const URL = "mongodb://user:pass@sec1:27017,sec2:27017/db?replicaSet=rs";
const OPTIONS = {
    "db": {
        "readPreference": "nearest",
        "bufferMaxEntries": 0
    },
    "replSet": {
        "replicaSet": "rs",
        "connectWithNoPrimary": true
    }
};

var MongoClient = require('mongodb').MongoClient;
MongoClient.connect(URL, OPTIONS, function (err, db) {
    if (err) {
        console.log(err);
    } else {
        console.log("connect ok");
    }
});

MongoError: no connection available for operation and number of stored operation > 0
    at Function.MongoError.create (/data/test/node_modules/nimbus_mongo/node_modules/mongodb/node_modules/mongodb-core/lib/error.js:31:11)
    at Store.add (/data/test/node_modules/nimbus_mongo/node_modules/mongodb/lib/topology_base.js:30:32)
    at ReplSet.auth (/data/test/node_modules/nimbus_mongo/node_modules/mongodb/node_modules/mongodb-core/lib/topologies/replset.js:1099:37)
    at ReplSet.auth (/data/test/node_modules/nimbus_mongo/node_modules/mongodb/lib/replset.js:467:23)
    at authenticate (/data/test/node_modules/nimbus_mongo/node_modules/mongodb/lib/db.js:1519:21)
    at Db.authenticate (/data/test/node_modules/nimbus_mongo/node_modules/mongodb/lib/db.js:1557:44)
    at options (/data/test/node_modules/nimbus_mongo/node_modules/mongodb/lib/mongo_client.js:248:23)
    at /data/test/node_modules/nimbus_mongo/node_modules/mongodb/lib/db.js:236:5
    at ReplSet.connect.connectHandler (/data/test/node_modules/nimbus_mongo/node_modules/mongodb/lib/replset.js:339:7)
    at g (events.js:199:16)