title: How to get data for a list of ids in Firestore?
body: <p>I have the following relantionship of <strong>Many to Many</strong> in a Firebase Firestore Database:</p>
  <p><strong>Teacher</strong> (collection)<br>
  <strong>Student</strong> (collection)</p>
  <p>A Teacher can have many students.<br>
  A Student can have many teachers.<br>
  In my database, the <strong>Teacher</strong> (collection) has a property <strong>studentIDs</strong>: [1,2,3 ... 100]</p>
  <p>At this moment I use Array 'in' multiple times to fetch all the students data from a specified Teacher:</p>
  <pre><code>const studentIDs = [1,2,3..10];
  const students = await userRef.where(firebase.firestore.FieldPath.documentId(), 'in', studentIDs).get();
  ....
  </code></pre>
  <p>The issue is that the <strong>'in'</strong> is limitted to max 10 items, so if the Teacher has 100 Students I need to do 10 requests.</p>
  <p>How do you solve this issue? What's the best way to get data in Firestore for a large list of documents IDs ? [1, 2, 3, 4, 5 ... 1000]</p>