callstack · okwasniewski · Jan 9, 2026 · Jan 9, 2026
diff --git a/apps/TesterIntegrated/swift/App.swift b/apps/TesterIntegrated/swift/App.swift
@@ -1,6 +1,7 @@
 import Brownie
 import ReactBrownfield
 import SwiftUI
+import UIKit
 
 let initialState = BrownfieldStore(
   counter: 0,
@@ -83,6 +84,11 @@ struct MyApp: App {
             ReactNativeView(moduleName: "ReactNative")
               .navigationBarHidden(true)
           }
+
+          NavigationLink("Push UIKit Screen") {
+            UIKitExampleViewControllerRepresentable()
+              .navigationBarTitleDisplayMode(.inline)
+          }
         }
       }.navigationViewStyle(StackNavigationViewStyle())
     }
@@ -118,3 +124,11 @@ struct MyApp: App {
     }
   }
 }
+
+struct UIKitExampleViewControllerRepresentable: UIViewControllerRepresentable {
+  func makeUIViewController(context: Context) -> UIKitExampleViewController {
+    UIKitExampleViewController()
+  }
+
+  func updateUIViewController(_ uiViewController: UIKitExampleViewController, context: Context) {}
+}
diff --git a/apps/TesterIntegrated/swift/SwiftExample.xcodeproj/project.pbxproj b/apps/TesterIntegrated/swift/SwiftExample.xcodeproj/project.pbxproj
@@ -10,6 +10,7 @@
 		2869185C23129ECF00458242 /* App.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2869185B23129ECF00458242 /* App.swift */; };
 		2869186323129ED100458242 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 2869186223129ED100458242 /* Assets.xcassets */; };
 		2869186623129ED100458242 /* LaunchScreen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 2869186423129ED100458242 /* LaunchScreen.storyboard */; };
+		76208ADC2F11557800737E1D /* UIKitExampleViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 76208ADB2F11557800737E1D /* UIKitExampleViewController.swift */; };
 		AC7E040409DFEE553311B27E /* libPods-SwiftExample.a in Frameworks */ = {isa = PBXBuildFile; fileRef = CF9653D1882655DA02862F71 /* libPods-SwiftExample.a */; };
 		BFSTORE001000000000000001 /* BrownfieldStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = BFSTORE001000000000000002 /* BrownfieldStore.swift */; };
 		ED52AE6E1313AAE3C968412D /* PrivacyInfo.xcprivacy in Resources */ = {isa = PBXBuildFile; fileRef = 33BE347ABB4EE17F7F99D32D /* PrivacyInfo.xcprivacy */; };
@@ -23,6 +24,7 @@
 		2869186723129ED100458242 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		33BE347ABB4EE17F7F99D32D /* PrivacyInfo.xcprivacy */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xml; path = PrivacyInfo.xcprivacy; sourceTree = "<group>"; };
 		5BE9069F7C8AF5853F650B68 /* Pods-SwiftExample.debug.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-SwiftExample.debug.xcconfig"; path = "Target Support Files/Pods-SwiftExample/Pods-SwiftExample.debug.xcconfig"; sourceTree = "<group>"; };
+		76208ADB2F11557800737E1D /* UIKitExampleViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UIKitExampleViewController.swift; sourceTree = "<group>"; };
 		BFSTORE001000000000000002 /* BrownfieldStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BrownfieldStore.swift; sourceTree = "<group>"; };
 		CF9653D1882655DA02862F71 /* libPods-SwiftExample.a */ = {isa = PBXFileReference; explicitFileType = archive.ar; includeInIndex = 0; path = "libPods-SwiftExample.a"; sourceTree = BUILT_PRODUCTS_DIR; };
