title: Format date in Angular based on Timezone
body: <p>I'm receiving dates from my API that are in UTC format.  I need to output the dates using the user's local timezone.  Each user is assigned a timezone that I pull from a different API.</p>
  
  <p>Using the following documentation I was able to make things work for all time zones with a + (i.e. +100, +200, etc.).  However when I have a timezone with a - (i.e. -800).  This does not work.</p>
  
  <p><strong>Works:</strong></p>
  
  <pre><code>{{element.myDate | date:'d-MMM-yyyy HH:mm' : '+800' }}
  </code></pre>
  
  <p>Orginal Value: 7-Jan-2019 00:46</p>
  
  <p>New Value: 7-Jan-2019 16:46</p>
  
  <p><strong>Does NOT Work (timezone is ignored):</strong></p>
  
  <pre><code>{{element.myDate | date:'d-MMM-yyyy HH:mm' : '-800' }}
  </code></pre>
  
  <p>Orginal Value: 7-Jan-2019 00:46</p>
  
  <p>New Value: 7-Jan-2019 00:46</p>
  
  <p><strong>Angular Class used after calling API</strong></p>
  
  <pre><code>export class MyClass {
    constructor(
      public myDate: Date,
      public otherData: string
    ) {}
  }
  </code></pre>