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emitter-kit v5.2.2

stable CocoaPods Compatible Carthage Compatible Platform

A replacement for NSNotificationCenter#addObserver and NSObject#addObserver that is type-safe and not verbose.

import EmitterKit

// A generic event emitter (but type-safe)!
var event = Event<T>()

// Any emitted data must be the correct type.
event.emit(data)

// This listener will only be called once.
// You are *not* required to retain it.
event.once { data: T in
  print(data)
}

// This listener won't stop listening;
// unless you stop it manually,
// or its Event<T> is deallocated.
// You *are* required to retain it.
var listener = event.on { data: T in
  print(data)
}

// Stop the listener manually.
listener.isListening = false

// Restart the listener (if it was stopped).
listener.isListening = true

 

Targeting

A target allows you to associate a specific AnyObject with an emit call. This is useful when emitting events associated with classes you can't add properties to (like UIView).

When calling emit with a target, you must also call on or once with the same target in order to receive the emitted event.

let myView = UIView()
let didTouch = Event<UITouch>()

didTouch.once(myView) { touch in
  print(touch)
}

didTouch.emit(myView, touch)

 

NSNotification

The Notifier class helps when you are forced to use NSNotificationCenter (for example, if you want to know when the keyboard has appeared).

// You are **not** required to retain this after creating your listener.
var event = Notifier(UIKeyboardWillShowNotification)

// Handle NSNotifications with style!
listener = event.on { (notif: Notification) in
  print(notif.userInfo)
}

 

Key-Value Observation (KVO)

// Any NSObject descendant will work.
var view = UIView()

// "Make KVO great again!" - Donald Trump
listener = view.on("bounds") { (change: Change<CGRect>) in
  print(change)
}

 

Thread Safety

⚠️ None of the classes in EmitterKit are thread-safe!

The following actions must be done on the same thread, or you need manual locking:

 

v5.2.2 changelog

v5.2.1 changelog

v5.2.0 changelog

v5.1.0 changelog

v5.0.0 changelog

The changelog for older versions can be found here.