Error handling

Handle.swift

func handle(_ errors: [Error]) -> Action {
  
  func invalidToken(error: Client.Error) -> Action? {
    guard error.message == "INVALID_TOKEN" else { return nil }
    return InvalidateToken()
  }
    
  func paymentRequired(error: Client.Error) -> Action? {
    guard error.message == "PAYMENT_REQUIRED" else { return nil }
    return FailCaseCreation(context: .init(error), paymentRequired: true)
  }
    
  let handlers = [
    invalidToken,
    paymentRequired
  ]
  
  return errors
    .flatMap(handlers.apply)
    .fallback(DefaultAction())
}

Syntax.swift

public extension Array {
  public func fallback<NonOptional>(_ default: NonOptional) -> NonOptional 
    where Element == Optional<NonOptional> 
  {
      return self.flatten().first ?? `default`
  }
  
  public func flatten<Unwrapped>() -> [Unwrapped]
    where Element == Optional<Unwrapped> 
  {
    return self.compactMap { $0 }
  }
  
   public func apply<Value, Result>(_ value: Value) -> [Result]
    where Element == (Value) -> Result
  {
    return self.map { $0(value) }
  }
}