import firebase from 'firebase';

const config = {
  apiKey: 'API_KEY',
  authDomain: '****',
  databaseURL: '****',
  storageBucket: '****'
};

firebase.initializeApp(config);


// 中略


const loginWithFb = () => {
  return Facebook.logInWithReadPermissionsAsync('APP_ID', {
    permissions: ['public_profile']
  });
};

// ログインボタンのonPressにbind
async onPress() {
  const { type, token } = await loginWithFb();

  if (type === 'success') {
    const credential = firebase.auth.FacebookAuthProvider.credential(token);

    firebase.auth().signInWithCredential(credential).catch((error) => {
      console.log(error);
    });
  }
}

componentDidMount() {
  const auth = firebase.auth.FacebookAuthProvider;
  console.log(auth);
  // undefined
}

// ちゃんと保存される
firebase.database().ref('users/' + 1).set({
  name: 'hoge'
});

// firebase_をチェーンに追加
const credential = firebase.firebase_.auth.FacebookAuthProvider.credential(token);

firebase.auth().signInWithCredential(credential)
firebase.auth().signOut();