title: How to round up date to midnight in Swift?
body: <p>Adding number of days to a date, and I would round up to midnight. How is it possible in Swift?</p>
  <pre class="lang-swift prettyprint-override"><code>guard let expirationDate = Calendar.current.date(byAdding: .day, value: expirationDays, to: p.createdAt!) else {
      return false
  }
  </code></pre>