Explain advantages of Virtual DOM?

Q: Explain advantages of Virtual DOM?

**Optimised Re-rendering:** The Virtual DOM allows React to optimise how it updates the real DOM. React strategically determines the most efficient way to apply changes, including avoiding unnecessary DOM manipulations. **Reduced Browser Repaints:** By updating the real DOM in a controlled manner, React minimises browser repaints and reflows, which can be resource-intensive and slow down the user interface. **Performance Gains:** The Virtual DOM's approach to updating the UI helps reduce the performance bottlenecks associated with direct manipulation of the DOM. This leads to smoother user experiences, especially in complex applications where there are frequent updates.

Difficulty: 5/10

performance, reconciliation, abstraction

1
Optimised Re-rendering: The Virtual DOM allows React to optimise how it updates the real DOM. React strategically determines the most efficient way to apply changes, including avoiding unnecessary DOM manipulations.
2
Reduced Browser Repaints: By updating the real DOM in a controlled manner, React minimises browser repaints and reflows, which can be resource-intensive and slow down the user interface.
3
Performance Gains: The Virtual DOM's approach to updating the UI helps reduce the performance bottlenecks associated with direct manipulation of the DOM. This leads to smoother user experiences, especially in complex applications where there are frequent updates.

Scenario Questions

0-2 years experience

1If you need to update a list of items in a React component, how does the Virtual DOM help you avoid manually manipulating the DOM?
2What happens under the hood when you call setState in a component that uses the Virtual DOM?
3Suppose you have a button that toggles a class on an element; why would you let React handle the update instead of using document.querySelector and classList?

Follow-up Questions

Can you give an example of a situation where the Virtual DOM diff might still cause a noticeable lag?
How does React decide when to skip the diff entirely?
What impact does the size of the component tree have on Virtual DOM performance?