Then

✨ Syntactic sugar for Swift

Basics

Initialize UILabel then set its properties.

private let titleLabel = UILabel().then {
    $0.textAlignment = .center
    $0.adjustsFontSizeToFitWidth = true
    $0.transform = CGAffineTransform(rotationAngle: -.pi / 6)
}

This is the same as:

private let titleLabel: UILabel = {
    let titleLabel = UILabel()
    titleLabel.textAlignment = .center
    titleLabel.adjustsFontSizeToFitWidth = true
    titleLabel.transform = CGAffineTransform(rotationAngle: -.pi / 6)
    return titleLabel
}()

Usage

• You can use then() to all of NSObject subclasses.

  let animation = CABasicAnimation(keyPath: "fillColor").then {
      $0.fromValue = fromColor.cgColor
      $0.toValue = toColor.cgColor
      $0.duration = duration
      $0.beginTime = CACurrentMediaTime() + delay
      $0.timingFunction = CAMediaTimingFunction(name: .easeOut)
  }

• You can make extensions for your own types.

  extension TransportType: Then {}
  
  let instance = TransportType.car.then {
      $0.availability = .full
  }

• Use with() when copying the value types.

  let frame = oldFrame.with {
      $0.size.width = 200
      $0.size.height = 100
  }
  frame.width  // will be 200
  frame.height // will be 100

• Use do() to do something with less typing.

  UserDefaults.standard.do {
      $0.set(username, forKey: .username)
      $0.set(email, forKey: .email)
      $0.synchronize()
  }

Real World Example

Here's an example usage in a real project.

// MARK: - NotificationsCell

final class NotificationsCell: UITableViewCell {

    // MARK: - Properties

    /// Container
    private let containerView = UIView()

    /// Notification image view
    private let notificationImageView = UIImageView().then {
        $0.image = Asset.Avatar.avatarPlaceholder.image
        $0.contentMode = .scaleAspectFill
    }

    /// Notification title label
    private let titleLabel = UILabel().then {
        $0.setContentHuggingPriority(.defaultHigh, for: .horizontal)
        $0.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        $0.numberOfLines = LayoutConstants.titleNumberOfLines
    }

    /// Notification subtitle label
    private let subtitleLabel = UILabel().then {
        $0.numberOfLines = LayoutConstants.subtitleNumberOfLines
    }

    /// Date of notification completion label
    private let dateLabel = UILabel().then {
        $0.setContentHuggingPriority(.defaultLow, for: .horizontal)
        $0.setContentCompressionResistancePriority(.defaultHigh, for: .horizontal)
        $0.textAlignment = .right
    }
    
    ...
}

Installation

• Using CocoaPods:

  pod 'incetro-then'

• Using Swift Package Manager:

  import PackageDescription
  
  let package = Package(
      name: "MyAwesomeApp",
      dependencies: [
          .package(url: "https://github.com/Incetro/Then", .branch("main")),
      ]
  )

License

Then is under MIT license. See the LICENSE file for more info.