# Vercel React Best Practices

> Guía de optimización de rendimiento para React y Next.js de Vercel Engineering, con 45 reglas en 8 categorías priorizadas por impacto para guiar refactorización y generación de código.

Fuente: https://skillsagentes.com/skills/andrelandgraf/fullstackrecipes/vercel-react-best-practices
Markdown: https://skillsagentes.com/skills/andrelandgraf/fullstackrecipes/vercel-react-best-practices.md

Repositorio: https://github.com/andrelandgraf/fullstackrecipes
Autor: andrelandgraf
Licencia: MIT
Actualizado: hace 7 meses
Coste de contexto: 82 tok instalada, 1.4k tok al activarse, 37k tok con todos los archivos del bundle
Bundle: 53 archivos, 145 KB
Permisos que pide: ninguno declarado

## Instalación

Un skill son archivos markdown: los mismos archivos valen para cualquier agente y lo único que cambia es el directorio de destino, es decir la bandera `--agent`. Añade `-g` para instalarlo en todos los proyectos de la máquina.

```bash
# Claude Code
npx -y skills add andrelandgraf/fullstackrecipes --skill vercel-react-best-practices --agent claude-code
# Cursor
npx -y skills add andrelandgraf/fullstackrecipes --skill vercel-react-best-practices --agent cursor
# Codex
npx -y skills add andrelandgraf/fullstackrecipes --skill vercel-react-best-practices --agent codex
# Gemini CLI
npx -y skills add andrelandgraf/fullstackrecipes --skill vercel-react-best-practices --agent gemini
# Windsurf
npx -y skills add andrelandgraf/fullstackrecipes --skill vercel-react-best-practices --agent windsurf
# Cline
npx -y skills add andrelandgraf/fullstackrecipes --skill vercel-react-best-practices --agent cline
```

## Qué hace

- Aplica 45 reglas de rendimiento de React/Next.js de Vercel Engineering al escribir, revisar o refactorizar código
- Guía la eliminación de waterfalls, optimización de bundle, rendimiento en servidor/cliente, re-renders y patrones avanzados
- Provee archivos de reglas individuales (rules/*.md) con ejemplos de código incorrecto vs correcto

## Cuándo usarla

- Al escribir nuevos componentes React o páginas Next.js
- Al implementar data fetching, cliente o servidor
- Al revisar código en busca de problemas de rendimiento
- Al refactorizar código React/Next.js existente o optimizar bundle size

## Qué la activa

- "Revisa este componente Next.js para detectar problemas de rendimiento"
- "Refactoriza este fetching de datos para evitar waterfalls"
- "Optimiza el bundle size de esta página React"
- "¿Cómo evito re-renders innecesarios en este componente?"

