$scope.customOrder = function (item) {
        var empStatus = item.empState;
        switch (empStatus) {
            case 'Working':
                return 1;

            case 'Leave':
                return 2;

            case 'Resigned':
                return 4;

            case 'Someother':
                return 3;
        }
    };

<table class="table">
            <thead class="active">
            <tr>
                <th>
                    <a href="" ng-click="orderByemployeeField=sorterFunc; reverseemployeeSort = !reverseemployeeSort">
                        employee ID <span ng-show="orderByemployeeField == sorterFunc"><span ng-show="!reverseemployeeSort">^</span><span ng-show="reverseemployeeSort">v</span></span>
                    </a>
                </th>
                <th>
                    <a href="" ng-click="orderByemployeeField=customOrder; reverseemployeeSort = !reverseemployeeSort">
                        employee State <span ng-show="orderByemployeeField == 'employeeState'"><span ng-show="!reverseemployeeSort">^</span><span ng-show="reverseemployeeSort">v</span></span>
                    </a>
                </th>
                <th>
                    <a href="" ng-click="orderByemployeeField='daysCount'; reverseemployeeSort = !reverseemployeeSort">
                        Days Count <span ng-show="orderByemployeeField == 'daysCount'"><span ng-show="!reverseemployeeSort">^</span><span ng-show="reverseemployeeSort">v</span></span>
                    </a>
                </th>
            </tr>
            </thead>
            <tbody ng-if="!fromOffice">
            <tr ng-repeat="employee in employees | filter:search  | orderBy: orderByemployeeField:reverseemployeeSort" id="row{{employee.assetId}}" ng-mouseover="showRowTitle($event, employee)"
                ng-click="showemployeesOrAlarmsSiteMap($event,employee.assetId)" style="cursor: pointer" ng-dblclick="employeeInformation(employee)">
                <td><a href="" ui-sref="app.cesemployeedetails({ employeeID:employee.assetId })" style="text-decoration: underline">{{employee.assetId}}</a></td>
                <td>{{employee.employeeState}}</td>
                <td>{{employee.daysCount}}</td>
            </tr>
            </tbody>
            <tbody ng-if="fromOffice">
            <tr ng-repeat="employee in employees | filter:search | orderBy: orderByemployeeField:reverseemployeeSort | orderBy : customOrder"
                ng-if="employee.siteId == selectedSiteId" style="cursor: pointer">
                <td>{{employee.assetId}}}</td>
                <td>{{employee.employeeState}}</td>
                <td>{{employee.daysCount}}</td>
            </tr>
            </tbody>
        </table>

$scope.orderByemployeeField = customOrder