- connecting: Indicates Mongoose is attempting to connect to MongoDB.
- connected: Indicates successful connection to MongoDB.
- open: Indicates the connection to MongoDB is open and ready to use.
- disconnected: Indicates the connection to MongoDB is lost.
- close: Indicates the connection to MongoDB is closed.
- reconnected: Indicates successful reconnection to MongoDB after disconnection.
- error: Indicates an error occurred during the connection process.
- fullsetup: Indicates all servers in the MongoDB replica set have been successfully contacted and set up.
- all: Indicates all connection events have been emitted.