title: offset for $location.hash and $anchorScroll()
body: <p>I have anchor scrolling according to an <code>id</code> - as this  - </p>
  
  <pre><code>function ($scope, $location, $anchorScroll) {
        $scope.gotoBottom = function() {
          // set the location.hash to the id of
          // the element you wish to scroll to.
          $location.hash('bottom');
  
          // call $anchorScroll()
          $anchorScroll();
        };
  </code></pre>
  
  <p><a href="https://docs.angularjs.org/api/ng/service/$anchorScroll" rel="nofollow noreferrer">(taken from angularjs.org)</a></p>
  
  <p>I have to set an offset for this <code>$location.hash('bottom')</code> due to a fixed header (common problem <a href="https://stackoverflow.com/questions/10732690/offsetting-an-html-anchor-to-adjust-for-fixed-header">offsetting an html anchor to adjust for fixed header</a> )  .</p>
  
  <p>How to get that offset ? </p>