If you’re gearing up for a ReactJS interview in 2025, you’ve come to the right place. ReactJS is one of the most popular libraries for building amazing web apps, and knowing it well can open doors to some fantastic opportunities. In this blog, we’ve compiled 100 of the most common ReactJS interview questions you might face, ranging from beginner-level basics to advanced topics. Whether you’re just starting or a pro brushing up for a tough interview, this guide has covered you. Let’s start.
Brief Overview of ReactJS
ReactJS is a popular JavaScript library developed by Facebook (now Meta) for building user interfaces, especially for web applications. It focuses on making the creation of dynamic, fast, and responsive UI components easier.
React’s big selling point? It lets you build web apps where users can interact with different parts of the page without reloading the whole thing. Think of it like giving your website a superpower to feel fast and smooth.
Key Features of ReactJS
- Component-Based Architecture:
- Everything in React is built as reusable pieces called components. It’s like using building blocks to create your app.
- Virtual DOM:
- React creates a lightweight copy of the real DOM. This makes updates super quick because it calculates changes before applying them to the actual page.
- One-Way Data Binding:
- Data in React flows in one direction, which makes it easier to debug and manage.
- React Hooks:
- Hooks like useState and useEffect let you manage state and side effects in functional components without writing classes.
- React Developer Tools:
- A browser extension to help you debug and inspect your React components easily.
- Support for JSX:
- JSX allows you to write HTML-like syntax directly in your JavaScript code, making it easier to build UI components.
Use Cases of ReactJS in 2025
- Web Applications:
- Whether it’s a social media platform, e-commerce site, or dashboard, ReactJS is perfect for building apps that feel fast and dynamic.
- Single Page Applications (SPAs):
- With React, you can create SPAs where only parts of the page refresh, giving users a seamless experience.
- Mobile App Development:
- Thanks to React Native, you can use React concepts to build mobile apps for iOS and Android.
- Progressive Web Apps (PWAs):
- React helps in building apps that work like websites but feel like native apps, even offline.
- Enterprise-Scale Solutions:
- Big companies love React for its flexibility and scalability. From CRMs to internal tools, it’s used in large projects.
Basic ReactJS Questions and Answers
These questions are perfect for beginners getting started with ReactJS.
Q: What is JSX?
A: JSX is a syntax extension for JavaScript. It lets you write HTML-like code inside your JavaScript files, making it easier to design UI components.
Q: What is a React component?
A: A React component is like a building block of your app. It’s a small, reusable piece of code that controls how a part of your UI looks and works.
Q: What’s the difference between functional and class components?
A: Functional components are simple JavaScript functions that return JSX. Class components are ES6 classes with more features, but functional components are preferred nowadays because of React Hooks.
Q: What are props in React?
A: Props (short for properties) are like inputs you pass to a component. They help you send data from one component to another.
Q: What is state in React?
A: State is an object in a component that holds data that can change over time. For example, a counter value or user input can be stored in the state.
Q: How is state different from props?
A: Props: Passed to a component and are read-only.
State: Managed inside a component and can be updated.
Q: What is the purpose of render() in a React class component?
A: The render() method tells React what to display on the screen. It returns the JSX for your component.
Q: What is a React fragment?
A: A React fragment (<React.Fragment> or <>) lets you group multiple elements without adding extra HTML elements like <div>.
Q: Can you explain the virtual DOM?
A: The virtual DOM is a lightweight copy of the real DOM. React uses it to calculate changes and only updates what’s necessary, making updates faster.
Q: How do you pass data from a parent to a child component?
A: You pass data using props. For example:
<ChildComponent name=”John” />
Q: What is the use of key in lists?
A: A key helps React identify which list items have changed, making updates efficient.
Q: What does useState do in React?
A: useState is a React Hook that lets you add state to a functional component. Example:
const [count, setCount] = useState(0)
Q: What are events in React?
