使用angularjs对表列进行自定义排序和排序

尝试对记录优先级列进行排序时，必须根据H-M-L-NO GO和viceversa进行排序。尝试使用，但无法对优先级列执行排序

$scope.filterPriority = function () {
        if(toggled) {
            $scope.peoples.sort(function (a, b) {
                return (priorityArray[a.priority] || Infinity ) - (priorityArray[b.priority] || Infinity);
            });
            $scope.sortBy = 'priority';
            $scope.sortDescending = !$scope.sortDescending;
        } else {
            $scope.peoples.sort(function (a, b) {
                return (priorityArray[b.priority] || Infinity ) - (priorityArray[a.priority] || Infinity);
            });
            $scope.sortBy = 'priority';
            $scope.sortDescending = !$scope.sortDescending;
        }   
        toggled = !toggled;
    };
    /* sorting for remaining columns */
    $scope.sortBy = 'name';
    $scope.sortDescending = false;

    $scope.sort = function(column) {
        if ($scope.sortBy === column) {
            $scope.sortDescending = !$scope.sortDescending;
        } else {
            $scope.sortBy = column;
            $scope.sortDescending = false;
        }
    }

我在plunker url中的方法是