The Virtual DOM (VDOM) is a representation of the real DOM in memory. It is a lightweight, tree-like data structure that mirrors the actual DOM tree. When there are changes to the data model, the VDOM is updated instead of the real DOM. This makes updates to the UI much faster, as it only requires updating the VDOM and then reconciling the changes with the real DOM.
Here are some of the reasons why VDOM is faster than real DOM updates:
Diffing: The VDOM uses a diffing algorithm to efficiently identify the minimum set of changes that need to be made to the real DOM. This avoids the need to re-render the entire DOM tree, which can be expensive.
Batch Updates: VDOM updates are batched together, so that multiple changes can be applied to the real DOM in a single operation. This further reduces the number of times the real DOM needs to be updated.
Selective Updates: VDOM updates are only applied to the parts of the real DOM that have actually changed. This is in contrast to direct DOM updates, which can re-render entire sections of the DOM even if they haven't changed.
No Reflow or Repaint: Updating the VDOM does not trigger reflow or repaint. This means that the browser does not need to recalculate the layout of the page or redraw the pixels on the screen. This can save a significant amount of time, especially for complex UIs.
Overall, the VDOM is a powerful tool that can significantly improve the performance of web applications. By using the VDOM, developers can create more responsive and performant UIs that provide a better user experience.
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