title: How do I find a difference between two moment.unix()
body: <p>I convert a unix timestamp based on a time zone like this:</p>
  
  <pre><code>var event_time = moment.unix(first_start).tz(timezone);
  </code></pre>
  
  <p>Then I need to find out:</p>
  
  <ol>
  <li><p>if event_time is the same day as today (<code>moment()</code>)</p></li>
  <li><p>if the difference between today and event_time is less or equals 30 minutes</p></li>
  <li><p>otherwise return formatted <code>event_time.format('HH:mm'</code>)</p></li>
  </ol>
  
  <p>But turns out that I get alway false doing this</p>
  
  <pre><code>moment.unix(event_time).tz(timezone).isSame(moment())
  </code></pre>