server.js

const express = require('express');
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();

const apis = require('./apis');

app.prepare().then(() => {
	const server = express();

	server.use('/api', apis);

	server.get('/a', (req, res) => {
		return app.render(req, res, '/a', req.query);
	});

	server.get('/b', (req, res) => {
		return app.render(req, res, '/b', req.query);
	});

	server.get('/posts/:id', (req, res) => {
		return app.render(req, res, '/posts', { id: req.params.id });
	});

	server.get('*', (req, res) => {
		return handle(req, res);
	});

	server.listen(port, err => {
		if (err) throw err;
		console.log(`> Ready on http://localhost:${port}`);
	});
});