The native DOM doesn’t have an idea of “data flow”, it’s just a big tree that you can modify in whatever way you see fit through its imperative API. For example you could add an event handler to a child node which directly modifies one of its ancestor nodes. With React, your “nodes” in the tree are functions. The child node has no idea about what its ancestors are, it only knows what it is passed as arguments (i.e. “props”). The only way implement a similar thing would be to raise the state/event handling code to the ancestor node, and passing relevant information down as props, thus giving the unidirectional data flow. Of course, if you really needed to, you could drop back down to the native DOM API, with React’s useRef and useEffect hooks, but the default behavior is this unidirectional data flow through function composition.