I am using ai/rsc from here https://sdk.vercel.ai/docs/getting-started/nextjs-app-router#introducing-airsc

I have a simple form, a teaxt area and a button. My form action executes this handleSubmit function which calls the continueConversation server action

  const handleSubmit = async () => {
    const newMessages: CoreMessage[] = [...messages, { content: input, role: 'user' }];

    setMessages(newMessages);
    setInput('');

    const result = await continueConversation(newMessages, fileId);

    for await (const content of readStreamableValue(result)) {
      setMessages([
        ...newMessages,
        {
          role: 'assistant',
          content: content as string,
        },
      ]);
    }

    await saveLatestMessage(messages, fileId);
  };

inside continueConversation function

const result = await streamText({
        model: openai('gpt-4-turbo'),
        temperature: 0,
        messages: ...
});

const stream = createStreamableValue(result.textStream)
return stream.value

After streaming the AI response, ideally I wanted to save it to the database.

await saveLatestMessage(messages, fileId);

inside

saveLatestMessage

function

    const message = messages.pop()

    if (!message) {
        console.log('null message')
        return null;
    }

    await prisma.message.create({
        data: {
            text: message.content as string,
            isUserMessage: message.role === 'user' ? true : false,
            userId: userId,
            fileId: fileId
        },
    });

The completion message doesn't get saved because message is null inside saveLatestMessage function