code: function(target, source) {
    var translations = {
      // SSL translation options
      sslCA: 'ca',
      sslCRL: 'crl',
      sslValidate: 'rejectUnauthorized',
      sslKey: 'key',
      sslCert: 'cert',
      sslPass: 'passphrase',
      // SocketTimeout translation options
      socketTimeoutMS: 'socketTimeout',
      connectTimeoutMS: 'connectionTimeout',
      // Replicaset options
      replicaSet: 'setName',
      rs_name: 'setName',
      secondaryAcceptableLatencyMS: 'acceptableLatency',
      connectWithNoPrimary: 'secondaryOnlyConnectionAllowed',
      // Mongos options
      acceptableLatencyMS: 'localThresholdMS'
    };
  
    for (var name in source) {
      if (translations[name]) {
        target[translations[name]] = source[name];
      } else {
        target[name] = source[name];
      }
    }
  
    return target;
  }
docs: Merge options with translation