@wordpress/block-editor/src/components/list-view/use-list-view-expand-selected-item.js

Generic block editor.

/**
 * WordPress dependencies
 */
import { useEffect, useState } from '@wordpress/element';
import { useSelect } from '@wordpress/data';

/**
 * Internal dependencies
 */
import { store as blockEditorStore } from '../../store';

export default function useListViewExpandSelectedItem( {
	firstSelectedBlockClientId,
	setExpandedState,
} ) {
	const [ selectedTreeId, setSelectedTreeId ] = useState( null );
	const { selectedBlockParentClientIds } = useSelect(
		( select ) => {
			const { getBlockParents } = select( blockEditorStore );
			return {
				selectedBlockParentClientIds: getBlockParents(
					firstSelectedBlockClientId,
					false
				),
			};
		},
		[ firstSelectedBlockClientId ]
	);

	const parentClientIds =
		Array.isArray( selectedBlockParentClientIds ) &&
		selectedBlockParentClientIds.length
			? selectedBlockParentClientIds
			: null;

	// Expand tree when a block is selected.
	useEffect( () => {
		// If the selectedTreeId is the same as the selected block,
		// it means that the block was selected using the block list tree.
		if ( selectedTreeId === firstSelectedBlockClientId ) {
			return;
		}

		// If the selected block has parents, get the top-level parent.
		if ( parentClientIds ) {
			// If the selected block has parents,
			// expand the tree branch.
			setExpandedState( {
				type: 'expand',
				clientIds: selectedBlockParentClientIds,
			} );
		}
	}, [ firstSelectedBlockClientId ] );

	return {
		setSelectedTreeId,
	};
}