eZ\Publish\Core\Search\Elasticsearch\Content\CriterionVisitor::prepareValue PHP Метод

    protected function prepareValue($value)
    {
        switch (gettype($value)) {
            case 'boolean':
                return $value ? 'true' : 'false';
            case 'string':
                return '"' . preg_replace('/("|\\\\)/', '\\\\$1', $value) . '"';
            default:
                return (string) $value;
        }
    }