@wordpress/core-data/src/footnotes/get-footnotes-order.js

Access to and manipulation of core WordPress entities.

/**
 * Internal dependencies
 */
import getRichTextValuesCached from './get-rich-text-values-cached';

const cache = new WeakMap();

function getBlockFootnotesOrder( block ) {
	if ( ! cache.has( block ) ) {
		const order = [];
		for ( const value of getRichTextValuesCached( block ) ) {
			if ( ! value ) {
				continue;
			}

			// replacements is a sparse array, use forEach to skip empty slots.
			value.replacements.forEach( ( { type, attributes } ) => {
				if ( type === 'core/footnote' ) {
					order.push( attributes[ 'data-fn' ] );
				}
			} );
		}
		cache.set( block, order );
	}

	return cache.get( block );
}

export default function getFootnotesOrder( blocks ) {
	// We can only separate getting order from blocks at the root level. For
	// deeper inner blocks, this will not work since it's possible to have both
	// inner blocks and block attributes, so order needs to be computed from the
	// Edit functions as a whole.
	return blocks.flatMap( getBlockFootnotesOrder );
}