_DynamicProperty

_DynamicProperty.swift

// A speculative _ViewRendererHost implementation which uses Mirror (Swift reflection) to find all
// of the dynamic properties (`DynamicProperty`) associated with a given view (`View`), observe
// the changes to these properties and automatically refresh the view whenever any of these property change.

protocol _DynamicProperty {
    var objectWillChange: AnyPublisher<Void, Never> { get }
}

extension ObservedObject: _DynamicProperty {
    var objectWillChange: AnyPublisher<Void, Never> {
        wrappedValue.objectWillChange
            .map { _ in () }
            .eraseToAnyPublisher()
    }
}

final class _ViewRendederHost<View: SwiftUI.View> {
    private let view: View
    private var bag = [AnyCancellable]()

    init(view: View) {
        self.view = view

        Mirror(reflecting: view)
            .children
            .compactMap { $0.value as? _DynamicProperty }
            .forEach(subscribe(to:))
    }

    private func subscribe(to property: _DynamicProperty) {
        property.objectWillChange
            .sink { [unowned self] _ in self.update() }
            .store(in: &bag)
    }

    private func update() {
        let body = view.body // Create a new body with the updated values

        print(body)
        // TODO: render body using some internal SwiftUI mechanism
    }
}