According to the documentation useNewUrlParser, useUnifiedTopology, useFindAndModify, and useCreateIndex are no longer supported. Mongoose 6 always behaves as if useNewUrlParser, useUnifiedTopology and useCreateIndex are true, and useFindAndModify is false. So it asks us to remove these options from our code. When trying to connect to the DB, but precisely with useCreateIndex our code will not work.
According to the documentation useNewUrlParser, useUnifiedTopology, useFindAndModify, and useCreateIndex are no longer supported. Mongoose 6 always behaves as if useNewUrlParser, useUnifiedTopology and useCreateIndex are true, and useFindAndModify is false. So it asks us to remove these options from our code. When trying to connect to the DB, but precisely with useCreateIndex our code will not work.