1. Introduction to React & JSX

What is React, Virtual DOM, and how JSX transforms HTML inside JavaScript.

By DevBytes Team • Updated 2026-08-09

Code Implementation & Snippet

React.js Example

import React from "react";

export default function WelcomeCard({ username }) {
  return (
    <div className="p-4 bg-blue-500 text-white rounded-2xl">
      <h1 className="text-xl font-bold">Hello, {username}!</h1>
      <p className="text-xs mt-1">Welcome to modern React development.</p>
    </div>
  );
}

Core Concepts Explained

1React is a component-based JavaScript library for building interactive user interfaces created by Facebook.

2JSX is a syntax extension for JavaScript that looks similar to HTML, allowing you to write markup directly inside JS files.

3React uses a Virtual DOM to compute minimal DOM updates, ensuring fast rendering performance.

Interview & Revision Takeaways

•Master React.js Complete Course: Zero to Mastery concepts.
•Practice challenge: Create a functional component that accepts a `title` prop and displays it inside an `<h1>` tag.

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