A: Events in React are like browser events (e.g., onClick, onChange). You can attach them to elements to handle user actions.
Q: How do you handle forms in React?
A: You can use state to manage form inputs and handle the onSubmit event to process form data.
Q: What is defaultProps in React?
A: defaultProps lets you set default values for props if they aren’t provided. Example:
MyComponent.defaultProps = { color: “blue” };
Q: How do you conditionally render content in React?
A: You can use JavaScript conditions like if or the ternary operator. Example:
{isLoggedIn ? <Dashboard /> : <Login />}
Q: What does React.createElement do?
A: It’s a React method that creates a virtual DOM element. JSX is just a shorthand for this.
Q: What are controlled and uncontrolled components?
A: Controlled Components: Manage their value through state (e.g., <input> with value controlled by state).
Uncontrolled Components: Use refs to access their value directly from the DOM.
Q: How do you update the state in React?
A: Use the setState method in class components or the setState function from useState in functional components.
Q: Why do we need React?
A: React makes it easier to build fast, interactive user interfaces with reusable components and efficient updates using the virtual DOM.
These questions should help beginners get a good grasp of React’s basics. Let’s move on to intermediate concepts!
Intermediate ReactJS Questions and Answers
Here’s a collection of questions that dive deeper into React concepts like lifecycle methods, hooks, and conditional rendering.
Q: How does the virtual DOM work in React?
A: The virtual DOM is a lightweight version of the real DOM. React updates it first, calculates the differences (or “diffing”), and only updates the parts of the real DOM that changed.
Q: What are lifecycle methods in React?
A: Lifecycle methods are functions you can override in class components to run code at specific stages of a component’s life, like mounting, updating, or unmounting.
Q: Can you name some common lifecycle methods?
A: componentDidMount: Runs after the component is added to the DOM.
componentDidUpdate: Runs after the component updates.
componentWillUnmount: Runs before the component is removed from the DOM.
Q: What replaced lifecycle methods in functional components?
A: React Hooks like useEffect can handle side effects, making lifecycle methods less necessary in functional components.
Q: What is the difference between useEffect and useLayoutEffect?
A: useEffect: Runs after the DOM updates. It’s great for fetching data or subscriptions.
useLayoutEffect: Runs before the DOM updates, useful for layout adjustments.
Q: How do you clean up effects in useEffect?
A: Return a cleanup function from useEffect. Example:
useEffect(() => {
const interval = setInterval(() => console.log(“tick”), 1000);
return () => clearInterval(interval); // Cleanup
}, []);
Q: What is conditional rendering in React?
A: It’s displaying different content based on a condition. Use JavaScript logic like if or the ternary operator in your JSX.
Q: How do you write conditional rendering using a ternary operator?
A:
{isLoggedIn ? <Dashboard /> : <Login />}
Q: What does useReducer do in React?
A: useReducer is a Hook for managing complex state logic, similar to Redux. It takes a reducer function and an initial state.
Q: When would you use useMemo?
A: Use useMemo to memoize a value so it doesn’t get recalculated unless its dependencies change. It helps optimize performance.
Example:
const computedValue = useMemo(() => expensiveCalculation(a, b), [a, b]);
Q: What is useCallback used for?
A: useCallback memoizes a function so it doesn’t get recreated unnecessarily, which is useful for preventing unnecessary renders in child components.
Q: Can you explain the key prop in React?
A: The key prop is used in lists to help React identify which items have changed, added, or removed. It ensures efficient updates.
Q: What is the significance of the useEffect cleanup function in React?
A: The cleanup function in useEffect is essential for preventing memory leaks and unwanted side effects in React components. When useEffect returns a function, React runs that function before executing the next effect and when the component unmounts. This is particularly useful for tasks like:
- Clearing intervals or timeouts to prevent duplicate executions.
- Unsubscribing from API calls or event listeners to avoid unexpected behavior.
- Cancelling pending API requests to prevent updates on unmounted components.
