React.js for Noobs

React.js has been popular among web app developers recently and a lot of websites has adopted the library because of the perks it provides. This post is not about pros and cons of the React.js library, although you can find a myriad of articles and posts on the web comparing React.js with other front-end frameworks.
In layman’s terms, React.js is a JavaScript library which handles the view component of the MVC architecture. React.js is used to manipulate the DOM of a webpage in an efficient manner to render a web application.