Use type parameter with set

src/main/webapp/app/search/metadata/metadata.component.ts

@@ -12,7 +12,7 @@ export class MetadataComponent {
   @Input() parameter!: string;
 
   testString = '';
-  selectedItems = new Set();
+  selectedItems = new Set<string>();
 
   constructor(public messageService: MetadataMessageService) {}
 
@@ -33,6 +33,6 @@ export class MetadataComponent {
     for (const selectedItem of this.selectedItems) {
       this.messageService.updateFilterSelection(this.parameter, selectedItem);
     }
-    this.selectedItems = new Set();
+    this.selectedItems = new Set<string>();
   }
 }