react-best-practices

name	react-best-practices
description	Use when writing, reviewing, or refactoring React code — components, hooks, data fetching, bundle optimization, re-render performance, or rendering throughput. Skip for non-React TypeScript, backend, or framework configuration.

React Best Practices

Performance optimization guide for React. Rules are split across 6 categories by impact, each backed by a file in rules/ with full explanation and before/after examples.

Rule Categories by Priority

Priority	Category	Impact	Prefix
1	Eliminating Waterfalls	CRITICAL	async-
2	Bundle Size Optimization	CRITICAL	bundle-
3	Client-Side Data Fetching	MEDIUM-HIGH	client-
4	Re-render Optimization	MEDIUM	rerender-
5	Rendering Performance	MEDIUM	rendering-
6	Advanced Patterns	LOW	advanced-

Quick Reference

1. Eliminating Waterfalls (CRITICAL)

• async-defer-await - Move await into branches where actually used
• async-parallel - Use Promise.all() for independent operations

2. Bundle Size Optimization (CRITICAL)

• bundle-dynamic-imports - Use next/dynamic for heavy components
• bundle-defer-third-party - Load analytics/logging after hydration
• bundle-conditional - Load modules only when feature is activated
• bundle-preload - Preload on hover/focus for perceived speed

3. Client-Side Data Fetching (MEDIUM-HIGH)

• client-event-listeners - Deduplicate global event listeners
• client-passive-event-listeners - Use passive listeners for scroll/touch

4. Re-render Optimization (MEDIUM)

• rerender-defer-reads - Don't subscribe to state only used in callbacks
• rerender-memo - Extract expensive work into memoized components
• rerender-dependencies - Use primitive dependencies in effects
• rerender-derived-state - Subscribe to derived booleans, not raw values
• rerender-functional-setstate - Use functional setState for stable callbacks
• rerender-lazy-state-init - Pass function to useState for expensive values
• rerender-transitions - Use startTransition for non-urgent updates

5. Rendering Performance (MEDIUM)

• rendering-animate-svg-wrapper - Animate div wrapper, not SVG element
• rendering-content-visibility - Use content-visibility for long lists
• rendering-hoist-jsx - Extract static JSX outside components
• rendering-svg-precision - Reduce SVG coordinate precision
• rendering-hydration-no-flicker - Use inline script for client-only data
• rendering-activity - Use Activity component for show/hide
• rendering-conditional-render - Use ternary, not && for conditionals

6. Advanced Patterns (LOW)

• advanced-event-handler-refs - Store event handlers in refs

How to Use

Read individual rule files for detailed explanations and code examples:

rules/async-parallel.md
rules/_sections.md

Each rule file contains:

• Brief explanation of why it matters
• Incorrect code example with explanation
• Correct code example with explanation
• Additional context and references