What is the Virtual DOM in ReactJS, and how does it improve performance?
Virtual DOM is one of the most powerful features of React JS, let's explore how it works.
The Virtual DOM is a concept that is unique to ReactJS. It is a simplified version of the real Document Object Model (DOM) that is employed in the development of online applications. React uses the Virtual DOM to efficiently update the Real DOM and track changes made to a web page.
To understand the Virtual DOM, it's important to first understand what the DOM is. The DOM is a tree-like structure that represents a web page. It is created by the browser when it loads an HTML page, and it allows JavaScript to interact with and modify the web page in real-time. The DOM is a complex structure, and any changes made to it can be costly in terms of performance.
When a change is made to a web page, the browser must recalculate the layout of the entire page, which can be a slow and expensive process, especially for large and complex web applications. To avoid this problem, React uses a Virtual DOM.
The Virtual DOM is a lightweight representation of the actual DOM. It is a tree-like structure that is similar to the real DOM, but much simpler. When a component in a React application is updated, React creates a new Virtual DOM, which is a copy of the previous Virtual DOM, and it then compares the two to identify the changes that need to be made to the actual DOM.
Here's how it works:
When a component in a React application is updated, React creates a new Virtual DOM that represents the new state of the component.
React then compares the new Virtual DOM with the previous one to identify the changes that need to be made to the actual DOM.
React calculates the minimum number of changes required to update the actual DOM and applies them efficiently.
By using the Virtual DOM, React is able to avoid making costly changes to the actual DOM. Instead, it updates the DOM only where necessary, which makes the process of updating a web page much faster and more efficient.
One of the benefits of the Virtual DOM is that it allows React to batch updates, which can further improve performance. When a change is made to a component in a React application, React updates the Virtual DOM for the entire application, not just for the specific component. This allows React to batch updates and make changes to the actual DOM all at once, rather than making multiple changes over several cycles.
Another benefit of the Virtual DOM is that it allows React to be agnostic to the actual browser implementation of the DOM. This means that React can run on any browser that supports JavaScript, without requiring specific modifications to the browser's implementation of the DOM.
In summary, the Virtual DOM is a powerful concept that allows React to efficiently update the actual DOM by minimizing the number of changes made to it. This leads to faster and more efficient web applications, especially for those that are large and complex. By using the Virtual DOM, React is able to provide an exceptional user experience that is fast, responsive, and scalable.