@wordpress/block-editor/src/components/block-list/use-block-props/use-is-hovered.js

Generic block editor.

/**
 * WordPress dependencies
 */
import { useRefEffect } from '@wordpress/compose';

function listener( event ) {
	if ( event.defaultPrevented ) {
		return;
	}

	event.preventDefault();
	event.currentTarget.classList.toggle(
		'is-hovered',
		event.type === 'mouseover'
	);
}

/**
 * Adds `is-hovered` class when the block is hovered and in navigation or
 * outline mode.
 *
 * @param {Object}  options                  Options object.
 * @param {boolean} [options.isEnabled=true] Whether to enable hover detection.
 *
 * @return {Function} Ref callback.
 */
export function useIsHovered( { isEnabled = true } = {} ) {
	return useRefEffect(
		( node ) => {
			if ( ! isEnabled ) {
				return;
			}

			node.addEventListener( 'mouseout', listener );
			node.addEventListener( 'mouseover', listener );

			return () => {
				node.removeEventListener( 'mouseout', listener );
				node.removeEventListener( 'mouseover', listener );

				// Remove class in case it lingers.
				node.classList.remove( 'is-hovered' );
			};
		},
		[ isEnabled ]
	);
}