Client

Defined in: src/Client.ts:14

Extends

EventEmitter

Constructors

Constructor

new Client(token, options?): Client

Defined in: src/Client.ts:227

Parameters

token

string

options?

defaultFormattingMode?

FormattingMode

defaultName?

string

Returns

Client

Properties

capabilities

capabilities: Capability[]

Defined in: src/Client.ts:24

List of capabilities this chatbox license can do. Typically, guest connections can only use read. Connections with a license will usually have read, command and tell.

defaultFormattingMode

defaultFormattingMode: FormattingMode

Defined in: src/Client.ts:45

Default formatting mode for say and tell messages. Defaults to “markdown”

defaultName

defaultName: undefined | string

Defined in: src/Client.ts:39

Default name for chatbox messages

endpoint

endpoint: string

Defined in: src/Client.ts:34

Endpoint of the Chatbox server. Must include wss:// and the version route. Defaults to wss://chat.reconnected.cc/v2/.

owner

owner: string

Defined in: src/Client.ts:18

Minecraft username of the owner of the chatbox license

players

players: User[]

Defined in: src/Client.ts:29

List of currently online players

running

running: boolean

Defined in: src/Client.ts:47

waitTimeRestart

waitTimeRestart: number = 60000

Defined in: src/Client.ts:215

captureRejections

static captureRejections: boolean

Defined in: node_modules/@types/node/events.d.ts:459

Value: boolean

Change the default captureRejections option on all new EventEmitter objects.

Since

v13.4.0, v12.16.0

captureRejectionSymbol

readonly static captureRejectionSymbol: typeof captureRejectionSymbol

Defined in: node_modules/@types/node/events.d.ts:452

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

See how to write a custom rejection handler.

Since

v13.4.0, v12.16.0

defaultMaxListeners

static defaultMaxListeners: number

Defined in: node_modules/@types/node/events.d.ts:498

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

errorMonitor

readonly static errorMonitor: typeof errorMonitor

Defined in: node_modules/@types/node/events.d.ts:445

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

Methods

[captureRejectionSymbol]()?

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

Defined in: node_modules/@types/node/events.d.ts:136

Type Parameters

K

K

Parameters

error

Error

event

string | symbol

args

…AnyRest

Returns

void

addListener()

addListener<K>(eventName, listener): this

Defined in: node_modules/@types/node/events.d.ts:597

Alias for emitter.on(eventName, listener).

Type Parameters

K

K

Parameters

eventName

string | symbol

listener

(…args) => void

Returns

this

Since

v0.1.26

close()

Call Signature

close(soft?): void

Defined in: src/Client.ts:59

Close the connection to the Chatbox server

Parameters

soft?

boolean

Keep running status as is

Returns

void

Call Signature

close(soft?): void

Defined in: src/Client.ts:317

Close the connection to the Chatbox server

Parameters

soft?

boolean

Keep running status as is

Returns

void

connect()

Call Signature

connect(callback?): void

Defined in: src/Client.ts:53

Connect to the Chatbox server

Parameters

callback?

(client?) => void

Callback to run when the connection is open

Returns

void

Call Signature

connect(callback?): void

Defined in: src/Client.ts:301

Connect to the Chatbox server

Parameters

callback?

(client?) => void

Callback to run when the connection is open

Returns

void

emit()

emit<K>(eventName, …args): boolean

Defined in: node_modules/@types/node/events.d.ts:859

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

Returns true if the event had listeners, false otherwise.

import { EventEmitter } from 'node:events';
const myEmitter = new EventEmitter();

// First listener
myEmitter.on('event', function firstListener() {
  console.log('Helloooo! first listener');
});
// Second listener
myEmitter.on('event', function secondListener(arg1, arg2) {
  console.log(`event with parameters ${arg1}, ${arg2} in second listener`);
});
// Third listener
myEmitter.on('event', function thirdListener(...args) {
  const parameters = args.join(', ');
  console.log(`event with parameters ${parameters} in third listener`);
});

console.log(myEmitter.listeners('event'));

myEmitter.emit('event', 1, 2, 3, 4, 5);

// Prints:
// [
//   [Function: firstListener],
//   [Function: secondListener],
//   [Function: thirdListener]
// ]
// Helloooo! first listener
// event with parameters 1, 2 in second listener
// event with parameters 1, 2, 3, 4, 5 in third listener

Type Parameters

K

K

Parameters

eventName

string | symbol

args

…AnyRest

Returns

boolean

Since

v0.1.26

eventNames()

eventNames(): (string | symbol)[]

Defined in: node_modules/@types/node/events.d.ts:922

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

getMaxListeners()

getMaxListeners(): number

Defined in: node_modules/@types/node/events.d.ts:774

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

Returns

number

Since

v1.0.0

listenerCount()

listenerCount<K>(eventName, listener?): number

Defined in: node_modules/@types/node/events.d.ts:868

Returns the number of listeners listening for the event named eventName. If listener is provided, it will return how many times the listener is found in the list of the listeners of the event.

