React js interview questions and Answers

Last updated on Feb 10, 2024
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React js interview questions

ReactJS is a JavaScript library for building reusable User interface components. It is a template-based language combined with different functions that support the HTML. Our recently updated React Interview Questions can help you crack your next interview. This means the result of any React's operation is an HTML code. You can use ReactJS to build all kinds of single-page applications.

Short Questions About React
What is the latest version of React? 18.0, released on March 29, 2022.
When was React first released? 29th May 2013
React JS is Created By Jordan Walke
License of ReactJS MIT License

React Developer Interview Questions

Here in this article, we will be listing frequently asked React js interview questions and Answers with the belief that they will be helpful for you to gain higher marks. Also, to let you know that this article has been written under the guidance of industry professionals and covered all the current competencies.

Q41. What is React Router?

React Router is the in-built routing library for React. React Router helps to keep your UI in sync with the respective URL. It works on a simple API having powerful features like lazy loading, locational transition, and dynamic route matching built right in.

Q42. How to render an array of objects in react?

Now, there are two ways to render this object as an array,


render() {
    const data =[{"name":"test1"},{"name":"test2"}];
    const listItems = => <li key={}>{}</li>);

    return (
      {listItems }

Or, you could directly write the map function in the return

render() {
    const data =[{"name":"test1"},{"name":"test2"}];
    return (
      {, idx){
         return (<li key={idx}>{}</li>)

Q43. What is the difference between state and props in React?
State Props
This is the data maintained inside the component. This is the data passed in from a parent component.
The component within shall update itself using the setState function. These are read-only functions present in the child component and have to be updated manually.

Note: React is a widely used open-source library used for building interactive user interfaces. It is a web platform licensed under MIT. This is one of the very popular react interview questions.

Q44. Which lifecycle method gets called by react as soon as a component is inserted into the DOM?
Q45. How to use the spread operator to react?
Q46. What are the steps to implement search functionality in reactjs?
Q47. How to define property in the react component?
Q48. What is StrictMode in React?
Q49. How to avoid prop drilling in React?

You can avoid Prop Drilling in the following ways:

  • Using a Context API
  • Using Render Props
Q50. What are the key benefits of ReactJS development?
Key Benefits of ReactJS Development
  • Allows Developers to Reuse the Components
  • It is Much Easier to Learn
  • The Benefit of Having JavaScript Library
  • SEO Friendly
  • It ensures faster rendering
  • The Increase in Community Base
  • The Support of Handy Tools
  • Scope for Testing the Codes etc

Top 20 React.js Interview Questions

Here you will find the list of Top React interview questions, which were written under the supervision of industry experts. These are the most common questions and usually asked in every interview for the role of the React Developers.

  • What is HOC?
  • What are the difference between Rest and Spread Operator?
  • What are the key benefits of using Arrow functions?
  • What is Pure Component?
  • What are Controlled and Uncontrolled components with example?
  • What is Refs?
  • What is the difference between class based component & function based components?
  • How to work React?
  • Why virtual Dom is faster than real dom?
  • How does virtual Dom work in react?
  • What are the difference between null & undefined?


Now that you have read all the react questions, it is time for you to go towards the next level. Applying for a developer position would require you to actually code and not just give answers to theoretical questions.

That’s why you should enhance your skills by complementing the above react developer interview questions with a practical mindset. Start coding small stuff, get your concepts crystal clear. It’s all about how you can apply your knowledge in different projects. Code and code, that’s the secret to winning the dream job!

Reviewed and verified by Umesh Singh
Umesh Singh

My name is Umesh Singh having 11+ experience in Node.JS, React JS, Angular JS, Next JS, PHP, Laravel, WordPress, MySQL, Oracle, JavaScript, HTML and CSS etc. I have worked on around 30+ projects. I lo...