May 7, 2025
As a fresher stepping into the world of front-end development, React is one of the most popular and sought-after libraries in the market. Knowing the react interview questions for freshers can help you prepare and ace your interview, whether you are applying for an entry-level position or internship.
React, developed by Facebook, is a JavaScript library that enables developers to build complex user interfaces efficiently. As of 2024, approximately 39.5% of developers worldwide utilize React.js, underscoring its widespread adoption and importance in front-end development. Familiarity with React is crucial for aspiring front-end developers, given its prominence in the industry.
This article covers the top 25 React interview questions for freshers, ranging from React fundamentals to advanced concepts.
React, developed by Facebook, is a powerful library used for building user interfaces, particularly single-page applications. It enables developers to build complex UIs by breaking them down into reusable components. React is popular because of its component-based architecture, virtual DOM, and efficient rendering. It simplifies the process of building interactive UIs, and it is widely used by both large companies and individual developers.
When interviewing for a React position, you can expect questions about the following topics:
Now that you have a basic understanding of React, let's move on to the React interview questions for freshers that you may encounter.
As a fresher gearing up for a React interview, it's crucial to grasp the core concepts and typical questions employers ask. This guide presents the top React interview questions for freshers to help you strengthen your foundation and enhance your confidence.
Why it's important: This is a fundamental question asked in almost every React interview to assess your basic understanding of the library. It helps interviewers determine if you have a clear grasp of the core concepts and objectives of React as a front-end library.
Sample Answer
React is an open-source JavaScript library developed by Facebook, designed for building user interfaces, especially for single-page applications (SPAs). React allows developers to create reusable UI components and manage application state efficiently. It uses a declarative syntax, meaning you describe how the UI should look for a given state, and React takes care of updating the UI when the state changes. This makes it easier to develop interactive UIs without worrying about directly managing DOM manipulations. React uses a virtual DOM to optimize rendering, improving performance by updating only the parts of the UI that need to change.
Tip: Familiarize yourself with React's core features, such as components, state, and props. Understanding these building blocks is key to working effectively with React.
Why it's important: Components are the core building blocks in React. This question evaluates whether you understand React’s modular approach and how the UI is constructed using smaller, self-contained units of code.
Sample Answer
In React, a component is a self-contained, reusable unit of code that controls its own rendering and behaviour. React applications are built by combining multiple components, which can be functional or class-based. Here are the key characteristics of React components:
Tip: Remember that React's modular structure allows for reusability. By breaking down the UI into components, you make the application more scalable, maintainable, and easier to test.
Why it's important: This question tests your understanding of how React components are structured. JSX is integral to React, and interviewers ask this to check if you’re familiar with React’s syntax for defining UI elements.
Sample Answer
JSX stands for JavaScript XML, which is a syntax extension for JavaScript that lets you write HTML-like code directly within JavaScript. This allows React developers to define elements and components in a more declarative manner. Instead of using JavaScript's document.createElement, JSX allows you to use HTML tags in the JavaScript code. It is compiled into regular JavaScript by a tool called Babel, which React uses to render the DOM efficiently. JSX improves readability and makes it easier to visualize the UI structure within the JavaScript code.
Tip: Don’t worry about the technicalities of JSX; focus on its benefits, such as simplifying UI construction. Remember, JSX is syntactic sugar for React.createElement calls.
Why it's important: Props are a fundamental concept in React, used for passing data between components. This question helps interviewers determine if you understand how data flows in a React application.
Sample Answer
Props, short for properties, are used to pass data from a parent component to a child component in React. They are immutable, meaning that a child component cannot modify its props. Props can be any type of data—strings, numbers, functions, or even other components—and they allow components to be dynamic and reusable. By accepting different props, a component can render different UI depending on the input, allowing developers to create flexible and reusable UI elements.
Tip: Props are essential for component reusability. Think of props as the input for a component’s output—similar to passing arguments into a function.
Why it's important: Understanding the difference between state and props is fundamental to React. This question helps interviewers gauge your understanding of how React handles data and manages changes in the UI.
