Encontrei a resposta, pois está chamando o URI do MongoDBhttp://docs.mongodb.org /manual/reference/connection-string/
Deve ser algo como:
var client = monq('mongodb://server0:port0,server1:port1,server2:port2/[dbname]?replicaSet=[replicaSet Name]
var client = monq('mongodb://server0:port0,server1:port1,server2:port2/[dbname]?replicaSet=[replicaSet Name]
