I did a little experimenting to see if I could keep the database name as part of the url. I prefer the promise syntax but it should still work for the callback syntax. Notice below that client.db() is called without passing any parameters.
MongoClient.connect(
'mongodb://localhost:27017/mytestingdb',
{ useNewUrlParser: true}
)
.then(client => {
// The database name is part of the url. client.db() seems
// to know that and works even without a parameter that
// relays the db name.
let db = client.db();
console.log('the current database is: ' + db.s.databaseName);
// client.close() if you want to
})
.catch(err => console.log(err));
My package.json lists monbodb ^3.2.5.
The 'useNewUrlParser' option is not required if you're willing to deal with a deprecation warning. But it is wise to use at this point until version 4 comes out where presumably the new driver will be the default and you won't need the option anymore.