title: React MomentJS get duration from start time and end time
body: <p>I've been trying to figure what's the best way to calculate duration of an event.</p>
  
  <p>I have a Collection with the following fields:</p>
  
  <pre><code>type Event {
   ..
   startsAt: "HH:mm MM-DD-YYYY"
   endsAt: "HH:mm MM-DD-YYYY"
   ..
  }
  </code></pre>
  
  <p>Ideally I would like to save </p>
  
  <pre><code>duration: String!
  </code></pre>
  
  <p>in my GraphQL mutation, when creating an Event.</p>
  
  <p>Could someone advise me how could this be done?</p>
  
  <p><strong>My stack:</strong> </p>
  
  <ul>
  <li>React </li>
  <li>Apollo</li>
  <li>GraphQL</li>
  </ul>
  
  <p><strong>I have the following installed:</strong><br>
   ..  </p>
  
  <ul>
  <li>MomentJS</li>
  <li>React Moment</li>
  </ul>
  
  <p>..</p>
  
  <p>Many thanks in advance</p>