title: Force localization of the allowedUnits in DateComponentsFormatter
body: <p>I have an app with only one language. I would like to force the language to be this when displaying a time interval since a date. E.g. "9 mths ago" Just in a specific language not english. Is there a way to do this using DateComponentsFormatter which otherwise does exactly what I want to do with the units.</p>
  
  <pre><code>    func format(duration: TimeInterval) -&gt; String {
          UserDefaults.standard.set(["da"], forKey: "AppleLanguages")
          UserDefaults.standard.synchronize()
          let formatter = DateComponentsFormatter()
          formatter.allowedUnits = [.year, .month, .day, .hour, .minute, .second]
          formatter.unitsStyle = .short
          formatter.includesApproximationPhrase = true
          formatter.maximumUnitCount = 1
  
          return formatter.string(from: -duration)!
      }
  
      format(duration: self.createdDate.timeIntervalSinceNow)
  </code></pre>
  
  <p>This returns e.g. "1 yr" when language is en.
  I would like to have it in a specific language ("yr" -> "år") this should be similarly done for the other allowed units.</p>
  
  <p>It works when the phone is set to the language of the app.</p>
  
  <p>I tried to set the language before creating the DateComponentsFormatter but it still returned in the language the phone is set to. </p>
  
  <p><strong>EDIT inserted working code below</strong></p>
  
  <p>Working code after modification from answer:</p>
  
  <pre><code>    func format(duration: TimeInterval) -&gt; String {
          var calendar = Calendar.current
          calendar.locale = Locale(identifier: "da")
          let formatter = DateComponentsFormatter()
          formatter.calendar = calendar
          formatter.allowedUnits = [.year, .month, .day, .hour, .minute, .second]
          formatter.unitsStyle = .short
          formatter.includesApproximationPhrase = true
          formatter.maximumUnitCount = 1
  
          return formatter.string(from: -duration)!
      }
  
      format(duration: self.createdDate.timeIntervalSinceNow)
  </code></pre>