Sample Answer
Props and state are both used for handling data in React, but they serve different purposes. Props are immutable and are used to pass data from a parent component to a child component. They allow a component to receive inputs, but the child cannot modify them. State, on the other hand, is used to store data within a component that can change over time. A component can update its state using setState (in class components) or useState (in functional components). While props are passed down from parent to child, state is typically internal to a component and can be changed by that component itself.
Tip: A simple way to think of this is that props are like the arguments passed to a function, while state is like the function’s internal data that can change during its execution.
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Why it's important: This question helps interviewers gauge your understanding of modern React practices and your ability to write cleaner, more maintainable code using functional components.
Sample Answer
React hooks are functions that allow developers to “hook into” React features such as state and lifecycle management from functional components. Before hooks, these features were only available in class components. The most common hooks include:
React hooks provide a cleaner and more efficient way to handle component logic and reduce the need for complex class-based components. With hooks, developers can write more concise and readable code.
Tip: Practice using hooks like useState and useEffect frequently to become comfortable with React’s functional component style.
Why it's important: Understanding this concept is critical as it explains how React optimizes rendering and efficiently updates the UI without performance bottlenecks, especially in large applications.
Sample Answer
The virtual DOM is a lightweight representation of the actual DOM, and is crucial to React’s performance. React uses it to minimize the need for direct manipulation of the real DOM, which can be slow and inefficient. When the state or props of a component change, React first updates the virtual DOM, then compares it to the real DOM using a process called "reconciliation." This allows React to determine the minimal set of changes needed to update the real DOM, resulting in faster performance and smoother updates. This system is what makes React’s rendering process so efficient, especially in large-scale applications.
Tip: Keep in mind that the virtual DOM helps React manage UI changes efficiently, preventing unnecessary re-renders and making React one of the fastest frameworks for UI rendering.
Why it's important: This question helps interviewers determine if you understand React’s evolution from class components to functional components, which are now preferred in modern React development thanks to hooks. It also assesses your ability to adapt to React's shift toward functional components.
Sample Answer
React has two main types of components: class components and functional components.
Since the introduction of hooks in React 16.8, functional components have become the preferred choice due to their simplicity and the power of hooks, which offer a more readable and maintainable way to manage state and side effects.
Tip: For new React projects, functional components are recommended due to their simplicity and the flexibility offered by hooks.
Why it's important: This question helps interviewers understand how you manage asynchronous operations in React.
Sample Answer
The useEffect hook is used in React to handle side effects in functional components. Side effects can include things like:
The hook accepts a function that is executed after the component renders. You can control when the effect runs by providing a dependency array. If the dependency array is empty, the effect runs only once after the initial render, mimicking componentDidMount. If dependencies are provided, the effect will run every time any dependencies change.
Tip: Pay attention to the dependencies in useEffect. Incorrect dependencies can lead to unnecessary re-renders or failure to capture changes when needed.
Why it's important: This question helps interviewers assess your understanding of how React handles forms and input elements. Form management is a common task in React applications, and understanding controlled vs. uncontrolled components is critical.
Sample Answer
In React, form elements can be handled in two primary ways: controlled components and uncontrolled components. Understanding the difference between these two components is important for managing data flow, particularly in forms.
Controlled Components:
A controlled component is a form element whose value is managed by the React state. In this approach, React controls the input's value through its internal state, ensuring the component’s value is always in sync with the state. This means that React is responsible for both rendering the value of the input and updating it based on user interaction.
Uncontrolled Components:
An uncontrolled component is a form element that manages its own internal state, meaning that React does not directly control its value. Instead of using the React state to manage the value, uncontrolled components use refs (references) to access the DOM element directly and retrieve its value when needed.
Tip: Highlight the key differences between controlled and uncontrolled components, and emphasize using controlled components for better predictability and manageability while noting uncontrolled components for simpler forms.
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Why it's important: The Context API is crucial in React for managing the global state across a component tree, eliminating the need for prop drilling. This question helps interviewers determine if you understand how to handle shared state across deeply nested components in a clean and efficient way.
