Virtual DOM: The Power of React

The real DOM (browser DOM) is the actual DOM tree that the browser renders and displays to the user. This means any changes made to the real DOM are immediately reflected on the user's screen, but direct manipulation can be inefficient for complex or frequent updates due to the performance cost of re-rendering the UI. In contrast, the virtual DOM is a lightweight, in-memory representation of the real DOM used by libraries like React to optimize updates. By handling updates in this way, React minimizes the performance impact on the browser and ensures a smoother user experience.

Real vs. virtual DOM

Understanding the difference between the real DOM and the virtual DOM is essential to grasp how React optimizes UI updates. In the following example, we’ll explore how React efficiently updates the UI by using the virtual DOM to minimize changes to the real DOM.

Step-by-step explanation

We have a simple React application that initially renders two header elements displaying Hello and React. We want to update the UI by adding a third header element displaying Element. The goal is to understand how React handles this update efficiently using the virtual DOM.

Step 1: Initial real DOM

Examine the starting point of our application by viewing the initial HTML structure rendered in the browser. In this step, the initial real DOM rendered by the browser is created.