Using Q, is this the best way to pass the results of two sequenced promises to the subsequent `then`/`spread` clause?

CombiningSequencedPromiseResultsWithQ.js

'use strict';

var Q = require('q');
var cmd = new require('commander').Command();
var client = new require('myAwesomeApi').Client();

var getUsername = function(done) {
  var username;
  cmd.prompt('Username: ', function(name) {
    if (!name) {
      done(new Error('You must provide a username!'));
    }
    else {
      done(null, username);
    }
  });
};

var getPassword = function(done) {
  cmd.password('Password: ', '*', function(pass) {
    if (!pass) {
      done(new Error('You must provide a password!'));
    }
    else {
      process.stdin.destroy();
      done(null, pass);
    }
  });
};

Q.napply(getUsername, null, []).then(function(username) {
  return Q.napply(getPassword, null, []).then(function(password) {
    return Q.resolve([username, password]);
  });
}).spread(function(username, password) {
  return Q.napply(client.login, client, [username, password]);
})

No, fail shouldn't go before done; in that case: it does change the semantics.

.then(f1, r1, p1).fail(f2).end() should be replaced with .then(f1, r1, p1).fail(f2).done() or .then(f1, r2, p1).done(undefined, f2). I often cap with an empty .done(); I sometimes use .done(f) or sometimes .done(f, r).

Also: if you're writing only for Node you can use .catch instead of .fail (and .finally instead of .fin).

Cool, I'll go with catch (definitely prefer its obviously semantic name over fail) and an empty done. Thanks again!