ThingList trackBy

src/main/angular/src/app/Thing/thing-list/thing-list.component.html

@@ -1,5 +1,5 @@
 <div class="tileContainer">
 
-  <app-thing-tile [now]="now" [thing]="thing" *ngFor="let thing of sorted()"></app-thing-tile>
+  <app-thing-tile [now]="now" [thing]="thing" *ngFor="let thing of sorted(); trackBy: Thing.trackBy"></app-thing-tile>
 
 </div>

src/main/angular/src/app/Thing/thing-list/thing-list.component.ts

@@ -16,6 +16,8 @@ import {Thing} from '../Thing';
 })
 export class ThingListComponent implements OnInit, OnDestroy {
 
+  protected readonly Thing = Thing;
+
   private readonly subs: Subscription[] = [];
 
   protected now: Date = new Date();