Type Parameters

K

K

Parameters

eventName

The name of the event being listened for

string | symbol

listener?

Function

The event handler function

Returns

number

Since

v3.2.0

listeners()

listeners<K>(eventName): Function[]

Defined in: node_modules/@types/node/events.d.ts:787

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

server.on('connection', (stream) => {
  console.log('someone connected!');
});
console.log(util.inspect(server.listeners('connection')));
// Prints: [ [Function] ]

Type Parameters

K

K

Parameters

eventName

string | symbol

Returns

Function[]

Since

v0.1.26

off()

off<K>(eventName, listener): this

Defined in: node_modules/@types/node/events.d.ts:747

Alias for emitter.removeListener().

Type Parameters

K

K

Parameters

eventName

string | symbol

listener

(…args) => void

Returns

this

Since

v10.0.0

on()

Call Signature

on(event, listener): this

on(event, listener): this

Defined in: src/Client.ts:130

The event received when a player posts a message in public chat. The read capability is required to receive chat events.

Parameters

event

"chat_ingame"

listener

(message) => void

Returns

this

Event

Call Signature

on(event, listener): this

Defined in: src/Client.ts:137

The event received when a player posts a message in Discord. The read capability is required to receive chat events.

Parameters

event

"chat_discord"

listener

(message) => void

Returns

this

Event

Call Signature

on(event, listener): this

Defined in: src/Client.ts:144

The event received when another chatbox sends a message. The read capability is required to receive chat events.

Parameters

event

"chat_chatbox"

listener

(message) => void

Returns

this

Event

Call Signature

on(event, listener): this

Defined in: src/Client.ts:152

The event received when a player runs a chatbox command (public backslash commands: \command, private owner-only caret/pipe commands: ^command) in-game. The command capability is required to receive command events.

Parameters

event

"command"

listener

(command) => void

Returns

this

Event

Call Signature

on(event, listener): this

Defined in: src/Client.ts:158

The event received when a player joins the game.

Parameters

event

"join"

listener

(join) => void

Returns

this

Event

Call Signature

on(event, listener): this

Defined in: src/Client.ts:164

The event received when a player leaves the game.

Parameters

event

"leave"

listener

(leave) => void

Returns

this

Event

Call Signature

on(event, listener): this

Defined in: src/Client.ts:170

The event received when a player dies in-game.

Parameters

event

"death"

listener

(death) => void

Returns

this

Event

Call Signature

on(event, listener): this

Defined in: src/Client.ts:176

The event received when a player changes world.

Parameters

event

"world_change"

listener

(worldChange) => void

Returns

this

Event

Call Signature

on(event, listener): this

Defined in: src/Client.ts:182

The event received when a player goes AFK in-game.

Parameters

event

"afk"

listener

(afk) => void

Returns

this

Event

Call Signature

on(event, listener): this

Defined in: src/Client.ts:188

The event received when a player returns from being AFK in-game.

Parameters

event

"afk_return"

listener

(afkReturn) => void

Returns

this

Event

Call Signature

on(event, listener): this

Defined in: src/Client.ts:197

The event received when a server restart has been scheduled. At the time of restartAt, the server will restart and the websocket will be disconnected.

Parameters

event

"server_restart_scheduled"

listener

(event) => void

Returns

this

See

https://docs.reconnected.cc/chatbox/websocket.html#server-restart-scheduled-event

Event

Call Signature

on(event, listener): this

Defined in: src/Client.ts:205

The event received when a previously scheduled server restart has now been cancelled.

Parameters

event

"server_restart_cancelled"

listener

(event) => void

Returns

this

See

https://docs.reconnected.cc/chatbox/websocket.html#server-restart-cancelled-event

Event

once()

once<K>(eventName, listener): this

Defined in: node_modules/@types/node/events.d.ts:659

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

server.once('connection', (stream) => {
  console.log('Ah, we have our first user!');
});

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 emitter.prependOnceListener() method can be used as an alternative to add the event listener to the beginning of the listeners array.

import { EventEmitter } from 'node:events';
const myEE = new EventEmitter();
myEE.once('foo', () => console.log('a'));
myEE.prependOnceListener('foo', () => console.log('b'));
myEE.emit('foo');
// Prints:
//   b
//   a

