graalvm/elide.runtime.node.events/EventAware

EventAware

interface EventAware : EventTarget, EventEmitter

Event-Aware

Describes a host-side object which behaves as an EventTarget, with all the internal machinery necessary to receive, dispatch, and manage events and event listeners.

This interface and the accompanying default implementation are designed to be used as JVM proxies. For example:

public class MyObject constructor (private val proxy: EventAware = EventAware.create()) : EventAware by proxy {
  // your object here
}

See the Usage section for more information.

Usage

The EventAware interface is designed to be used as a JVM proxy for host-side objects which need to behave as event-aware types.

Listeners are managed internally on behalf of the proxied object, and can be added and removed using the methods provided by the EventTarget interface.

Once implemented, events can be dispatched to a custom implementation, or to the proxied implementation. Objects are encouraged to dispatch their own events, originating internally, via dispatchEvent.

Interaction with Node Events

Node events can be dispatched through this interface on arbitrary objects; note as well that guest-side objects can implement EventTarget.

Types

Companion

object Companion

Factory methods for event-aware implementations.

Functions

addEventListener

abstract fun addEventListener(type: String, listener: EventListener)

abstract fun addEventListener(type: String, options: AddEventListenerOptions, listener: EventListener)

abstract fun addEventListener(type: String, listener: Value, options: Value?)

Adds a new handler for the type event. Any given listener is added only once per type and per capture option value.

addListener

abstract fun addListener(eventName: String, listener: EventListener)

abstract fun addListener(eventName: String, listener: Value)

Alias for emitter.on(eventName, listener).

abstract override fun close()

dispatchEvent

abstract fun dispatchEvent(event: Event): Boolean

Dispatches the event to the list of handlers for Event.type.

emit

abstract fun emit(eventName: String, vararg args: Any?): Boolean

Synchronously calls each of the listeners registered for the event named eventName, in the order they were registered, passing the supplied arguments to each.

eventNames

abstract fun eventNames(): List<String>

Returns an array listing the events for which the emitter has registered listeners. The values in the array are strings or Symbols.

getMaxListeners

abstract fun getMaxListeners(): Int

Returns the current max listener value for the emitter.

listenerCount

abstract fun listenerCount(eventName: String): Int

Returns the number of listeners listening to the event named eventName.

listeners

abstract fun listeners(eventName: String): List<EventListener>

Returns an array listing the listeners for the specified event.

off

abstract fun off(eventName: String, listener: Value)

Alias for emitter.removeListener(eventName, listener).

abstract fun on(eventName: String, listener: EventListener): EventEmitter

abstract fun on(eventName: String, listener: Value): EventEmitter

Adds the listener function to the end of the listeners array for the event named eventName. No checks are made to see if the listener has already been added.

once

abstract fun once(eventName: String, listener: EventListener)

abstract fun once(eventName: String, listener: Value)

Adds a one-time listener function for the event named eventName. The next time eventName is triggered, this listener is removed and then invoked.

prependListener

abstract fun prependListener(eventName: String, listener: EventListener)

abstract fun prependListener(eventName: String, listener: Value)

Adds the listener function to the beginning of the listeners array for the event named eventName. No checks are made to see if the listener has already been added.

prependOnceListener

abstract fun prependOnceListener(eventName: String, listener: EventListener)

abstract fun prependOnceListener(eventName: String, listener: Value)

Adds a one-time listener function for the event named eventName to the beginning of the listener array. The next time eventName is triggered, this listener is removed, and then invoked.

rawListeners

abstract fun rawListeners(eventName: String): List<EventListener>

Returns a copy of the array of listeners for the event named eventName, including any wrappers (such as those created by .once()).

removeAllListeners

abstract fun removeAllListeners()

Removes all listeners, or those of the specified eventName.

abstract fun removeAllListeners(eventName: String)

Removes all listeners, or those of the specified eventName.

removeEventListener

abstract fun removeEventListener(type: String, listener: EventListener)

abstract fun removeEventListener(type: String, listener: Value)

abstract fun removeEventListener(type: String, listener: EventListener, options: RemoveEventListenerOptions)

abstract fun removeEventListener(type: String, listener: EventListener, options: Value)

abstract fun removeEventListener(type: String, listener: Value, options: Value)

Removes the listener from the list of handlers for event type.

removeListener

abstract fun removeListener(eventName: String, listener: Value)

Removes the specified listener from the listener array for the event named eventName.

setMaxListeners

abstract fun setMaxListeners(count: Int)

Sets the maximum number of listeners for the emitter.