$scope.sortdata=function(column){
             if($scope.sortcolumn!=column)
         $scope.reversesort=true;
     $scope.sortcolumn = column;
     $scope.reversesort=!$scope.reversesort;
 }
 $scope.getsortclass=function(column){
     if($scope.sortcolumn==column){
         return $scope.reversesort?'arrow-down':'arrow-up'
     }`enter code here`
     return '';
 }