update

app/middleware/order-num.js

@@ -26,7 +26,7 @@ module.exports = options => {
         for (let d of data) {
           d = await getOrderNum(ctx, d);
         }
-      } else {
+      } else if (data) {
         data = await getOrderNum(ctx, data);
       }
       ctx.body.data = data;