Block Based KVO

Prefer the new block based KVO API with keypaths when using Swift 3.2 or later

  • Identifier: block_based_kvo
  • Enabled by default: Yes
  • Supports autocorrection: No
  • Kind: idiomatic
  • Analyzer rule: No
  • Minimum Swift compiler version: 5.0.0
  • Default configuration:
    KeyValue
    severity warning

Non Triggering Examples

let observer = foo.observe(\.value, options: [.new]) { (foo, change) in
   print(change.newValue)
}

Triggering Examples

class Foo: NSObject {
  override ↓func observeValue(forKeyPath keyPath: String?, of object: Any?,
                              change: [NSKeyValueChangeKey : Any]?,
                              context: UnsafeMutableRawPointer?) {}
}

class Foo: NSObject {
  override ↓func observeValue(forKeyPath keyPath: String?, of object: Any?,
                              change: Dictionary<NSKeyValueChangeKey, Any>?,
                              context: UnsafeMutableRawPointer?) {}
}