add ability to sort devices by age (powered-on-hours)

fixes #100

webapp/frontend/src/app/layout/common/dashboard-settings/dashboard-settings.component.html

@@ -18,6 +18,7 @@
                 <mat-select [(ngModel)]="dashboardSort">
                     <mat-option value="status">Status</mat-option>
                     <mat-option value="title">Title</mat-option>
+                    <mat-option value="age">Age</mat-option>
                 </mat-select>
             </mat-form-field>
         </div>

webapp/frontend/src/app/shared/device-sort.pipe.ts

@@ -39,6 +39,13 @@ export class DeviceSortPipe implements PipeTransform {
         }
     }
 
+    ageCompareFn(a: any, b: any) {
+        const left = a.smart?.power_on_hours
+        const right = b.smart?.power_on_hours
+
+        return left - right;
+    }
+
 
   transform(deviceSummaries: Array<unknown>, sortBy = 'status', dashboardDisplay = "name"): Array<unknown> {
     let compareFn = undefined
@@ -49,9 +56,12 @@ export class DeviceSortPipe implements PipeTransform {
         case 'title':
             compareFn = this.titleCompareFn(dashboardDisplay)
             break;
+        case 'age':
+            compareFn = this.ageCompareFn
+            break;
     }
 
-      //failed, unknown/empty, passed
+      // failed, unknown/empty, passed
       deviceSummaries.sort(compareFn);
 
     return deviceSummaries;