RoomMember

Defined in: src/models/room-member.ts:87

Typed Event Emitter class which can act as a Base Model for all our model and communication events. This makes it much easier for us to distinguish between events, as we now need to properly type this, so that our events are not stringly-based and prone to silly typos.

Type parameters:

Events - List of all events emitted by this TypedEventEmitter. Normally an enum type.
Arguments - A ListenerMap type providing mappings from event names to listener types.
SuperclassArguments - TODO: not really sure. Alternative listener mappings, I think? But only honoured for .emit?

Extends

TypedEventEmitter<RoomMemberEvent, RoomMemberEventHandlerMap>

Constructors

Constructor

new RoomMember(roomId, userId): RoomMember

Defined in: src/models/room-member.ts:146

Construct a new room member.

Parameters

roomId

string

The room ID of the member.

userId

string

The user ID of the member.

Returns

RoomMember

Overrides

TypedEventEmitter.constructor

Properties

disambiguate

disambiguate: boolean = false

Defined in: src/models/room-member.ts:129

True if the member’s name is disambiguated.

events

events: object = {}

Defined in: src/models/room-member.ts:133

The events describing this RoomMember.

member?

optional member?: DigitalWorldEvent

The m.room.member event for this RoomMember.

membership?

optional membership?: string

Defined in: src/models/room-member.ts:125

The membership state for this room member e.g. ‘join’.

name

name: string

Defined in: src/models/room-member.ts:103

The human-readable name for this room member. Similar to rawDisplayName, but disambiguated with a suffix of “ (@user_id:matrix.org)“ if another member shares the same displayname.

powerLevel

powerLevel: number = 0

Defined in: src/models/room-member.ts:117

The power level for this room member.

rawDisplayName

rawDisplayName: string

Defined in: src/models/room-member.ts:112

The ambiguous displayname of this room member, with some preprocessing:

Direction override characters (RTO and LRO) are removed.
If the displayname is empty, or contains only blank, non-printing, or diacritcic characters, it is replaced with the user ID.

requestedProfileInfo

requestedProfileInfo: boolean = false

Defined in: src/models/room-member.ts:90

roomId

readonly roomId: string

Defined in: src/models/room-member.ts:147

The room ID of the member.

typing

typing: boolean = false

Defined in: src/models/room-member.ts:96

True if the room member is currently typing.

user?

optional user?: User

Defined in: src/models/room-member.ts:121

The User object for this room member, if one exists.

userId

readonly userId: string

Defined in: src/models/room-member.ts:148

The user ID of the member.

captureRejections

static captureRejections: boolean

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:425

Value: boolean

Change the default captureRejections option on all new EventEmitter objects.

Since

v13.4.0, v12.16.0

Inherited from

TypedEventEmitter.captureRejections

captureRejectionSymbol

readonly static captureRejectionSymbol: typeof captureRejectionSymbol

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:418

Value: Symbol.for('nodejs.rejection')

See how to write a custom rejection handler.

Since

v13.4.0, v12.16.0

Inherited from

TypedEventEmitter.captureRejectionSymbol

defaultMaxListeners

static defaultMaxListeners: number

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:464

By default, a maximum of 10 listeners can be registered for any single event. This limit can be changed for individual EventEmitter instances using the emitter.setMaxListeners(n) method. To change the default for allEventEmitter instances, the events.defaultMaxListeners property can be used. If this value is not a positive number, a RangeError is thrown.

Take caution when setting the events.defaultMaxListeners because the change affects all EventEmitter instances, including those created before the change is made. However, calling emitter.setMaxListeners(n) still has precedence over events.defaultMaxListeners.

This is not a hard limit. The EventEmitter instance will allow more listeners to be added but will output a trace warning to stderr indicating that a “possible EventEmitter memory leak” has been detected. For any single EventEmitter, the emitter.getMaxListeners() and emitter.setMaxListeners() methods can be used to temporarily avoid this warning:

import { EventEmitter } from 'node:events';
const emitter = new EventEmitter();
emitter.setMaxListeners(emitter.getMaxListeners() + 1);
emitter.once('event', () => {
  // do stuff
  emitter.setMaxListeners(Math.max(emitter.getMaxListeners() - 1, 0));
});

The --trace-warnings command-line flag can be used to display the stack trace for such warnings.

