title: Get weekday (day of week) with ngb datepicker
body: <p>I am using Bootstrap 4 and Angular 2 and ngb.</p>
  
  <p>With the <a href="https://ng-bootstrap.github.io/#/components/datepicker/api" rel="nofollow noreferrer">datepicker</a> from ngb the user selects a date and i can easily get the day, the month and the year, becaue of the date structure:</p>
  
  <pre><code>Model: {
  "year": 2017,
  "month": 10,
  "day": 25
  }
  </code></pre>
  
  <p>But i also need the day of the week. I coundn't find any information about this in the api. Is it possible or what would be a good way to get the weekday?</p>
  
  <p>What i did so far is:</p>
  
  <pre><code>    this.date = this.datepicked.year + "-" + this.datepicked.month + "-" + this.datepicked.day;
      let date = new Date(this.date);
      this.day_of_week = date.getDay();
  </code></pre>
  
  <p>Is there a more elegant solution (supported by ngb)?</p>
  
  <p>Greetings,
  Steffi</p>