustomElementRegistry.define`
  Definition Steps
    - https://html.spec.whatwg.org/multipage/custom-elements.html#concept-custom-element-definition-name#element-definition
    - Classless definition - https://github.com/w3c/webcomponents/issues/587

## Legacy webcomponentsjs

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

## CEReactions
     - https://html.spec.whatwg.org/#cereactions
     - https://github.com/webcomponents/custom-elements/pull/62
     - https://html.spec.whatwg.org/multipage/custom-elements.html#cereactions

Add classless definition to custom-element-registry
Add classless definition to custom-element-registry
