title: Update an already existing element in Firebase
body: <p>I have a Node.js and Firebase project.</p>
  <p>How can I update a field in an array which already exists?</p>
  <p>Seems out that Firebase has only two array operations - <code>arrayUnion</code> and <code>arrayRemove</code>.</p>
  <p><a href="https://i.stack.imgur.com/yLoUB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/yLoUB.png" alt="enter image description here" /></a></p>
  <p>Say I have to update currency in BRSR. How do I do that?</p>