On https://docs.mongodb.com/drivers/node/current/fundamentals/connection/ there's a suggestion to change it to the default starting localhost port, "mongodb://localhost:27107" but this port is actually incorrect. I believe the default is always 27017.

This stumped me for a little bit and it was an error/typo that was actually hard to pickup.

It would probably be really good to fix this for other new starters who are using the Connection Guide in the documentation.