The emitted warning can be inspected with process.on('warning') and will have the additional emitter, type, and count properties, referring to the event emitter instance, the event’s name and the number of attached listeners, respectively. Its name property is set to 'MaxListenersExceededWarning'.

Since

v0.11.2

Inherited from

TypedEventEmitter.defaultMaxListeners

errorMonitor

readonly static errorMonitor: typeof errorMonitor

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:411

This symbol shall be used to install a listener for only monitoring 'error' events. Listeners installed using this symbol are called before the regular 'error' listeners are called.

Installing a listener using this symbol does not change the behavior once an 'error' event is emitted. Therefore, the process will still crash if no regular 'error' listener is installed.

Since

v13.6.0, v12.17.0

Inherited from

TypedEventEmitter.errorMonitor

Methods

[captureRejectionSymbol]()?

optional [captureRejectionSymbol]<K>(error, event, …args): void

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:103

Type Parameters

K

K

Parameters

error

Error

event

string | symbol

args

…AnyRest

Returns

void

Inherited from

TypedEventEmitter.[captureRejectionSymbol]

addListener()

addListener<T>(event, listener): this

Defined in: src/models/typed-event-emitter.ts:70

Alias for on.

Type Parameters

T

T extends EventEmitterEvents | RoomMemberEvent

Parameters

event

T

listener

Listener<RoomMemberEvent, RoomMemberEventHandlerMap, T>

Returns

this

Inherited from

TypedEventEmitter.addListener

emit()

Call Signature

emit<T>(event, …args): boolean

Defined in: src/models/typed-event-emitter.ts:86

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

Type Parameters

T

T extends RoomMemberEvent

Parameters

event

T

The name of the event to emit

args

…Parameters<RoomMemberEventHandlerMap[T]>

Arguments to pass to the listener

Returns

boolean

true if the event had listeners, false otherwise.

Inherited from

TypedEventEmitter.emit

Call Signature

emit<T>(event, …args): boolean

Defined in: src/models/typed-event-emitter.ts:87

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

Type Parameters

T

T extends RoomMemberEvent

Parameters

event

T

The name of the event to emit

args

…Parameters<RoomMemberEventHandlerMap[T]>

Arguments to pass to the listener

Returns

boolean

true if the event had listeners, false otherwise.

Inherited from

TypedEventEmitter.emit

emitPromised()

Call Signature

emitPromised<T>(event, …args): Promise<boolean>

Defined in: src/models/typed-event-emitter.ts:98

Similar to emit but calls all listeners within a Promise.all and returns the promise chain

Type Parameters

T

T extends RoomMemberEvent

Parameters

event

T

The name of the event to emit

args

…Parameters<RoomMemberEventHandlerMap[T]>

Arguments to pass to the listener

Returns

Promise<boolean>

true if the event had listeners, false otherwise.

Inherited from

TypedEventEmitter.emitPromised

Call Signature

emitPromised<T>(event, …args): Promise<boolean>

Defined in: src/models/typed-event-emitter.ts:102

Similar to emit but calls all listeners within a Promise.all and returns the promise chain

Type Parameters

T

T extends RoomMemberEvent

Parameters

event

T

The name of the event to emit

args

…Parameters<RoomMemberEventHandlerMap[T]>

Arguments to pass to the listener

Returns

Promise<boolean>

true if the event had listeners, false otherwise.

Inherited from

TypedEventEmitter.emitPromised

eventNames()

eventNames(): (string | symbol)[]

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:967

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

import { EventEmitter } from 'node:events';

const myEE = new EventEmitter();
myEE.on('foo', () => {});
myEE.on('bar', () => {});

const sym = Symbol('symbol');
myEE.on(sym, () => {});

console.log(myEE.eventNames());
// Prints: [ 'foo', 'bar', Symbol(symbol) ]

Returns

(string | symbol)[]

Since

v6.0.0

Inherited from

TypedEventEmitter.eventNames

getAvatarUrl()

getAvatarUrl(baseUrl, width, height, resizeMethod, allowDefault?, allowDirectLinks, useAuthentication?): string | null

Defined in: src/models/room-member.ts:391

Get the avatar URL for a room member.

