In documents, you suggest user use connect mongodb like this:

var MongoClient = require('mongodb').MongoClient,
  f = require('util').format,
  assert = require('assert');

var user = encodeURIComponent('dave');
var password = encodeURIComponent('abc123');
var authMechanism = 'DEFAULT';
var authSource = 'myproject';

// Connection URL
var url = f('mongodb://%s:%s@localhost:27017?authMechanism=%s&authSource=',
  user, password, authMechanism, authSource);

error 1:

When I run this code, it gives me mongodb name has a bad character [space]
And I print the URL:mongodb://dave:abc123@localhost:27017?authMechanism=DEFAULT&authSource= myproject

I add '%s' to the end of url, solved.

error 2:

Run code by fixed url, it give me: missing delimiting slash between hosts and options

I solved this problem by modify the URL like this: mongodb://%s:%s@localhost:27017/myproject?authMechanism=%s

This time it work perfect.

Is this a bug or I code something wrong?