如何在三個數據庫操作中避免厄運金字塔？

Question

有我需要執行三個數據庫操作一次，我從網絡服務

self.save(responses, child: child, year: year, completionBlock: 
    {(success, error) in 
      self.saveModifiedDate(child, year: year, completionBlock: { (result) in 
      self.fetchAll(child, year: year!, completionBlock: completionBlock) 
      }) 
     }) 

Answer 1

你可以嘗試使用或實現自己（這並不難）一個面向未來的類似API接收數據。一個好的框架是FutureKit。

代碼會再看看像

save(responses, child: child, year: year) 
    .onSuccess(saveModifiedDate) 
    .onSuccess(fetchAll) 
    .onSuccess { //final completion handler } 
    .onFailure { //handle error }