Anda kehilangan teamMembers
level objek Anda, jadi kode Anda perlu diubah menjadi seperti ini:
Team.findOne({'teamMembers.username': 'Bioshox'}, {'teamMembers.$': 1},
function (err, team) {
if (team) {
console.log(team.teamMembers[0].email);
}
}
);