Example:
useEffect(() => {
const timer = setInterval(() => {
console.log("Interval running...");
}, 1000);
return () => {
clearInterval(timer); // Cleanup function
console.log("Interval cleared");
};
}, []);Q: How does React handle forms?
A: React uses controlled components for forms, where the input’s value is tied to state.
Example:
const [name, setName] = useState(“”);
<input value={name} onChange={(e) => setName(e.target.value)} />;
Q: What is the Context API in React?
A: The Context API allows you to share data (like theme or user info) across components without passing props down manually.
Q: How do you use the Context API?
A: Create a context: const MyContext = React.createContext();
Provide the context: <MyContext.Provider value={data}>
Consume the context: useContext(MyContext)
Q: What are Higher-Order Components (HOCs)?
A: HOCs are functions that take a component and return a new component with additional functionality. They’re used for reusing logic.
Example:
function withAuth(WrappedComponent) {
return function (props) {
return isLoggedIn ? <WrappedComponent {…props} /> : <Login />;
};
}
Q: What is the purpose of React.StrictMode?
A: It helps highlight potential problems in your React app during development, like unsafe lifecycle methods or deprecated features.
Q: How do you optimize rendering in React?
A: Use React.memo to prevent unnecessary re-renders.
Use useMemo and useCallback for expensive calculations and functions.
Avoid inline functions and objects in JSX.
Q: What happens if you call setState in React?
A: It schedules a state update. React re-renders the component with the new state value. However, state updates are asynchronous, so you won’t see the new state immediately.
These intermediate questions give you a good handle on React’s more complex concepts.
Advanced ReactJS Questions and Answers
Let’s explore some advanced React concepts like design patterns, architecture, and optimization techniques.
Q: What is code splitting in React?
A: Code splitting is a technique to break your code into smaller bundles. This allows React to load only the necessary parts of your app when needed, improving performance. You can implement it using React’s lazy and Suspense.
Q: How do you implement lazy loading in React?
A: Use the React.lazy function to load components on demand, combined with Suspense for fallback loading UI.
Example:
const LazyComponent = React.lazy(() => import(‘./MyComponent’));
<Suspense fallback={<div>Loading…</div>}>
<LazyComponent />
</Suspense>
Q: What is server-side rendering (SSR) in React?
A: SSR generates the HTML for your app on the server instead of the browser. This improves SEO and makes your app load faster for users. Frameworks like Next.js make SSR easy.
Q: What are portals in React?
A: Portals let you render children into a DOM node outside the parent component’s hierarchy. It’s great for modals and tooltips.
Example:
ReactDOM.createPortal(child, document.getElementById(‘portal-root’));
Q: What is the difference between context and Redux?
A: Context API: Simple state sharing for smaller apps.
Redux: A powerful state management library for large apps with complex state logic. It provides a strict structure for managing data flow.
Q: What is reconciliation in React?
A: Reconciliation is React’s process of updating the DOM efficiently by comparing the virtual DOM with the previous version and applying only the differences (diffing algorithm).
Q: What are Higher-Order Components (HOCs) in React?
A: HOCs are functions that take a component and return a new component with additional functionality.
Example: Adding authentication logic:
function withAuth(Component) {
return function EnhancedComponent(props) {
return isLoggedIn ? <Component {…props} /> : <Login />;
};
}
Q: What is React.memo?
A: React.memo is a higher-order component that prevents a component from re-rendering if its props haven’t changed. It’s useful for optimizing functional components.
Q: What is prop drilling, and how can you avoid it?
A: Prop drilling is when you pass props through multiple components to get them to a deeply nested child. You can avoid it by using Context API or state management libraries like Redux.
Q: How does React handle errors with ErrorBoundary?
A: An ErrorBoundary is a component that catches JavaScript errors in its child component tree and displays a fallback UI instead of crashing the app.
