iOS Combine framework @Published doesnt capture post modification values-CodePudding

I noticed that sink is called only once

class StorefrontViewModel {
    @Published var page = 0
        @Published var string = "lorem ipsum"

        private var cancellableBag = Set<AnyCancellable>()

        init() {

            let publisher = $page
                .map { [unowned self] in
                    return $0 == 1 ? self.string.lowercased() : self.string.uppercased()
            }

            publisher
                .eraseToAnyPublisher()
                .assign(to: \.string, on: self)
                .store(in: &cancellableBag) // must store the subscriber to get the events
        }
}

    var pager = StorefrontViewModel()
        pager.$string.sink {  print($0)}
        pager.page = 1 // lorem ipsum
        pager.page = 2 // LOREM IPSUM
        pager.page = 3 // LOREM IPSUM
        pager.page = 4 // LOREM IPSUM
        pager.page = 1 // lorem ipsum
        pager.page = 1 // lorem ipsum

Here is the output LOREM IPSUM.

Wondering why sink is called even though I set pager.page value multiple times

CodePudding user response：

You never stored the cancellation token from sink so the stream was immediately cancelled. In the future, don't ignore the warning the compiler is giving you.