Coding Interview Questions on React JS

Coding Interview Questions on React JS

React JS Coding Interview Preparation Questions

Coding Interview Questions on React JS

Coding interview questions on React JS assess a candidate's proficiency in building user interfaces using this popular JavaScript framework. By evaluating core concepts like component lifecycle, state management, and performance optimization, these questions help recruiters identify candidates with a solid understanding of React JS fundamentals and their ability to apply them effectively in real-world scenarios.

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1 - What is the difference between state and props in React?

• Answer: State is data that is managed by the component and can be updated within the component. Props are data that is passed down to a component from its parent.
• 2) What is the purpose of the `render()` method in React?
•  Answer:* The `render()` method returns the UI for the component.
• 3) What is the difference between a class component and a functional component in React?
•  Answer:* Class components use the class syntax and have a lifecycle method, while functional components are simpler and use the function syntax.
• 4) What are the different ways to handle user input in React?
•  Answer:* Use the `onChange` handler for input elements, `onSubmit` for forms, and `onClick` for buttons.
• 5) How do you manage component state in React?
•  Answer:* Use the `useState` hook to create and manage state variables.
• 6) What is the purpose of a reducer in React?
•  Answer:* Reducers are pure functions that take an action and the current state, and return the new state.
• 7) How do you implement conditional rendering in React?
•  Answer:* Use the ternary operator, `&&` logical operator, or the `if` statement within the `render()` method.
• 8) What is the difference between a controlled and uncontrolled component in React?
•  Answer:* Controlled components are updated via the `value` prop, while uncontrolled components are updated via their DOM element's value.
• 9) How do you optimize React applications for performance?
•  Answer:* Use memoization, lazy loading, and React profiler to reduce re renders and improve performance.
• 10) What is the purpose of the `useEffect` hook in React?
•  Answer:* The `useEffect` hook is used to perform side effects, such as fetching data or setting up subscriptions, in React components.
• 11 - How do you handle asynchronous requests in React?
•  Answer:* Use promises, async/await, or the `fetch` API to make asynchronous requests and update the state accordingly.
• 12) What is the purpose of a context provider in React?
•  Answer:* Context providers allow components to share data without passing props through multiple levels of the component tree.
• 13) What is the difference between a forwardRef and a ref in React?
•  Answer:* A forwardRef is used to create a custom ref function that can be used on a function component, while a ref is used to access the DOM element of a class component.
• 14) How do you implement custom hooks in React?
•  Answer:* Use the `useCallback`, `useMemo`, and `useEffect` hooks to create custom hooks that can be reused across components.
• 15) What are the best practices for writing React components?
•  Answer:* Follow the React style guide, use component composition, and test your components thoroughly.
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• Course Overview
• This course covers essential React JS concepts and techniques for coding interviews. It includes fundamental concepts like JSX, state management, component lifecycle, and performance optimizations. The course prepares you with common coding questions on creating and manipulating React components, handling user interactions, and working with data.
• Course Description
• Master the art of acing coding interviews for React JS roles! This comprehensive course delves into frequently asked coding questions, providing detailed solutions and industry best practices. Enhance your understanding of React JS fundamentals, component structures, state management, and advanced concepts. By the end of this course, you will be fully prepared to demonstrate your React JS proficiency and secure your dream coding job.
• Key Features
• 1 - Comprehensive Tool Coverage: Provides hands-on training with a range of industry-standard testing tools, including Selenium, JIRA, LoadRunner, and TestRail.
• 2) Practical Exercises: Features real-world exercises and case studies to apply tools in various testing scenarios.
• 3) Interactive Learning: Includes interactive sessions with industry experts for personalized feedback and guidance.
• 4) Detailed Tutorials: Offers extensive tutorials and documentation on tool functionalities and best practices.
• 5) Advanced Techniques: Covers both fundamental and advanced techniques for using testing tools effectively.
• 6) Data Visualization: Integrates tools for visualizing test metrics and results, enhancing data interpretation and decision-making.
• 7) Tool Integration: Teaches how to integrate testing tools into the software development lifecycle for streamlined workflows.
• 8) Project-Based Learning: Focuses on project-based learning to build practical skills and create a portfolio of completed tasks.
• 9) Career Support: Provides resources and support for applying learned skills to real-world job scenarios, including resume building and interview preparation.
• 10) Up-to-Date Content: Ensures that course materials reflect the latest industry standards and tool updates.

Benefits of taking our course

 Functional Tools

1 - React Testing Library: A JavaScript library for testing React components, providing a higher level abstraction over the DOM for easier and more robust testing.

2) Enzyme: A JavaScript library for creating snapshots of React components, allowing for visual and functional testing.

3) Jest: A JavaScript testing framework that runs tests in a performant, reliable, and parallelizable manner.

4) RTL Query DOM: A JavaScript library that provides a simple and declarative API for querying the DOM, facilitating testing of React components without dealing with complex selectors.

5) Mock Service Worker: A JavaScript library that allows mocking of browser network requests for testing React components that depend on network interactions.

6) create react app: A command line tool for quickly setting up a new React application with preconfigured tooling and dependencies.

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• Use your credit or debit card for everyday purchases, including groceries, gas, and utilities.
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