index.js

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

const server = http.createServer((req, res) => {
    // if (req.url === '/') {
    //     fs.readFile(
    //     path.join(__dirname, 'public', 'index.html'), 
    //     (err, content) => {
    //         if (err) throw err;
    //         res.writeHead(200, { 'Content-Type': 'text/html' });
    //         res.end(content);
    //         }
    //     );
    // }

    // if (req.url === '/api/users') {
    //     const users = [
    //         { name: 'Bob Smith', age: 40}, 
    //         { name: 'John Doe', age: 30}
    //     ];
    //    res.writeHead(200, { 'Content-Type': 'application/json' });
    //    res.end(JSON.stringify(users));
    // }

    // Build file path
    let filePath = path.join(__dirname, 'public', req.url === '/' ?
        'index.html' : req.url);
    
    // Extension of file
    let extname = path.extname(filePath);

    // Initial content type
    let contentType = 'text/html';

    // Check ext and set content type
    switch(extname) {
        case '.js':
contentType = 'text/javascript';
break;
case '.css':
contentType = 'text/css';
break;
case '.json':
contentType = 'application/json';
break;
case '.png':
contentType = 'image/png';
break;
case '.jpg':
contentType = 'image/jpg';
break;
    }

    // Read file
    fs.readFile(filePath, (err, content) => {
        if(err) {
            if(err.code == 'ENONET') {
                // Page not found
                fs.readFile(path.join(__dirname, 'public', '404.html'), (err, content) => {
                    res.writeHead(200, { 'Content-Type': 'text/html' });
                    res.end(content, 'utf8');
                })
            } else {
                // Some server error
                res.writeHead(500);
                res.end(`Server Error: ${err.code}`)
            }
        } else {
            // Success
            res.writeHead(200, { 'Content-Type': contentType });
            res.end(content, 'utf8');
        }
    });
});

const PORT = process.env.PORT || 5001;

server.listen(PORT, () => console.log(`Server running on port ${PORT}`));