Example:
class ErrorBoundary extends React.Component {
componentDidCatch(error, info) {
console.log(error, info);
}
render() {
return this.state.hasError ? <h1>Something went wrong.</h1> : this.props.children;
}
}
Q: What are custom hooks?
A: Custom hooks are reusable functions in React that let you share logic across components. They’re just regular functions starting with use.
Example:
function useFetch(url) {
const [data, setData] = useState(null);
useEffect(() => {
fetch(url).then(response => response.json()).then(setData);
}, [url]);
return data;
}
Q: What is tree shaking in React?
A: Tree shaking removes unused code during the build process. React supports it when you use ES6 imports/exports, helping reduce bundle size.
Q: What are React render props?
A: Render props let you share logic between components using a prop that takes a function.
Example:
<DataFetcher render={(data) => <div>{data}</div>} />
Q: How do you manage side effects in React applications?
A: Use the useEffect Hook to handle side effects like fetching data, setting up subscriptions, or modifying the DOM.
Q: What is React Fiber?
A: React Fiber is React’s new reconciliation engine that enables faster rendering, better animations, and interruptible updates for improved performance.
Q: How do you improve React app performance?
A: Use React.memo, useMemo, and useCallback.
Code split with React.lazy.
Optimize state updates.
Use dynamic imports for large modules.
Avoid unnecessary renders with shouldComponentUpdate.
Q: What are the benefits of Next.js over Create React App (CRA)?
A: Next.js: Built-in SSR, static site generation (SSG), and better SEO.
CRA: Simpler setup for SPAs but lacks advanced features like SSR.
Q: What is suspense in React?
A: Suspense is a feature for handling lazy loading and asynchronous rendering in React. You can show fallback content while waiting for a component to load.
Q: How does React handle concurrent rendering?
A: React’s concurrent rendering allows it to work on multiple tasks simultaneously, prioritizing important updates like user interactions for a smoother experience.
Q: What is hydration in React?
A: Hydration is the process of taking server-rendered HTML and attaching event listeners to make it interactive. It’s common in SSR frameworks like Next.js.
These advanced questions are perfect for understanding React’s deeper concepts and best practices.
ReactJS Hooks Questions and Answers
Let’s break down some commonly asked questions on React Hooks like useState, useEffect, useContext, and more. These hooks are essential for modern React development.
Q: What is the purpose of useState in React?
A: useState is a React Hook that allows you to add state to functional components. It returns an array with the current state and a function to update it. Example:
const [count, setCount] = useState(0);
setCount(count + 1); // Updates the state
Q: How does useEffect work in React?
A: useEffect is used to handle side effects in functional components, such as fetching data, manipulating the DOM, or setting up subscriptions.
Example:
useEffect(() => {
console.log(“Effect runs after every render”);
}, [dependency]); // Runs when ‘dependency’ changes
Q: What are the common use cases for useEffect?
A:
Fetching data from an API.
Listening to events (e.g., window resize).
Cleaning up subscriptions or timers.
Q: What is useContext and when would you use it?
A: useContext lets you consume context data in functional components without manually passing props down the component tree.
Example:
const value = useContext(MyContext);
Q: How do you manage complex state logic with useReducer?
A: useReducer is useful for managing state that depends on many actions. It takes a reducer function and an initial state.
Example:
const reducer = (state, action) => {
switch (action.type) {
case ‘increment’: return { count: state.count + 1 };
case ‘decrement’: return { count: state.count – 1 };
default: return state;
}
};
const [state, dispatch] = useReducer(reducer, { count: 0 });
Q: What is the difference between useRef and useState?
A:
useState triggers a re-render when the state changes.
useRef doesn’t trigger a re-render and is used to store mutable values or access DOM elements.
Example:
const inputRef = useRef(null);
inputRef.current.focus(); // Accesses the DOM element
Q: How do you optimize performance with useMemo?
A: useMemo memoizes a value, so it’s only recalculated when its dependencies change. It prevents expensive calculations from running on every render.
