title: How to sum time string in an array?
body: <p>Suppose, I've an array of different time string. </p>
  
  <pre><code>let a: any = ["7:20", "5:50", "6:30"];
  </code></pre>
  
  <p>I want to sum up these HH:mm time strings. I am building up an app using Ionic 4 (Angular). I have already used momentjs for these. But, unfortunately yet I can't find any solution. </p>
  
  <p><em>Update:</em>
  <strong>Expected Result:</strong>
  7:20 + 5:50 + 6:30 = 19:40 (HH:33)</p>