check-ios-bus/Modules/BusX/BusUI/src/BusUI.Button.swift

import Combine

extension BusUI {
  public final class Button: ObservableObject {
    public let v = PassthroughSubject<Void, Never>()
    var subscriptions = [AnyCancellable]()
   
    public init(_ key: String) {
      Bus.sendSync(
        key,
        v.map { true }.eraseToAnyPublisher(),
        &subscriptions
      )
    }
  }
}