Observables

public enum Observables

Contains factory methods for creating common Observable instances for use with the Tealium SDK.

  • Creates a custom observable from a subscription handler.

    The handler is invoked every time the returned Observable is subscribed to. Within the handler, call observer.onNext(_:) to emit elements and observer.onComplete() to signal termination.

    The Disposable returned from the handler is disposed when the subscription is externally disposed, allowing the handler to cancel any ongoing work.

    Declaration

    Swift

    static func create<Element>(subscriptionHandler: @escaping Observable<Element>.SubscriptionHandler) -> Observable<Element>

    Parameters

    subscriptionHandler

    A block invoked on each subscription. Receives an Observer and must return a Disposable that will be disposed when the subscription is cancelled.

    Return Value

    An Observable that invokes subscriptionHandler on each subscription.

  • Returns an observable that will send only one event once the asyncFunction has completed.

    Declaration

    Swift

    static func callback<Element>(from asyncFunction: @escaping (@escaping (Element) -> Void) -> Void) -> Observable<Element>

    Parameters

    asyncFunction

    is the function that needs to be called and needs to report the completion to the provided observer. This function will only be called when an observer subscribes to the returned Observable. Every subscription will cause the asyncFunction to be called again.

    Return Value

    a Observable that, when a new observer subscribes, will call the asyncFunction and emit a new event to the subscribers when the function completes.

  • Returns an observable that will send only one event once the asyncFunction has completed.

    Declaration

    Swift

    static func callback<Element>(from asyncFunction: @escaping (@escaping (Element) -> Void) -> any Disposable) -> Observable<Element>

    Parameters

    asyncFunction

    is the function that needs to be called and needs to report the completion to the provided observer. This function will only be called when an observer subscribes to the returned Observable. Every subscription will cause the asyncFunction to be called again. The Disposable returned by this function will be disposed if the subscription is disposed before the event is emitted, allowing to cancel the ongoing work.

    Return Value

    a Observable that, when a new observer subscribes, will call the asyncFunction and emit a new event to the subscribers when the function completes.

  • Returns an observable that just reports the provided elements in order to each new subscriber.

    Declaration

    Swift

    static func just<Element>(_ elements: Element...) -> Observable<Element>

  • Returns an observable that just reports the provided elements in order to each new subscriber.

    Declaration

    Swift

    static func from<Element>(_ elements: [Element]) -> Observable<Element>

  • Returns an observable that completes immediately without emitting any elements.

    Declaration

    Swift

    static func empty<Element>() -> Observable<Element>

  • Combines the latest values from all provided observables into an array.

    The first emission occurs once every source observable has emitted at least one element. After that, a new array is emitted each time any source emits a new value.

    Completion: Completes when all sources complete, or early if any source completes without ever having emitted a value (since a full combination can never be formed).

    Declaration

    Swift

    static func combineLatest<Element>(_ observables: [Observable<Element>]) -> Observable<[Element]>