title: Firestore: What's the pattern for adding new data in Web v9?
body: <p>I have seen in many places that to access nested documents and collections the pattern is something like <code>db.collection(&quot;users&quot;).doc(&quot;frank&quot;).collection(&quot;pets&quot;)</code> etc.</p>
  <p>This makes a lot of sense to me and is easy to understand. The trouble is, my (React) project is set up in the <em>Web version 9</em> way. I've combed the docs over and over and can't see anything that goes beyond referencing X doc in Y collection.</p>
  <p>I need to reference Users &gt; uid &gt; someCollection</p>
  <p>But in the <em>Web Version 9</em> way I can only do: <code>doc(db, &quot;users&quot;, uid)</code></p>
  <p>How do I go deeper?</p>