Question

我正在使用FacebookAuthProvider by firebase从我的平台登录用户。

我正在firestore的expo中使用react native，在我尝试添加一些检查以将用户登录后重定向到正确的屏幕之前，它一直运行良好。登录后，有两个不同的角色（管理员和用户）必须分开。

if (/* user is administrator */) {
  this.props.navigation.navigate('Admin');
} else {
  this.props.navigation.navigate('Main');
}

将此方法添加到按角色分开的用户之后，出现此错误：

反应本机TypeError：无法读取未定义的属性“导航”

稍后，我将添加更多详细信息（日志文件等，一旦我学会了如何从本地计算机上对它们进行grep ）。

为了更好地理解，我将整个代码放在这里（抱歉，缩进会降低可读性）：

const auth = firebase.auth();
const firebaseUser = '';
const usersRef = firebase.firestore().collection('users');

async handleFacebookButton() {

const { type, token,  } = await Facebook.logInWithReadPermissionsAsync(FACEBOOK_APP_ID, {
  permissions: ['public_profile', 'email']
});
if (type === 'success') {
  //Firebase credential is created with the Facebook access token.
  const credential = firebase.auth.FacebookAuthProvider.credential(token);
  auth.signInAndRetrieveDataWithCredential(credential)
  .then(function(userCredential) {
    newUserCheck = userCredential.additionalUserInfo.isNewUser;
    console.log('newUserCheck = ', newUserCheck)
  });
  this.setState({loggedIn: "You are signed in"})
  this.setState({signedIn: true})
  console.log('you are signed in');


firebase.auth().onAuthStateChanged(function(user) {
if (user) {

  firebaseUser = {name: user.displayName, uid: user.uid, email: user.email}
  console.log(firebaseUser.name, ' and ',  firebaseUser.uid);

    var existingRef = usersRef.doc(firebaseUser.uid);
    existingRef.get().then(function(documentSnapshot) {
      // check if user is registered
        if(documentSnapshot) {
          data = documentSnapshot.data();
          console.log('existing user exists!!');
            // check if user is an administrator
            if (data.administrator == true) {
                console.log('existing administrator exists!!');

                this.props.navigation.navigate('Admin');
              } else { this.props.navigation.navigate('Main');
                }
        }
    });

    (error => {   
      console.log('user not accessed: ', error);
    });

    //User is not yet in firebase database and needs to be saved
    // double check that user is a new user
    if (newUserCheck == true) {
    this.ref
          .doc(uid)
          .set({
            id: firebaseUser.uid,
            username: firebaseUser.name,
            email: firebaseUser.email,
          })
    this.props.navigation.navigate('ChooseRoute')
  }
}
})
}
  // If login type is not success:
  (error => {   
    this.setState({loggedIn: "Login failed: log in again"})
    this.setState({ errorMessage: error.message });

    });
}

Answer 1

我修好了！！ 3天后-这是一个有约束力的问题-经过几次失败的尝试，找出了要绑定的函数的正确部分，我将'auth（）。onAuthStateChanged和'documentSnapshot'都转换为粗箭头函数，并且错误消失了!!感谢天才ES6 ...！希望这可以帮助其他人...

反应原生TypeError：无法读取未定义的属性“导航”

1 个答案: