JSX 

JSX is known as JavaScript XML. It is a syntax extension for JavaScript. This syntax is transformed into React Framework JavaScript calls. It expands ES6 to make HTML-like text and JavaScript react code to coexist. It is unnecessary to use JSX but recommended to use in ReactJS. 

Components 

Components are the core of ReactJS. Each of the various components that make up a ReactJS application, and each has their own logic and controls. When working on more complex projects, these reusable components make it easier to maintain the code. 

One-way Data Binding 

If the data flow is in a different direction, then more features are needed. Because components are designed to be immutable, meaning that their data cannot be altered. Flux is a pattern that keeps your data unidirectional. This increases the application’s flexibility and efficiency. 

Virtual DOM

Representation of the original DOM object is virtual DOM object. It operates as one-way data binding. Every time the web application is changed, the entire user interface will be re-rendered in virtual DOM representation. Then it compares the differences between the old DOM representation and the new DOM. When it is finished, the real DOM will update only the elements that have changed. This makes the program run faster and uses less memory. 

Simplicity

ReactJS makes the application simple and easy to understand by using JSX files. ReactJS is a component-based methodology, which allows for flexible reuse of the code. This makes it easy to use and learn. 

Performance

ReactJS is renowned for being a great performer. This feature makes it much better than other frameworks currently in use. The DOM is a cross-platform programming API that works with HTML, XML, or XHTML. The DOM is totally contained in memory. As a result, while creating a component, we did not write directly to the DOM. Instead, we are creating virtual components that will transform into the DOM, resulting in a smoother and quicker performance.