Improve DeepLinking by accessing the stored value of @Published properties directly

Sources/XUI/DeepLink/DeepLinkable+Receiver.swift

@@ -12,39 +12,25 @@ extension DeepLinkable {
         as type: Receiver.Type,
         where filter: (Receiver) -> Bool = { _ in true }
     ) -> Receiver! {
-        firstReceiver(ofType: type, where: filter) { $0.children }
-            ?? firstReceiver(ofType: type, where: filter) {
-                Mirror(reflecting: $0)
-                    .values { $0 as? DeepLinkable }
-            }
-    }
-
-}
-
-extension DeepLinkable {
-
-    // MARK: Helpers - DeepLink
-
-    private func firstReceiver<Receiver>(
-        ofType type: Receiver.Type,
-        where filter: (Receiver) -> Bool,
-        children: (DeepLinkable) -> [DeepLinkable]
-    ) -> Receiver? {
         var visited = Set<ObjectIdentifier>()
         var stack = [DeepLinkable]()
         return firstReceiver(
             where: { ($0 as? Receiver).map(filter) ?? false },
             visited: &visited,
-            stack: &stack,
-            children: children
+            stack: &stack
         ) as? Receiver
     }
 
+}
+
+extension DeepLinkable {
+
+    // MARK: Helpers - DeepLink
+
     private func firstReceiver(
         where filter: (Any) -> Bool,
         visited: inout Set<ObjectIdentifier>,
-        stack: inout [DeepLinkable],
-        children: (DeepLinkable) -> [DeepLinkable]
+        stack: inout [DeepLinkable]
     ) -> Any? {
 
         visited.insert(ObjectIdentifier(self))
@@ -54,7 +40,7 @@ extension DeepLinkable {
         }
 
         stack.append(
-            contentsOf: children(self)
+            contentsOf: children
                 .filter { !visited.contains(ObjectIdentifier($0)) }
         )
 
@@ -64,16 +50,8 @@ extension DeepLinkable {
 
         stack.removeFirst()
         return next
-            .firstReceiver(where: filter, visited: &visited, stack: &stack, children: children)
+            .firstReceiver(where: filter, visited: &visited, stack: &stack)
     }
 
 }
 
-extension Mirror {
-
-    fileprivate func values<Value>(_ compactMap: (Any) -> Value?) -> [Value] {
-        children.compactMap { compactMap($0.value) }
-            + (superclassMirror?.values(compactMap) ?? [])
-    }
-
-}

Sources/XUI/DeepLink/DeepLinkable.swift

@@ -7,14 +7,33 @@
 //
 
 public protocol DeepLinkable: AnyObject {
-    @DeepLinkableBuilder var children: [DeepLinkable] { get }
+    var children: [DeepLinkable] { get }
 }
 
 extension DeepLinkable {
 
-    @DeepLinkableBuilder
     public var children: [DeepLinkable] {
-        get {}
+        Mirror(reflecting: self)
+            .values(extractDeepLinkable)
+    }
+
+    private func extractDeepLinkable(from object: Any) -> DeepLinkable? {
+        if let value = object as? DeepLinkable {
+            return value
+        } else if let value = object as? DeepLinkableWrapper {
+            return extractDeepLinkable(from: value.content)
+        } else {
+            return nil
+        }
+    }
+
+}
+
+extension Mirror {
+
+    fileprivate func values<Value>(_ compactMap: (Any) -> Value?) -> [Value] {
+        children.compactMap { compactMap($0.value) }
+            + (superclassMirror?.values(compactMap) ?? [])
     }
 
 }

Sources/XUI/DeepLink/DeepLinkableWrapper.swift

@@ -0,0 +1,47 @@
+//
+//  DeepLinkableWrapper.swift
+//  XUI
+//
+//  Created by Paul Kraft on 01.03.21.
+//  Copyright © 2021 QuickBird Studios. All rights reserved.
+//
+
+public protocol DeepLinkableWrapper {
+    var content: Any { get }
+}
+
+extension Published: DeepLinkableWrapper {
+
+    public var content: Any {
+        guard let value = Mirror(reflecting: self).descendant("storage", "value") else {
+            assertionFailure("We could not extract a wrappedValue from a Published property wrapper.")
+            return ()
+        }
+        return value
+    }
+
+}
+
+extension Binding: DeepLinkableWrapper {
+    public var content: Any { wrappedValue }
+}
+
+extension State: DeepLinkableWrapper {
+    public var content: Any { wrappedValue }
+}
+
+extension ObservedObject: DeepLinkableWrapper {
+    public var content: Any { wrappedValue }
+}
+
+extension EnvironmentObject: DeepLinkableWrapper {
+    public var content: Any { wrappedValue }
+}
+
+extension Store: DeepLinkableWrapper {
+    public var content: Any { wrappedValue }
+}
+
+extension Optional: DeepLinkableWrapper {
+    public var content: Any { flatMap { $0 } ?? () }
+}

Tests/XUITests/DeepLinkTests.swift

@@ -0,0 +1,28 @@
+
+import XCTest
+@testable import XUI
+
+class ParentViewModel: ViewModel, ObservableObject {
+    @Published var child: ChildViewModel?
+}
+
+class ChildViewModel: ViewModel, ObservableObject {
+
+}
+
+final class DeepLinkTests: XCTestCase {
+
+    func testMirror() {
+        let viewModel = ParentViewModel()
+        XCTAssertNil(viewModel.firstReceiver(as: ChildViewModel.self))
+        viewModel.child = .init()
+        XCTAssertNotNil(viewModel.firstReceiver(as: ChildViewModel.self))
+        viewModel.child = nil
+        XCTAssertNil(viewModel.firstReceiver(as: ChildViewModel.self))
+    }
+
+    static var allTests = [
+        ("testMirror", testMirror),
+    ]
+
+}

Tests/XUITests/XCTestManifests.swift

@@ -3,6 +3,7 @@ import XCTest
 #if !canImport(ObjectiveC)
 public func allTests() -> [XCTestCaseEntry] {
     return [
+        testCase(DeepLinkTests.allTests),
         testCase(XUITests.allTests),
     ]
 }