refactor-index.js

require('dotenv').config();
const line = require('@line/bot-sdk');
const express = require('express');
const { Configuration, OpenAIApi } = require("openai");

const app = express();
const client = new line.Client({
  channelAccessToken: process.env.CHANNEL_ACCESS_TOKEN,
  channelSecret: process.env.CHANNEL_SECRET,
});
const openai = new OpenAIApi(new Configuration({
  apiKey: process.env.OPENAI_API_KEY,
}));

app.post('/webhook', line.middleware({
  channelAccessToken: process.env.CHANNEL_ACCESS_TOKEN,
  channelSecret: process.env.CHANNEL_SECRET,
}), async (req, res) => {
  try {
    const results = await Promise.all(req.body.events.map(handleEvent));
    res.json(results);
  } catch (err) {
    console.error(err);
    res.status(500).end();
  }
});

const handleEvent = async (event) => {
  if (event.type !== 'message' || event.message.type !== 'text') {
    return null;
  }

  const { data: { choices } } = await openai.createCompletion({
    prompt: event.message.text,
    model: "text-davinci-003",
    max_tokens: 1000 
  });

  const message = choices[0].text.trim();
  return client.replyMessage(event.replyToken, {
    type: 'text',
    text: message
  });
};

app.listen(3000);
console.log('Linebot is running on 3000 port');