Query user settings and users in mongodb

query_users.js

var uids = [];
db.objects.find({_key: /^user:\d+:settings/, showemail: 1}).forEach(function(obj) {
	uids.push(obj._key.split(':')[1]);
});

var userKeys = uids.map(function (uid) {
	return 'user:' + uid;
});
print(uids);
db.objects.find({_key: {$in: userKeys}}).forEach(function (userObj) {
	print(userObj.username, userObj.email);
});