Type Parameters

K

K

Parameters

eventName

The name of the event.

string | symbol

listener

(…args) => void

The callback function

Returns

this

Since

v0.3.0

prependListener()

prependListener<K>(eventName, listener): this

Defined in: node_modules/@types/node/events.d.ts:886

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. Multiple calls passing the same combination of eventName and listener will result in the listener being added, and called, multiple times.

server.prependListener('connection', (stream) => {
  console.log('someone connected!');
});

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

Type Parameters

K

K

Parameters

eventName

The name of the event.

string | symbol

listener

(…args) => void

The callback function

Returns

this

Since

v6.0.0

prependOnceListener()

prependOnceListener<K>(eventName, listener): this

Defined in: node_modules/@types/node/events.d.ts:902

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

server.prependOnceListener('connection', (stream) => {
  console.log('Ah, we have our first user!');
});

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

Type Parameters

K

K

Parameters

eventName

The name of the event.

string | symbol

listener

(…args) => void

The callback function

Returns

this

Since

v6.0.0

rawListeners()

rawListeners<K>(eventName): Function[]

Defined in: node_modules/@types/node/events.d.ts:818

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

import { EventEmitter } from 'node:events';
const emitter = new EventEmitter();
emitter.once('log', () => console.log('log once'));

// Returns a new Array with a function `onceWrapper` which has a property
// `listener` which contains the original listener bound above
const listeners = emitter.rawListeners('log');
const logFnWrapper = listeners[0];

// Logs "log once" to the console and does not unbind the `once` event
logFnWrapper.listener();

// Logs "log once" to the console and removes the listener
logFnWrapper();

emitter.on('log', () => console.log('log persistently'));
// Will return a new Array with a single function bound by `.on()` above
const newListeners = emitter.rawListeners('log');

// Logs "log persistently" twice
newListeners[0]();
emitter.emit('log');

Type Parameters

K

K

Parameters

eventName

string | symbol

Returns

Function[]

Since

v9.4.0

reconnect()

Call Signature

reconnect(wait?): void

Defined in: src/Client.ts:65

Close and reconnect to the Chatbox server

Parameters

wait?

boolean

Whether to wait before reconnecting.

Returns

void

Call Signature

reconnect(wait): void

Defined in: src/Client.ts:327

Close and reconnect to the Chatbox server

Parameters

wait

boolean = false

Whether to wait before reconnecting.

Returns

void

removeAllListeners()

removeAllListeners(eventName?): this

Defined in: node_modules/@types/node/events.d.ts:758

Removes all listeners, or those of the specified eventName.

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).

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

Parameters

eventName?

string | symbol

Returns

this

Since

v0.1.26

removeListener()

removeListener<K>(eventName, listener): this

Defined in: node_modules/@types/node/events.d.ts:742

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

const callback = (stream) => {
  console.log('someone connected!');
};
server.on('connection', callback);
// ...
server.removeListener('connection', callback);

removeListener() will remove, at most, one instance of a listener from the listener array. If any single listener has been added multiple times to the listener array for the specified eventName, then removeListener() must be called multiple times to remove each instance.

Once an event is emitted, all listeners attached to it at the time of emitting are called in order. This implies that any removeListener() or removeAllListeners() calls after emitting and before the last listener finishes execution will not remove them fromemit() in progress. Subsequent events behave as expected.

import { EventEmitter } from 'node:events';
class MyEmitter extends EventEmitter {}
const myEmitter = new MyEmitter();

const callbackA = () => {
  console.log('A');
  myEmitter.removeListener('event', callbackB);
};

const callbackB = () => {
  console.log('B');
};

myEmitter.on('event', callbackA);

myEmitter.on('event', callbackB);

// callbackA removes listener callbackB but it will still be called.
// Internal listener array at time of emit [callbackA, callbackB]
myEmitter.emit('event');
// Prints:
//   A
//   B

// callbackB is now removed.
// Internal listener array [callbackA]
myEmitter.emit('event');
// Prints:
//   A

Because listeners are managed using an internal array, calling this will change the position indices of any listener registered after the listener being removed. This will not impact the order in which listeners are called, but it means that any copies of the listener array as returned by the emitter.listeners() method will need to be recreated.

When a single function has been added as a handler multiple times for a single event (as in the example below), removeListener() will remove the most recently added instance. In the example the once('ping') listener is removed:

import { EventEmitter } from 'node:events';
const ee = new EventEmitter();

function pong() {
  console.log('pong');
}

ee.on('ping', pong);
ee.once('ping', pong);
ee.removeListener('ping', pong);

ee.emit('ping');
ee.emit('ping');

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

Type Parameters

K

K

Parameters

eventName

string | symbol

listener

(…args) => void

Returns

this

Since

v0.1.26

say()

Call Signature

say(text, name?, mode?): Promise<Success>

Defined in: src/Client.ts:85

Sends a message to the in-game public chat.

