title: FieldValue.delete() can only appear at the top level of your update data - Firestore
body: <p>This is my database:</p>
  
  <p><a href="https://i.stack.imgur.com/UQ5N9.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/UQ5N9.png" alt="enter image description here"></a></p>
  
  <p>How can I delete key "2" in lotteryIDs under the map private? I tried this:</p>
  
  <pre><code>db.collection("users").document(currentUser.uid).updateData([
  "private": ["lotteryIDs" : ["2" : FieldValue.delete()]]
  ])
  </code></pre>
  
  <p>And now I got the error as described in the title. Using:</p>
  
  <pre><code>"private/lotteryIDs/\(id)": FieldValue.delete
  </code></pre>
  
  <p>obviously did not work out well. I could not find it in the <a href="https://cloud.google.com/firestore/docs/manage-data/delete-data" rel="nofollow noreferrer">docs</a> where they only explain how to delete top-level fields, not fields within objects.</p>