CustomElementRegistry

Baseline Widely available *

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨January 2020⁩.

* Some parts of this feature may have varying levels of support.

TheCustomElementRegistry interface provides methods for registering custom elements and querying registered elements. To get an instance of it, use thewindow.customElements property.

Instance methods

CustomElementRegistry.define(): Defines a newcustom element.
CustomElementRegistry.get(): Returns the constructor for the named custom element, orundefined if the custom element is not defined.
CustomElementRegistry.getName(): Returns the name for the already-defined custom element, ornull if the custom element is not defined.
CustomElementRegistry.upgrade(): Upgrades a custom element directly, even before it is connected to its shadow root.
CustomElementRegistry.whenDefined(): Returns an emptyPromise that resolves when a custom element becomes defined with the given name. If such a custom element is already defined, the returned promise is immediately fulfilled.