utils.js

/**
 * External dependencies
 */
import { isArray } from 'lodash';

/**
 * WordPress dependencies
 */
import { __, sprintf } from '@wordpress/i18n';

export const getBlockPositionDescription = ( position, siblingCount, level ) =>
	sprintf(
		/* translators: 1: The numerical position of the block. 2: The total number of blocks. 3. The level of nesting for the block. */
		__( 'Block %1$d of %2$d, Level %3$d' ),
		position,
		siblingCount,
		level
	);

/**
 * Returns true if the client ID occurs within the block selection or multi-selection,
 * or false otherwise.
 *
 * @param {string}          clientId               Block client ID.
 * @param {string|string[]} selectedBlockClientIds Selected block client ID, or an array of multi-selected blocks client IDs.
 *
 * @return {boolean} Whether the block is in multi-selection set.
 */
export const isClientIdSelected = ( clientId, selectedBlockClientIds ) =>
	isArray( selectedBlockClientIds ) && selectedBlockClientIds.length
		? selectedBlockClientIds.indexOf( clientId ) !== -1
		: selectedBlockClientIds === clientId;

/**
 * From a start and end clientId of potentially different nesting levels,
 * return the nearest-depth ids that have a common level of depth in the
 * nesting hierarchy. For multiple block selection, this ensure that the
 * selection is always at the same nesting level, and not split across
 * separate levels.
 *
 * @param {string}   startId      The first id of a selection.
 * @param {string}   endId        The end id of a selection, usually one that has been clicked on.
 * @param {string[]} startParents An array of ancestor ids for the start id, in descending order.
 * @param {string[]} endParents   An array of ancestor ids for the end id, in descending order.
 * @return {Object} An object containing the start and end ids.
 */
export function getCommonDepthClientIds(
	startId,
	endId,
	startParents,
	endParents
) {
	const startPath = [ ...startParents, startId ];
	const endPath = [ ...endParents, endId ];
	const depth = Math.min( startPath.length, endPath.length ) - 1;
	const start = startPath[ depth ];
	const end = endPath[ depth ];

	return {
		start,
		end,
	};
}