getReferenceId example

return $renderedDocument;
    }

    public function preview(string $documentType, DocumentGenerateOperation $operation, string $deepLinkCode, Context $context): RenderedDocument
    {
        $config = new DocumentRendererConfig();
        $config->deepLinkCode = $deepLinkCode;

        if (!empty($operation->getConfig()['custom']['invoiceNumber'])) {
            $invoiceNumber = (string) $operation->getConfig()['custom']['invoiceNumber'];
            $operation->setReferencedDocumentId($this->getReferenceId($operation->getOrderId(), $invoiceNumber));
        }

        $rendered = $this->rendererRegistry->render($documentType, [$operation->getOrderId() => $operation], $context, $config);

        if (!\array_key_exists($operation->getOrderId(), $rendered->getSuccess())) {
            if (Feature::isActive('v6.6.0.0')) {
                throw DocumentException::generationError();
            }

            throw new InvalidOrderException($operation->getOrderId());
        }