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This is the first development version of the Bindable UI databinding library. API is not yet stable, use at your own risk.

Installation

Include the following line in your Podfile:

pod 'Bindable/NSObject', :git => 'git@github.com:Q42/Bindable.git'

Or, via HTTPS:

pod 'Bindable/NSObject', :git => 'https://github.com/Q42/Bindable.git'

Example

Create a view model:

class MainViewModel {
  private let ageSource = VariableSource<Int>(value: 0)

  let age: Variable<Int>
  let title: Variable<String>
  
  init() {
    age = ageSource.variable
    title = age.map { "Age: \($0)" }
  }


  func up() {
    ageSource.value += 1
  }

  func down() {
    ageSource.value -= 1
  }
}

And use it in your view controller:

let viewModel = MainViewModel()

// Manually subscribe for change events
ageSubscription = viewModel.age.subscribe { event in
  print("New age: \(event.value)")
}

// Or data bind a UILabel
titleLabel.bind(\.text, to: viewModel.title)

Since 0.8.0 it is also possible to use @Bindable instead of a source. Using the same example:

class MainViewModel {
  @Bindable private(set) var age: Int = 0
  
  let title: Variable<String>
  
  init() {
    title = $age.map { "Age: \($0)" }
  }


  func up() {
    age += 1
  }

  func down() {
    age -= 1
  }
}

The variable's will be exposed by using:

let viewModel = MainViewModel()

// Manually subscribe for change events
ageSubscription = viewModel.$age.subscribe { event in
  print("New age: \(event.value)")
}

// Or data bind a UILabel
titleLabel.bind(\.text, to: viewModel.$title)

CocoaHeadsNL presentation

Tom Lokhorst presented at the September 2017 CocoaHeadsNL meetup. Comparing several methods for reactivally updating UI's, including Bindable. The description of Bindable starts at 27:33:

https://vimeo.com/237530468#t=27m33s

Releases

• 0.8.1 - 2020-01-22 - Use class for property wrapper
• 0.8.0 - 2020-01-15 - Add @Bindable property wrapper
• 0.7.0 - 2019-06-10 - Swift 5.1 in podspec, remove UIKit extension
• 0.6.2 - 2019-05-09 - Change retain logic of NSObject.bind
• 0.6.1 - 2019-04-28 - Add convenient extension functions
• 0.6.0 - 2019-04-25 - Strong references to subscriptions are now required
• 0.5.0 - 2018-09-13 - Update to Swift 4.2, refactor internal to use classes
• 0.4.1 - 2018-05-02 - Add Variable+KVO
• 0.3.0 - 2018-04-24 - Split out NSObject subspec
• 0.2.0 - 2018-02-26 - Fix occasional "execute on wrong queue" issue
• 0.1.0 - 2017-05-31 - Initial public release
• 0.0.0 - 2016-12-14 - Initial private version for project at Q42

License & Credits

Bindable is written by Tom Lokhorst of Q42 and available under the MIT license, so feel free to use it in commercial and non-commercial projects.