React Hooks Interview Questions: Level 3

Advanced Questions

React Hooks Interview Questions

Advanced React Hooks interview questions are designed to assess a candidate’s in-depth understanding of React Hooks, including how they work, best practices, and advanced concepts. Here are some advanced interview questions focused on React Hooks:

1. State Management with Hooks

• Question: Explain the difference between useState and useReducer. In what scenarios would you choose useReducer over useState?
• Answer: useState is ideal for simple state management with individual state variables, while useReducer is useful for complex state logic and managing state transitions with actions. You’d choose useReducer when dealing with multiple state variables or complex operations, like updating a shopping cart or handling multiple form fields.

2. Handling Side Effects

• Question: What are dependency arrays in useEffect, and why are they important? How would you handle an effect that depends on dynamic data?
• Answer: Dependency arrays control when the useEffect function runs, based on the variables listed. If the array is empty, the effect runs once on mount. If it contains variables, the effect re-runs when those variables change. To handle dynamic data, ensure the dependencies are correctly listed to avoid unintended re-renders or infinite loops.

3. Performance Optimization

• Question: How do useMemo and useCallback help optimize React applications? What are the risks of overusing them?
• Answer: useMemo memoizes computed values to avoid recalculations, while useCallback memoizes functions to prevent re-renders when passing callbacks to child components. Overuse can lead to complex code and memory overhead. Use these hooks only when needed to optimize performance.

4. Custom Hooks

• Question: Describe a scenario where you would create a custom Hook. What are the benefits of custom Hooks in a React application?
• Answer: A custom Hook is useful for encapsulating common logic, such as form validation or data fetching. Custom Hooks promote code reuse and separation of concerns. For example, a custom Hook for fetching data abstracts the fetching logic, allowing reuse across multiple components.

5. Context and Global State

• Question: What is the role of useContext in React? How can you avoid “prop drilling” using context?
• Answer: useContext allows functional components to consume values from a React context without passing props through multiple levels (prop drilling). By providing a context at a higher level in the component tree, you can share state across components without passing props down through each level.

6. Managing Component Lifecycle

• Question: Explain the differences between useEffect and useLayoutEffect. When would you use useLayoutEffect instead of useEffect?
• Answer: useEffect runs after the component is painted to the screen, while useLayoutEffect runs before painting, affecting the layout. Use useLayoutEffect when changes must happen before rendering, such as DOM measurements or critical layout manipulations.

7. Managing Refs and Imperative Handles

• Question: How can useRef be used to manage DOM elements in functional components? Explain the use of useImperativeHandle in React.
• Answer: useRef provides a reference to DOM elements or values that persist across renders, useful for focus management or accessing DOM attributes. useImperativeHandle allows you to expose imperative methods to parent components, facilitating controlled components or specialized behaviors.

8. What are the key differences between React vs Vue js

Here’s a comparison of React vs Vue.js in tabular format:

These advanced questions cover a range of topics, from state management to performance optimization and lifecycle handling, providing a comprehensive assessment of a candidate’s expertise with React Hooks.

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