Class AnyObservableAbstract

A non-type-safe observable implementation meant as a base for more advanced, type safe observables like Observable or AsyncObservable, etc.

Hierarchy (View Summary)

Implements

Constructors

constructor

Properties

equalityCheck listenerMap value

Methods

destroy dispatch getListenerCount listen listenToEvent removeAllListeners removeListener setValue

Constructors

constructor

Properties

equalityCheck

equalityCheck: undefined | EqualityCheck<any>

The function used to check equality between different values. This can be manually set at any time to change the function used.

Protected ReadonlylistenerMap

listenerMap: WeakMap<
    ObservableListener<any>,
    TypedEventListenerWithRemoval<ObservableValueUpdateEvent>,
> = ...

This is necessary so we can fire listeners that listen directly to the value, not the emitted event.

value

value: any

The value currently contained with the observable.

Do not set this directly: use setValue instead. (If you try to set this value directly, it won't fire listeners which defeats the entire purpose of using an observable.

Methods

destroy

  • destroy(): void

    Clean up all listeners and any other internal state.

    Returns void

Protecteddispatch

getListenerCount

  • getListenerCount(): number

    Get a count of all currently attached listeners. If a listener is removed, it will no longer be counted.

    Returns number

listen

  • listen(
        fireImmediately: boolean,
        callback: ObservableListener<any>,
    ): RemoveListenerCallback

    Listen to changes in the observable's value.

    Parameters

    • fireImmediately: boolean

      If true, the callback will immediately be fired with whatever the current value is.

    • callback: ObservableListener<any>

      The callback to fire when a new value is set on the observable.

    Returns RemoveListenerCallback

    A callback to remove the listener.

listenToEvent

  • listenToEvent<
        const EventDefinition extends
            Readonly<
                {
                    type: | "observable-value-update"
                    | "observable-value-resolve"
                    | "observable-value-error"
                    | "observable-destroy"
                    | "observable-callback-call"
                    | "observable-params-update"
                    | "observable-interval-run"
                    | "observable-interval-skip"
                    | "observable-interval-rate-limited";
                },
            >,
    >(
        eventDefinition: EventDefinition,
        listenerCallback: TypedEventListenerWithRemoval<
            ExtractEventByType<ObservableEvents, EventDefinition["type"]>,
        >,
        options?: PartialWithUndefined<{}>,
    ): RemoveListenerCallback

    Listen to any event omitted by the observable rather than just the value changing.

    Type Parameters

    • const EventDefinition extends Readonly<
          {
              type: | "observable-value-update"
              | "observable-value-resolve"
              | "observable-value-error"
              | "observable-destroy"
              | "observable-callback-call"
              | "observable-params-update"
              | "observable-interval-run"
              | "observable-interval-skip"
              | "observable-interval-rate-limited";
          },
      >

    Parameters

    Returns RemoveListenerCallback

    A callback to remove the listener.

removeAllListeners

  • removeAllListeners(): number

    Remove all currently attached event listeners.

    Returns number

    The number of listeners that were removed.

removeListener

  • removeListener(callback: ObservableListener<any>): boolean

    Removes a listener from the observable.

    Parameters

    Returns boolean

    true if the callback was removed. false if the callback was not removed (meaning it was never added in the first place).

setValue

  • setValue(...args: [newValue: any, equalityCheck?: EqualityCheck<any>]): boolean

    Set a new value to the observable. The new value will only be set and listeners will only be fired if the new value is not equal to the current value ("equal" determined by the equalityCheck constructor parameter) or if equality checking is disabled.

    Parameters

    Returns boolean

    true if the new value was set, false otherwise.

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