Parameters

baseUrl

string

The base hub URL See DigitalWorldClient#getHubUrl.

width

number

The desired width of the thumbnail.

height

number

The desired height of the thumbnail.

resizeMethod

string

The thumbnail resize method to use, either “crop” or “scale”.

allowDefault?

boolean = true

(optional) Passing false causes this method to return null if the user has no avatar image. Otherwise, a default image URL will be returned. Default: true. (Deprecated)

allowDirectLinks

boolean

(optional) If true, the avatar URL will be returned even if it is a direct hyperlink rather than a content URL. If false, any non-content URLs will be ignored. Setting this option to true will expose URLs that, if fetched, will leak information about the user to anyone who they share a room with.

useAuthentication?

boolean = false

(optional) If true, the caller supports authenticated media and wants an authentication-required URL. Note that server support for authenticated media will not be checked - it is the caller’s responsibility to do so before calling this function. Note also that useAuthentication implies allowRedirects. Defaults to false (unauthenticated endpoints).

Returns

string | null

the avatar URL or null.

getDMInviter()

getDMInviter(): string | undefined

Defined in: src/models/room-member.ts:342

If this member was invited with the is_direct flag set, return the user that invited this member

Returns

string | undefined

user id of the inviter

getLastModifiedTime()

getLastModifiedTime(): number

Defined in: src/models/room-member.ts:325

Get the timestamp when this RoomMember was last updated. This timestamp is updated when properties on this RoomMember are updated. It is updated before firing events.

Returns

number

The timestamp

getMaxListeners()

getMaxListeners(): number

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:819

Returns the current max listener value for the EventEmitter which is either set by emitter.setMaxListeners(n) or defaults to EventEmitter.defaultMaxListeners.

Returns

number

Since

v1.0.0

Inherited from

TypedEventEmitter.getMaxListeners

getMxcAvatarUrl()

getMxcAvatarUrl(): string | undefined

Defined in: src/models/room-member.ts:425

get the mxc avatar url, either from a state event, or from a lazily loaded member

Returns

string | undefined

the mxc avatar url

isKicked()

isKicked(): boolean

Defined in: src/models/room-member.ts:329

Returns

boolean

isOutOfBand()

isOutOfBand(): boolean

Defined in: src/models/room-member.ts:169

Returns

boolean

does the member come from a channel that is not sync? This is used to store the member seperately from the sync state so it available across browser sessions.

listenerCount()

listenerCount(event): number

Defined in: src/models/typed-event-emitter.ts:115

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

Parameters

event

EventEmitterEvents | RoomMemberEvent

The name of the event being listened for

Returns

number

Inherited from

TypedEventEmitter.listenerCount

listeners()

listeners(event): Function[]

Defined in: src/models/typed-event-emitter.ts:122

Returns a copy of the array of listeners for the event named event.

Parameters

event

EventEmitterEvents | RoomMemberEvent

Returns

Function[]

Inherited from

TypedEventEmitter.listeners

markOutOfBand()

markOutOfBand(): void

Defined in: src/models/room-member.ts:160

Mark the member as coming from a channel that is not sync

Returns

void

off()

off<T>(event, listener): this

Defined in: src/models/typed-event-emitter.ts:129

Alias for removeListener

Type Parameters

T

T extends EventEmitterEvents | RoomMemberEvent

Parameters

event

T

listener

Listener<RoomMemberEvent, RoomMemberEventHandlerMap, T>

Returns

this

Inherited from

TypedEventEmitter.off

on()

on<T>(event, listener): this

Defined in: src/models/typed-event-emitter.ts:150

Adds the listener function to the end of the listeners array for the event named event.

No checks are made to see if the listener has already been added. Multiple calls passing the same combination of event and listener will result in the listener being added, and called, multiple times.

By default, event listeners are invoked in the order they are added. The prependListener method can be used as an alternative to add the event listener to the beginning of the listeners array.

Type Parameters

T

T extends EventEmitterEvents | RoomMemberEvent

Parameters

event

T

The name of the event.

listener

Listener<RoomMemberEvent, RoomMemberEventHandlerMap, T>

The callback function

Returns

this

a reference to the EventEmitter, so that calls can be chained.

Inherited from

TypedEventEmitter.on

once()

once<T>(event, listener): this

Defined in: src/models/typed-event-emitter.ts:169

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

Returns a reference to the EventEmitter, so that calls can be chained.

By default, event listeners are invoked in the order they are added. The prependOnceListener method can be used as an alternative to add the event listener to the beginning of the listeners array.

