What is React?

React is a JavaScript library that is used for building user interfaces. It was developed by Facebook and is now maintained by Facebook and a community of individual developers and companies. React is known for its ability to create reusable UI components, which can be used across different parts of an application. React is also known for its performance, as it uses a virtual DOM to efficiently update the UI when changes are made.

One of the key features of React is its use of a declarative programming model. This means that developers can describe what they want the UI to look like, and React will take care of updating the actual UI to match that description. This is in contrast to an imperative programming model, where developers have to manually update the UI in response to changes in the application state.

React is often used in combination with other libraries and frameworks, such as Redux for state management and React Router for routing. React can also be used with different build tools, such as Webpack and Babel, to create a development environment that is tailored to the needs of the project. React has a large and active community, which means that there are many resources available for learning and troubleshooting.