Why does React use Virtual DOM and how does it work?

React uses Virtual DOM to optimize user interface updates. Instead of directly modifying the real DOM (which is costly in terms of performance), React first updates a virtual representation of the DOM — a lightweight copy of the UI structure in memory.

How it works:

1. When the component's state changes, React creates a new Virtual DOM.
2. Then React compares the new Virtual DOM with the previous version (this process is called "diffing").
3. Based on the differences, React calculates the minimal set of changes needed to update the real DOM.
4. These changes are applied to the real DOM in a single batch, significantly reducing the number of expensive DOM operations.

This improves performance and makes UI updates more efficient and predictable.