CODEWITHSUNDEEP
swiftswiftuilldb
Frederick C. Lee
Frederick C. Lee

Reputation: 9493

Unable to view a passing SwiftUI parameter value via debugger

Scenario: I want to look at a parameter of the CountryRegionListModel() in the debugger.
The following are the view and it's dependent model snippets:

enter image description here

import Combine
import UIKit

protocol URLResource {
    associatedtype DataModel: Decodable
    var url: URL? { get }
}

struct CovidResource<T: Decodable>: URLResource {
    typealias DataModel = T
    var url = URL(string: "https://disease.sh/v3/covid-19/apple/countries/Canada")
}

// =====================================================================================================

class CountryRegionListModel: ObservableObject {
    @Published var countryRegionList: [String] = []

    // Data Persistence:
    var cancellables: Set<AnyCancellable> = []

    // ---------------------------------------------------------------------------

    func getList<Resource>(urlDataModel: Resource) where Resource: URLResource {
        let remoteDataPublisher = URLSession.shared.dataTaskPublisher(for: urlDataModel.url!)
            .map(\.data)
            .receive(on: DispatchQueue.main)
            .decode(type: Resource.DataModel.self, decoder: JSONDecoder())

        remoteDataPublisher
            .sink(receiveCompletion: { completion in
                switch completion {
                case .finished:
                    print("Publisher Finished")
                case let .failure(anError):
                    Swift.print("received error: ", anError)
                }
            }, receiveValue: { [self] someValue in
                self.countryRegionList = someValue as! [String]
            }).store(in: &cancellables)
    }
}

Here I'm calling a child picker view to display the data that is injected into it.
I want to check this data: countryListViewModel.countryRegionList via the debugger: 

CountryRegionPickerView(countryRegionList: $countryListViewModel.countryRegionList)

enter image description here

I don't understand why this is occurring.
How can I check to see if I got data passing into the child view?

Upvotes: 0

Views: 60

Answers (1)

rob mayoff
rob mayoff

Reputation: 385500

Since your countryListViewModel is stored in a property wrapper, there is no stored property named countryListViewModel. Instead the stored property is named _countryListViewModel. The debugger doesn't understand this (possibly because the compiler isn't explaining it properly in the debug info).

The countryListViewModel property is actually a computed property, and its getter is essentially just _countryListViewModel.wrappedValue. So try this instead:

po _countryListViewModel.wrappedValue.countryRegionList

Or (since countryRegionList is also a wrapped property) possibly this:

po _countryListViewModel.wrappedValue._countryRegionList.wrappedValue

Upvotes: 1

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