When a React component updates, it creates a new Virtual DOM tree, compares it with the previous version, and updates only the parts of the actual DOM that have changed. This process is called “reconciliation” and is much faster than updating the entire DOM, which can be a slow and resource-intensive operation.
React also makes use of a technique called “keyed reconciliation,” which enables it to update a list of items efficiently. By assigning a unique key to each item in the list, React can identify which items have been added, removed, or modified, and update only those items, instead of re-rendering the entire list.
Additionally, React encourages a “one-way data flow” architecture, where data flows in a single direction from the parent component to its children. This approach makes it easier to reason about the application’s state and reduces the likelihood of bugs and performance issues.
Overall, React’s Virtual DOM implementation, keyed reconciliation, and one-way data flow architecture contribute to its speed and performance. By minimizing the number of DOM updates and efficiently updating lists of items, React can provide a fast and responsive user experience, even for complex and dynamic web applications.