ReactJS is an open source JavaScript library created by Facebook, which is used to develop the user interface, it is one the most popular JavaScript library.

ReactJS is not a framework

ReactJS is interactive UI in web and mobile application UI.

Advantages:

• Easy to learn, use of JSX
• Quick development
• Simple design using JSX
• Better user experience and its using virtual DOM implementation
• One-way data binding
• It uses server-side rendering
• Only View part of MVC

Disadvantages:

• It is Java Script library not a framework
• Coding will get complex, most of the syntaxes must be JavaScript nature
• Learning curve is bit high for new developers