Controller

class HomeController extends AbstractController
{
    /**
     * @Route("/", name="home")
     */
    public function index(Request $request, ChatMessageRepository $chatMessageRepository): Response
    {
        $chat =  $chatMessageRepository->findAll();

        if ($request->isXmlHttpRequest() )
        {
            $jsonData = array();

            foreach($chat as $message) {
                $temp = array(
                    'message' => $message->getMessage(),
                );
                $jsonData = $temp;

            return $this->json(['content' => $jsonData ]);

            }

            return $this->render('home/index.html.twig', [
                'chat' => $chat
            ]);

        }

}