React Js

What is React.js?

React is an open source JavaScript library that is used for creating interactive UIs specifically for single-page applications. It also allows developers to create reusable UI components. React allows us to make large web applications that can change data, without reloading the page. The main purpose of React is to be quick, scalable, and simple. React can be used with a combination of different JavaScript libraries or frameworks, like Angular JS in MVC. React JS is simply called React or React.js

Virtual Document Object Model?
Virtual DOM allows the UI to be efficient in diffing the UI changes. 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 computer programmer to code as if the entire page is rendered on every modification whereas react library only renders components that modify.

What is React- Native?
React-native is open source mobile application framework using only JavaScript announced by Facebook in 2015. which provides the react architecture to native applications like IOS, Android and UPD. It uses the same design style as React, which allows to use or include a rich mobile UI library or declarative elements. It uses the same fundamental UI building blocks as regular iOS and Android apps. The most effective part of using react-native is to allow adopt components written in Objective-C, Java, or Swift.

What is Component?
Components are the building block of any React App. Simply component is a JavaScript class or function that optionally accepts inputs and return a react element that describes how a section of the UI should appear.

Why React?

Simplicity

• Reacts is simple and easy to understand.
• The component-based approach and well-defined lifecycle.
• Able to build a professional web and mobile applications.
• React uses a special syntax called JSX which allows you to combine HTML with JavaScript

Easy to learn

• Anyone can easily understand with basic previous knowledge in programming.
• Needed only basic knowledge of CSS and HTML.

Native Approach

• React is a diehard fan of reusability. It supports reusability of extensive code.Therefore, at the same time, we can make IOS, Android and Web applications.

Data Binding

• React uses one-way data binding and Flux (Application Architecture). which contrals the flow of data to components through one control point. debugging the self-contained components of large ReactJS apps will be easier.

Testability

•  ReactJS applications are easier to test. 
• React views can be treated as function of the state.