Class NativeEventEmitter

Abstract base class for implementing event-emitting modules. This implements a subset of the standard EventEmitter node module API.

Hierarchy

  • default
    • NativeEventEmitter

Constructors

constructor

Methods

addListener emit listenerCount removeAllListeners removeSubscription

Constructors

constructor

  • new NativeEventEmitter(nativeModule?: NativeModule): NativeEventEmitter

  • Parameters

    • OptionalnativeModule: NativeModule

      the NativeModule implementation. This is required on IOS and will throw an invariant error if undefined.

    Returns NativeEventEmitter

Methods

addListener

  • addListener(
        eventType: string,
        listener: (event: any) => void,
        context?: Object,
    ): EmitterSubscription

  • Add the specified listener, this call passes through to the NativeModule addListener

    Parameters

    • eventType: string

      name of the event for which we are registering listener

    • listener: (event: any) => void

      the listener function

    • Optionalcontext: Object

      context of the listener

    Returns EmitterSubscription

emit

  • emit(eventType: string, ...params: any[]): void

  • Emits an event of the given type with the given data. All handlers of that particular type will be notified.

    Parameters

    • eventType: string

      Name of the event to emit

    • ...params: any[]

    Returns void

    Example

    emitter.addListener('someEvent', function(message) {
        console.log(message);
      });

      emitter.emit('someEvent', 'abc'); // logs 'abc'

listenerCount

  • listenerCount(eventType: string): number

  • Returns the number of listeners that are currently registered for the given event.

    Parameters

    • eventType: string

      Name of the event to query

    Returns number

removeAllListeners

  • removeAllListeners(eventType: string): void

  • Parameters

    • eventType: string

      name of the event whose registered listeners to remove

    Returns void

removeSubscription

  • removeSubscription(subscription: EmitterSubscription): void

  • Removes a subscription created by the addListener, the EventSubscription#remove() function actually calls through to this.

    Parameters

    Returns void

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