Nightwatch elementCount before an amount of time

Trying to test with Nightwatch.js, that a dropdown has a given number of items before a certain amount of time.

On way is to :

browser
  .pause(300)
  .assert.elementCount('#project_switch .dropdown-item', 3)

But this is ugly, forcing to spread so many .pause(value) in the test code thus making the e2e test far longer than what is necessary!

I think I should switch from browser.assert to browser.expect which offers the before(ms) but what is the way to count the elements with browser.expect ?