title: Firestore read counts of documents size
body: <p>I'm trying to get the amount of documents in a specific collection as the following :</p>
  <pre><code>const userCol = db.collection('users').get().then(queryResult =&gt; {
     if (queryResult.exists)
         console.log(queryResult.size); // amount of documents
  });
  </code></pre>
  <p>So as I use <code>.get()</code> to read the documents that means that I get <code>x</code> <strong>reads</strong> of the amount of documents exists?
  If that's true then is there a way to just get the amount of documents without having to read every each one of them?</p>