Class ObserverEmitter<TEvent>Abstract Internal

An emitter implementation consisting of a set of observers.

Type Parameters

  • TEvent

Hierarchy (view full)

Constructors

constructor

Properties

observers

Accessors

observed

Methods

destroy emitEvent filter indexed init map next observe unobserve from

Constructors

constructor

Properties

Private observers

observers: Set<Observer<TEvent>> = ...

Accessors

Protected observed

  • get observed(): boolean

  • Returns boolean

    True if this emitter has any observers, false otherwise.

Methods

Protected destroy

  • destroy(): void

  • Called after all observers have been detached.

    Returns void

Protected emitEvent

  • emitEvent(event): void

  • Emit an event to observers.

    Parameters

    • event: TEvent

      The event to emit.

    Returns void

filter

  • filter(f): Emitter<TEvent>

  • Filter events emitted by this emitter.

    Parameters

    • f: ((event) => boolean)

      The predicate to apply to each event.

        • (event): boolean

        • Parameters

          Returns boolean

    Returns Emitter<TEvent>

    An emitter than only emits events emitted by this emitter for which f returns true.

indexed

  • indexed(): Emitter<number>

  • Creates an emitter that counts events emitted by this emitter.

    Returns Emitter<number>

    An emitter that emits the index, starting at zero, of every event emitted by this emitter.

  • indexed<TOut>(f): Emitter<TOut>

  • Apply a function to all events and their index (starting at zero) emitted by this emitter.

    Type Parameters

    • TOut

    Parameters

    • f: ((event, index) => TOut)

    Returns Emitter<TOut>

    An emitter that applies the function f to all events emitted by this emitter.

Protected init

  • init(): void

  • Called before the first observer is attached.

    Returns void

map

  • map<TOut>(f): Emitter<TOut>

  • Apply a function to all events emitted by this emitter.

    Type Parameters

    • TOut

    Parameters

    • f: ((event) => TOut)

      The function to apply to events.

    Returns Emitter<TOut>

    An emitter that applies the function f to all events emitted by this emitter.

next

  • next(): Promise<TEvent>

  • Create a promise that resolves the next time an event is emitted by this emitter.

    Returns Promise<TEvent>

    A promise that resolves to the next event emitted by this emitter.

observe

  • observe(observer): (() => void)

  • Attach an observer.

    Parameters

    Returns (() => void)

    A function that can be called to detach the observer. Alternatively unobserve can be called.

      • (): void

      • Returns void

unobserve

Static from

  • from<TEvent>(observable): Emitter<TEvent>

  • Create an emitter from another observable (cell or emitter). The resulting emitter emits an even whenever the input observable emits an event.

    Type Parameters

    • TEvent

    Parameters

    Returns Emitter<TEvent>

    An emitter that emits the same events as observable.

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