Class Observable

Classdesc

Abstract base class; normally only used for creating subclasses and not instantiated in apps. An event target providing convenient methods for listener registration and unregistration. A generic change event is always available through module:ol/Observable~Observable#changed.

Fires

import("./events/Event.js").default

Api

Hierarchy (view full)

Constructors

constructor

Properties

disposed on once un

Methods

addEventListener changed dispatchEvent dispose disposeInternal getListeners getRevision hasListener onInternal onceInternal removeEventListener unInternal

Constructors

constructor

  • new Observable(): Observable

  • Returns Observable

Properties

Protected disposed

disposed: boolean

The object has already been disposed.

on

on: ObservableOnSignature<EventsKey>

once

once: ObservableOnSignature<EventsKey>

un

un: ObservableOnSignature<void>

Methods

addEventListener

  • addEventListener(type, listener): void

  • Parameters

    • type: string

      Type.

    • listener: Listener

      Listener.

    Returns void

changed

  • changed(): void

  • Increases the revision counter and dispatches a 'change' event.

    Returns void

    Api

dispatchEvent

  • dispatchEvent(event): undefined | boolean

  • Dispatches an event and calls all listeners listening for events of this type. The event parameter can either be a string or an Object with a type property.

    Parameters

    • event: string | BaseEvent

      Event object.

    Returns undefined | boolean

    false if anyone called preventDefault on the event object or if any of the listeners returned false.

    Api

dispose

  • dispose(): void

  • Clean up.

    Returns void

Protected disposeInternal

  • disposeInternal(): void
  • Protected

    Extension point for disposable objects.

    Returns void

getListeners

  • getListeners(type): undefined | Listener[]

  • Get the listeners for a specified event type. Listeners are returned in the order that they will be called in.

    Parameters

    • type: string

      Type.

    Returns undefined | Listener[]

    Listeners.

getRevision

  • getRevision(): number

  • Get the version number for this object. Each time the object is modified, its version number will be incremented.

    Returns number

    Revision.

    Api

hasListener

  • hasListener(type?): boolean

  • Parameters

    • Optional type: string

      Type. If not provided, true will be returned if this event target has any listeners.

    Returns boolean

    Has listeners.

Protected onInternal

  • onInternal(type, listener): EventsKey | EventsKey[]
  • Protected

    Parameters

    • type: string | string[]

      Type.

    • listener: ((arg0) => unknown)

      Listener.

        • (arg0): unknown

        • Parameters

          • arg0: Event | BaseEvent

          Returns unknown

    Returns EventsKey | EventsKey[]

    Event key.

Protected onceInternal

  • onceInternal(type, listener): EventsKey | EventsKey[]
  • Protected

    Parameters

    • type: string | string[]

      Type.

    • listener: ((arg0) => unknown)

      Listener.

        • (arg0): unknown

        • Parameters

          • arg0: Event | BaseEvent

          Returns unknown

    Returns EventsKey | EventsKey[]

    Event key.

removeEventListener

  • removeEventListener(type, listener): void

  • Parameters

    • type: string

      Type.

    • listener: Listener

      Listener.

    Returns void

Protected unInternal

  • unInternal(type, listener): void
  • Protected

    Unlisten for a certain type of event.

    Parameters

    • type: string | string[]

      Type.

    • listener: ((arg0) => unknown)

      Listener.

        • (arg0): unknown

        • Parameters

          • arg0: Event | BaseEvent

          Returns unknown

    Returns void

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