A friendly challenge to anyone w/ functional chops to improve this function. No holds barred: op overloading, enum/struct/class, everything-is-a-singleton... go for it! The only rule is no forced unwrapping (e.g. !).

:(

import Foundation
import ImageIO

func datesFromImagesInDir(dir: String) -> [NSDate] {
  let fm = NSFileManager.defaultManager()
  var error: NSError?

  let df = NSDateFormatter()
  df.dateFormat = "yyyy:MM:dd HH:mm:ss"

  typealias rn_CGPropDictionary = Dictionary<String, AnyObject>

  var dates = [NSDate]()

  let options = [(kCGImageSourceShouldCache as String): false]

  if let imageURLs = fm.contentsOfDirectoryAtPath(dir, error: &error) as? [String] {
    for fileName in imageURLs {
      if let url = NSURL(fileURLWithPath: dir)?.URLByAppendingPathComponent(fileName) {
        if let imageSource = CGImageSourceCreateWithURL(url, nil) {
          if let imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, 0, options) as? rn_CGPropDictionary {
            if let exif = imageProperties[kCGImagePropertyExifDictionary] as? rn_CGPropDictionary {
              if let originalDateString = exif[kCGImagePropertyExifDateTimeOriginal] as? String {
                if let date = df.dateFromString(originalDateString) {
                  dates.append(date)
                }
              }
            }
          }
        }
      }
    }
  }

  return dates
}