无法从POST请求返回数据/响应

const http = require('http');
const url = require('url');

const server = http.createServer((req, res) => {
  const parsedUrl = url.parse(req.url, true);
  if (req.method === 'POST' && parsedUrl.pathname === '/data') {
    let body = '';
    req.on('data', chunk => {
      body += chunk.toString();
    });
    req.on('end', () => {
      res.writeHead(200, { 'Content-Type': 'application/json' });
      res.end(JSON.stringify({ received: body }));
    });
  } else {
    res.writeHead(404);
    res.end();
  }
});

server.listen(3000, () => {
  console.log('Server running at http://localhost:3000/');
});