React JS in Simple terms

-->React is a Javascript library(not a framework) that allows us to create user interfaces .In practice it's a library that focuses only on the view, which is what we see on the screen.
Imagine a web page as series of objects, which have their own designand perform certain actions.React allows us to create these objects(also called as components) and assign them a status
(information about the components can be modified) through props(which are called properties).

-->Now ,STATE AND PROPS are two forms of data being passed into a view.
-->Same data passed into a view will always result in the same outputted view.
-->Different data passed into a view will result in different ouputted view.
Hence for Every action there is REACTion.

Now moving on to the point what makes it so popular and why so many developers are shifting to it ?
React has low learning curve and allows us to have a lot of flexiblity by giving us the opportunity to integrate other frameworks.I recommend it as first framework to study (obviously after you have studied JS)
There are many reasons to it which are listed below-
-->JSX: It makes it possible to bring HTML directly into your JS which allowing us to create a new UI feature and see it in real time.
-->Components: It allows us to break our web app into individual simple objects (such as navbar ,footer , div ,other elements like that) and work on them easily.
-->Props-It makes us possible to populate components using custom data.
-->State-It makes us possible to store all the changes in one section.
-->Virtual DOM- DOM is programming concept which used to make HTML pages interactive.Virtual DOM makes app fast and user experience superlative.
Reusable components,easy data flow,easy debugging,easy testing,SEO friendly ..did i miss anything ? drop it down in comments.
Thanks for reading! :)