title: How to get just the last added doc from a whole collection. OnSnapshot
body: <p>Im trying to get just de last document added in a specific collection. Reading the docs i got the following code:</p>
  
  <pre><code>db.collection("Orders")
  .onSnapshot(function(snapshot) {
      snapshot.docChanges.forEach(function(change) {
          if (change.type === "added") {
              console.log("New order: ", change.doc.data());
          }
          if (change.type === "modified") {
              console.log("Modified order: ", change.doc.data());
          }
          if (change.type === "removed") {
              console.log("Removed order: ", change.doc.data());
          }
      });
  });
  </code></pre>
  
  <p>But its bring more than one doc. bring all because its read like all are new.
  To make context, its a orders db, so i need the app to be listen for the last order added, not all. 
  I'll really appreciate any help!
  Thansk!</p>