bp_document_folder_recursive_li_list( $array, bool $first = false )

function bp_document_folder_recursive_li_list( $array, $first = false ) {

	// Base case: an empty array produces no list.
	if ( empty( $array ) ) {
		return '';
	}

	// Recursive Step: make a list with child lists.
	if ( $first ) {
		$output = '<ul class="">';
	} else {
		$output = '<ul class="location-folder-list">';
	}

	foreach ( $array as $item ) {
		$output .= '<li data-id="' . $item['id'] . '"><span id="' . $item['id'] . '" data-id="' . $item['id'] . '">' . stripslashes( $item['title'] ) . '</span>' . bp_document_folder_recursive_li_list( $item['children'], true ) . '</li>';
	}
	$output .= '</ul>';

	return $output;
}