React et al use a virtual DOM, not shadow DOM (unless you specifically render it to shadow DOM). They are a better* way to manipulate DOM in that you no longer

React et al use a virtual DOM, not shadow DOM (unless you specifically render it to shadow DOM). They are a better* way to manipulate DOM in that you no longer need to manipulate the DOM, you just build a function that returns what the DOM should look like and it figures out what transforms need to happen. *They’re pitched as a better way, and I think it’s better, but people can reasonably disagree