 		E74DC3AFAC0967529ED1C063 /* Pods-SwiftExample.release.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-SwiftExample.release.xcconfig"; path = "Target Support Files/Pods-SwiftExample/Pods-SwiftExample.release.xcconfig"; sourceTree = "<group>"; };
@@ -43,6 +45,7 @@
 		2869184F23129ECF00458242 = {
 			isa = PBXGroup;
 			children = (
+				76208ADB2F11557800737E1D /* UIKitExampleViewController.swift */,
 				2869185B23129ECF00458242 /* App.swift */,
 				BFSTORE001000000000000003 /* Generated */,
 				2869186223129ED100458242 /* Assets.xcassets */,
@@ -168,10 +171,14 @@
 			inputFileListPaths = (
 				"${PODS_ROOT}/Target Support Files/Pods-SwiftExample/Pods-SwiftExample-frameworks-${CONFIGURATION}-input-files.xcfilelist",
 			);
+			inputPaths = (
+			);
 			name = "[CP] Embed Pods Frameworks";
 			outputFileListPaths = (
 				"${PODS_ROOT}/Target Support Files/Pods-SwiftExample/Pods-SwiftExample-frameworks-${CONFIGURATION}-output-files.xcfilelist",
 			);
+			outputPaths = (
+			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
 			shellScript = "\"${PODS_ROOT}/Target Support Files/Pods-SwiftExample/Pods-SwiftExample-frameworks.sh\"\n";
@@ -243,10 +250,14 @@
 			inputFileListPaths = (
 				"${PODS_ROOT}/Target Support Files/Pods-SwiftExample/Pods-SwiftExample-resources-${CONFIGURATION}-input-files.xcfilelist",
 			);
+			inputPaths = (
+			);
 			name = "[CP] Copy Pods Resources";
 			outputFileListPaths = (
 				"${PODS_ROOT}/Target Support Files/Pods-SwiftExample/Pods-SwiftExample-resources-${CONFIGURATION}-output-files.xcfilelist",
 			);
+			outputPaths = (
+			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
 			shellScript = "\"${PODS_ROOT}/Target Support Files/Pods-SwiftExample/Pods-SwiftExample-resources.sh\"\n";
@@ -259,6 +270,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				76208ADC2F11557800737E1D /* UIKitExampleViewController.swift in Sources */,
 				2869185C23129ECF00458242 /* App.swift in Sources */,
 				BFSTORE001000000000000001 /* BrownfieldStore.swift in Sources */,
 			);
@@ -340,10 +352,7 @@
 				ONLY_ACTIVE_ARCH = YES;
 				OTHER_CFLAGS = "$(inherited)";
 				OTHER_CPLUSPLUSFLAGS = "$(inherited)";
-				OTHER_LDFLAGS = (
-					"$(inherited)",
-					" ",
-				);
+				OTHER_LDFLAGS = "$(inherited)  ";
 				REACT_NATIVE_PATH = "${PODS_ROOT}/../../node_modules/react-native";
 				SDKROOT = iphoneos;
 				SWIFT_ACTIVE_COMPILATION_CONDITIONS = "$(inherited) DEBUG";
@@ -407,10 +416,7 @@
 				MTL_FAST_MATH = YES;
 				OTHER_CFLAGS = "$(inherited)";
 				OTHER_CPLUSPLUSFLAGS = "$(inherited)";
-				OTHER_LDFLAGS = (
-					"$(inherited)",
-					" ",
-				);
+				OTHER_LDFLAGS = "$(inherited)  ";
 				REACT_NATIVE_PATH = "${PODS_ROOT}/../../node_modules/react-native";
 				SDKROOT = iphoneos;
 				SWIFT_COMPILATION_MODE = wholemodule;

diff --git a/apps/TesterIntegrated/swift/UIKitExampleViewController.swift b/apps/TesterIntegrated/swift/UIKitExampleViewController.swift
@@ -0,0 +1,116 @@
+import UIKit
+import Brownie
+
+class UIKitExampleViewController: UIViewController {
+  private var store: Store<BrownfieldStore>?
+  private var cancelSubscription: (() -> Void)?
