title: How to convert date and time to different timezones in momentjs
body: <p>In my angular app I have a selectbox, where the user can select to which timezone he/she wants to convert a specific time. Currently I'm using momentjs for date-time manipulations, the problem is I don't know, how to change the date-times's timezone dynamically, as momentjs has only <code>.utc()</code> method.</p>
  
  <p>Till now I used only one timezone, so I've hard-coded the <code>utc()</code> method.</p>
  
  <p>My service:</p>
  
  <pre><code>public convertDate(): void {
      this.date = moment(this.date).utc().format("DD/MM/YYYY - HH:mm");
  }
  </code></pre>
  
  <p>Should be (pseudo code):</p>
  
  <pre><code>public convertDate(selectedTimezone: string): void {
      this.date = moment(this.date).selectedTimezone().format("DD/MM/YYYY - HH:mm");
  }
  </code></pre>