What is react and why is it cool?

React.js is the most popular front-end JavaScript library for building Web applications. It’s an open-source JavaScript library that is used for building user interfaces specifically for single-page applications. It’s used for handling the view layer for web and mobile apps. React was first created by Jordan Walke, a software engineer working for Facebook. React first deployed on Facebook’s newsfeed in 2011 and on Instagram.com in 2012.

React allows developers to create large web applications that can change data, without reloading the page. The main purpose of React is to be fast, scalable, and simple.

Some of its main characteristics are:

JSX

In React, instead of using regular JavaScript for templating, it uses JSX. JSX is a variant of JavaScript that allows HTML quoting and uses these HTML tag syntax to render subcomponents. HTML syntax is processed into JavaScript calls of React Framework.

Component based

React uses a component based type of development, in which every part of the final application is developed independently and interaction between the different components is programmed accordingly.

Single-Way data flow

In React, a set of immutable values are passed to the components renderer as properties in its HTML tags. The component cannot directly modify any properties but can pass a call back function with the help of which we can do modifications. This complete process is known as “properties flow down; actions flow up”.

Virtual Document Object Model

React creates an in-memory data structure cache which computes the changes made and then updates the browser. This allows a special feature that enables the programmer to code as if the whole page is rendered on each change whereas react library only renders components that actually change.