What is React?

React is a JavaScript library for building user interfaces. It is maintained by Meta (Facebook).

React lets you build complex UIs from small, reusable pieces called components.

Key Concepts

• Components — reusable UI pieces
• JSX — JavaScript XML syntax
• Virtual DOM — fast rendering
• State & Props — data management

Syntax

REACT

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function Welcome(props) {
    return <h1>Hello, {props.name}</h1>;
}

const root = ReactDOM.createRoot(
    document.getElementById('root')
);
root.render(<Welcome name="SukhNexus" />);

Your First React Component

REACT

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import React from "react";

function App() {
    return (
        <div>
            <h1>Hello, React!</h1>
            <p>Welcome to SukhNexus Academy</p>
        </div>
    );
}

export default App;

Try It Yourself

Practice

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Exercise

What is a component in React?

Answer

A reusable piece of UI that returns JSX.

Quick Quiz

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What does JSX stand for?

JavaScript XML

Java Syntax Extension

JSON XML

JavaScript Extension

JSX stands for JavaScript XML — a syntax extension for JavaScript.

Retry Quiz

Interview Questions

What is the Virtual DOM?

A lightweight copy of the real DOM that React uses to optimize updates by comparing changes before applying them.

Tutorial Complete

Back to React