Mastering the Interview: 20 ReactJS Interview Questions for Senior Frontend Developers

As a seasoned frontend developer specializing in ReactJS, landing a senior position requires more than just expertise in the framework. Employers are seeking candidates who can not only solve complex problems but also demonstrate a deep understanding of React’s core concepts and best practices. In this blog post, we’ll explore 20+ interview questions commonly asked during senior frontend developer interviews.

1. Explain the Virtual DOM and its importance in React.

Answer: The Virtual DOM is a lightweight copy of the real DOM that React maintains. It allows React to efficiently update the UI by minimizing direct manipulation of the actual DOM. Here’s a simple example:

const element = <h1>Hello, World!</h1>;
ReactDOM.render(element, document.getElementById('root'));

2. Describe the key differences between state and props in React.

Answer: In React, both state and props are used to pass data, but they serve different purposes. State is mutable and managed within a component, while props are immutable and passed down from a parent component. Here’s an example:

class ExampleComponent extends…