当我运行 nodemon file.js 时，它显示此内容（cmd）：

(node:23816) DeprecationWarning: current URL string parser is deprecated, and will be removed in a future version. To use the new parser, pass option { useNewUrlParser: true } to MongoClient.connect.
(node:23816) DeprecationWarning: current Server Discovery and Monitoring engine is deprecated, and will be removed in a future version. To use the new Server Discover and Monitoring engine, pass option { useUnifiedTopology: true } to the MongoClient constructor.

And then when i POST in Postman show this (cmd) : 
events.js:287
      throw er; // Unhandled 'error' event
      ^

ReferenceError: response is not defined
    at D:\Desktop\swag-shop-api\server.js:21:7
    at D:\Desktop\swag-shop-api\node_modules\mongoose\lib\model.js:4889:16
    at D:\Desktop\swag-shop-api\node_modules\mongoose\lib\helpers\promiseOrCallback.js:24:16
    at D:\Desktop\swag-shop-api\node_modules\mongoose\lib\model.js:4912:21
    at model.<anonymous> (D:\Desktop\swag-shop-api\node_modules\mongoose\lib\model.js:493:7)
    at D:\Desktop\swag-shop-api\node_modules\kareem\index.js:315:21
    at next (D:\Desktop\swag-shop-api\node_modules\kareem\index.js:209:27)
    at D:\Desktop\swag-shop-api\node_modules\kareem\index.js:182:9
    at D:\Desktop\swag-shop-api\node_modules\kareem\index.js:507:38
    at processTicksAndRejections (internal/process/task_queues.js:79:11)
Emitted 'error' event on Function instance at:
    at D:\Desktop\swag-shop-api\node_modules\mongoose\lib\model.js:4891:13
    at D:\Desktop\swag-shop-api\node_modules\mongoose\lib\helpers\promiseOrCallback.js:24:16
    [... lines matching original stack trace ...]
    at processTicksAndRejections (internal/process/task_queues.js:79:11)
[nodemon] app crashed - waiting for file changes before starting...

但是当我执行 db.products.find({}) 时，它显示我从 postman 发布的所有信息

请问有人可以帮帮我吗...

server.js 文件：