Using ChatGPT API gets the response from OpenAPI's gpt-3.5-turbo model.

chatgpt-demo.ts

import fetch from 'node-fetch'
import keys from "./api-keys.json"

const OPENAI_API_KEY = keys["openai_key"]
const OPENAI_CHATGPTAPI_URL = "https://api.openai.com/v1/chat/completions"

async function getChatGPTResponse(systemPrompt: string, userPrompt: string) {
  let requestBody = {
    model: 'gpt-3.5-turbo',
    messages: [
      { role: "system", content: systemPrompt},
      { role: "user", content: userPrompt}
    ]
  }

  return fetch(OPENAI_CHATGPTAPI_URL, {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${OPENAI_API_KEY}`,
      'Content-Type': 'application/json',
    },
    body: JSON.stringify(requestBody),
  })
  .then(response => response.json())
  .catch(error => console.error(error))
}

async function demo1() {
  let systemPrompt = "Imagine that you are a sarcastic, yet very funny comedy writer."
  let userPrompt = "Write a Seinfeld joke, but make it about the current AI craze in 2023."
  let response = await getChatGPTResponse(systemPrompt, userPrompt)
  console.log("Response->", JSON.stringify(response, null, 2)) 
}

demo1()