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Geting Start with React.js

Virtual DOM in React:

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  • What it is: A lightweight, in-memory representation of the actual DOM that React uses to efficiently update the UI.
  • How it works:
  • Rendering: React creates a virtual DOM tree when you render a component.
  • Reconciliation: When data changes, React creates a new virtual DOM tree and compares it with the previous one to identify differences.
  • Diffing Algorithm: React employs a diffing algorithm to determine the minimum changes needed in the actual DOM.
  • Updating the Actual DOM: React updates only the necessary elements in the real DOM, minimizing expensive DOM manipulations. React isn't the only library utilizing a virtual DOM strategy; Vue.js also employs it. Svelte offers a different approach, optimizing applications by compiling components into small JavaScript modules. Setting up your Environment:
  1. Install Node.js and npm (or yarn) node
  2. *Create a React App *
npx create-react-app my-react-app
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Core React Concepts:

  1. Components: React applications are built using reusable components. These are independent, self-contained blocks of code that define how a part of the UI should look and behave.

  2. JSX: JSX (JavaScript XML) is a syntax extension that allows you to write HTML-like structures within your JavaScript code. It's a convenient way to define the UI of your components.

  3. Props: Components can receive data or configuration options from their parent components using props. This allows for building flexible and reusable components.

  4. State: Components can manage their own internal state using the useState hook. State allows components to react to user interactions or data changes and update their UI accordingly.

Building a Basic App:

  1. cd my-react-app
  2. npm start (or yarn start) http://localhost:3000/browser
  3. create-react-app includes an App.js
import React from 'react';

function App() {
  return (
    <h1>Hello, React!</h1>
export default App;
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