d

src/Bus.swift

@@ -0,0 +1,55 @@
+import Combine
+import SwiftUI
+
+public enum Bus { }
+
+extension Bus {
+  public final class Service {
+    static private(set) weak var singleton: Service?
+    let broadcaster = PassthroughSubject<(key: String, value: Any), Never>()
+    
+    deinit {
+        Self.singleton = nil
+    }
+    
+    public init() {
+        Self.singleton = self
+    }
+    
+    func send(_ key: String, _ value: Any) {
+        broadcaster.send((key, value))
+    }
+  }
+}
+
+public extension Bus {
+    static func receive<T>(
+        _ subscriptions: inout Set<AnyCancellable>,
+        _ keys: Set<String>,
+        _ handler: @escaping ((String, T) -> Void)
+    ) {
+        Service.singleton?.broadcaster
+            .compactMap { v -> (String, T)? in
+                guard
+                    keys.contains(v.key),
+                    let value = v.value as? T
+                else {
+                    return nil
+                }
+                return (v.key, value)
+            }
+            .sink { v in handler(v.0, v.1) }
+            .store(in: &subscriptions)
+    }
+
+    static func sendAsync<T: Equatable>(
+        _ subscriptions: inout Set<AnyCancellable>,
+        _ key: String,
+        _ node: AnyPublisher<T, Never>
+    ) {
+        node
+            .receive(on: DispatchQueue.main)
+            .sink { v in Service.singleton?.send(key, v) }
+            .store(in: &subscriptions)
+    }
+}