Class: abstract EventListener<E>

Abstract event listener class.

To create a custom event listener, extend the EventListener class and implement the [listen]EventListener#listen method. The [listen]EventListener#listen method will receive the payload dispatched by EventDispatchService.

You will also need to implement one of the interfaces that is enforced by the EventListenService method you intend to use. For example [EventListenService.on]EventListenService#on requires the EventListenOnInterface interface.

There are additional abstract classes available which have implemented the basic types for you. So far we have EventListenerOn... more to come!

Example

// event payload type
type MyEventPayload = {id: number, active: boolean};
 
// example event class
class MyEvent extends EventSync<MyEventPayload> {}
 
// example listener class
class MyListenOn extends EventListener<MyEvent>
  implements EventListenOnInterface
{
  // default options
  options = {};
 
  // custom handler
  listen(event: MyEvent): void {
    console.log(event.payload);
  }
}
 
// new listener
const myListener = new MyListener();
 
// subscribe to the event
EventListenService.on(MyEvent, myListener);
 
// and you can remove the listener easily
listener.remove();

Extended by

• EventListenerOn

Type Parameters

Implements

• EventListenerInterface<E>

Constructors

new EventListener()

new EventListener<E>(): EventListener<E>

Returns

EventListener<E>

Methods

listen()

abstract listen(event): EventReturnType<E>

Listen to an event.

Parameters

Returns

EventReturnType<E>

Implementation of

EventListenerInterface.listen

Defined in

.tmp/repos/rockets/packages/nestjs-event/src/listeners/event-listener.ts:60 (opens in a new tab)

remove()

remove(): void

Remove the subscription.

Returns

void

Implementation of

EventListenerInterface.remove

Defined in

.tmp/repos/rockets/packages/nestjs-event/src/listeners/event-listener.ts:85 (opens in a new tab)

subscription()

subscription(emitterListener): void

Internal

Called after successful subscription.

Parameters

Returns

void

Implementation of

EventListenerInterface.subscription

Defined in

.tmp/repos/rockets/packages/nestjs-event/src/listeners/event-listener.ts:68 (opens in a new tab)