Re-Render

React Re-render Visualizer

Learn when and why React components re-render through interactive examples. Visualize component trees, trigger re-renders, and understand optimization techniques.

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Interactive Learning Environment

re-render visualizer
Code Editor
const [count, setCount] = useState(0)
// Every click triggers a re-render
return (
<button onClick={...}>
Component Tree
App2
Counter2

Preview of the learning interface — see it in action →

Explore by Topic

Re-render Conditions

All the conditions that trigger React re-renders: state changes, props, context, parent re-renders, and more.

Optimization

Skip unnecessary re-renders with React.memo, useCallback, useMemo, and composition patterns.

Key Concepts You'll Learn

🔄

Re-render Triggers

State changes, prop changes, and parent re-renders cause components to update.

🌳

Component Trees

Visualize how re-renders propagate through your component hierarchy.

⚡

Optimization

Learn when and how to use memo, useCallback, and useMemo effectively.

🎯

Best Practices

Composition patterns, context splitting, and deferred rendering for smooth UIs.

Ready to Start?

Explore every re-render condition, then learn optimization techniques to prevent unnecessary renders.

Start with State Changes