BindingObject auto didChange

BindingObjectAutoDidChange.swift

import SwiftUI
import Combine

@propertyWrapper struct MyObjectBinding<BindableObjectType: BindableObject> : DynamicViewProperty where BindableObjectType.PublisherType == PassthroughSubject<(), Never> {
    init(initialValue: BindableObjectType) {
        delegateValue = Wrapper(bindableObject: initialValue)
    }
    
    @dynamicMemberLookup struct Wrapper {
        var bindableObject: BindableObjectType
        
        subscript<Subject>(dynamicMember keyPath: ReferenceWritableKeyPath<BindableObjectType, Subject>) -> Binding<Subject> {
            Binding<Subject>(getValue: {
                self.bindableObject[keyPath: keyPath]
                }, setValue: {
                    self.bindableObject[keyPath: keyPath] = $0
                    self.bindableObject.didChange.send(())
            })
        }
    }
    
    var delegateValue: Wrapper
    var value: BindableObjectType {
        get {
            delegateValue.bindableObject
        }
        set {
            delegateValue.bindableObject = newValue
        }
    }
}

final class DummyStore: BindableObject {
    let didChange = PassthroughSubject<(), Never>()
    var isOn: Bool = true
}

let _store = DummyStore()
struct ContentView : View {
    @MyObjectBinding var store: DummyStore = _store
    @ObjectBinding var nativeStore: DummyStore = _store
    var body: some View {
        List(0...100) { _ in
            Toggle(isOn: self.$store.isOn) {
                Text("is it on?")
            }
        }
    }
}


#if DEBUG
struct ContentView_Previews : PreviewProvider {
    static var previews: some View {
        ContentView()
            
    }
}
#endif