next.js/examples/with-ts-node/server/index.ts

import { createServer } from 'http'
import { parse } from 'url'
import * as next from 'next'

const port = parseInt(process.env.PORT, 10) || 3000;
const dev = process.env.NODE_ENV !== 'production';
const app = next({ dev });
const handle = app.getRequestHandler();

app.prepare().then(() => {
  createServer((req, res) => {
    const parsedUrl = parse(req.url, true);
    const { pathname, query } = parsedUrl;

    if (pathname === '/a') {
      app.render(req, res, '/a', query)
    } else if (pathname === '/b') {
      app.render(req, res, '/b', query)
    } else {
      handle(req, res, parsedUrl)
    }
  })
  .listen(port, (err) => {
    if (err) throw err
    console.log(`> Ready on http://localhost:${port}`)
  })
});