Refactoring day1

node_modules/mongoose/lib/helpers/query/castUpdate.js

@@ -105,14 +105,6 @@ module.exports = function castUpdate(schema, obj, options, context, filter) {
     }
   }
 
-  if (Object.keys(ret).length === 0 &&
-      options.upsert &&
-      Object.keys(filter).length > 0) {
-    // Trick the driver into allowing empty upserts to work around
-    // https://github.com/mongodb/node-mongodb-native/pull/2490
-    return { $setOnInsert: filter };
-  }
-
   return ret;
 };