MongoDB authentication with Javascript

var MongoClient = require('mongodb').MongoClient;
var url = 'mongodb://localhost/admin';

console.time('auth');
MongoClient.connect(url, function(err, db) {
    db.authenticate('admin', 'password', function(err, result) {
        console.log(err);
        db.close();
        console.timeEnd('auth');
    });
});