What is ReactJs?

React.js (also known as React or ReactJS) is a free and open-source front-end JavaScript library for building user interfaces (UIs) and single-page applications. It is maintained by Meta (formerly Facebook) and a community of individual developers and companies.

Quick Start

npx create-react-app my-app
cd my-app
npm start

NPM (Node Package Manager) or NPX (Node Package Execute) this are the topic of Node.js

Breakdown of npm:

    npm install -g create-react-app my-app

Here we are saying that hay npm can you install create-react-app in my-app and also make sure it is install globally or -g and remember it is downlode inside your device

Breakdown of npx:

    npx create-react-app my-app

Breakdown of replace my-app with .:

    npx create-react-app .

We are saying that hay npx install create-react-app and make sure that it is derect insert in current file

• Without my-app tree structure

   Project/
    ├── node_modules/
    ├── public/
    │   ├── favicon.ico
    │   ├── index.html
    │   ├── logo192.png
    │   ├── logo512.png
    │   ├── manifest.json
    │   └── robots.txt
    ├── src/
    │   ├── App.css
    │   ├── App.js
    │   ├── App.test.js
    │   ├── index.css
    │   ├── index.js
    │   ├── logo.svg
    │   ├── reportWebVitals.js
    │   └── setupTests.js
    ├── .gitignore
    ├── package.json
    ├── README.md
    └── yarn.lock (or package-lock.json)

• With my-app tree structure

    Project/
    └── my-app/
        └── create-react-app/

Breakdown of npx:

    cd my-app
    npm start

• cd my-app stands for enter inside my-app folder

• npm start is a commound to start run the index.js folder