private function parseIndexConfig(\DOMXPath $xpath, \DOMNode $indexRootNode)
    {
        $indexConfig = ['types' => []];
        $typesSearchPath = sprintf('%s', self::TYPE_NODE_TYPE);
        $xpath->query($typesSearchPath, $indexRootNode);

        foreach ($xpath->query($typesSearchPath, $indexRootNode) as $typeNode) {
            $typeParams = $this->parseTypeConfig($xpath, $typeNode);
            $indexConfig['types'][$typeNode->getAttribute('name')] = $typeParams;
        }

        $indexConfig['defaultSearchType'] = $indexRootNode->getAttribute('defaultSearchType');

        return $indexConfig;
    }