diff --git a/lib/extend/helper.ts b/lib/extend/helper.ts
index 37ddb5ae0e..6bfe45be4d 100644
--- a/lib/extend/helper.ts
+++ b/lib/extend/helper.ts
@@ -37,7 +37,7 @@ interface HexoContext extends Hexo {
 }
 
 interface StoreFunction {
-  (this: HexoContext, ...args: any[]): string;
+  (this: HexoContext, ...args: any[]): any;
 }
 
 interface Store {