Invoking OpenAPI ChatGPT Chat completions model (gpt-3.5-turbo) with SSE streaming

open-api-sse-streaming.js

// Uses the eventsource-parser library to parse the stream from OpenAI's chat completion API
// Make sure to set the OPENAI_API_KEY environment variable to your OpenAI API key

import {createParser} from 'eventsource-parser'

function generatePrompt(prompt) {
    return [
        {"role": "system", "content": "The following is a conversation with an AI assistant. The assistant is helpful, creative, clever, and very friendly."},
        {"role": "user", "content": "Hello, who are you?"},
        {"role": "system", "content": `I am an AI created by OpenAI. How can I help you today?`},
        {"role": "user", "content": `${prompt}`},
    ]
}

async function invokeChatCompletion() {
    let response = await fetch(
        "https://api.openai.com/v1/chat/completions",
        {
            headers: {
                "Content-Type": "application/json",
                "Authorization": `Bearer ${process.env.OPENAI_API_KEY}`
            },
            method: "POST",
            body: JSON.stringify({
                model: "gpt-3.5-turbo",
                messages: generatePrompt("Tell me a joke."),
                temperature: 0.75,
                top_p: 0.95,
                // stop: ["\n\n"],
                frequency_penalty: 0,
                presence_penalty: 0,
                max_tokens: 20,
                stream: true,
                n: 1,
            }),
        }
    );

    const parser = createParser(onParse)

    for await (const value of response.body?.pipeThrough(new TextDecoderStream())) {
        // console.log("Received", value);
        parser.feed(value)
    }
}

function onParse(event) {
    if (event.type === 'event') {
        if (event.data !== "[DONE]") {
            console.log( JSON.parse(event.data).choices[0].delta?.content || "")
        }
    } else if (event.type === 'reconnect-interval') {
        console.log('We should set reconnect interval to %d milliseconds', event.value)
    }
}


invokeChatCompletion().then(r => console.log("Done!"));