React Interview Preparation

Key Topics to Focus On

1. Hooks

• Integral part of React
• Must-know Hooks: UState, useEffect
  • useState: Widely used hook for state management
  • useEffect: Controls side effects, crucial to understand dependency array
• Other Important Hooks (listed in order of importance):
  • useContext
  • useReducer
  • useMemo
  • useCallback
  • useRef

2. Higher-Order Components (HOCs)

• Understand basics: What, Why, When, How
• Be prepared to code examples
• Useful in machine coding rounds

3. Lifecycle Methods

• Class component fundamentals
• Three phases: Mounting, Updating, Unmounting
  • Mounting: componentDidMount, componentWillMount
  • Updating: componentDidUpdate
  • Unmounting: componentWillUnmount
• Know the order and purpose of each method

4. State Management

• State and Props
  • Props Drilling: Passing data through component hierarchy
  • React Context: Solves props drilling issues
• Sibling Data Transfer: Know methods to pass data between sibling components
• Redux and Zustand
  • Redux Toolkit (RTK): Modern approach to Redux
  • Zustand: Upcoming state management library

5. Custom Hooks

• Advanced usage, especially for big companies
• Write code and examples
• Improves code cleanliness, maintainability, reusability

6. Lazy Loading

• Also known as Code Splitting or Chunking
• Concept of Suspense
• Enhances application performance

7. Virtual DOM

• Understand what it is and how it works
• Reconciliation Algorithm: Includes React Fiber and Diffing Algorithm

8. Server Side Rendering (SSR) and Client Side Rendering (CSR)

• Hot topics due to Next.js
• Know advantages, differences, and impact on SEO and performance

9. Routing and Role-Based Access Control (RBAC)

• Routing: React Router, protected routes
• Dynamic Routing
• RBAC: How to manage roles and permissions in your application

10. Testing

• Unit Testing: React Testing Library
• Know how to write test cases
• Initial learning curve is high, but very important for interviews
• Types of Testing: Component Testing, Flow Testing

11. Async Tasks

• API Calls, Events Handling
• UseEffect in-depth
• Promises: Must-know concept

12. Performance Optimization

• Lazy Loading and Asset Optimization
• Bundling, Server-Level Optimization
• Rendering Performance: Write optimized code
• Topics: Shimmer UI, CDN Optimization

13. Reusability, Modularity, and Testability

• Important pillars for writing good code
• Break components into smaller, reusable parts
• Make your code readable and maintainable

14. Styling

• Various methods: Tailwind, Stylex (by Facebook), Bootstrap, Material UI
• Understand pros and cons of each approach

15. Accessibility

• Focus on making applications accessible, e.g., for Microsoft interviews

Miscellaneous Tips

• Use industry-standard coding practices
• Engagement and discussing advanced topics like security add value
• Endorse tools and approaches learned from multiple resources

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