Sample Answer
The Context API in React allows you to share values like state or functions across components without the need to manually pass props at every level of the component tree. It consists of three key parts:
Tip: Use the Context API for managing global state across your application, but avoid using it for small, localized state management to prevent unnecessary complexity.
Why it's important: This question tests whether you understand how to improve application performance by splitting code into smaller, more manageable chunks.
Sample Answer
Code splitting allows you to split your React application into smaller, more manageable chunks that can be loaded on demand rather than all at once. This is particularly useful for reducing the initial load time of an application, which can be a significant issue for larger apps. Tools like Webpack and React’s React.lazy() enable code splitting, allowing developers to only load certain parts of the application when the user needs them. For example, a user might only need the code for the home page initially, and the code for other pages can be loaded dynamically as needed. This enhances the overall performance and responsiveness of your app.
Tip: Implement code splitting in large applications, particularly for features that are not immediately necessary on initial load. This can help you improve user experience and application performance.
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Why it's important: Lifecycle methods are essential for managing side effects, updating component states, and controlling the behaviour of a component during different stages of its existence. Understanding lifecycle methods is crucial for any React developer, especially when working with class components.
Sample Answer
In React, lifecycle methods are special functions that are called at different stages of a component’s life. These methods allow you to perform specific tasks at key points in the component’s lifecycle. For class components, common lifecycle methods include:
For functional components, React introduced the useEffect hook, which serves a similar purpose as these lifecycle methods and allows you to handle side effects like data fetching and subscriptions.
Tip: If you're working with class components, familiarize yourself with lifecycle methods. For functional components, use useEffect to handle lifecycle operations like data fetching and cleanup.
Why it's important: This question evaluates your understanding of composability and whether you can write reusable code to enhance components in a modular fashion.
Sample Answer
A Higher-Order Component (HOC) is a pattern in React where a function takes a component and returns a new component with additional functionality or props. HOCs are commonly used to add shared behaviour to components, such as authentication checks, logging, or connecting to external libraries like Redux.
A HOC can be used to enhance a component by adding a feature like loading indicators or data fetching. The key idea behind HOCs is that they don’t modify the original component but instead return a new component with the desired enhancements.
Tip: Practice creating your own HOCs for tasks like adding authentication or handling errors. They’re a great way to compose functionality across multiple components without repeating code.
Why it's important: This question helps interviewers assess if you understand how to manage the global state effectively and how Redux fits into React’s data flow.
Sample Answer
Redux is a predictable state container for JavaScript applications, often used with React for state management in large-scale applications. Redux centralizes the application’s state into a single store, making it easier to manage and debug. Here’s how it works:
Tip: Redux is great for managing the global state in large applications, but it’s not always necessary for smaller apps. Use it when your app’s state becomes too complex to manage with React’s built-in useState.
Why it's important: This question evaluates your understanding of how navigation works in React applications, especially single-page applications (SPA). It helps interviewers assess if you know the difference between React Router, which is specific to SPAs, and traditional navigation methods that work with multiple-page reloads.
Sample Answer
React Router is a library for handling navigation within single-page applications (SPAs). Unlike traditional navigation that reloads the entire page whenever a user moves between views, React Router enables dynamic navigation without page reloads.
React Router provides components like Route, Link, and BrowserRouter to handle view switching and manage navigation states. This allows for a smoother user experience, as only the necessary parts of the page are updated. Traditional navigation, on the other hand, involves loading an entirely new page from the server for each different view, which can lead to slower performance and a less fluid user experience.
Tip: React Router is essential for building SPAs. Practice working with routes, navigation, and URL states to get comfortable with dynamic navigation in React applications.
Why it's important: This question checks if you understand how React optimizes the rendering of lists, which is crucial for performance, especially when working with dynamic data or frequent updates.
Sample Answer
In React, keys are unique identifiers used for list items to help React efficiently determine which items have changed, been added, or removed when the list updates. Keys improve performance by allowing React to skip re-rendering the entire list and only update the changed items. It’s important that keys are unique among sibling elements, and should remain consistent across re-renders to avoid unnecessary component re-renders. For example, using a unique ID from the data as the key ensures the list behaves correctly when items are reordered or modified.
