title: order by combination of two fields in angular
body: <p>I know that it is possible to sort a table in angular with two column separately, i.e. first sort by name then sort by family.</p>
  
  <p><a href="https://plnkr.co/edit/bJIIlmGLyGWsxD5AQti0" rel="nofollow">https://plnkr.co/edit/bJIIlmGLyGWsxD5AQti0</a></p>
  
  <pre><code>var friends = [
    {name: 'a',   family: 'z',  age: 10},
    {name: 'z',   family: 'b',  age: 19},
    {name: 'c',   family: 'z',  age: 21},
    {name: 'z',   family: 'd',  age: 35},
    {name: 'z',  family: 'e',  age: 29}
  ];
  
  $scope.propertyName = 'age';
  $scope.reverse = true;
  $scope.friends = orderBy(friends, $scope.propertyName, $scope.reverse);
  
  $scope.sortBy = function(propertyName) {
    $scope.reverse = (propertyName !== null &amp;&amp; $scope.propertyName === propertyName)
        ? !$scope.reverse : false;
    $scope.propertyName = propertyName;
    $scope.friends = orderBy(friends, ['name','family'], $scope.reverse);
  };
  }]);
  })(window.angular);
  </code></pre>
  
  <p>I wonder if it is possible to sort them by combining the two fields, e.g order by "name" and "family" alphabetically, so it is appearing as "a,b,c,d,e"?</p>