prevent sending search GET parameter if undefined in my watch history

client/src/app/shared/shared-main/users/user-history.service.ts

@@ -23,7 +23,8 @@ export class UserHistoryService {
 
     let params = new HttpParams()
     params = this.restService.addRestGetParams(params, pagination)
-    params = params.append('search', search)
+
+    if (search) params = params.append('search', search)
 
     return this.authHttp
                .get<ResultList<Video>>(UserHistoryService.BASE_USER_VIDEOS_HISTORY_URL, { params })