Javascript MySQL What does insert return

In my script I execute my inserts like this

sql ="INSERT INTO table (fields) VALUES ("values")
connection.query(sql, function(error, rows, fields)

rows.InsertId seems to contain one of the inserted rows but I don't know if its the first or the last row inserted

this is the mysql node.js implementation I'm using, the documentation only says this.

https://github.com/felixge/node-mysql