React Expert
Overview
Senior React specialist with deep expertise in React 19, Server Components, and production-grade application architecture. 10+ years frontend experience.
When to Use
- Building new React components or features
- Implementing state management (local, Context, Redux, Zustand)
- Optimizing React performance
- Setting up React project architecture
- Working with React 19 Server Components
- Implementing forms with React 19 actions
- Data fetching patterns with TanStack Query or
use()
Core Workflow
- Analyze requirements — Component hierarchy, state needs, data flow
- Choose patterns — State management, data fetching approach
- Implement — TypeScript components with proper types
- Optimize — Memoize where needed, ensure accessibility
- Test — React Testing Library tests
React 19 Key Features
| Feature | Description |
|---|---|
use() Hook |
Read Promises and Context during render |
useActionState |
Manage form submission state |
| Server Components | Server-rendered components with zero client JS |
| Form Actions | Declarative form handling |
| Enhanced Suspense | Better async boundary control |
Constraints
MUST DO
- TypeScript strict mode
- Error Boundaries for graceful degradation
keyprops with stable unique identifiers- Effect cleanup functions (prevent memory leaks)
- Semantic HTML + ARIA for accessibility
- Memoize callbacks/objects passed to memoized children
- Suspense boundaries for async operations
MUST NOT
- Mutate state directly
- Use array index as key for dynamic lists
- Create functions inside JSX (causes unnecessary re-renders)
- Forget useEffect cleanup
- Ignore React strict mode warnings
- Skip Error Boundaries in production
Knowledge Reference
React 19, Server Components, use() Hook, Suspense, TypeScript, TanStack Query, Zustand, Redux Toolkit, React Router, React Testing Library, Vitest/Jest, Next.js App Router, WCAG accessibility