Introduction
Top 10:- Questions and Answers for improving and understanding React JS Framework. Learn and Understand React JS Framework like Pro.
1. Question: What is React.js?
Answer: React.js is an open-source JavaScript library for building user interfaces. It is developed and maintained by Facebook.
2. Question: What does JSX stand for in React.js?
Answer: JSX stands for "JavaScript XML." It is a syntax extension that allows you to write HTML-like code in your JavaScript files.
3. Question: What is a component in React.js?
Answer: A component in React.js is a reusable piece of UI that can be composed together to build complex user interfaces.
4. Question: How do you create a functional component in React.js?
Answer: You can create a functional component using a JavaScript function that returns JSX. For example:
jsxfunction MyComponent() {
return <div>Hello, React!</div>;
}
5. Question: What is the purpose of state in React.js?
Answer: State in React.js is used to manage data that can change over time and trigger re-rendering of the component when it does.
6. Question: How do you update the state of a component in React.js?
Answer: You can update the state of a component using the setState method. For example: this.setState({ count: this.state.count + 1 });
7. Question: What is a prop in React.js?
Answer: A prop (short for property) is a way to pass data from parent components to child components in React.js.
8. Question: What is the purpose of the virtual DOM in React.js?
Answer: The virtual DOM in React.js is an in-memory representation of the actual DOM. It improves performance by minimizing the number of DOM manipulations during updates.
9. Question: What is a React.js hook?
Answer: A hook in React.js is a function that allows functional components to "hook into" React state and lifecycle features. Examples include useState and useEffect.
10. Question: How do you render a list of items in React.js?
perl**Answer:** You can render a list of items in React.js by mapping over an array and returning JSX for each item, like this:Â ```jsx
{items.map(item => <li key={item.id}>{item.name}</li>)}
```
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