NSUserDefaults

NSUserDefaults+Extension.swift

@objc public enum Features: Int {
   case ScheduledSendingCoachmark = 0
   case AccountVerifyFailureToggle
}

extension Features {
   
   private var userDefaultsKey: String {
     switch(self) {
      case .ScheduledSendingCoachmark:
         return NSUserDefaults.Keys.ScheduledSendingCoachmark
      case .AccountVerifyFailureToggle:
         return NSUserDefaults.Keys.AccountVerifyFailureToggle
   }
}

extension NSUserDefaults {

  private struct Keys {
    static let ScheduledSendingCoachmark = "ScheduledSendingCoachmark"
    static let AccountVerifyFailureToggle = "AccountVerifyFailureToggle"
  }
  
  public func shown(feature feature:Features) -> Bool {
    return bool(forKey: feature.userDefaultsKey)
  }
  
  public func save(feature feature:Features, value: Bool = true) {
    setBool(value, forKey: feature.userDefaultsKey)
    synchronize()
  }
  
  public func dbg_reset(feature feature:Features) {
    save(feature:feature, value: false)
  }
}


> Usage

let appGroup = NSUserDefaults(suiteName: "name of app group") 
let standard = NSUserDefaults.standardUserDefaults()

print( appGroup.shown(feature: .ScheduledSendingCoachmark) ) // return false...
print( standard.shown(feature: .ScheduledSendingCoachmark) ) // return false...