mLab-recommended Mongoose driver options for production applications. Note: this example is for the Mongoose 4.3.x driver. For the most up-to-date information on driver settings, please visit the Node.js driver documentation: https://mongodb.github.io/node-mongodb-native/

mongoose-connection-settings-example.js

// Recommended driver settings for the Mongoose 4.3.x driver.

var mongoose = require('mongoose');    

var uri = 'mongodb://<dbuser>:<dbpassword>@<host1>:<port1>,<host2>:<port2>/<dbname>?replicaSet=<replicaSetName>';

var options = {
  "server" : {
    "socketOptions" : {
      "keepAlive" : 300000,
      "connectTimeoutMS" : 30000
    }
  },
  "replset" : {
    "socketOptions" : {
      "keepAlive" : 300000,
      "connectTimeoutMS" : 30000
    }
  }
}

mongoose.connect(uri, options);

var db = mongoose.connection;

db.on('error', console.error.bind(console, 'connection error:'));