Type Parameters

T

T extends EventEmitterEvents | RoomMemberEvent

Parameters

event

T

The name of the event.

listener

Listener<RoomMemberEvent, RoomMemberEventHandlerMap, T>

The callback function

Returns

this

a reference to the EventEmitter, so that calls can be chained.

Inherited from

TypedEventEmitter.once

prependListener()

prependListener<T>(event, listener): this

Defined in: src/models/typed-event-emitter.ts:186

Adds the listener function to the beginning of the listeners array for the event named event.

Type Parameters

T

T extends EventEmitterEvents | RoomMemberEvent

Parameters

event

T

The name of the event.

listener

Listener<RoomMemberEvent, RoomMemberEventHandlerMap, T>

The callback function

Returns

this

a reference to the EventEmitter, so that calls can be chained.

Inherited from

TypedEventEmitter.prependListener

prependOnceListener()

prependOnceListener<T>(event, listener): this

Defined in: src/models/typed-event-emitter.ts:202

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

Type Parameters

T

T extends EventEmitterEvents | RoomMemberEvent

Parameters

event

T

The name of the event.

listener

Listener<RoomMemberEvent, RoomMemberEventHandlerMap, T>

The callback function

Returns

this

a reference to the EventEmitter, so that calls can be chained.

Inherited from

TypedEventEmitter.prependOnceListener

rawListeners()

rawListeners(event): Function[]

Defined in: src/models/typed-event-emitter.ts:243

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

Parameters

event

EventEmitterEvents | RoomMemberEvent

Returns

Function[]

Inherited from

TypedEventEmitter.rawListeners

recalculateDisambiguatedName()

recalculateDisambiguatedName(roomState): boolean

Defined in: src/models/room-member.ts:241

Recalculate the disambiguation flag for this member based on current room state. This should be called when another member’s display name changes and may affect whether this member needs disambiguation.

Parameters

roomState

RoomState

The current room state to use for disambiguation check

Returns

boolean

true if the member’s name changed as a result of the disambiguation update

Remarks

Fires RoomMemberEvent.Name

removeAllListeners()

removeAllListeners(event?): this

Defined in: src/models/typed-event-emitter.ts:219

Removes all listeners, or those of the specified event.

It is bad practice to remove listeners added elsewhere in the code, particularly when the EventEmitter instance was created by some other component or module (e.g. sockets or file streams).

Parameters

event?

EventEmitterEvents | RoomMemberEvent

The name of the event. If undefined, all listeners everywhere are removed.

Returns

this

a reference to the EventEmitter, so that calls can be chained.

Inherited from

TypedEventEmitter.removeAllListeners

removeListener()

removeListener<T>(event, listener): this

Defined in: src/models/typed-event-emitter.ts:232

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

Type Parameters

T

T extends EventEmitterEvents | RoomMemberEvent

Parameters

event

T

listener

Listener<RoomMemberEvent, RoomMemberEventHandlerMap, T>

Returns

this

a reference to the EventEmitter, so that calls can be chained.

Inherited from

TypedEventEmitter.removeListener

setMaxListeners()

setMaxListeners(n): this

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:813

By default EventEmitters will print a warning if more than 10 listeners are added for a particular event. This is a useful default that helps finding memory leaks. The emitter.setMaxListeners() method allows the limit to be modified for this specific EventEmitter instance. The value can be set to Infinity (or 0) to indicate an unlimited number of listeners.

Returns a reference to the EventEmitter, so that calls can be chained.

Parameters

n

number

Returns

this

Since

v0.3.5

Inherited from

TypedEventEmitter.setMaxListeners

setMembershipEvent()

setMembershipEvent(event, roomState?): void

Defined in: src/models/room-member.ts:184

Update this room member’s membership event. May fire “RoomMember.name” if this event updates this member’s name.

Parameters

event

DigitalWorldEvent

The m.room.member event

roomState?

RoomState

Optional. The room state to take into account when calculating (e.g. for disambiguating users with the same name).

Returns

void

Remarks

Fires RoomMemberEvent.Name Fires RoomMemberEvent.Membership

setPowerLevel()

setPowerLevel(powerLevel, powerLevelEvent): void

Defined in: src/models/room-member.ts:274

Update this room member’s power level event. Will fire “RoomMember.powerLevel” if the new power level is different

Parameters

powerLevel

number

The power level of the room member.

powerLevelEvent

DigitalWorldEvent

Returns

void

Remarks

Fires RoomMemberEvent.PowerLevel

setTypingEvent()

setTypingEvent(event): void

Defined in: src/models/room-member.ts:292

Update this room member’s typing event. May fire “RoomMember.typing” if this event changes this member’s typing state.

