What is ReactJS? and Why to use it?

ReactJS ia a opensource javasccript library developed by Facebook which is used for building awesome user interfaces specifically for single page applications.if you are aware of MVC Architecture then ReactJS handles the "V" that is "VIEW" layer of MVC. React also allows us to create reusable UI components.

React allows developers to create large web applications which can change data, without reloading the page. The main purpose of React is to be fast, scalable, and simple. It works only on user interfaces in application. This corresponds to view in the MVC template. It can be used with a combination of other JavaScript libraries or frameworks, such as Angular JS in MVC.

Let us take a closer look at some important features of React:-

JSX

In React, instead of using regular JavaScript for templating, it uses JSX. JSX is simple JavaScript which allows HTML quoting and uses these HTML tag syntax to render subcomponents. HTML syntax is processed into JavaScript calls of React Framework. We can also write in pure old JavaScript.

React Native

React has native libraries which were announced by Facebook in 2015, which provides the react architecture to native applications like IOS, Android and UPD.

Why React Js?

Now, the main question arises in front of us is why one should use ReactJS. There are so many open-source platforms for making the front-end web application development easier, like Angular. Let us take a quick look on the benefits of React over other competitive technologies or frameworks. With the front-end world changing on a daily basis, it’s hard to devote time to learning a new framework – especially when that framework could ultimately become a dead end. So, if you're looking for the next best thing but you're feeling a little bit lost in the framework jungle, I suggest checking out React.

• Simplicity
• ReactJS is just simpler to grasp right away. The component-based approach, well-defined lifecycle, and use of just plain JavaScript make React very simple to learn, build a professional web (and mobile applications), and support it. React uses a special syntax called JSX which allows you to mix HTML with JavaScript. This is not a requirement; Developer can still write in plain JavaScript but JSX is much easier to use.
• Easy to learn
• Anyone with a basic previous knowledge in programming can easily understand React while Angular and Ember are referred to as ‘Domain specific Language’, implying that it is difficult to learn them. For react you just need basic knowledge of CSS and HTML.
• Native Approach
• React can be used to create mobile applications (React Native). And React is a diehard fan of reusability, meaning extensive code reusability is supported. So at the same time we can make IOS, Android and Web application.
• Data Binding
• React uses one-way data binding and an application architecture called Flux controls the flow of data to components through one control point – the dispatcher. It's easier to debug self-contained components of large ReactJS apps.
• Performance
• React does not offer any concept of a built-in container for dependency. You can use Browserify, Require JS, EcmaScript 6 modules which we can use via Babel, ReactJS-di to inject dependencies automatically.
• Testability
• ReactJS applications are super easy to test. React views can be treated as functions of the state, so we can manipulate with state we pass to the ReactJS view and take a look at the output and triggered actions, events, functions, etc.