swift extention具有循环索引elemnt的数组

Posted 2021-05-19

extension Array where Element: Equatable {
  func calculateNextIndex(for currentIndex: Int) -> Int {
    let newIndex = currentIndex < self.count - 1 ? currentIndex + 1 : 0
    return newIndex
  }
  
  func fetchNextElement(after currentIndex: Int) -> Element {
    let nextIndex = self.calculateNextIndex(for: currentIndex)
    return self[nextIndex]
  }
  
  func fetchNextElement(from element: Element) -> Element?  {
    guard let index = self.index(where: { $0 == element }) else { return .none }
    return self.fetchNextElement(after: index)
  }
}