SwiftUI (Combine) Publishers

KeyValueObserving.swift

class MyDefaults: BindableObject {
    public var didChange: AnyPublisher<Bool, Never>
    
    init() {
        let defaults = UserDefaults.standard
        didChange = Publishers.Merge(
            defaults.publisher(for: \.userOption1),
            defaults.publisher(for: \.userOption2)
        )
        .receive(on: RunLoop.main)
        .eraseToAnyPublisher()
    }
}

Publishers.swift

class MyDataNotificationCenterModel: BindableObject {
    public var didChange: NotificationCenter.default.publisher(for: .MyNotification)
        .receive(on: RunLoop.main)
}

class MyDataKVOModel: NSObject, BindableObject {
    public var didChange: MyObject.publisher(for: \.myKeyPath)
        .receive(on: RunLoop.main)
}