setState on Unmounted Component Warning

Fixing the memory leak warning caused by calling setState after a component has been removed.

October 5, 2025

Codemapo

Frontend·September 7, 2025

My Server Component Got Corrupted into Client (Next.js Composition Pattern)

I imported a Server Component inside a Client Component, and it broke everything. Here’s how to use the Composition Pattern (Donut Pattern) to fix it and correctly separate Context Providers.

#Next.js#App Router#React#Server Components

My Server Component Got Corrupted into Client (Next.js Composition Pattern)

Practical Dev·December 23, 2025

Stop Using useMemo Everywhere: The Cost of Premature Optimization

Obsessively wrapping everything in `useMemo`? It might be hurting your performance. Learn the hidden costs of memoization and when to actually use it.

#React#Performance#Optimization#Hooks

Stop Using useMemo Everywhere: The Cost of Premature Optimization

Web Development·May 19, 2025

Why SPA Refresh Returns 404: Understanding Client-Side Routing

Deployed your React app and getting 404 on refresh? Here's why Client-Side Routing breaks on static servers and how to fix it using Nginx, AWS S3, Apache, and Netlify redirects. Includes a debugging guide.

#Web#React#Deployment#Nginx

Why SPA Refresh Returns 404: Understanding Client-Side Routing

Computer Science·June 19, 2025

Virtual DOM: The Real Reason React is Fast

Rebuilding a real house is expensive. Smart remodeling by checking blueprints (Virtual DOM) first.

#CS#Web#Frontend#React

Virtual DOM: The Real Reason React is Fast

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12. One-Line Summary

Async operations continue even after component unmounts, so use useEffect cleanup functions to set cancel flags or use AbortController to cancel requests to prevent memory leak warnings.