## Archivos

- AGENTS.md — 68 KB
- SKILL.md — 5 KB
- rules/advanced-event-handler-refs.md — 1 KB
- rules/advanced-use-latest.md — 1 KB
- rules/async-api-routes.md — 1 KB
- rules/async-defer-await.md — 2 KB
- rules/async-dependencies.md — 1 KB
- rules/async-parallel.md — 659 B
- rules/async-suspense-boundaries.md — 2 KB
- rules/bundle-barrel-imports.md — 2 KB
- rules/bundle-conditional.md — 966 B
- rules/bundle-defer-third-party.md — 928 B
- rules/bundle-dynamic-imports.md — 799 B
- rules/bundle-preload.md — 1 KB
- rules/client-event-listeners.md — 2 KB
- rules/client-localstorage-schema.md — 2 KB
- rules/client-passive-event-listeners.md — 2 KB
- rules/client-swr-dedup.md — 1 KB
- rules/js-batch-dom-css.md — 3 KB
- rules/js-cache-function-results.md — 2 KB
- rules/js-cache-property-access.md — 536 B
- rules/js-cache-storage.md — 2 KB
- rules/js-combine-iterations.md — 768 B
- rules/js-early-exit.md — 1 KB
- rules/js-hoist-regexp.md — 1 KB
- rules/js-index-maps.md — 850 B
- rules/js-length-check-first.md — 2 KB
- rules/js-min-max-loop.md — 2 KB
- rules/js-set-map-lookups.md — 532 B
- rules/js-tosorted-immutable.md — 2 KB
- rules/rendering-activity.md — 566 B
- rules/rendering-animate-svg-wrapper.md — 1 KB
- rules/rendering-conditional-render.md — 938 B
- rules/rendering-content-visibility.md — 818 B
- rules/rendering-hoist-jsx.md — 993 B
- rules/rendering-hydration-no-flicker.md — 2 KB
- rules/rendering-svg-precision.md — 588 B
- rules/rerender-defer-reads.md — 983 B
- rules/rerender-dependencies.md — 833 B
- rules/rerender-derived-state.md — 732 B
- rules/rerender-functional-setstate.md — 3 KB
- rules/rerender-lazy-state-init.md — 2 KB
- rules/rerender-memo-with-default-value.md — 1 KB
- rules/rerender-memo.md — 1 KB
- rules/rerender-simple-expression-in-memo.md — 1023 B
- rules/rerender-transitions.md — 1 KB
- rules/server-after-nonblocking.md — 2 KB
- rules/server-auth-actions.md — 3 KB
- rules/server-cache-lru.md — 1 KB
- rules/server-cache-react.md — 2 KB
- rules/server-dedup-props.md — 2 KB
- rules/server-parallel-fetching.md — 2 KB
- rules/server-serialization.md — 1006 B

## SKILL.md

Reproducido tal cual desde andrelandgraf/fullstackrecipes bajo MIT. Esta sección es el documento original y está en inglés.

# Vercel React Best Practices

Comprehensive performance optimization guide for React and Next.js applications, maintained by Vercel. Contains 45 rules across 8 categories, prioritized by impact to guide automated refactoring and code generation.

## When to Apply

Reference these guidelines when:

- Writing new React components or Next.js pages
- Implementing data fetching (client or server-side)
- Reviewing code for performance issues
- Refactoring existing React/Next.js code
- Optimizing bundle size or load times

## Rule Categories by Priority

| Priority | Category                  | Impact      | Prefix       |
| -------- | ------------------------- | ----------- | ------------ |
| 1        | Eliminating Waterfalls    | CRITICAL    | `async-`     |
| 2        | Bundle Size Optimization  | CRITICAL    | `bundle-`    |
| 3        | Server-Side Performance   | HIGH        | `server-`    |
| 4        | Client-Side Data Fetching | MEDIUM-HIGH | `client-`    |
| 5        | Re-render Optimization    | MEDIUM      | `rerender-`  |
| 6        | Rendering Performance     | MEDIUM      | `rendering-` |
| 7        | JavaScript Performance    | LOW-MEDIUM  | `js-`        |
| 8        | 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-api-routes` - Start promises early, await late in API routes
- `async-suspense-boundaries` - Use Suspense to stream content

### 2. Bundle Size Optimization (CRITICAL)

- `bundle-barrel-imports` - Import directly, avoid barrel files
- `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. Server-Side Performance (HIGH)

- `server-cache-react` - Use React.cache() for per-request deduplication
- `server-cache-lru` - Use LRU cache for cross-request caching
- `server-serialization` - Minimize data passed to client components
- `server-parallel-fetching` - Restructure components to parallelize fetches
- `server-after-nonblocking` - Use after() for non-blocking operations

### 4. Client-Side Data Fetching (MEDIUM-HIGH)

- `client-swr-dedup` - Use SWR for automatic request deduplication
- `client-event-listeners` - Deduplicate global event listeners

### 5. 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

### 6. 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

### 7. 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

### 8. Advanced Patterns (LOW)

- `advanced-event-handler-refs` - Store event handlers in refs
- `advanced-use-latest` - useLatest for stable callback refs

