从 Firestore 获取文档数据后无法设置 state

Question

I am trying to do a User Profile page and after getting the data from Firestore, I'm unable to set the data into the userProfile state.

  const {userProfile, setUserProfile} = useState(null);

  const getUserProfile = async () => {
    await firestore().collection("Users")
    .doc(user.uid)
    .get()
    .then(documentSnapshot => {
      if (documentSnapshot.exists) {
        console.log('User data from Firestore: ', documentSnapshot.data());
        setUserProfile(documentSnapshot.data());
      }
    });    
  }

  useEffect (() => {
    if (userProfile == null) {
      getUserProfile();
      console.log("User Data in userProfile state: ", userProfile);
    }
  }, [userProfile]) 

I got this error:

The console log shows that the userProfile state is undefined, however, I can retrieve the data from Firestore without any issues as shown in the console log.

Answer 1

const {userProfile, setUserProfile} = useState(null); <----- error is here

  const getUserProfile = async () => {
    await firestore().collection("Users")
    .doc(user.uid)
    .get()
    .then(documentSnapshot => {
      if (documentSnapshot.exists) {
        console.log('User data from Firestore: ', documentSnapshot.data());
        setUserProfile(documentSnapshot.data());
      }
    });    
  }

  useEffect (() => {
    if (userProfile == null) {
      getUserProfile();
      console.log("User Data in userProfile state: ", userProfile);
    }
  }, [userProfile]) 

Instead of of const {userProfile, setUserProfile} = useState(null);

replace it with const [userProfile, setUserProfile] = useState(null);

Because u are using curly brackets in {userProfile,setUserProfile}

u need to replace it with square brackets [userProfile,setUserProfile]