- What is React?
- What is useMemo?
- What are the features of React?
- What is JSX?
- What is DOM?
- What is Virtual DOM?
- What is component life cycle of React class component?
- What are fragments in React?
- What are props in React?
- What are synthetic events in React?
- What are the difference between Package.json and Package.lock.json?
- What are the differences between client side and server side rendering?
- What is state in Reactjs?
- What are props?
- What are the differences between State and Props in React?
- What is props drilling?
- What are the disadvantages of props drilling and how can we avoid props drilling?
- What are Pure components in React?
- What are Refs in React?
- What is meant by forward ref?
- What are Error boundaries?
- What are Higher Order Components in React?
- What are the differences between controlled and uncontrolled components?
- What is useCallback?
- What are the differences between useMemo and useCallback?
- What are keys in React?
- What is Lazy loading in React?
- What is Suspense in React?
- What are custom hooks?
- What is useReducer hook?
- What are Portals in React?
- What is context in React?
- Practical question: Give an example of context API usage.
- What is the purpose of callback function as an argument of setState()?
- Practical question: Create a custom hook for increment/decrement counter.
- Which lifecycle hooks in class component are replaced with useEffect in functional components?
- What is Strict mode in React?
- What are the different ways to pass data from child component to parent component in React?
- Practical question: How to send data from child to parent using callback functions?
- Practical question: How to send the data from child component to parent using useRef?
- How do you optimize your React application?
- How would you consume a RESTful JSON API in Reactjs?
- Different design patterns used in React?
- Context API vs Redux
- Prop types in React (How to apply validation on props in React)
- What are React Mixins?
- What are the different hooks you have used?
- What are render props in React?
- What are the different types of exports and imports?
- What are the differences between createElement vs cloneElement in React?
- When to use useState and useReducer?
- What are protected routes in React?
- Does React Router support a context menu?
- Difference between Class Components and Functional Components with Hooks?
- How does React reconciliation (Virtual DOM diffing) work?
- Controlled vs Uncontrolled components – explain with examples.
- How do you optimize re-rendering in React?
- What are React Server Components (RSCs) and how do they differ from CSR/SSR?
JavaScript & Advanced Concepts
- How to implement debouncing & throttling in React?
- Explain closures in JS with a React-related example.
- Deep copy vs Shallow copy in JS objects.
- Handling immutability in React with nested state updates.
UI Development & Styling
- CSS Modules vs Styled Components vs Tailwind CSS – when to use what?
- Implementing responsive design systems in React.
State Management & Architecture
- Redux vs Context API – when to choose one over the other?
- Best practices to structure large-scale React apps for scalability.
Performance & Testing
- Identifying and fixing performance bottlenecks in React apps.
- Strategies for unit & integration testing React components (Jest, RTL, etc.).