181. What is React 19's biggest architectural improvement?
- a) React Compiler for auto-optimization
- b) Actions API for data mutations
- c) Document Metadata management
- d) All of the above
Answer: D - Combines compile-time optimizations with runtime enhancements.
182. How to implement micro-frontends with React?
- a) Module Federation (Webpack 5)
- b) Iframe isolation
- c) Web Components integration
- d) All of the above
Answer: D - Module Federation enables shared dependency loading.
183. What is the key benefit of React Server Components?
- a) Zero client-side bundle impact
- b) Automatic code splitting
- c) Built-in WebSocket support
- d) All of the above
Answer: A - Server Components don't ship JS to the client.
184. How to manage state across micro-frontends?
- a) Custom events + localStorage
- b) Redux with shared store
- c) URL-based state
- d) All of the above
Answer: D - Depends on coupling level between apps.
185. What is the purpose of React 19's useActionState?
- a) Handle form submissions with loading/error states
- b) Replace Redux actions
- c) Manage animation states
- d) All of the above
Answer: A - Simplifies common async operation patterns.
186. How to implement feature flags in micro-frontends?
- a) Runtime configuration injection
- b) Build-time environment variables
- c) Centralized feature service
- d) All of the above
Answer: D - Different strategies suit different rollout needs.
187. What is the benefit of React Compiler?
- a) Automatic memoization
- b) Dead code elimination
- c) Both A and B
- d) No runtime impact
Answer: C - Analyzes component code to apply optimizations.
188. How to handle CSS isolation in micro-frontends?
- a) Shadow DOM
- b) CSS-in-JS with unique prefixes
- c) Atomic CSS (Tailwind)
- d) All of the above
Answer: D - Shadow DOM provides strongest isolation.
189. What is React 19's Directives API?
- a) Compiler hints for optimization
- b) Replacement for useEffect
- c) GraphQL-like queries
- d) All of the above
Answer: A - Attributes like "use noinline" guide compilation.
190. How to version micro-frontends independently?
- a) Semantic Versioning
- b) Blue-Green deployments
- c) Backward-compatible APIs
- d) All of the above
Answer: D - Requires contract testing between teams.
191. What is the purpose of React 19's Asset Loading?
- a) Automatic dependency tracking
- b) Preload critical resources
- c) Both A and B
- d) Replace Webpack
Answer: C - Knows which assets/components are needed together.
192. How to implement A/B testing in micro-frontends?
- a) Feature flags with config service
- b) Canary releases
- c) Dynamic import() based on user segment
- d) All of the above
Answer: D - Requires coordination between routing and feature delivery.
193. What is the benefit of React's use hook?
- a) Consume Context without Provider
- b) Handle promises in components
- c) Both A and B
- d) Replace useState
Answer: C - Unifies async data handling patterns.
194. How to share dependencies in micro-frontends?
- a) Webpack Module Federation
- b) Externals in build config
- c) CDN-loaded libraries
- d) All of the above
Answer: D - Avoid duplicate React instances loading.
195. What is React 19's hydration improvement?
- a) Progressive enhancement
- b) Lazy element attachment
- c) Both A and B
- d) No hydration needed
Answer: C - Reduces jank during initial load.
196. How to monitor micro-frontend performance?
- a) RUM (Real User Monitoring)
- b) Synthetic monitoring
- c) Distributed tracing
- d) All of the above
Answer: D - Correlate metrics across independently deployed apps.
197. What is the purpose of React's useFormStatus?
- a) Track form submission state
- b) Replace Formik
- c) Automatic validation
- d) All of the above
Answer: A - Provides pending/error states during form submission.
198. How to secure micro-frontend communication?
- a) PostMessage with origin checks
- b) JWT in shared storage
- c) Backend-for-frontend pattern
- d) All of the above
Answer: D - Avoid XSS and CSRF vulnerabilities between apps.
199. What is React 19's metadata management?
- a) Built-in title/meta tag updates
- b) SEO optimization
- c) Both A and B
- d) Replace next/head
Answer: C - Allows setting metadata from any component.
200. How to implement gradual micro-frontend migration?
- a) Side-by-side rendering
- b) Route-based splitting
- c) Iframe embedding legacy code
- d) All of the above
Answer: D - Strangler pattern minimizes risk during transition.