8. Perbandingan: ObservableObject vs @Observable

Aspek	`ObservableObject` + `@Published`	`@Observable`
Framework	Combine (tidak tersedia di Linux)	Observation (Swift standard)
Granularitas	Per-object (all-or-nothing)	Per-property (fine-grained)
Boilerplate	`@Published` di setiap property	Tidak ada anotasi per-property
Binding	`@ObservedObject`, `@StateObject`, `@EnvironmentObject`	`@State`, `@Bindable`, `@Environment`
Thread safety	Tidak otomatis	Tidak otomatis
iOS/macOS minimum	iOS 13 / macOS 10.15	iOS 17 / macOS 14
Performa rendering	Sering over-render	Minimal re-render
Non-SwiftUI support	Via Combine publisher	Via `withObservationTracking`
Swift 6 compatibility	Perlu extra annotation	Lebih natural dengan `@MainActor`
Nested observable	Tidak otomatis	Otomatis (nested @Observable di-track)

Contoh Nested Observable

swift
// ObservableObject — nested TIDAK otomatis di-observe
class AddressViewModel: ObservableObject {
    @Published var city: String = ""
}

class UserViewModel: ObservableObject {
    // Perubahan di nested.city TIDAK akan men-trigger UserViewModel.objectWillChange
    // Harus subscribe manual ke nested.objectWillChange dan forward ke self.
    var address = AddressViewModel()

    private var cancellable: AnyCancellable?
    init() {
        // Boilerplate manual untuk propagate nested changes
        cancellable = address.objectWillChange
            .sink { [weak self] _ in self?.objectWillChange.send() }
    }
}

// @Observable — nested OTOMATIS di-track
@Observable
final class Address {
    var city: String = ""
}

@Observable
final class UserViewModel {
    // Perubahan di address.city otomatis di-track oleh SwiftUI
    // yang mengakses viewModel.address.city di body-nya.
    var address = Address()
}