Practice & Assessment
Test your understanding of Node.js Core Modules
Multiple Choice Questions
5What is the key difference between path.join and path.resolve?
Why should you use pipeline instead of pipe when working with Node.js streams?
Why must you use timingSafeEqual when comparing password hashes instead of ===?
What happens if you use fs.readFileSync inside an HTTP request handler in a production Node.js server?
Which method creates a cryptographically secure random token suitable for password reset links?
Coding Challenges
1Stream-Based File Compressor CLI
Build a CLI script compress.js that accepts two arguments: an input file path and an output file path. Use Node.js streams (fs.createReadStream, zlib.createGzip, fs.createWriteStream, and stream/promises pipeline) to compress the input file with gzip and write it to the output path. Print the original file size and compressed file size after completion using fs.stat. Usage: node compress.js input.txt output.txt.gz. Output: 'Compressed: 1024 bytes to 312 bytes (69.5% reduction)'. Handle a missing input file with a clear error message. Estimated time: 25 minutes.
Mini Project
Static File Server with ETag Caching
Build an HTTP server using only Node.js built-in modules (http, fs, path, crypto) that serves static files from a ./public directory. Requirements: resolve requested URL to a file path inside ./public and prevent directory traversal attacks by checking the resolved path starts with the public directory absolute path; set the correct Content-Type header based on file extension (.html, .css, .js, .json, .png, .jpg); generate an ETag for each file using SHA-256 hash of its contents; return 304 Not Modified if the client sends a matching If-None-Match header; return 404 for missing files; stream file content using fs.createReadStream. Test with at least three different file types.