Parameters

text

The message to send.

string | User

name?

string

The name of the chatbox to show. If no name is specified, it will default to the username of the license owner.

mode?

FormattingMode

The formatting mode to use. You can use these formatting modes:

markdown - Discord-like Markdown syntax. Supports URLs, but not colours.
format - Minecraft-like formatting codes using ampersands (e.g. &e for yellow). Supports colours, but not URLs.
minimessage - HTML-like tags (e.g. <yellow></yellow> for yellow). Supports colours and hover events.

If no mode is specified, it will default to the mode specified in the constructor.

Returns

Promise<Success>

A Success object containing if the message was sent.

Call Signature

say(text, name?, mode?): Promise<Success>

Defined in: src/Client.ts:253

Sends a message to the in-game public chat.

Parameters

text

string

The message to send.

name?

string

The name of the chatbox to show. If no name is specified, it will default to the username of the license owner.

mode?

FormattingMode = ...

The formatting mode to use. You can use these formatting modes:

markdown - Discord-like Markdown syntax. Supports URLs, but not colours.
format - Minecraft-like formatting codes using ampersands (e.g. &e for yellow). Supports colours, but not URLs.
minimessage - HTML-like tags (e.g. <yellow></yellow> for yellow). Supports colours and hover events.

If no mode is specified, it will default to the mode specified in the constructor.

Returns

Promise<Success>

A Success object containing if the message was sent.

setMaxListeners()

setMaxListeners(n): this

Defined in: node_modules/@types/node/events.d.ts:768

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

tell()

Call Signature

tell(user, text, name?, mode?): Promise<Success>

Defined in: src/Client.ts:106

Sends a private message to an in-game player.

Parameters

user

The username or UUID of the user to send the message to.

string | User

text

string

The message to send.

name?

string

The name of the chatbox to show. If no name is specified, it will default to the username of the license owner.

mode?

FormattingMode

The formatting mode to use. You can use these formatting modes:

markdown - Discord-like Markdown syntax. Supports URLs, but not colours.
format - Minecraft-like formatting codes using ampersands (e.g. &e for yellow). Supports colours, but not URLs.
minimessage - HTML-like tags (e.g. <yellow></yellow> for yellow). Supports colours and hover events.

If no mode is specified, it will default to the mode specified in the constructor.

Returns

Promise<Success>

A Success object containing if the message was sent.

Call Signature

tell(user, text, name?, mode?): Promise<Success>

Defined in: src/Client.ts:273

Sends a private message to an in-game player.

Parameters

user

The username or UUID of the user to send the message to.

string | User

text

string

The message to send.

name?

string

The name of the chatbox to show. If no name is specified, it will default to the username of the license owner.

mode?

FormattingMode = ...

The formatting mode to use. You can use these formatting modes:

markdown - Discord-like Markdown syntax. Supports URLs, but not colours.
format - Minecraft-like formatting codes using ampersands (e.g. &e for yellow). Supports colours, but not URLs.
minimessage - HTML-like tags (e.g. <yellow></yellow> for yellow). Supports colours and hover events.

If no mode is specified, it will default to the mode specified in the constructor.

Returns

Promise<Success>

A Success object containing if the message was sent.

addAbortListener()

static addAbortListener(signal, resource): Disposable

Defined in: node_modules/@types/node/events.d.ts:437

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

getEventListeners()

static getEventListeners(emitter, name): Function[]

Defined in: node_modules/@types/node/events.d.ts:358

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

getMaxListeners()

static getMaxListeners(emitter): number

Defined in: node_modules/@types/node/events.d.ts:387

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

listenerCount()

static listenerCount(emitter, eventName): number

Defined in: node_modules/@types/node/events.d.ts:330

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

The event name

string | symbol

Returns

number

Since

v0.9.12

on()

Call Signature

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

Defined in: node_modules/@types/node/events.d.ts:303

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

Call Signature

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

Defined in: node_modules/@types/node/events.d.ts:308

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

once()

Call Signature

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

Defined in: node_modules/@types/node/events.d.ts:217

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

Call Signature

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

Defined in: node_modules/@types/node/events.d.ts:222

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

setMaxListeners()

static setMaxListeners(n?, …eventTargets?): void

Defined in: node_modules/@types/node/events.d.ts:402

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