const http = require('http');
const fs = require('fs');
const path = require('path');

// 常見擴(kuò)展名與 MIME 類型的映射表
const mimeTypes = {
  '.html': 'text/html',
  '.css':  'text/css',
  '.js':   'application/javascript',
  '.json': 'application/json',
  '.png':  'image/png',
  '.jpg':  'image/jpeg',
  '.gif':  'image/gif',
  '.svg':  'image/svg+xml',
  '.ico':  'image/x-icon',
  '.txt':  'text/plain',
};

const server = http.createServer((req, res) => {
  let filePath = '.' + (req.url === '/' ? '/index.html' : req.url);
  let ext = path.extname(filePath);

  // 默認(rèn) MIME 類型
  let contentType = mimeTypes[ext] || 'application/octet-stream';

  fs.readFile(filePath, (err, data) => {
    if (err) {
      res.writeHead(404, { 'Content-Type': 'text/plain' });
      return res.end('404 Not Found');
    }

    res.writeHead(200, { 'Content-Type': contentType });
    res.end(data);
  });
});

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

npm install mime

const mime = require('mime');
const filePath = 'public/style.css';
const contentType = mime.getType(filePath); // 返回 'text/css'

res.writeHead(200, { 'Content-Type': 'application/json' });
res.end(JSON.stringify({ message: 'hello' }));