The reason for the virtual DOM: in react, the entire world is a function that gets rerun on every render. The whole point is to be able to define some state and

The reason for the virtual DOM: in react, the entire world is a function that gets rerun on every render. The whole point is to be able to define some state and then render the whole world in accordance with that new state. When react was conceived, Dom updates were very slow and could bottleneck the application. Knowing that your entire UI is running inside a function that gets re-executed with every render, gives a tremendous amount of safety and predictability to your application and makes testing a breeze. But you can't actually rerender the whole world every time because performance, so instead React relies on a JavaScript object to hold a representation of the UI, and then surgically updates only the pieces that need updating. This was React's big thing. The reason people want to move away from virtual dom is because browsers have gotten faster and now the Dom updates aren't the biggest source of overhead.