ReactJS is an open source JavaScript library maintained by Facebook and others for building user interfaces in single-page applications. It aims to help developers create large apps with data that changes over time in a simple and declarative way. React handles just the view layer and uses virtual DOM for high performance by only updating what changes in the real DOM. Key features include reusable components, server-side rendering for SEO, and efficiency through the virtual DOM. JSX allows mixing HTML and JavaScript, and project setup involves creating a directory and HTML file to start coding components.

1. ReactJS
A JAVASCRIPT LIBRARY FOR BUILDING USER INTERFACES

2. It is an open source Javascript library for creating
user interfaces that aims to address challenges
encountered in developing single-page
applications.
It is maintained by Facebook, Instagram and a
community of individual developers and
corporations.
What is ReactJS?

3. React is intended to help developers build large
applications that use data that changes over
time. Its goal is to be simple, declarative and
composable. React only handles the user
interface in an app.
Why ReactJS?

4. 1. Components - React gives you the ability to create
your own components that you can later reuse,
combine,manipulate and nest to your heart’s content.
1. It’s awesome for SEO - because you can run React.js
on the server, and the virtual DOM will be rendered and
returned to the browser as a regular web page
Features of ReactJS

5. 3. It is extremely Efficient - React.js creates its own virtual
DOM where your components actually live. This approach
gives you enormous flexibility and amazing gains in
performance because React.js calculates what changes
need to be made in the DOM beforehand and updates the
DOM tree accordingly.
Features of ReactJS(contd)

6. JSX
JSX is a JavaScript syntax extension that looks similar to
XML. It allows you to mix HTML with JavaScript.
React.js turns those bits of HTML into functions with a special
JSXTransformer.

7. Project Setup
● Create a directory for your project
● Make a HTML file call it anything
● And let’s start to code

8. Thanks for listening !!!