React Techniques & Checklist

Concise, actionable checklist covering fundamentals, hooks, data, state, performance and tooling.

🧠 Core React Fundamentals Essential

  • JSX and Virtual DOM
  • Props, State, and Lifecycle methods
  • Conditional Rendering
  • Lists and Keys
  • Controlled vs Uncontrolled Components
  • Refs and Forward Refs
  • React Fragments, Portals, and StrictMode
Focus: clear mental model of render, reconciliation, and component boundaries.

⚙️ Hooks (Deep) High Priority

  • useState, useEffect, useRef
  • useContext, useReducer
  • useMemo, useCallback, useLayoutEffect
  • Custom hooks: composition, separation of concerns
  • Hook-related performance patterns

🌐 API Handling & Data Fetching

  • fetch / axios; async/await & try/catch
  • Loading, error states & global error handling
  • Debounce/throttle, AbortController for cancellations
  • Caching, pagination; use React Query / SWR for robustness
Tip: centralize API logic and handle token refresh & retries explicitly.

🧩 State Management

  • Local state vs Context API
  • Redux Toolkit, Zustand, Jotai — choose by complexity
  • Middlewares: thunk, saga (when side-effects grow)
  • Immutability, pure reducers, normalized state

🎨 Styling & UI

  • Tailwind CSS, Sass, CSS Modules
  • Styled Components / Emotion
  • Theme management (dark/light) and CSS variables
  • Responsive design & accessibility (ARIA)

🧱 Routing & Navigation

  • React Router v6+: dynamic & nested routes
  • Protected routes / route guards
  • Lazy loading with React.lazy and Suspense

🔐 Error Handling

  • Error Boundaries / componentDidCatch
  • Try/catch in async flows and global error contexts
  • Fallback UIs and retry logic for transient failures

🧪 Testing

  • Unit tests with Jest & React Testing Library
  • Mocking API calls and snapshot testing
  • Integration & E2E tests (Cypress)
  • Measure coverage and test critical flows

⚡ Performance

  • Memoization: React.memo, useMemo, useCallback
  • Code splitting, lazy loading, tree shaking
  • Virtualization: react-window / react-virtualized / virtuoso
  • Use React Profiler and Lighthouse to find bottlenecks

📦 Build Tools & Env

  • Vite / Webpack basics; Babel for transpilation
  • Environment variables (.env) and build config
  • ESLint, Prettier, lint-staged and Husky for quality

🚀 Next.js / SSR Concepts

  • SSR vs CSR vs SSG
  • Next.js routing, App Router, API routes
  • Image optimization, middleware, incremental static regen

🔄 Version Control & CI/CD

  • Git branching strategies, PR reviews
  • CI basics: GitHub Actions, Vercel, Netlify
  • Automated tests and deploy previews

☁️ Advanced / Real-World Topics

  • Auth: JWT, OAuth, Firebase Auth, RBAC
  • Real-time: WebSockets, optimistic updates
  • Form handling: Formik, React Hook Form, Yup
  • File uploads, streaming, performance tuning

🧰 TypeScript (Optional)

  • Typing props, hooks, state; interfaces vs types
  • Generic components and API typing
  • Use tsconfig strict modes for safety
When to adopt: medium+ codebases or teams needing stronger guarantees.

🧠 System Design for Frontend

  • Component architecture & folder structure
  • Reusable, composable component design
  • API layer abstraction, container/presenter patterns
  • Document decisions: trade-offs, scaling considerations
// Quick snippet: debounce example
function debounce(fn, wait=200){
  let t;
  return (...args)=>{
    clearTimeout(t);
    t = setTimeout(()=>fn(...args), wait);
  }
}


🧠 1. Core React Fundamentals React Component types (Functional vs Class) JSX and Virtual DOM Props, State, and Lifecycle methods Conditional Rendering Lists and Keys Controlled vs Uncontrolled Components Refs and Forward Refs React Fragments, Portals, and StrictMode

⚙️ 2. Hooks (Deep Understanding) useState, useEffect, useRef useContext, useReducer useMemo, useCallback useLayoutEffect Custom Hooks — when and how to build them Performance optimization with hooks

🌐 3. API Handling and Data Fetching Fetch API / Axios integration Async/Await and Promises Loading and Error states Caching & Pagination Debouncing & Throttling API calls AbortController for request cancellation Global API handling using Context or Redux Using React Query / SWR for data fetching

🧩 4. State Management Local component state Context API Redux Toolkit / Zustand / Jotai Redux middleware: Thunk / Saga Immutability and Pure Functions State normalization and structure

🎨 5. Styling and UI Management Tailwind CSS, Sass, CSS Modules Styled Components / Emotion Theme management (Dark/Light) Responsive Design & Accessibility (ARIA)

🧱 6. Routing and Navigation React Router (v6+) Dynamic & Nested Routes Route Guards / Protected Routes Lazy loading with React.lazy() and Suspense

🔐 7. Error Handling ErrorBoundary and componentDidCatch Try/Catch in async functions Handling API errors gracefully Global error context Fallback UI and Retry logic

🧪 8. Testing Unit Testing with Jest and React Testing Library Mocking API calls Snapshot Testing Integration and Component Tests Test coverage and best practices

⚡ 9. Performance Optimization Memoization (React.memo, useMemo, useCallback) Lazy Loading & Code Splitting React Profiler Avoiding unnecessary re-renders Infinite Scrolling & Virtualization (React Window / Virtuoso)

📦 10. Build Tools & Environment Webpack / Vite basics Babel — JSX and ES6 transpilation Environment Variables (.env) ESLint, Prettier setup

🚀 11. Next.js / SSR Concepts (Optional but Valuable) SSR vs CSR vs SSG API Routes in Next.js Image optimization & metadata Middleware and Routing in Next.js 13+ (App Router)

🔄 12. Version Control & CI/CD Git branching strategies Pull Request and Code Review best practices Basic CI/CD with GitHub Actions / Vercel

☁️ 13. Advanced / Real-World Topics Authentication (JWT, OAuth, Firebase Auth) Role-based Access Control File uploads Infinite scroll / pagination Optimistic UI updates WebSockets / Real-time data Form Handling (Formik, React Hook Form, Yup validation)

🧰 14. TypeScript (If applicable) Typing props, state, hooks Interface vs Type Generic components Type safety with API responses

🧠 15. System Design for Frontend Component architecture & folder structure Reusable and scalable component design API layer abstraction Design patterns (Container-Presenter, Compound Components)s