How to use Combine sinks

[murataksu740]

I do not open the bug part because the problem may not be related to the library.

    @Published private(set) var current: User?
    
    private let secret: CurrentValueSubject<Secret?, Never> = .init(try? Authenticator.keychain.secrets.get().first)
    
    var bin: Set<AnyCancellable> = []
    
    init() {
        getUser()
        _ = $current.sink { user in
            print(user)
        }
    }
        
    func getUser() {
        secret.removeDuplicates { $0?.identifier == $1?.identifier }
                   .flatMap { secret -> AnyPublisher<User?, Never> in
                       guard let secret = secret else { return Just(nil).eraseToAnyPublisher() }
                       // Fetch the user.
                       return Endpoint.user(secret.identifier)
                           .unlock(with: secret)
                           .session(.instagram)
                           .map(\.user)
                           .catch { _ in Just(nil) }
                           .eraseToAnyPublisher()
                   }
                   .receive(on: RunLoop.main)
                   .assign(to: \.current, on: self)
                   .store(in: &bin)
    }

Value: <empty>

Can anyone help with this?

[sbertix]

Hey @murataksu740,
.
No bugs, your code is just faulty.

First you're not retaining your sink.
You should store(in: &bin) that too instead of discarding the result with _ = .

Your other mistake is that in getUser the publisher only starts streaming when secret changes, not when you actually call it.

init() {
	getUser()
	$current.sink { print($0) }.store(in: &bin)
}
        
func getUser() {
	guard let secret = self.secret.value else { return }
	// Fetch the user.
	Endpoint.user(secret.identifier)
		.unlock(with: secret)
		.session(.instagram)
		.map(\.user)
		.catch { _ in Just(nil) }
		.receive(on: RunLoop.main)
		.assign(to: \.current, on: self)
		.store(in: &bin)
}

You tried to adapt the code in the Followers example without actually capturing what was going on.
Make sure you check out some more resources on Combine to help you better understand what's going on there.