Parameters

event

DigitalWorldEvent

The typing event

Returns

void

Remarks

Fires RoomMemberEvent.Typing

addAbortListener()

static addAbortListener(signal, resource): Disposable

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:403

Listens once to the abort event on the provided signal.

Listening to the abort event on abort signals is unsafe and may lead to resource leaks since another third party with the signal can call e.stopImmediatePropagation(). Unfortunately Node.js cannot change this since it would violate the web standard. Additionally, the original API makes it easy to forget to remove listeners.

This API allows safely using AbortSignals in Node.js APIs by solving these two issues by listening to the event such that stopImmediatePropagation does not prevent the listener from running.

Returns a disposable so that it may be unsubscribed from more easily.

import { addAbortListener } from 'node:events';

function example(signal) {
  let disposable;
  try {
    signal.addEventListener('abort', (e) => e.stopImmediatePropagation());
    disposable = addAbortListener(signal, (e) => {
      // Do something when signal is aborted.
    });
  } finally {
    disposable?.[Symbol.dispose]();
  }
}

Parameters

signal

AbortSignal

resource

(event) => void

Returns

Disposable

Disposable that removes the abort listener.

Since

v20.5.0

Inherited from

TypedEventEmitter.addAbortListener

getEventListeners()

static getEventListeners(emitter, name): Function[]

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:325

Returns a copy of the array of listeners for the event named eventName.

For EventEmitters this behaves exactly the same as calling .listeners on the emitter.

For EventTargets this is the only way to get the event listeners for the event target. This is useful for debugging and diagnostic purposes.

import { getEventListeners, EventEmitter } from 'node:events';

{
  const ee = new EventEmitter();
  const listener = () => console.log('Events are fun');
  ee.on('foo', listener);
  console.log(getEventListeners(ee, 'foo')); // [ [Function: listener] ]
}
{
  const et = new EventTarget();
  const listener = () => console.log('Events are fun');
  et.addEventListener('foo', listener);
  console.log(getEventListeners(et, 'foo')); // [ [Function: listener] ]
}

Parameters

emitter

EventEmitter<DefaultEventMap> | EventTarget

name

string | symbol

Returns

Function[]

Since

v15.2.0, v14.17.0

Inherited from

TypedEventEmitter.getEventListeners

getMaxListeners()

static getMaxListeners(emitter): number

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:354

Returns the currently set max amount of listeners.

For EventEmitters this behaves exactly the same as calling .getMaxListeners on the emitter.

For EventTargets this is the only way to get the max event listeners for the event target. If the number of event handlers on a single EventTarget exceeds the max set, the EventTarget will print a warning.

import { getMaxListeners, setMaxListeners, EventEmitter } from 'node:events';

{
  const ee = new EventEmitter();
  console.log(getMaxListeners(ee)); // 10
  setMaxListeners(11, ee);
  console.log(getMaxListeners(ee)); // 11
}
{
  const et = new EventTarget();
  console.log(getMaxListeners(et)); // 10
  setMaxListeners(11, et);
  console.log(getMaxListeners(et)); // 11
}

Parameters

emitter

EventEmitter<DefaultEventMap> | EventTarget

Returns

number

Since

v19.9.0

Inherited from

TypedEventEmitter.getMaxListeners

listenerCount()

static listenerCount(emitter, eventName): number

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:297

A class method that returns the number of listeners for the given eventName registered on the given emitter.

import { EventEmitter, listenerCount } from 'node:events';

const myEmitter = new EventEmitter();
myEmitter.on('event', () => {});
myEmitter.on('event', () => {});
console.log(listenerCount(myEmitter, 'event'));
// Prints: 2

Parameters

emitter

EventEmitter

The emitter to query

eventName

string | symbol

The event name

Returns

number

Since

v0.9.12

Inherited from

TypedEventEmitter.listenerCount

on()

Call Signature

static on(emitter, eventName, options?): AsyncIterator<any[]>

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:270

import { on, EventEmitter } from 'node:events';
import process from 'node:process';

const ee = new EventEmitter();

// Emit later on
process.nextTick(() => {
  ee.emit('foo', 'bar');
  ee.emit('foo', 42);
});

for await (const event of on(ee, 'foo')) {
  // The execution of this inner block is synchronous and it
  // processes one event at a time (even with await). Do not use
  // if concurrent execution is required.
  console.log(event); // prints ['bar'] [42]
}
// Unreachable here

Returns an AsyncIterator that iterates eventName events. It will throw if the EventEmitter emits 'error'. It removes all listeners when exiting the loop. The value returned by each iteration is an array composed of the emitted event arguments.

