[update]

src/app/core/base/base-list.ts

@@ -74,4 +74,8 @@ export class BaseList {
         )
     }
 
+    getIndex(i){
+        return this.paginator.pageIndex * this.paginator.pageSize + i + 1
+    }
+
 }

src/app/core/service/common/promotion.service.ts

@@ -10,7 +10,7 @@ export class PromotionService extends BaseService{
     constructor(
         public http: HttpClient
     ) {
-        super('/common/promotionwwwwwwwwwwww', http)
+        super('/common/promotion', http)
     }
 
 }