Example:
const computedValue = useMemo(() => heavyCalculation(input), [input]);
Q: What is useCallback, and how is it different from useMemo?
A: useCallback memoizes a function so it doesn’t get recreated unnecessarily.
useMemo memoizes a value or result.
Example:
const memoizedCallback = useCallback(() => handleClick(id), [id]);
Q: What is the purpose of useImperativeHandle?
A: useImperativeHandle customizes the instance value exposed by ref. It’s often used with forwardRef.
Example:
useImperativeHandle(ref, () => ({
focus: () => inputRef.current.focus(),
}));
Q: How can you manage multiple state updates using useState?
A: Use multiple useState calls for separate pieces of state or manage a single object state carefully.
Example:
const [name, setName] = useState(”);
const [age, setAge] = useState(0);
State Management: Redux vs. Context API (Scenario-Based Questions)
Here’s a deep dive into Redux, Context API, and their comparisons, along with 10 scenario-based questions to help you understand when and why to use them.
Q: What is Redux?
Redux is a state management library often used for managing the global state of large applications. It centralizes the application’s state in a store, making state predictable and easy to debug.
Q: What is the Context API?
The Context API is a React feature that allows you to share state or data across the component tree without having to pass props manually at every level.
Q: Comparison Between Redux and Context API
| Feature | Redux | Context API |
| Complexity | Higher: Requires additional setup. | Lower: Built into React. |
| Scalability | Best for large apps with complex logic. | Better for small to medium apps. |
| State Logic | Manages advanced state logic via reducers. | Manages simpler, less complex state. |
| Debugging Tools | Powerful tools like Redux DevTools. | No built-in debugging tools. |
| Middleware | Supports middleware like redux-thunk. | Doesn’t support middleware. |
| Performance | Optimized with selectors and middleware. | May cause unnecessary renders. |
Q: When should you use Redux over the Context API?
A: Use Redux when your app is large, has complex state logic, or when you need advanced tools for debugging. Context API is better for smaller apps with simpler state-sharing needs.
Q: Your app has many unrelated components that need to share the same data. Which state management tool is better?
A: Redux is better in this case because it centralizes the state in one store, making it easy for unrelated components to access shared data.
Q: You are building a small app that only shares a theme and user authentication state. Which option should you choose?
A: The Context API is sufficient for sharing theme and authentication state in a small app. Redux would be overkill here.
Q: What would you use for managing a to-do list app with basic features?
A: The Context API is a good choice because the app’s state is simple and localized. Redux isn’t necessary unless you plan to scale it significantly.
Q: You need to handle asynchronous operations like API calls while managing global state. Which tool should you use?
A: Redux, because it supports middleware like redux-thunk or redux-saga for handling asynchronous operations.
Q: Your app is experiencing performance issues due to unnecessary renders when using the Context API. What should you do?
A: Use memoization techniques or consider switching to Redux, as it offers better performance optimizations with selectors and middleware.
Q: How would you structure state management for an e-commerce app with features like cart, user profiles, and product filters?
A: Redux is ideal for an e-commerce app because it can handle complex state logic across multiple features like cart management, user data, and filters.
Q: Your team prefers a minimalistic setup with less boilerplate. Which option should you choose?
A: The Context API, as it is built into React and doesn’t require extra libraries or configurations like Redux.
Q: What would you use if your app requires state to persist even after a page reload?
A: Redux combined with middleware like redux-persist to store state in local storage or session storage. The Context API doesn’t provide a built-in solution for this.
Q: You have an app where some parts need local state, and others need global state. How would you manage it?
A: Use React’s local useState for managing local state.
Use Redux or Context API for global state, depending on the complexity of the app.
These questions and explanations should help you understand the strengths and limitations of both Redux and the Context API, as well as how to use them effectively in real-world scenarios.
