ReactJS is a free open-source JavaScript library maintained by Facebook. It is used for building rich and dynamic user interfaces with minimum effort and simplified coding. ReactJs follows the Model View Controller (MVC) architecture which is responsible for handling view Layer of UIs. ReactJS is one of the most popular JavaScript front-end libraries which has a strong foundation and a large community. It can be used for the development of both web and mobile apps.

Back in 2011, Jordan Walke builds a prototype “FaxJS” to handle the exploding updates and increasing features of Facebook Ads in rescue of the Facebook team. This marked the foundation of ReactJS. It was first used in Facebook feed in 2011, subsequently picked by Instagram and so on. Though it was made open source in 2013, which is seen as an official launch. Boosted efficiency and easy upgradation improved the user experience and ReactJS got more acknowledgement with time. In 2015 with the giants like Netflix joining the community RecactJS proved to be revolutionary. Community is ever growing since then.

ReactJS is component-based coding that allows splitting of logic into reusable independent codes. Making it faster and simpler. React creates a Virtual Document Object Model (DOM) allowing user to apply updates in a virtual environment and specific sections of webpage without having to reload the whole page. ReactJS knows when the state of an application is changed and have the intelligence to determine when a change to the DOM is unnecessary and skip the DOM manipulation which is otherwise an expensive and slow process. React will efficiently update and render just the right components when the data changes. This exceptionally improves performance of mobile / web applications. The use of JSX (JavaScript extension syntax) to accept HTML quotes and HTML tag syntax allows dynamic contents on webpages. This also supports the building of machine-readable codes. Though it isn't necessary to use JSX in React development, it is recommended. ReactJS uses one direction downward data binding. In such a structure, nesting child components within parent components is common which makes activities quick and modular

Component based approach of ReactJS provides easy customization and flexibility while building UIs. Each component of the ReactJS application is reusable which gives reusable piece of HTML code as output. Its components can also be nested with other components allows the creation of complex applications built of simple building blocks. The open-source library is continuously evolving, easy to access and to start with while developing any application. Coding in JavaScript rather than HTML is easy to learn. React supports various extensions and comes with wide set of tools for developers to build SEO friendly websites. Hassle free maintenance, testing and debugging makes it a preferrable choice with the giants like Netflix, Uber, Airbnb, The New York Times a few to name with.

The Java Script based coding is easy to learn. The ease of access to the open-source framework further improves the productivity and efficiency of the developers. React’s capability to simplify complex logics into modular component-based structure is developer friendly. ReactJs framework comes with a wide range of React dev tools and Chrome dev tools for developers. It is already backed by a strong community worldwide and is being used my many fortune 500 companies which builds which leads developers
to be entrusted more into ReactJs.

People are more interactive in online world today instead of the real, ReactJS is providing the same. Responsive webpage elements like chats, animations etc. are not only the need of hour but an immensely rising virtual world. Since 2013, after React became open source it is ever growing. ReactJS is already backed by a huge community of developers and the family is growing day by day. React is far ahead in competition compared to its rivals because of the competitive features and the number one web framework used by software developers across the world. However, developers should focus on improving their skills in JavaScript and becoming quality programmers, demand for front-end React developers will also increase in near future on a global scale.

The constantly updating library might need the developers to stay alert and adaptive to the changes. Though not a disadvantage in a way! It’s need of the hour.
ReactJS covers only the UI Layers of the app, which is only the view part. For complete development other technologies might be needed. Although the user interactive part for any application is uncompromisable and like a lifeline. ReactJs thus plays a role not less than anything! The number of advantages it is adding to the programming world is shadowing the disadvantages if there are any. So, no cons we can say.