在我的 React Native 应用中，我有一个自定义登录 Facebook 按钮：

<Button onPress={() => this.handleFacebookLogin()}>
  <Text>Login with Face</Text>
</Button>

以及 handleFacebookLogin 函数：

 handleFacebookLogin () {
     LoginManager.logInWithReadPermissions(['public_profile', 'email', 'user_friends']).then(
       function (result) {
         if (result.isCancelled) {
           console.log('Login cancelled')
         } else {
           console.log('Login success with permissions: ' + result.grantedPermissions.toString())
           AccessToken.getCurrentAccessToken().then(
             (data) => {
               signInFacebookLoginInFirebase(data.accessToken)
               //this.signInFacebookLoginInFirebase(data.accessToken)
             }
           )
         }
       },
       function (error) {
         console.log('Login fail with error: ' + error)
         alert('Error at login, no network ?')
       }
     )
 }

但是我收到此错误：

Possible Unhandled Promise Rejection (id: 20): ReferenceError: signInFacebookLoginInFirebase is not defined TypeError: _this2.signInFacebookLoginInFirebase is not a function

TypeError：_this2.signInFacebookLoginInFirebase 不是函数

以及 signInFacebookLoginInFirebase 方法：

   signInFacebookLoginInFirebase(facebookToken){
     const credential = Fb.firebase.auth.FacebookAuthProvider.credential(facebookToken);
     Fb.firebase
       .auth()
       .signInWithCredential(credential)
       .then(() => alert('Account accepted'))
       .catch((error) => alert('Account disabled'));
   }