What is the virtual DOM used for in React?

The virtual DOM is a crucial concept in React that provides a way for the library to optimize UI rendering and updates efficiently. When state or props change in a React application, instead of directly manipulating the actual DOM—which can be slow and performance-draining—React creates a lightweight representation of the DOM known as the virtual DOM. This virtual DOM allows React to quickly determine what changes have occurred by performing a diffing algorithm that compares the current virtual DOM with a previous version.

When differences are identified, React can then apply only the necessary updates to the actual DOM in a batch process. This minimizes the number of direct interactions with the DOM and leads to significant performance improvements, particularly in applications with frequent updates or complex user interfaces. Hence, the purpose of the virtual DOM is to facilitate quick comparison for UI updates, making it an essential feature of React’s rendering mechanism.