diff --git a/src/lib/services/tag-service.ts b/src/lib/services/tag-service.ts
index 1bdcc58bd9..254f1772ed 100644
--- a/src/lib/services/tag-service.ts
+++ b/src/lib/services/tag-service.ts
@@ -22,7 +22,7 @@ export default class TagService {
         return this.tagStore.getAll();
     }
 
-    async getTagsByType(type): Promise<ITag[]> {
+    async getTagsByType(type: string): Promise<ITag[]> {
         return this.tagStore.getTagsByType(type);
     }