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Are you preparing for a React JS interview? Here are some of the most commonly asked questions that you should be ready to answer.
1. What is React JS?
React JS is a JavaScript library for building user interfaces. It is maintained by Facebook and a community of individual developers and companies.
2. What are the key features of React JS?
- Virtual DOM
- Component-based architecture
- JSX – JavaScript XML
- One-way data binding
3. What are the differences between a class component and a functional component?
A class component uses ES6 class syntax and inherits from React.Component, while a functional component is just a plain JavaScript function that returns JSX.
4. What is JSX?
JSX is a syntax extension for JavaScript that allows you to write HTML-like code in your JavaScript files. It makes your React components more readable and easier to write.
5. What is the Virtual DOM in React?
The Virtual DOM is a lightweight copy of the real DOM. When the state of a component changes, React creates a new Virtual DOM tree and compares it with the old one to find the differences. Then, it updates only the necessary parts of the real DOM to reflect those changes.
6. How does data flow in React?
Data flows from parent components to child components through props. Child components can also communicate with parent components using callback functions.
7. What are the different lifecycle methods in React?
- componentDidMount
- componentDidUpdate
- componentWillUnmount
These are just a few of the many questions you could be asked in a React JS interview. Make sure to study and understand the fundamentals of React to ace your interview!
