The Virtual DOM is a lightweight copy of the actual DOM. React uses this concept to optimize updates to the user interface by minimizing direct manipulation of the DOM, which can be slow and inefficient.

How the Virtual DOM Works:

1. Initial Rendering:
   • The first part of the image labeled "Virtual DOM" shows the initial state of the Virtual DOM. This is a representation of the current state of the actual DOM.
2. New Virtual DOM:
   • When a change occurs (like a state change or a prop update), React creates a new Virtual DOM. The middle part of the image labeled "New Virtual DOM" shows this new version. Here, React compares the previous Virtual DOM with the new one to determine what has changed. The red circles indicate the parts of the DOM that have been modified.
3. Reconciliation:
   • React performs a "diffing" algorithm to compare the old and new Virtual DOM. It identifies the differences (or "diffs") and marks the affected nodes. The third part of the image, labeled "Affected nodes," shows the nodes that need to be updated.
4. Updating the Actual DOM:
   • After determining which nodes have changed, React updates only those specific parts of the actual DOM. This selective update process is much faster and more efficient than re-rendering the entire DOM, which is why React can achieve high performance.