You get 60 to 90 minutes to build a small app live (a photo search, a movie list from JSON, a recipe app, a list with counters). How do you spend the time and what do interviewers look for?

Predict first

Does a debounced, cancellable search view model with an injected service and a SwiftUI screen compile against the iOS SDK?

import SwiftUI

struct Photo: Identifiable, Decodable, Hashable { let id: String; let title: String }

protocol PhotoService: Sendable { func search(_ text: String) async throws -> [Photo] }

@MainActor @Observable final class SearchViewModel {
    enum State: Equatable { case idle, loading, loaded([Photo]), failed(String) }
    private(set) var state: State = .idle
    private let service: PhotoService
    private var task: Task<Void, Never>?
    init(service: PhotoService) { self.service = service }

    func queryChanged(_ text: String) {
        task?.cancel()                                   // only the latest query may update the screen
        guard !text.isEmpty else { state = .idle; return }
        task = Task {
            try? await Task.sleep(for: .milliseconds(300))      // debounce
            guard !Task.isCancelled else { return }
            state = .loading
            do { let r = try await service.search(text); if !Task.isCancelled { state = .loaded(r) } }
            catch { if !Task.isCancelled { state = .failed("Could not load photos") } }
        }
    }
}

struct SearchScreen: View {
    @State private var model: SearchViewModel
    @State private var text = ""
    init(service: PhotoService) { _model = State(initialValue: SearchViewModel(service: service)) }
    var body: some View {
        NavigationStack {
            Group {
                switch model.state {
                case .idle: ContentUnavailableView("Search photos", systemImage: "magnifyingglass")
                case .loading: ProgressView()
                case .loaded(let photos): List(photos) { Text($0.title) }
                case .failed(let message): ContentUnavailableView(message, systemImage: "exclamationmark.triangle")
                }
            }
            .searchable(text: $text)
            .onChange(of: text) { _, new in model.queryChanged(new) }
            .navigationTitle("Photos")
        }
    }
}

• Yes, it compiles
• No: @Observable cannot be used with @MainActor
• No: ContentUnavailableView needs a description