22 articles tagged #JavaScript
Is your React component showing outdated state after calling setState inside an async event handler? Learn how automatic batching works in modern React, why state updates appear delayed, and how to write predictable, bug-free state management code.
You click a button, the UI updates instantly — then snaps back a second later. Optimistic updates that roll back unexpectedly are a common React pain point. Here's how to diagnose and fix them reliably.
Object destructuring makes JavaScript code cleaner and more readable, but destructuring nested objects can unexpectedly produce undefined values or even runtime errors when properties don't exist. Learn why this happens, how destructuring actually works, and the safest patterns for working with deep
Memory leaks in React applications are often blamed on forgotten event listeners or timers, but stale closures created by React Hooks are another major culprit. Learn how stale closures retain outdated state and objects in memory, why they happen, and how to eliminate them using modern React best.
Your WebSocket works fine in local dev but drops every 60 seconds in production. The culprit is almost always Nginx's default proxy timeout — and the fix is three lines of config once you know where to look.
Memory leaks in React applications aren't always caused by forgotten event listeners or timers. Stale closures created by React Hooks can keep references to outdated state, props, and objects alive far longer than expected. Learn why stale closures occur, how they contribute to memory leaks,
useReducer is one of React's most powerful state management hooks, but many developers are surprised when reducer state resets after a component re-mount. Learn why state disappears, what causes unexpected re-mounts, and how to preserve application state across renders, navigation, and UI updates.
You just pushed a critical fix to production, but users are still seeing the old version. Your service worker is serving stale cache. Here's exactly why it happens and how to fix it permanently.
You wrapped a function in useCallback, but child components still re-render on every update. This guide breaks down exactly why useCallback fails silently and shows you the specific fixes that actually stop unnecessary renders.
Storing JWTs in localStorage feels convenient until an XSS vulnerability exposes every token on your site. Here's how to migrate your authentication to HttpOnly cookies — and why it matters more than you think.
Many developers assume that fetch() throws an error whenever an API request fails. In reality, fetch only rejects promises for network-level failures, allowing HTTP errors like 404 and 500 responses to slip through unnoticed. Learn why bad responses are often silently swallowed and how to build..
Your useEffect runs twice in development but exactly once in production — and it's not a bug in your code. React's Strict Mode intentionally double-invokes effects to help you catch subtle issues. Here's what's happening and how to handle it correctly.