ReactJS is a javascript library maintained by Facebook and instagram. It is mainly used to create user interfaces in JavaScript for different platforms.You can use ReactDOM for web applications, React Native for mobile app development (sharing the majority of code between Android and iOS), and cross-platform hybrid desktop applications with Electron.

Features of ReactJS :

1. Speed
2. Simplicity
3. Scalability

Points covered here are :

1. ReactJS Environment Setup

Environment Setup

Tools required for ReactJS Environment

1. Node.js
   

2. VS code(Visual studio code)

   

Steps to setup React Environment

Install Node.js

1. Create a directory for React.js App
2. Open command prompt
3. Create a directory for React.js App
4. Open command prompt

Go to Reactjs Directory location

Type command for React Environment
npm install create-react-app -g or
npx create-react-app my-app

Here -g means installation type is global

Second command :
create-react-app AppName

Go to AppName directory and type npm start

After starting your first React Application, You will get default screen on the browser.

Hope you would get basic knowledege on how react is been setup .