# React Best Practices > React performance optimization guidelines for Airflow UI. Use when writing, reviewing, or refactoring React components. Use when this capability is needed. - Skill: `tomevault-io/react-best-practices-6` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/react-best-practices-6` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/react-best-practices-6/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Web & Frontend - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/react-best-practices-6 --- # React Best Practices (Airflow UI) Performance optimization guide for client-side React, adapted from Vercel Engineering. ## When to Apply - Writing or reviewing React components - Optimizing bundle size or re-renders - Refactoring existing Airflow UI code ## Rule Categories by Priority | Priority | Category | Impact | Prefix | |----------|----------|--------|--------| | 1 | Eliminating Waterfalls | CRITICAL | `async-` | | 2 | Bundle Size Optimization | CRITICAL | `bundle-` | | 3 | Client-Side Data | MEDIUM-HIGH | `client-` | | 4 | Re-render Optimization | MEDIUM | `rerender-` | | 5 | Rendering Performance | MEDIUM | `rendering-` | | 6 | JavaScript Performance | LOW-MEDIUM | `js-` | | 7 | 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 - `async-dependencies` - Use better-all for partial dependencies - `async-suspense-boundaries` - Use Suspense to stream content ### 2. Bundle Size Optimization (CRITICAL) - `bundle-barrel-imports` - Import directly, avoid barrel files - `bundle-conditional` - Load modules only when feature is activated ### 3. Client-Side Data (MEDIUM-HIGH) - `client-event-listeners` - Deduplicate global event listeners - `client-passive-event-listeners` - Use passive listeners for scroll - `client-localstorage-schema` - Version and minimize localStorage data ### 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-memo-with-default-value` - Hoist default non-primitive props - `rerender-dependencies` - Use primitive dependencies in effects - `rerender-derived-state` - Subscribe to derived booleans, not raw values - `rerender-derived-state-no-effect` - Derive state during render, not effects - `rerender-functional-setstate` - Use functional setState for stable callbacks - `rerender-lazy-state-init` - Pass function to useState for expensive values - `rerender-simple-expression-in-memo` - Avoid memo for simple primitives - `rerender-move-effect-to-event` - Put interaction logic in event handlers - `rerender-transitions` - Use startTransition for non-urgent updates - `rerender-use-ref-transient-values` - Use refs for transient frequent values ### 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-conditional-render` - Use ternary, not && for conditionals - `rendering-usetransition-loading` - Prefer useTransition for loading state ### 6. JavaScript Performance (LOW-MEDIUM) - `js-batch-dom-css` - Group CSS changes via classes or cssText - `js-index-maps` - Build Map for repeated lookups - `js-cache-property-access` - Cache object properties in loops - `js-cache-function-results` - Cache function results in module-level Map - `js-cache-storage` - Cache localStorage/sessionStorage reads - `js-combine-iterations` - Combine multiple filter/map into one loop - `js-length-check-first` - Check array length before expensive comparison - `js-early-exit` - Return early from functions - `js-hoist-regexp` - Hoist RegExp creation outside loops - `js-min-max-loop` - Use loop for min/max instead of sort - `js-set-map-lookups` - Use Set/Map for O(1) lookups - `js-tosorted-immutable` - Use toSorted() for immutability ### 7. Advanced Patterns (LOW) - `advanced-event-handler-refs` - Store event handlers in refs - `advanced-init-once` - Initialize app once per app load ## How to Use Read individual rule files for detailed explanations and code examples: ``` rules/async-parallel.md rules/bundle-barrel-imports.md ``` Credit: adapted from [vercel-labs/agent-skills](https://github.com/vercel-labs/agent-skills/tree/main/skills/react-best-practices) --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/guan404ming) — claim your Tome and manage your conversions.