title: How to calculate an age precisely with Momentjs?
body: <p>I would like to calculate the age of a person from his date of birth.</p>
  
  <p>I know it's possible to return the number of months or years since birth through <code>moment().diff(date_of_birth, 'months')</code>.</p>
  
  <p>I would like to return something more specific, like this:</p>
  
  <p><code>23 days</code> (if the person is less than a month old) or <code>2 months</code> or <code>1 year 2 months</code></p>
  
  <p>Can we do that with Momentjs?</p>