`useSyncExternalStore` Usage example question

Question Link

https://react.dev/reference/react/useSyncExternalStore#subscribing-to-a-browser-api

Summary

Hello!
I have a question about usage of useSyncExternalStore example

in this example, you can check navigator.onLine status using useSyncExternalStore.

Yeah, example works well, but i have one more question.

you can also implement this feature using useEffect
https://codesandbox.io/s/magical-http-qrpjss?file=/src/App.js:24-627

import { useEffect, useState } from "react";

export default function App() {
  const [isOnline, setIsOnline] = useState(navigator.onLine);

  const handleOnline = () => setIsOnline(true);
  const handleOffline = () => setIsOnline(false);

  useEffect(() => {
    window.addEventListener("online", handleOnline);
    window.addEventListener("offline", handleOffline);

    return () => {
      window.removeEventListener("online", handleOnline);
      window.removeEventListener("offline", handleOffline);
    };
  }, []);

  return <h1>{isOnline ? "✅ Online" : "❌ Disconnected"}</h1>;
}

It also works.

if window event can fire some action, we can implement same feature using setState without useSyncExternalStore so i need more explanation that why we use useSyncExternalStore in this situation.

it`s my sheer of curiosity.

can you explain more reason or example about this case?

Thank you!!

Comece pela entrada vinculada da documentação do React sobre useSyncExternalStore, especialmente pelo exemplo “subscribing to a browser API”, e compare-a com a implementação de useEffect na issue. O trabalho estará concluído quando a documentação explicar claramente por que o exemplo usa useSyncExternalStore e quando a alternativa é apropriada.