How to use the mongodb-core.Server function in mongodb-core

}
          // Execute command
          _server.command(_ns, _command, function(err, r) {
            // Destroy the connection
            _server.destroy();
            // Return an error
            if (err && options.ignoreError) return resolve({ ok: 1 });
            if (err) return reject(err);
            // Return the ismaster command
            resolve(r.result);
          });
        });
      };

      // Create an instance
      var s = new CoreServer(opt);

      s.on('error', function(err) {
        if (options.ignoreError) return resolve({ ok: 1 });
        if (options.reExecuteOnError) {
          options.reExecuteOnError = false;
          return executeCommand(ns, command, credentials, s);
        }

        reject(err);
      });

      s.on('close', function(err) {
        if (options.ignoreError) return resolve({ ok: 1 });
        if (options.reExecuteOnError) {
          options.reExecuteOnError = false;
          return executeCommand(ns, command, credentials, s);

// Execute command
          _server.command(_ns, _command, function(err, r) {
            // Destroy the connection
            _server.destroy();
            // Return an error
            if (err && options.ignoreError) return resolve({ ok: 1 });
            if (err) return reject(err);
            // Return the ismaster command
            resolve(r.result);
          });
        });
      };

      // Create an instance
      var s = new CoreServer(opt);

      s.on('error', function(err) {
        if (options.ignoreError) return resolve({ ok: 1 });
        if (options.reExecuteOnError) {
          options.reExecuteOnError = false;
          return executeCommand(ns, command, credentials, s);
        }

        reject(err);
      });

      s.on('close', function(err) {
        if (options.ignoreError) return resolve({ ok: 1 });
        if (options.reExecuteOnError) {
          options.reExecuteOnError = false;
          return executeCommand(ns, command, credentials, s);

case 0:
                  // Copy the basic options
                  opt = clone(self.clientOptions);

                  opt.host = self.options.bind_ip;
                  opt.port = self.options.port;
                  opt.connectionTimeout = 5000;
                  opt.socketTimeout = 5000;
                  opt.pool = 1;

                  // Ensure we only connect once and emit any error caught
                  opt.reconnect = false;
                  opt.emitError = true;

                  // Create an instance
                  s = new CoreServer(opt);
                  // Add listeners

                  s.on('error', function (err) {
                    reject(err);
                  });

                  s.on('timeout', function (err) {
                    reject(err);
                  });

                  s.on('connect', function (_server) {
                    _server.command('system.$cmd', {
                      ismaster: true
                    }, function (err, r) {
                      // Destroy the connection
                      _server.destroy();

name: name,
      architecture: architecture,
      version: release
    },
    platform: nodejsversion
  }

  // Build default client information
  clonedOptions.clientInfo = this.clientInfo;
  // Do we have an application specific string
  if(options.appname) {
    clonedOptions.clientInfo.application = { name: options.appname };
  }

  // Create an instance of a server instance from mongodb-core
  var server = new CServer(clonedOptions);
  // Server capabilities
  var sCapabilities = null;

  // Define the internal properties
  this.s = {
    // Create an instance of a server instance from mongodb-core
      server: server
    // Server capabilities
    , sCapabilities: null
    // Cloned options
    , clonedOptions: clonedOptions
    // Reconnect
    , reconnect: clonedOptions.reconnect
    // Emit error
    , emitError: clonedOptions.emitError
    // Pool size

case 0:
                  // Copy the basic options
                  opt = clone(self.clientOptions);

                  opt.host = self.options.bind_ip;
                  opt.port = self.options.port;
                  opt.connectionTimeout = 5000;
                  opt.socketTimeout = 5000;
                  opt.pool = 1;

                  // Ensure we only connect once and emit any error caught
                  opt.reconnect = false;
                  opt.emitError = true;

                  // Create an instance
                  s = new CoreServer(opt);

                  s.on('error', function (err) {
                    reject(err);
                  });

                  s.on('close', function (err) {
                    reject(err);
                  });

                  s.on('timeout', function (err) {
                    reject(err);
                  });

                  s.on('connect', function (_server) {
                    // Do we have credentials
                    var authenticate = function authenticate(_server, _credentials, _callback) {

return new Promise(function(resolve, reject) {
      // Create options for command from client options
      var opt = createCommandOptions(self, options);

      // Create an instance
      var s = new CoreServer(opt);
      // Add listeners
      s.on('error', function(err) {
        reject(err);
      });

      s.on('timeout', function(err) {
        reject(err);
      });

      s.on('connect', function(_server) {
        _server.command(
          'system.$cmd',
          {
            ismaster: true
          },
          function(err, r) {

name: name,
      architecture: architecture,
      version: release
    },
    platform: nodejsversion
  }

  // Build default client information
  clonedOptions.clientInfo = this.clientInfo;
  // Do we have an application specific string
  if(options.appname) {
    clonedOptions.clientInfo.application = { name: options.appname };
  }

  // Create an instance of a server instance from mongodb-core
  var server = new CServer(clonedOptions);

  // Define the internal properties
  this.s = {
    // Create an instance of a server instance from mongodb-core
      server: server
    // Server capabilities
    , sCapabilities: null
    // Cloned options
    , clonedOptions: clonedOptions
    // Reconnect
    , reconnect: clonedOptions.reconnect
    // Emit error
    , emitError: clonedOptions.emitError
    // Pool size
    , poolSize: clonedOptions.size
    // Store Options

return new Promise((resolve, reject) => {
    const server = new mongodb.Server(parse(url))
    server.on('connect', () => {
      resolve(server)
    })
    server.connect()
  })
}

new Promise((resolve, reject) => {
        let server = new Server({
          host,
          port,
        })
        server.on('error', e => reject(e))
        server.on('connect', connection => {
          connection.command('system.$cmd', { ping: 1 }, (e, result) => {
            connection.destroy()
            if (e) {
              reject(e)
            } else {
              if (result.result.ok === 1) {
                resolve()
              } else {
                reject(new Error('MongoDB Is Not OK'))
              }
            }