Feature: observations

[vadymmarkov]

I refactored implementation so the API lets you pass any object as an observer, while also passing an observation closure. The observation closure will be removed automatically when the weekly captured observer has been deallocated. You can always remove observer manually by cancelling the token.

Storage observations

// Add observer
let token = storage.addStorageObserver(self) { observer, storage, change
  switch change {
  case .add(let key):
    print("Added \(key)")
  case .remove(let key):
    print("Removed \(key)")
  case .removeAll:
    print("Removed all")
  case .removeExpired:
    print("Removed expired")
  }
}

// Remove observer
token.cancel()

// Remove all observers
storage.removeAllStorageObservers()

Key observations

let key = "user1"

let token = storage.addObserver(self, forKey: key) { observer, storage, change in
  switch change {
  case .edit(let before, let after):
    print("Changed object for \(key) from \(String(describing: before)) to \(after)")
  case .remove:
    print("Removed \(key)")
  }
}

// Remove observer by token
token.cancel()

// Remove observer for key
storage.removeObserver(forKey: "user1")

// Remove all observers
storage.removeAllKeyObservers()

[vadymmarkov]

Ping @RomainBoulay

[onmyway133]

Great job @vadymmarkov 🚀

[RomainBoulay]

👍👍