Adding item lines to Item Sublist

/**
         * @description This function is to add new item lines to a item sublist
         * @param arr
         * @param transferRec
         * @return transferID
         */function addItemLines(arr,transferRec)
       {
           for( let i =0; i<arr.length; i++)
           {
               //set value to item line item field
               transferRec.selectNewLine({ sublistId : 'item' ,line:i });
               transferRec.setCurrentSublistValue({
                   sublistId:'item',
                   fieldId:'item',
                   line: i,
                   value: arr[i]
               });
               transferRec.commitLine({sublistId:'item'});
           }
           let transferID = transferRec.save();
           return transferID;
       }