Use type parameter with sets

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

@@ -37,9 +37,9 @@ export class SearchComponent implements OnInit, OnDestroy {
   gitFilesAggregation?: IGitFilesAggregation;
 
   private filterSelectionSubscription: Subscription = new Subscription();
-  private selectedRepositories = new Set();
-  private selectedUniversities = new Set();
-  private selectedFileFormats = new Set();
+  private selectedRepositories = new Set<string>();
+  private selectedUniversities = new Set<string>();
+  private selectedFileFormats = new Set<string>();
 
   public paramGroup: QueryParamGroup;
   private componentDestroyed$ = new Subject<void>();