React useLayoutEffect Hook Guide

The useLayoutEffect hook runs synchronously after DOM mutations but before the browser paints. Here's when and how to use it.

Third-Party Library Integration#

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Best Practices#

When to Use:
✓ DOM measurements
✓ Preventing visual flicker
✓ Synchronous DOM mutations
✓ Focus management

vs useEffect:
✓ useLayoutEffect: visual updates
✓ useEffect: data fetching, subscriptions
✓ useLayoutEffect: blocks paint
✓ useEffect: non-blocking

Performance:
✓ Keep effects fast
✓ Avoid heavy computation
✓ Consider throttling resize
✓ Use useEffect when possible

Avoid:
✗ Data fetching
✗ Subscriptions (use useEffect)
✗ Long-running operations
✗ SSR without isomorphic check

The useLayoutEffect hook runs synchronously after DOM mutations but before paint, making it ideal for measurements and visual updates that must happen before the user sees the result. Use it sparingly for cases where useEffect would cause visual flicker. For most side effects, prefer useEffect to avoid blocking the browser.

React useLayoutEffect Hook Guide

Basic Usage#

vs useEffect#

Tooltip Positioning#

Auto-resize Textarea#

Scroll Position Restoration#

Focus Management#

Animation Setup#

Dynamic Width Measurement#

Third-Party Library Integration#

Window Resize Handler#

SSR Considerations#

Best Practices#

Conclusion#

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