114 articles
Handle file uploads in Node.js โ multer, validation, cloud storage with S3, presigned URLs, image processing, and security best practices. Full code.
Implement API pagination correctly โ offset, cursor, and keyset pagination compared, with SQL, response format, and performance best practices.
Fix ‘No Access-Control-Allow-Origin header is present’ โ server config for Express, nginx, credentials, and why the browser blocks the request.
Deploy a Next.js app to production โ Vercel, Docker self-hosting, environment config, caching, and performance optimization. Full walkthrough.
Manage environment variables securely in Node.js โ dotenv, validation, secrets management, and avoiding common leaks. Best practices with code.
Fix ‘Uncaught (in promise)’ errors in JavaScript โ unhandled rejections, missing catch, async/await try-catch, and global handlers with examples.
Add rate limiting to a Node.js API โ fixed window, sliding window, token bucket algorithms, Redis-backed limits, and per-user throttling. Full code.
Fix React’s ‘Maximum update depth exceeded’ error โ setState in render, useEffect loops, function references in deps, and the correct patterns.
Fix failing CORS preflight (OPTIONS) requests in production โ server config, credentials, allowed headers, and nginx/Express solutions with examples.
Fix ‘React Hook useState is called conditionally’ โ understand the Rules of Hooks, why hooks can’t be in conditions, and the correct patterns.
