items.swift

public class Items: ObservableObject {    
    @Published public var categories: [Category: [Item]] = [:]
        
    init() {
        for category in Category.allCases {
            _ = NookPlazaAPIService
                .fetch(endpoint: category)
                .replaceError(with: ItemResponse(total: 0, results: []))
                .eraseToAnyPublisher()
                .map{ $0.results }
                .receive(on: DispatchQueue.main)
                .sink(receiveValue: { [weak self] items in self?.categories[category] = items })
        }
    }
}