ReferenceError: Can't find variable: document

[DevVibhor]

Hi, I am getting this error after adding this into my App.js
`
import { AppRegistry } from "react-native";
import App from "./App";

AppRegistry.registerComponent("App", () => App);

AppRegistry.runApplication("App", {
rootTag: document.getElementById("root")
});
`

I was following the documentation from https://necolas.github.io/react-native-web/