How can I solve this problem with mongoose connection?

Question

This code worked for a while and I don't know what I did but it gives me this error. I saw a some guys said that update the Node, but it doesn't work for me. Mine is latest one.

This is error message

mongodb connection failed 
TypeError:[objectOptions,urlOptions,exports.DEFAULT_OPTIONS].flatMap is not a function

at parseOptions(/root/app/node_modules/mongodb/lib/connection_string.js:258:77) 

at new MongoClient (/root/app/node_modules/mongodb/lib/mongo_client.js:62:63)

at Promise (/root/app/node_modules/mongoose/lib/connection.js:784:16)
at new Promise (<anonymous>)

at NativeConnection.Connection.openUri (/root/app/node_modules/mongoose/lib/connection.js:781:19)

at _mongoose._promiseOrCallback.cb (/root/app/node_modules/mongoose/lib/index.js:342:10)

at Promise (/root/app/node_modules/mongoose/lib/helpers/promiseOrCallback.js:32:5)

at new Promise (<anonymous>)

at promiseOrCallback (/root/app/node_modules/mongoose/lib/helpers/promiseOrCallback.js:31:10)

at Mongoose._promiseOrCallback (/root/app/node_modules/mongoose/lib/index.js:1181:10)

and this is my connection code //mongoDB connection

const connect = () => {
  if(process.env.NODE_ENV !== 'production'){
    mongoose.set('debug', true);
  }
mongoose.connect('mongodb+srv://<name>:<pw>@cluster0.ukhax.mongodb.net/Users?retryWrites=true&w=majority',(error) => {
    if(error){console.log("mongodb connection failed");
    console.log(error);}
    else{console.log("User mongodb connected");}
  });
};

connect();

Answer 1

Mongoose from time to time adds breaking changes. mongoos.connect has become an async method that returns a promise, so you need to change your code from callback based to promise based:

const connect = () => {
  if(process.env.NODE_ENV !== 'production'){
    mongoose.set('debug', true);
  }

mongoose.connect('mongodb+srv://<name>:<pw>@cluster0.ukhax.mongodb.net/Users?retryWrites=true&w=majority')
    .then(() => {
      console.log("User mongodb connected");
      connect()
      })
    .catch(e => console.log(e))

Answer 2

Had the same error. Worked for me after downgrading mongoose to "mongoose": "^6.2.8". Thanks