## How to Use

Read individual rule files for detailed explanations and code examples:

```
rules/async-parallel.md
rules/bundle-barrel-imports.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

## Full Compiled Document

For the complete guide with all rules expanded: `AGENTS.md`

## Dónde encaja

- Categoría: [Herramientas para desarrolladores](https://skillsagentes.com/categorias/herramientas-desarrollo.md) — Skills que cambian cómo tu agente escribe, revisa y despliega código.
- Creador: [andrelandgraf](https://skillsagentes.com/creators/andrelandgraf.md) — 0 skills en el directorio
- [Todas las skills](https://skillsagentes.com/skills.md)
- [Ranking de instalaciones](https://skillsagentes.com/ranking.md)

## Otras skills del mismo repositorio

- [Authoring Recipes](https://skillsagentes.com/skills/andrelandgraf/fullstackrecipes/authoring-recipes.md): Guías para escribir contenido de fullstackrecipes: setup recipes, skills expuestas, cookbooks, templates y utilidades instalables del registro, pensadas para mantenedores del proyecto, no para consumidores del stack.
- [Use Fullstackrecipes](https://skillsagentes.com/skills/andrelandgraf/fullstackrecipes/use-fullstackrecipes.md): Descubre y sigue las recetas de fullstackrecipes (guías de setup, skills, cookbooks) obteniendo su Markdown; la meta-skill para encontrar y aplicar recetas correctamente.
- [Authentication Best Practices](https://skillsagentes.com/skills/andrelandgraf/fullstackrecipes/authentication-best-practices.md): Lee sesiones en cliente y servidor, protege rutas y ejecuta sign in/up/out con Better Auth. Úsalo al restringir páginas/APIs por autenticación o al conectar flujos de auth.
- [Better Auth Components](https://skillsagentes.com/skills/andrelandgraf/fullstackrecipes/better-auth-components.md): Añade componentes de UI y páginas para flujos de autenticación: inicio de sesión, registro, recuperación de contraseña, restablecimiento de contraseña y verificación de email.
- [Analytics Best Practices](https://skillsagentes.com/skills/andrelandgraf/fullstackrecipes/analytics-best-practices.md): Rastrea eventos personalizados y conversiones con Vercel Web Analytics mediante track(). Úsalo al instrumentar acciones de usuario, conversiones o envíos de formularios.

## Skills relacionadas

- [Domain Modeling](https://skillsagentes.com/skills/mattpocock/skills/domain-modeling.md): Construye y afila el modelo de dominio de un proyecto. Úsalo para fijar la terminología o un lenguaje ubicuo, registrar una decisión arquitectónica, o cuando otro skill necesita mantener el modelo.
- [Template Skill](https://skillsagentes.com/skills/anthropics/skills/template-skill.md): Plantilla vacía del repositorio de skills de Anthropic: frontmatter de relleno y un encabezado. Es un punto de partida para copiar, no un skill que se pueda ejecutar.
- [Claude Opus 4 5 Migration](https://skillsagentes.com/skills/anthropics/claude-code/claude-opus-4-5-migration.md): Migra prompts y código desde Claude Sonnet 4.0, Sonnet 4.5 u Opus 4.1 hacia Opus 4.5, actualizando strings de modelo y ajustando prompts según diferencias de comportamiento conocidas. No migra Haiku 4.5.
- [Command Development](https://skillsagentes.com/skills/anthropics/claude-code/command-development.md): Guía para crear slash commands en Claude Code: estructura de archivos, frontmatter YAML, argumentos dinámicos, referencias a archivos y buenas prácticas.
- [Hook Development](https://skillsagentes.com/skills/anthropics/claude-code/hook-development.md): Guía completa para crear e implementar hooks de plugins de Claude Code, con énfasis en la API avanzada de hooks basados en prompt.

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