title: Async arrow function expected no return value
body: <p>I'm building an application with Firebase oAuth. I followed all the instructions, but my code is returning an error saying that 'asyn arrow function expected no return value'.</p>
  <p>I saw that there are multiple posts with the same title, but have not found an answer.</p>
  <p><a href="https://i.stack.imgur.com/uWbro.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/uWbro.png" alt="enter image description here" /></a></p>
  <pre><code>import firebase from 'firebase/app';
  import 'firebase/firestore';
  import 'firebase/auth';
  
  export const auth = firebase.auth();
  export const firestore = firebase.firestore();
  
  const config = {
    apiKey: 'XXXXXXXXX',
    authDomain: 'XXXXXXXXX',
    projectId: 'XXXXXXXXX',
    storageBucket: 'XXXXXXXXX',
    messagingSenderId: 'XXXXXXXXX',
    appId: 'XXXXXXXXX',
  };
  firebase.initializeApp(config);
  
  export const createUserProfileDocument = async (userAuth, additionalData) =&gt; {
    if (!userAuth) return;
  
    const userRef = firestore.doc(`users/${userAuth.uid}`);
  
    const snapShot = await userRef.get();
  
    if (!snapShot.exists) {
      const { displayName, email } = userAuth;
      const createdAt = new Date();
      try {
        await userRef.set({
          displayName,
          email,
          createdAt,
          ...additionalData,
        });
      } catch (error) {
        console.log('error creating user', error.message);
      }
    }
  
    return userRef;
  };
  
  
  const provider = new firebase.auth.GoogleAuthProvider();
  provider.setCustomParameters({ prompt: 'select_account' });
  export const signInWithGoogle = () =&gt; auth.signInWithPopup(provider);
  
  export default firebase;
  </code></pre>