An AbortSignal can be used to cancel waiting on events:

import { on, EventEmitter } from 'node:events';
import process from 'node:process';

const ac = new AbortController();

(async () => {
  const ee = new EventEmitter();

  // Emit later on
  process.nextTick(() => {
    ee.emit('foo', 'bar');
    ee.emit('foo', 42);
  });

  for await (const event of on(ee, 'foo', { signal: ac.signal })) {
    // The execution of this inner block is synchronous and it
    // processes one event at a time (even with await). Do not use
    // if concurrent execution is required.
    console.log(event); // prints ['bar'] [42]
  }
  // Unreachable here
})();

process.nextTick(() => ac.abort());

Use the close option to specify an array of event names that will end the iteration:

import { on, EventEmitter } from 'node:events';
import process from 'node:process';

const ee = new EventEmitter();

// Emit later on
process.nextTick(() => {
  ee.emit('foo', 'bar');
  ee.emit('foo', 42);
  ee.emit('close');
});

for await (const event of on(ee, 'foo', { close: ['close'] })) {
  console.log(event); // prints ['bar'] [42]
}
// the loop will exit after 'close' is emitted
console.log('done'); // prints 'done'

Parameters

emitter

EventEmitter

eventName

string | symbol

options?

StaticEventEmitterIteratorOptions

Returns

AsyncIterator<any[]>

An AsyncIterator that iterates eventName events emitted by the emitter

Since

v13.6.0, v12.16.0

Inherited from

TypedEventEmitter.on

Call Signature

static on(emitter, eventName, options?): AsyncIterator<any[]>

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:275

import { on, EventEmitter } from 'node:events';
import process from 'node:process';

const ee = new EventEmitter();

// Emit later on
process.nextTick(() => {
  ee.emit('foo', 'bar');
  ee.emit('foo', 42);
});

for await (const event of on(ee, 'foo')) {
  // The execution of this inner block is synchronous and it
  // processes one event at a time (even with await). Do not use
  // if concurrent execution is required.
  console.log(event); // prints ['bar'] [42]
}
// Unreachable here

An AbortSignal can be used to cancel waiting on events:

import { on, EventEmitter } from 'node:events';
import process from 'node:process';

const ac = new AbortController();

(async () => {
  const ee = new EventEmitter();

  // Emit later on
  process.nextTick(() => {
    ee.emit('foo', 'bar');
    ee.emit('foo', 42);
  });

  for await (const event of on(ee, 'foo', { signal: ac.signal })) {
    // The execution of this inner block is synchronous and it
    // processes one event at a time (even with await). Do not use
    // if concurrent execution is required.
    console.log(event); // prints ['bar'] [42]
  }
  // Unreachable here
})();

process.nextTick(() => ac.abort());

Use the close option to specify an array of event names that will end the iteration:

import { on, EventEmitter } from 'node:events';
import process from 'node:process';

const ee = new EventEmitter();

// Emit later on
process.nextTick(() => {
  ee.emit('foo', 'bar');
  ee.emit('foo', 42);
  ee.emit('close');
});

for await (const event of on(ee, 'foo', { close: ['close'] })) {
  console.log(event); // prints ['bar'] [42]
}
// the loop will exit after 'close' is emitted
console.log('done'); // prints 'done'

Parameters

emitter

EventTarget

eventName

string

options?

StaticEventEmitterIteratorOptions

Returns

AsyncIterator<any[]>

An AsyncIterator that iterates eventName events emitted by the emitter

Since

v13.6.0, v12.16.0

Inherited from

TypedEventEmitter.on

once()

Call Signature

static once(emitter, eventName, options?): Promise<any[]>

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:184

Creates a Promise that is fulfilled when the EventEmitter emits the given event or that is rejected if the EventEmitter emits 'error' while waiting. The Promise will resolve with an array of all the arguments emitted to the given event.

