The API documentaiton for the events on the Db object is quite opaque:
http://mongodb.github.io/node-mongodb-native/2.0/api/Db.html#event:authenticated

Most of the events have no description at all, while some have a single sentence that does not clarify much, for example:

Db fullsetup event, emitted when all servers in the topology have been connected to.

What happens if the topology changes? Replica-set configurations can change, to say nothing of elections in replica-sets. Does this event fire again? Elections cause disconnection from the primary after-all.

Db parseError event

What is a parse error? Parsing JSON, BSON or something else? When can it occur?

All of the events could really do with a sentence or two describing their use.