Performance Optimization in ReactJS
Here’s a list of 10 questions focusing on performance optimization techniques in React, including memoization, lazy loading, and tools for analysis and debugging.
Q: How does React.memo improve performance?
A: React.memo is a higher-order component that prevents a component from re-rendering if its props haven’t changed. This reduces unnecessary renders, improving performance.
Example:
const MemoizedComponent = React.memo(MyComponent);
Q: What is lazy loading, and how does it enhance performance in React?
A: Lazy loading delays the loading of a component or resource until it’s needed, reducing the initial load time of the app.
Example using React.lazy:
const LazyComponent = React.lazy(() => import(‘./Component’));
Q: What is useMemo, and how does it optimize performance?
A: useMemo memoizes a value, ensuring it is only recalculated when its dependencies change. This prevents expensive computations from running unnecessarily.
Example:
const computedValue = useMemo(() => expensiveCalculation(a, b), [a, b]);
Q: What is useCallback, and how does it differ from useMemo?
A: useCallback: Memoizes a function.
useMemo: Memoizes a value or result.
Use useCallback to avoid recreating functions passed as props, preventing unnecessary renders in child components.
Example:
const memoizedCallback = useCallback(() => handleClick(id), [id]);
Q: How does splitting code into smaller chunks improve performance?
A: Code splitting reduces the initial load time by loading only the parts of the app needed immediately. Tools like React.lazy or Webpack’s dynamic import() help achieve this.
Q: What tools can you use to analyze React performance?
A: React Developer Tools: For inspecting component renders and state.
Profiler API: Measures performance directly in React.
Performance tab in DevTools: For tracking JavaScript and rendering performance.
Q: What is the purpose of the Profiler in React Developer Tools?
A: The Profiler measures how long components take to render and re-render, helping you identify performance bottlenecks.
Q: How does dynamic import help with performance optimization?
A: Dynamic import allows you to load modules asynchronously, ensuring only the required code is fetched when needed.
Example:
const module = import(‘./largeModule’);
Q: How do you reduce unnecessary renders in React?
A: Use React.memo for functional components.
Use PureComponent for class components.
Avoid inline functions and objects in JSX.
Use useMemo and useCallback for expensive computations and functions.
Q: How can you optimize lists with a large number of items in React?
A: Use virtualization libraries like react-window or react-virtualized, which only render the visible portion of the list instead of rendering all items at once.
Example:
import { FixedSizeList } from ‘react-window’;
These questions and answers cover key techniques and tools for optimizing performance in React applications, making them perfect for interviews and practical use.
Testing in ReactJS
Here are some commonly asked questions on testing in ReactJS using Jest, Enzyme, and React Testing Library:
Q: How do you test a functional component with React Testing Library?
A: Use utilities like render() to render the component and fireEvent() to simulate user interactions.
Example:
import { render, fireEvent } from ‘@testing-library/react’;
const { getByText } = render(<Button onClick={mockHandler}>Click Me</Button>);
fireEvent.click(getByText(‘Click Me’));
Q: What is Jest, and why is it used in React?
A: Jest is a JavaScript testing framework widely used for React applications. It supports unit testing, mocks, snapshots, and code coverage out of the box.
Q: How do you write a snapshot test with Jest?
A: Use Jest’s toMatchSnapshot method to compare a component’s rendered output to a saved snapshot.
Example:
import renderer from ‘react-test-renderer’;
const tree = renderer.create(<MyComponent />).toJSON();
expect(tree).toMatchSnapshot();
Q: What is the difference between Jest and Enzyme?
A: Jest: A testing framework for running tests.
Enzyme: A library for shallow, mount, or render testing React components, focusing on component behavior.
Q: How do you simulate a click event with Enzyme?
A: Use Enzyme’s simulate() method to trigger events.
Example:
wrapper.find(‘button’).simulate(‘click’);
Miscellaneous ReactJS Questions
Here are additional questions covering TypeScript, server-side rendering, Next.js, and more:
Q: What is the difference between server-side rendering (SSR) and client-side rendering (CSR)?
