title: How would you get a document field?
body: <p>Firestore db</p>
  
  <pre><code>users
    vaffle
      alias: "Vaffle"
      gemcount: 10
  </code></pre>
  
  <p>How can I access a document field? 
  What I've tried: </p>
  
  <pre><code>let ref = db.collection("users").doc("vaffle")
  this.alias = ref.data().alias
  </code></pre>