What is ReactJs and how does it works

Adarsha Regmi
2 min readFeb 5


Beginner guide to reactJs

What is ReactJS and How Does it Work?

Basic introduction ::

ReactJS is a popular JavaScript library used for building user interfaces. It was developed by Facebook and is now maintained by Facebook and a community of individual developers. ReactJS allows developers to build complex user interfaces with reusable components, making it easier to create, maintain, and update applications.

ReactJS uses a component-based architecture. Components are small, reusable pieces of code that represent individual parts of a user interface. These components can be combined to create larger, more complex user interfaces. Components are also responsible for managing their own state, which is a collection of data that determines how the component behaves and what it displays.

How it works ?

ReactJS uses a virtual DOM, which is a virtual representation of the actual DOM (Document Object Model). The virtual DOM is a lightweight version of the actual DOM, and ReactJS uses it to update the actual DOM more efficiently. When a component’s state changes, ReactJS updates the virtual DOM to reflect those changes. Then, ReactJS calculates the difference between the current virtual DOM and the previous virtual DOM, and makes only the minimum necessary updates to the actual DOM. This results in a faster and more efficient update process.

ReactJS also includes a feature called JSX, which allows developers to write HTML-like code in their components. JSX makes it easier for developers to see the structure of their components and understand how they will look and behave in the user interface.

Use cases

ReactJS is widely used by many companies, including Facebook, Airbnb, Netflix, and more. It’s a popular choice for building web applications because of its ease of use, performance, and flexibility. ReactJS can be used with a variety of other tools and technologies, making it a versatile option for building web applications.

In conclusion, ReactJS is a popular JavaScript library for building user interfaces. It uses a component-based architecture and a virtual DOM to make updates more efficient. ReactJS also includes JSX, which makes it easier to write and understand components. ReactJS is widely used and is a popular choice for building web applications.