我遇到了一个问题，auth.currentUser.uid最初= null，并且uid仅在几秒钟后加载，但是站点有时间陷入错误，我发现如果您将常量等同于auth.currentUser.uid，那么它将被更新并工作，但问题是userUID仅在if语句中更改，我需要全局更改它

if (auth.currentUser != null) {
    let userUID = (auth.currentUser.uid);
  };


  console.log(userUID);


  useEffect(() => {

    const q = query(collection(db, "customers", auth.currentUser.uid, "subscriptions"));

    onSnapshot(q, (querySnapshot) => {
      querySnapshot.forEach(async (subscription) => {
          setSubscription({
            role: subscription.data().role,
            current_period_start:
              subscription.data().current_period_start.seconds,
            current_period_end: subscription.data().current_period_end.seconds,
          });
        });
      });
    }, [auth.currentUser.uid]);