1th of 3 Questions.
What is React?
It's a JavaScript library for building user interfaces. It allows developers to create reusable UI components that update efficiently and automatically when data changes. React follows a declarative approach, making it easier to manage the state of an application and render dynamic content.
The major features of ReactJS are as follows:
It uses VirtualDOM.
Follows Unidirectional data flow or data binding
Uses reusable/composable UI components to develop the view
Increases the application’s performance with Virtual DOM
JSX makes code easy to read and write
It renders both on client and server side
Easy to integrate with other frameworks (Angular, BackboneJS) since it is only a view library
Easy to write UI Test cases and integration with tools such as JEST.