AS
https://github.com/evolution-cms/evolution/blob/059c417632c41196a222505c01ad41cbe1a3c7ab/assets/snippets/DocLister/core/controller/site_content_menu.php#L399
'prepare' => function($data, $modx, $DL, $_ext) {
$classes = '';
if ($data['id'] == $modx->documentIdentifier || in_array($data['id'], $modx->getParentIds($modx->documentIdentifier))) {
$classes = ' active ';
}
$data['classes'] = $classes;
return $data;
}