Tip: Always use unique and stable values as keys, such as IDs from the data, to ensure React can efficiently track each element and perform minimal updates.
Why it's important: SSR is a technique used to improve the initial page load speed and SEO of React applications. This question assesses your knowledge of how React rendering can be optimized for both performance and search engine visibility.
Sample Answer
Server-side rendering (SSR) refers to the process of rendering React components on the server instead of the client. With SSR, the server sends the fully rendered HTML page to the browser, allowing users to view the content immediately without waiting for JavaScript to execute. This results in faster initial load times and better SEO performance, as search engines can crawl the fully rendered content right away, rather than relying on JavaScript execution. Popular frameworks like Next.js are built around SSR, making it easier to implement SSR in React applications.
Tip: Familiarize yourself with Next.js, a popular framework for React that provides built-in support for server-side rendering, helping improve performance and SEO in your applications.
Why it's important: This question checks your understanding of more advanced state management techniques in React. The useReducer hook is typically used when state logic becomes more complex than what useState can handle.
Sample Answer
The useReducer hook is similar to useState but is better suited for handling complex state logic, especially when the state depends on multiple actions. Unlike useState, which only manages simple values, useReducer allows you to define how the state should change in response to different action types. It uses a reducer function, which takes the current state and an action, and returns the new state. This approach is ideal for managing the state in more complex scenarios, such as when working with multiple form inputs or managing large lists.
Tip: Use useReducer when managing more complex state transitions. It makes your state logic more predictable, especially for large-scale forms or nested components.
Why it's important: This question tests your understanding of a common pattern in React that allows components to share logic and data.
Sample Answer
Render props is a pattern in React where a component accepts a function as a prop, and that function returns a React element. The component passes data to this function, and the function returns a new element to be rendered. This pattern allows for sharing logic between components without the need for higher-order components (HOCs) or prop drilling.
Tip: Render props are useful for sharing reusable behaviour in a flexible way, but avoid excessive nesting of render props, as it can lead to harder-to-read code. Instead, consider using hooks or context when appropriate.
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Why it's important: Forms are an essential part of web development. This question helps assess your understanding of managing form elements and handling user input in React.
Sample Answer
In React, forms are typically handled with controlled components, where the form elements like <input>, <select>, and <textarea> have their values tied to the React state. The form’s data is stored in the component’s state, and as the user interacts with the form, the state is updated through the setState method (for class components) or the useState hook (for functional components). This allows React to keep track of the form data and perform actions like validation or submission.
Tip: For simple forms, use controlled components. For more complex forms, consider using libraries like Formik or React Hook Form, which simplify form state management and validation.
Why it's important: Fragments help in grouping elements without adding extra nodes to the DOM. This question evaluates your ability to manage component structure efficiently.
Sample Answer
In React, a fragment is a lightweight component that allows you to group multiple elements without adding additional nodes to the DOM. This is useful when you need to return multiple elements from a component but don’t want to introduce unnecessary wrapper elements like <div>. Fragments can be written as either:
Tip: Use fragments when returning multiple elements from a component to keep the DOM clean and avoid unnecessary wrapper elements, especially for rendering lists.
Why it's important: This question evaluates your understanding of performance optimization in React by preventing unnecessary re-renders.
Sample Answer
React.memo is a higher-order component that memoizes a component’s rendered output. It prevents unnecessary re-renders of functional components when the props have not changed. React.memo performs a shallow comparison of the component’s props, and if the props are the same, it skips rendering. It is particularly useful for optimizing the performance of components that receive the same props and don’t need to be re-rendered frequently.
Tip: Use React.memo for functional components that rely on unchanged props. It can improve performance, especially in large applications with complex component trees. Avoid using it excessively on every component, as it can add overhead if misused.
Why it's important: This question tests your understanding of how React manages events and ensures cross-browser compatibility.
