Introduction of React Js
React is a JavaScript library created by Facebook for building user interfaces, especially for web applications.
It lets developers build reusable UI components that update efficiently when data changes.
Instead of reloading a whole page, React updates only the parts that change, making apps faster.
In simple terms, React helps create dynamic, interactive, and smooth web experiences easily.
Key Features of React.js
Component-Based Architecture
UI is broken down into reusable components.
Each component manages its own state and logic.
Virtual DOM
React uses a virtual DOM to efficiently update and render components.
It compares the virtual DOM with the real DOM and updates only the parts that changed.
Declarative Syntax
You describe what you want to see, and React takes care of the how.
This makes code more predictable and easier to debug.
JSX (JavaScript XML)
A syntax extension that allows you to write HTML-like code in JavaScript.
Makes writing UI components more intuitive.
Unidirectional Data Flow
Data flows from parent to child components, making the app easier to understand and maintain.
Hooks (React 16.8+)
Functions like useState, useEffect, etc., allow you to use state and lifecycle features in functional components
It helps in remember things (like tasks) and react to changes (like showing reminders)
Important Extensions:-
Chrome Extension
React Developer Tools
VS Code Extension
Thunder Client
ES7 React/Redux/GraphQL/React-Native
Bracket pair colorization
Auto Rename Tag
Links
Node.js official website: https://nodejs.org
React official website learning articles: https://react.dev/learn
Commands for creating & running a React app
# create a new React project (using NPX)
npx create-react-app my-app # creates folder “my-app” with boilerplate :contentReference[oaicite:5]{index=5}
cd my-app # change into the project folder
npm start # start the development server and view the app in browser :contentReference[oaicite:6]{index=6}