This method is intentionally generic and works with the web platform EventTarget interface, which has no special'error' event semantics and does not listen to the 'error' event.

import { once, EventEmitter } from 'node:events';
import process from 'node:process';

const ee = new EventEmitter();

process.nextTick(() => {
  ee.emit('myevent', 42);
});

const [value] = await once(ee, 'myevent');
console.log(value);

const err = new Error('kaboom');
process.nextTick(() => {
  ee.emit('error', err);
});

try {
  await once(ee, 'myevent');
} catch (err) {
  console.error('error happened', err);
}

The special handling of the 'error' event is only used when events.once() is used to wait for another event. If events.once() is used to wait for the ’error' event itself, then it is treated as any other kind of event without special handling:

import { EventEmitter, once } from 'node:events';

const ee = new EventEmitter();

once(ee, 'error')
  .then(([err]) => console.log('ok', err.message))
  .catch((err) => console.error('error', err.message));

ee.emit('error', new Error('boom'));

// Prints: ok boom

An AbortSignal can be used to cancel waiting for the event:

import { EventEmitter, once } from 'node:events';

const ee = new EventEmitter();
const ac = new AbortController();

async function foo(emitter, event, signal) {
  try {
    await once(emitter, event, { signal });
    console.log('event emitted!');
  } catch (error) {
    if (error.name === 'AbortError') {
      console.error('Waiting for the event was canceled!');
    } else {
      console.error('There was an error', error.message);
    }
  }
}

foo(ee, 'foo', ac.signal);
ac.abort(); // Abort waiting for the event
ee.emit('foo'); // Prints: Waiting for the event was canceled!

Parameters

emitter

EventEmitter

eventName

string | symbol

options?

StaticEventEmitterOptions

Returns

Promise<any[]>

Since

v11.13.0, v10.16.0

Inherited from

TypedEventEmitter.once

Call Signature

static once(emitter, eventName, options?): Promise<any[]>

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:189

This method is intentionally generic and works with the web platform EventTarget interface, which has no special'error' event semantics and does not listen to the 'error' event.

import { once, EventEmitter } from 'node:events';
import process from 'node:process';

const ee = new EventEmitter();

process.nextTick(() => {
  ee.emit('myevent', 42);
});

const [value] = await once(ee, 'myevent');
console.log(value);

const err = new Error('kaboom');
process.nextTick(() => {
  ee.emit('error', err);
});

try {
  await once(ee, 'myevent');
} catch (err) {
  console.error('error happened', err);
}

import { EventEmitter, once } from 'node:events';

const ee = new EventEmitter();

once(ee, 'error')
  .then(([err]) => console.log('ok', err.message))
  .catch((err) => console.error('error', err.message));

ee.emit('error', new Error('boom'));

// Prints: ok boom

An AbortSignal can be used to cancel waiting for the event:

import { EventEmitter, once } from 'node:events';

const ee = new EventEmitter();
const ac = new AbortController();

async function foo(emitter, event, signal) {
  try {
    await once(emitter, event, { signal });
    console.log('event emitted!');
  } catch (error) {
    if (error.name === 'AbortError') {
      console.error('Waiting for the event was canceled!');
    } else {
      console.error('There was an error', error.message);
    }
  }
}

foo(ee, 'foo', ac.signal);
ac.abort(); // Abort waiting for the event
ee.emit('foo'); // Prints: Waiting for the event was canceled!

Parameters

emitter

EventTarget

eventName

string

options?

StaticEventEmitterOptions

Returns

Promise<any[]>

Since

v11.13.0, v10.16.0

Inherited from

TypedEventEmitter.once

setMaxListeners()

static setMaxListeners(n?, …eventTargets): void

Defined in: node_modules/.pnpm/@types+node@22.20.0/node_modules/@types/node/events.d.ts:369

import { setMaxListeners, EventEmitter } from 'node:events';

const target = new EventTarget();
const emitter = new EventEmitter();

setMaxListeners(5, target, emitter);

Parameters

n?

number

A non-negative number. The maximum number of listeners per EventTarget event.

eventTargets

…(EventEmitter<DefaultEventMap> | EventTarget)[]

Zero or more {EventTarget} or {EventEmitter} instances. If none are specified, n is set as the default max for all newly created {EventTarget} and {EventEmitter} objects.

Returns

void

Since

v15.4.0

Inherited from

TypedEventEmitter.setMaxListeners