title: How to delete a field in a Firestore Document?
body: <p>How to delete a Document Field in Cloud Firestore? ... I'm using the code below but I can not.</p>
  <pre><code>this.db.doc(`ProfileUser/${userId}/followersCount/FollowersCount`).update({ 
  [currentUserId]: firebase.firestore.FieldValue.delete()})
  </code></pre>
  <p>Is it possible, and if so, how?</p>