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