A: SSR: HTML is generated on the server and sent to the client, improving initial load time and SEO.
CSR: The browser renders HTML using JavaScript on the client-side, which can delay the initial view but reduce server load.
Q: How is TypeScript used with React?
A: TypeScript adds type safety to React, helping catch errors during development. Use .tsx files for React components.
Example:
const MyComponent: React.FC<{ name: string }> = ({ name }) => <div>{name}</div>;
Q: What is Next.js, and how does it relate to React?
A: Next.js is a React framework for building server-rendered applications. It supports SSR, static site generation (SSG), and client-side rendering (CSR) out of the box.
Q: How does React handle internationalization (i18n)?
A: React uses libraries like react-i18next or react-intl to manage translations and language switching in components.
Q: What is the purpose of hydration in server-rendered React apps?
A: Hydration attaches event listeners and makes the static server-rendered HTML interactive by reusing React components on the client.
Tips for Cracking ReactJS Interviews
If you’re preparing for a ReactJS interview, here are some actionable tips to help you stand out and ace the process:
1. Master the Fundamentals
- Understand Core Concepts: Be crystal clear on React fundamentals like JSX, components, props, state, and lifecycle methods.
- Know Modern Features: Familiarize yourself with React Hooks (useState, useEffect, useContext, etc.) and concepts like context, lazy loading, and memoization.
2. Practice Live Coding
Use platforms like LeetCode, HackerRank, or CodeSandbox to simulate live coding interviews.
Be comfortable coding React components from scratch and solving problems while explaining your thought process.
Practice implementing features like:
- A dynamic to-do list.
- Fetching data from an API and displaying it.
- State management for a shopping cart.
3. Brush Up on Data Structures and Algorithms (DSA)
Even for ReactJS interviews, some companies test your problem-solving skills. Focus on:
- Arrays, strings, and hashmaps.
- Basic recursion and sorting algorithms.
- Implementing components that use these structures (e.g., a dynamic table).
4. Learn State Management Libraries
- Understand when and how to use Redux, Context API, or MobX. Be ready to discuss trade-offs.
- Practice building apps with global state management.
5. Contribute to Open Source
- Contributing to React or related open-source projects shows practical experience and teamwork.
- Look for beginner-friendly issues in repositories on GitHub tagged with “good first issue”.
6. Build Projects
Showcase projects on GitHub or portfolio sites to demonstrate your ReactJS expertise. Examples:
- A weather app using APIs.
- A blog or e-commerce platform.
- An interactive dashboard with charts and data visualizations.
7. Prepare for System Design Discussions
For senior roles, you may need to discuss how to structure a large React app. Focus on:
- Component architecture and folder organization.
- State management strategies.
- Performance optimizations.
8. Study Testing and Debugging
- Learn how to write tests using Jest, Enzyme, or React Testing Library.
- Be familiar with debugging tools like React Developer Tools.
9. Mock Interviews
- Practice mock interviews with friends, mentors, or on platforms like Pramp or Interviewing.io.
- Get feedback on your coding speed, clarity, and problem-solving approach.
10. Stay Updated
React evolves quickly. Stay updated with the latest features and best practices:
- Follow React’s official blog and community forums.
- Experiment with the latest versions of React (e.g., server components, concurrent rendering).
Conclusion
Preparing for a ReactJS interview in 2025 requires a solid understanding of core concepts, hooks, state management, performance optimization, and best practices. These Top 100 ReactJS Interview Questions cover a wide range of topics, from fundamental principles to advanced techniques, helping you build confidence for your next interview. Remember, preparation is key. Practice coding, build real-world projects, and stay updated with the latest trends in ReactJS. Combine that with a clear understanding of problem-solving and state management, and you’ll be ready to impress your interviewers. Good luck with your ReactJS journey—your next big opportunity is soon approaching.
