title: firestore not updating results
body: <p>I am working with firestore in NodeJS, and wrote the function below, this function receives the results array as a parameter, which contains the firestore doc id that needs to be updated.</p>
  <p>So, for each document, i am calling the set method to add the fileName field to this document. But for some reason, the result only updated when i have a single id in this results array.</p>
  <p>Can someone help me?</p>
  <pre><code>async function update(results, fileName) {
      
          results.forEach(data =&gt; {
      
            let id = firestore.collection('My_collection').doc(data.DOC_ID)
      
            id.set(
              { filename: fileName}, {merge:true}
            )
          })
      }  
  </code></pre>