+
+  private let counterLabel: UILabel = {
+    let label = UILabel()
+    label.font = .systemFont(ofSize: 24, weight: .bold)
+    label.textAlignment = .center
+    label.translatesAutoresizingMaskIntoConstraints = false
+    return label
+  }()
+
+  private let userLabel: UILabel = {
+    let label = UILabel()
+    label.font = .systemFont(ofSize: 18)
+    label.textAlignment = .center
+    label.translatesAutoresizingMaskIntoConstraints = false
+    return label
+  }()
+
+  private let nameTextField: UITextField = {
+    let field = UITextField()
+    field.borderStyle = .roundedRect
+    field.placeholder = "Enter name"
+    field.translatesAutoresizingMaskIntoConstraints = false
+    return field
+  }()
+
+  private let incrementButton: UIButton = {
+    var config = UIButton.Configuration.borderedProminent()
+    config.title = "Increment"
+    let button = UIButton(configuration: config)
+    button.translatesAutoresizingMaskIntoConstraints = false
+    return button
+  }()
+
+  override func viewDidLoad() {
+    super.viewDidLoad()
+    setupUI()
+    setupStore()
+  }
+
+  private func setupUI() {
+    title = "UIKit Example"
+    view.backgroundColor = .systemBackground
+
+    let titleLabel = UILabel()
+    titleLabel.text = "UIKit + Brownie Store"
+    titleLabel.font = .systemFont(ofSize: 20, weight: .bold)
+    titleLabel.textAlignment = .center
+    titleLabel.translatesAutoresizingMaskIntoConstraints = false
+
+    let stack = UIStackView(arrangedSubviews: [
+      titleLabel,
+      counterLabel,
+      userLabel,
+      nameTextField,
+      incrementButton
+    ])
+    stack.axis = .vertical
+    stack.spacing = 16
+    stack.translatesAutoresizingMaskIntoConstraints = false
+
+    view.addSubview(stack)
+
+    NSLayoutConstraint.activate([
+      stack.centerXAnchor.constraint(equalTo: view.centerXAnchor),
+      stack.centerYAnchor.constraint(equalTo: view.centerYAnchor),
+      stack.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 20),
+      stack.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -20)
+    ])
+
+    incrementButton.addTarget(self, action: #selector(incrementTapped), for: .touchUpInside)
+    nameTextField.addTarget(self, action: #selector(nameChanged), for: .editingChanged)
+  }
+
+  private func setupStore() {
+    store = StoreManager.get(key: BrownfieldStore.storeName, as: BrownfieldStore.self)
+
+    guard let store else {
+      counterLabel.text = "Store not found"
+      return
+    }
+
+    updateUI(with: store.state)
+
+    cancelSubscription = store.subscribe { [weak self] state in
+      self?.updateUI(with: state)
+    }
+  }
+
+  private func updateUI(with state: BrownfieldStore) {
+    counterLabel.text = "Count: \(Int(state.counter))"
+    userLabel.text = "User: \(state.user.name)"
+
+    if nameTextField.text != state.user.name && !nameTextField.isFirstResponder {
+      nameTextField.text = state.user.name
+    }
+  }
+
+  @objc private func incrementTapped() {
+    store?.set { $0.counter += 1 }
+  }
+
+  @objc private func nameChanged() {
+    guard let name = nameTextField.text else { return }
+    store?.set { $0.user.name = name }
+  }
+
+  deinit {
+    cancelSubscription?()
+  }
+}
diff --git a/packages/brownie/ios/BrownieStore.swift b/packages/brownie/ios/BrownieStore.swift
@@ -148,4 +148,28 @@ public class Store<State: Codable>: ObservableObject {
   public subscript<Value>(_ keyPath: KeyPath<State, Value>) -> Value {
     state[keyPath: keyPath]
   }
+
+  // MARK: - UIKit Support
+
+  /// Subscribe to state changes with a closure. Returns a cancellation function.
+  public func subscribe(onChange: @escaping (State) -> Void) -> () -> Void {
+    let cancellable = $state.sink { state in
+      onChange(state)
+    }
+    return { cancellable.cancel() }
+  }
+
+  /// Subscribe to specific property changes. Returns a cancellation function.
+  public func subscribe<Value: Equatable>(
+    _ keyPath: KeyPath<State, Value>,
+    onChange: @escaping (Value) -> Void
+  ) -> () -> Void {
+    let cancellable = $state
+      .map { $0[keyPath: keyPath] }
+      .removeDuplicates()
+      .sink { value in
+        onChange(value)
+      }
+    return { cancellable.cancel() }
+  }
 }