The above code block represents a simple DOM object. This object model allows scripts to dynamically access and update content, structure, and style of a document. However, direct DOM manipulation is slow and performance-costly, especially for complex modern websites. This is where the concept of Virtual DOM comes into play.
What is the use of Virtual DOM?
The Virtual DOM is a concept that was introduced to solve the same problem of slow DOM manipulation. It provides a way to track changes in the state of a web application without directly changing the Real DOM. This is done by creating a virtual representation of the UI, which is kept in memory and synced with the Real DOM through a process called reconciliation.
The above code block represents a simple Virtual DOM object. The Virtual DOM object is a lightweight copy of the Real DOM object. It has the same properties and methods but does not have the power to directly change what's on the screen.
What is the difference between Real DOM and Virtual DOM?
On the other hand, the Virtual DOM is a concept introduced by libraries like React to deal with this slowness. It is a lightweight copy of the Real DOM in memory. When a state change occurs in a component, a new Virtual DOM tree is created and compared with the old one. Only the changed objects are updated on the Real DOM, which makes the Virtual DOM faster.
In the above example, when the button is clicked, the state of the component changes. React creates a new Virtual DOM tree and compares it with the old one. Only the paragraph element with the counter is updated on the Real DOM, not the entire component.
Why is Virtual DOM faster?
The Virtual DOM is faster because it minimizes the number of times the Real DOM needs to be updated. Direct manipulation of the Real DOM is slow because it triggers reflows and repaints. However, the Virtual DOM works by determining the minimal number of operations needed to update the Real DOM to match the current state of the application, which leads to better performance and less memory usage.