LayoutSpecBuildable.swift

ASLayoutElememt+Extension.swift

extension ASLayoutElementStyle {
  
  @discardableResult
  func shrink(value: CGFloat = 1.0) -> Self {
    self.flexShrink = value
    return self
  }
  
  @discardableResult
  func grow(value: CGFloat = 1.0) -> Self {
    self.flexGrow = value
    return self
  }
  
  @discardableResult
  func nonShrink() -> Self {
    self.flexShrink = 0.0
    return self
  }
  
  @discardableResult
  func nonGrow() -> Self {
    self.flexGrow = 0.0
    return self
  }
  
  @discardableResult
  func width(_ value: CGFloat, unit: ASDimensionUnit = .points) -> Self {
    self.width = ASDimension.init(unit: unit, value: value)
    return self
  }
  
  @discardableResult
  func height(_ value: CGFloat, unit: ASDimensionUnit = .points) -> Self {
    self.height = ASDimension.init(unit: unit, value: value)
    return self
  }
  
  @discardableResult
  func maxWidth(_ value: CGFloat, unit: ASDimensionUnit = .points) -> Self {
    self.maxWidth = ASDimension.init(unit: unit, value: value)
    return self
  }
  
  @discardableResult
  func maxHeight(_ value: CGFloat, unit: ASDimensionUnit = .points) -> Self {
    self.maxHeight = ASDimension.init(unit: unit, value: value)
    return self
  }
  
  @discardableResult
  func minWidth(_ value: CGFloat, unit: ASDimensionUnit = .points) -> Self {
    self.minWidth = ASDimension.init(unit: unit, value: value)
    return self
  }
  
  @discardableResult
  func minHeight(_ value: CGFloat, unit: ASDimensionUnit = .points) -> Self {
    self.minHeight = ASDimension.init(unit: unit, value: value)
    return self
  }
  
  @discardableResult
  func size(_ value: CGSize) -> Self {
    self.preferredSize = value
    return self
  }
  
  @discardableResult
  func maxSize(_ value: CGSize) -> Self {
    self.maxSize = value
    return self
  }
  
  @discardableResult
  func minSize(_ value: CGSize) -> Self {
    self.minSize = value
    return self
  }
  
  @discardableResult
  func spacingAfter(_ value: CGFloat) -> Self {
    self.spacingAfter = value
    return self
  }
  
  @discardableResult
  func spacingBefore(_ value: CGFloat) -> Self {
    self.spacingBefore = value
    return self
  }
}

LayoutSpecBuildable.swift

enum LayoutSpecBuildableOptions {
  
  case safeArea
  case layoutMargins
}

protocol LayoutSpecBuildable {
  
  var layoutSpec: ASLayoutSpec { get }
}

private var layoutSpecBuildableConstrainedSizeKey: String = "LayoutSpecBuildable.constrainedSize"

extension LayoutSpecBuildable where Self: ASDisplayNode {
  
  var constraintedSize: ASSizeRange {
    get {
      return (objc_getAssociatedObject(
        self,
        &layoutSpecBuildableConstrainedSizeKey
        ) as? ASSizeRange) ?? ASSizeRangeUnconstrained
    }
    set {
      objc_setAssociatedObject(
        self,
        &layoutSpecBuildableConstrainedSizeKey,
        newValue,
        .OBJC_ASSOCIATION_RETAIN_NONATOMIC
      )
    }
  }
  
  func automaticallyManagesLayoutSpecBuilder(changeSet: LayoutSpecBuildableOptions...) {
    self.automaticallyManagesSubnodes = true
    self.automaticallyRelayoutOnSafeAreaChanges = changeSet.contains(.safeArea)
    self.automaticallyRelayoutOnLayoutMarginsChanges = changeSet.contains(.layoutMargins)
    self.layoutSpecBlock = { [weak self] (_, sizeRange) -> ASLayoutSpec in
      self?.constraintedSize = sizeRange
      return self?.layoutSpec ?? ASLayoutSpec()
    }
  }
}

TestNode.swift

import Foundation
import AsyncDisplayKit
import BonMot

final class TestNode: ASDisplayNode, LayoutSpecBuildable {
  
  private enum Const {
    
    static let titleStyle: StringStyle = .init(
      .font(UIFont.boldSystemFont(ofSize: 30.0)),
      .color(UIColor.darkGray),
      .alignment(.center)
    )
    
    static let subTitleStyle: StringStyle = .init(
      .font(UIFont.systemFont(ofSize: 18.0)),
      .color(UIColor.gray),
      .alignment(.center),
      .lineSpacing(4.0)
    )
    
    static let buttonTitleStyle: StringStyle = .init(
      .font(UIFont.boldSystemFont(ofSize: 16.0)),
      .color(UIColor.white)
    )
    
    static func contentInsets(safeAreaInsets: UIEdgeInsets) -> UIEdgeInsets {
      return .init(
        top: safeAreaInsets.top + UIScreen.main.bounds.height * 0.2,
        left: safeAreaInsets.left,
        bottom: safeAreaInsets.bottom + 40.0,
        right: safeAreaInsets.right
      )
    }
  }
  
  // MARK: - UI Components
  
  private lazy var titleNode: ASTextNode2 = {
    let node = ASTextNode2()
    node.attributedText = "Title".styled(with: Const.titleStyle)
    return node
  }()
  
  private lazy var subTitleNode: ASTextNode2 = {
    let node = ASTextNode2()
    node.attributedText = "Sub-Title".styled(with: Const.subTitleStyle)
    return node
  }()
  
  private lazy var writeButtonNode: ASButtonNode = {
    let node = ASButtonNode()
    node.backgroundColor = .orange
    node.contentEdgeInsets = .init(top: 16.0, left: 24.0, bottom: 16.0, right: 24.0)
    node.setAttributedTitle(
      "Button".styled(with: Const.buttonTitleStyle),
      for: .normal
    )
    node.cornerRadius = 8.0
    return node
  }()
  
  // MARK: - Props
  
  public var isHiddenTitleAndSubTitle: Bool = false
  
  override init() {
    super.init()
    self.backgroundColor = .white
    self.automaticallyManagesLayoutSpecBuilder(changeSet: .safeArea)
  }
  
  // MARK: - LayoutSpec
  
  var layoutSpec: ASLayoutSpec {
    LayoutSpec {
      InsetLayout(insets: Const.contentInsets(safeAreaInsets: safeAreaInsets)) {
        VStackLayout(spacing: 0.0, justifyContent: .spaceBetween, alignItems: .center) {
          contentLayoutSpec
          writeButtonNode
        }
      }
    }
  }
  
  private var contentLayoutSpec: ASLayoutSpec {
    if self.isHiddenTitleAndSubTitle {
      return LayoutSpec {
        EmptyLayout()
      }
    } else {
      return LayoutSpec {
        VStackLayout(spacing: 8.0, justifyContent: .start, alignItems: .center) {
          titleNode.styled({ $0.shrink() })
          subTitleNode.styled({ $0.shrink() })
        }
      }
    }
  }
}

Layout spec function builder convention

https://github.com/muukii/TextureSwiftSupport/blob/master/TextureSwiftSupport/SpecBuilder.swift