object array operation done

index.js

@@ -112,7 +112,7 @@ const app=createApp({
         console.log("------  _books : "+_books);
         // console.log("------this.books : "+this.books);
         try{
-          for(item in res){
+          for(item of res){
             _books.push(item);
           }
           // _books.concat(res);