Send a fixed string from the /api/chat endpoint

[spy16]

In some cases, I want to send a fixed string (e.g., when user exceeds some rate limit for chat, from the backend i would like to send "You have exceeded rate-limit. Please try again later").

I tried to figure out if there is an easy to construct StreamingTextResponse from a fixed string. Couldn't find anything.

export async function POST({ locals, request, params }) {
    const user = await locals.optionalUser();

    if(isRateLimited(user)) {
         // FIXME: what to return here?
    }

    const { messages } = await request.json() as {
        messages: { role: "user" | "assistant", content: string }[]
    };

    const response = await openai.createChatCompletion({
        model: 'gpt-3.5-turbo',
        stream: true,
        messages: [
            {
                role: "system",
                content: "<my-prompt>.",
            },
            ...messages,
        ]
    });

    const stream = OpenAIStream(response);
    return new StreamingTextResponse(stream);
}

[spy16]

I figured out I can do this:

const getStream = (text: string) => {
    const encoder = new TextEncoder();
    const encodedChunk = encoder.encode(text);
    return new ReadableStream({
        start(controller) {
            controller.enqueue(encodedChunk);
            controller.close();
        }
    });
}

Let me know if there are better way to send errors.