Sample Answer
React uses a synthetic event system to consistently handle events across all browsers. Synthetic events are normalized, meaning they provide the same interface regardless of the browser. React’s event handling model allows you to attach event listeners like onClick, onChange, or onSubmit directly to React components, and it automatically handles event delegation.
Tip: React’s synthetic events provide better performance and consistency across browsers. Avoid using native DOM event listeners when working within React components, as the synthetic event system is optimized for React’s rendering lifecycle.
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Why it's important: This question assesses your knowledge of React’s ability to handle asynchronous operations while improving user experience.
Sample Answer
React Suspense is a feature that helps manage asynchronous loading of components, particularly for lazy loading. It enables you to defer rendering parts of a UI until certain conditions are met, such as loading data or dynamically importing a component. Suspense works hand in hand with React.lazy() to support code splitting by loading only the components required at that moment.
Tip: React Suspense is best used for performance optimization in large applications but make sure to handle fallback UI properly to enhance the user experience while waiting for content.
Preparing answers to these questions ensures that you're ready to demonstrate your expertise. Now, let’s explore some resources that will further help you succeed in your React interview preparation.
When preparing for a React developer interview, having the right resources is crucial to mastering the concepts and performing confidently. Here are some valuable Topmate resources to help you get ready for your React interview:
1. Walmart UI - React Mock Interview
One of the best ways to practice React interview questions is through mock interviews. Prepare for your React developer interview with Topmate mock interviews! Get hands-on practice with real-world scenarios, master key React concepts, and receive personalized feedback to boost your confidence and ace the interview. Check out the Walmart UI - React Mock Interview with Reshma Veerasamy, where you can simulate an actual interview experience.
2. 75 ReactJS Interview Questions and Answers
If you're looking for a comprehensive list of 75 essential ReactJS interview questions and answers, 75 ReactJS Interview Questions and Answers by Akash Jain will help you get ready. The answers come with explanations, so you can fully understand each concept.
3. 100+ ReactJS Interview Q&A with Explanation & Code
For those wanting an even deeper dive, 100+ ReactJS Interview Q&A with Explanation & Code by Vikash offers over 100 ReactJS interview questions with detailed explanations and code examples. It’s perfect for tackling both theoretical and practical aspects of React in interviews.
4. React: 100+ Theory & 15+ Machine Coding Q's
Preparing for machine coding questions can be challenging, but React: 100+ Theory & 15+ Machine Coding Q's by Smaruthi Hema helps you get comfortable with 100+ theoretical React questions and 15+ machine coding questions that are typically asked in interviews.
5. Machine Coding Questions - Frontend (React JS)
Machine coding questions are an important part of React interviews, and Machine Coding Questions - Frontend (React JS) by Amit Singh focuses on frontend-related coding problems. Get to grips with React design patterns and coding challenges to ace the technical part of your interview.
6. Javascript + React Design Patterns
Understanding design patterns in JavaScript and React is critical for solving complex problems efficiently. Javascript + React Design Patterns by Saiteja Gatadi covers a range of important design patterns used in ReactJS applications, helping you build scalable and maintainable solutions.
These Topmate resources, combined with hands-on mock interviews and real-world scenarios, will ensure you're fully prepared for your React interview. Whether you're focusing on theory, coding challenges, or machine coding, these tools will set you up for success.
Nailing your React job interview goes beyond just knowing the syntax—it’s about demonstrating your deep understanding of React concepts, problem-solving abilities, and hands-on experience. Whether you’re interviewing for the role of a Front-End Developer, React Developer, or Software Engineer, preparing for the React interview questions for freshers in this guide will give you the edge you need.
At Topmate, we know how challenging job interviews can be. That's why we offer mock interviews with top industry professionals who simulate real interview conditions. These sessions allow you to refine your answers, get valuable feedback, and boost your confidence before the actual interview.
In addition to mock interviews, we provide personalized career advice, mentorship programs, job referrals, and industry-specific coaching to improve your chances of landing the job. By connecting with top professionals, you gain essential insights and unlock valuable networking opportunities.
Ready to land your dream React developer job? Book your free mock interview with a React expert today on Topmate and take the next step in your career!
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