Signal

 
public struct Signal<Payload>
extension Signal: Combine.Publisher

Signal is a typed interface for observing arbitrary values over time.

Signal delegates observers managing logic to the observeImpl closure, but provides flexible interface for observing.

Note

Signal is iOS12-compatible simplified alternative to Combine.Publisher. It’s behavior is aligned with Publisher for easier future migration to Combine. If your app supports iOS >= 13.0, use Signal as Combine.Publisher .

  • Handles received payloads.

    Declaration

    Swift

    public typealias Handler = (Payload) -> Void

  • A closure that implements observing.

    Declaration

    Swift

    public typealias ObserveImpl = (@escaping Handler) -> AnyCancelable

  • Adds an observer closure that will be called every time signal is triggered.

    Note

    Analogous to sink in Combine.

    Declaration

    Swift

    public func observe(_ handler: @escaping Handler) -> AnyCancelable

    Parameters

    handler

    A handler closure.

    Return Value

    Cancellable object that is used to cancel the subscription. If it is canceled or deinited the subscription will be cancelled immediately.

  • Creates a signal.

    Declaration

    Swift

    public init(observeImpl: @escaping ObserveImpl)

    Parameters

    observeImpl

    A closure that implements observing.

  • Declaration

    Swift

    public typealias Output = Payload

  • Declaration

    Swift

    public typealias Failure = Never

  • Declaration

    Swift

    public func receive<S>(subscriber: S) where Payload == S.Input, S : Subscriber, S.Failure == Never

  • Creates a signal that sends payload once to every subscribed.

    Note

    The created signal is analogous to the Combine.Just.

    Declaration

    Swift

    public init(just constant: Payload)

    Parameters

    just

    A payload.

  • Adds an observer closure that will be triggered only once.

    Note

    Analogous to prefix(1).sink in Combine.

    Declaration

    Swift

    public func observeNext(_ handler: @escaping Handler) -> AnyCancelable

    Parameters

    handler

    A handler closure.

    Return Value

    Cancellable object that is used to cancel the subscription. If it is canceled or deinited the subscription will be cancelled immediately.