레퍼런스
classes
CommandClient

@pikokr/command.ts / Exports / CommandClient

Class: CommandClient

Hierarchy

  • EventEmitter

    CommandClient

Table of contents

Constructors

Properties

Methods

Constructors

constructor

new CommandClient(discord, logger?, loggerOptions?): CommandClient

Parameters

NameType
discordClient<boolean>
loggerLogger<unknown>
loggerOptionsISettingsParam<unknown>

Returns

CommandClient

Overrides

EventEmitter.constructor

Defined in

src/core/structures/CommandClient.ts:19 (opens in a new tab)

Properties

ctsLogger

ctsLogger: Logger<unknown>

Defined in

src/core/structures/CommandClient.ts:14 (opens in a new tab)


discord

discord: Client<boolean>

Defined in

src/core/structures/CommandClient.ts:20 (opens in a new tab)


logger

logger: Logger<unknown>

Defined in

src/core/structures/CommandClient.ts:21 (opens in a new tab)


owners

owners: Set<string>

Defined in

src/core/structures/CommandClient.ts:17 (opens in a new tab)


registry

registry: Registry

Defined in

src/core/structures/CommandClient.ts:15 (opens in a new tab)


captureRejectionSymbol

Static Readonly captureRejectionSymbol: typeof captureRejectionSymbol

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

See how to write a custom rejection handler.

Since

v13.4.0, v12.16.0

Inherited from

EventEmitter.captureRejectionSymbol

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:402


captureRejections

Static captureRejections: boolean

Value: boolean (opens in a new tab)

Change the default captureRejections option on all new EventEmitter objects.

Since

v13.4.0, v12.16.0

Inherited from

EventEmitter.captureRejections

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:409


defaultMaxListeners

Static defaultMaxListeners: number

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.defaultMaxListenersproperty can be used. If this value is not a positive number, a RangeErroris thrown.

Take caution when setting the events.defaultMaxListeners because the change affects allEventEmitter 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 singleEventEmitter, 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

EventEmitter.defaultMaxListeners

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:446


errorMonitor

Static Readonly errorMonitor: typeof errorMonitor

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

EventEmitter.errorMonitor

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:395

Methods

[captureRejectionSymbol]

[captureRejectionSymbol](error, event, ...args): void

Parameters

NameType
errorError
eventstring
...argsany[]

Returns

void

Inherited from

EventEmitter.[captureRejectionSymbol]

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:112


addListener

addListener(eventName, listener): CommandClient

Alias for emitter.on(eventName, listener).

Parameters

NameType
eventNamestring | symbol
listener(...args: any[]) => void

Returns

CommandClient

Since

v0.1.26

Inherited from

EventEmitter.addListener

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:545


emit

emit(eventName, ...args): boolean

Synchronously calls each of the listeners registered for the event namedeventName, 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

Parameters

NameType
eventNamestring | symbol
...argsany[]

Returns

boolean

Since

v0.1.26

Inherited from

EventEmitter.emit

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:807


enableApplicationCommandsExtension

enableApplicationCommandsExtension(config): Promise<void>

Parameters

NameType
configApplicationCommandExtensionConfig

Returns

Promise<void>

Defined in

src/core/structures/CommandClient.ts:67 (opens in a new tab)


enableTextCommandsExtension

enableTextCommandsExtension(config): Promise<void>

Parameters

NameType
configTextCommandConfig

Returns

Promise<void>

Defined in

src/core/structures/CommandClient.ts:72 (opens in a new tab)


eventNames

eventNames(): (string | symbol)[]

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

EventEmitter.eventNames

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:870


fetchOwners

fetchOwners(): Promise<void>

Returns

Promise<void>

Defined in

src/core/structures/CommandClient.ts:41 (opens in a new tab)


getApplicationCommandsExtension

getApplicationCommandsExtension(): undefined | ApplicationCommandExtension

Returns

undefined | ApplicationCommandExtension

Defined in

src/core/structures/CommandClient.ts:77 (opens in a new tab)


getMaxListeners

getMaxListeners(): number

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

Inherited from

EventEmitter.getMaxListeners

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:722


isOwner

isOwner(user): Promise<boolean>

Parameters

NameType
userUser

Returns

Promise<boolean>

Defined in

src/core/structures/CommandClient.ts:37 (opens in a new tab)


listenerCount

listenerCount(eventName, listener?): number

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.

Parameters

NameTypeDescription
eventNamestring | symbolThe name of the event being listened for
listener?FunctionThe event handler function

Returns

number

Since

v3.2.0

Inherited from

EventEmitter.listenerCount

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:816


listeners

listeners(eventName): Function[]

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] ]

Parameters

NameType
eventNamestring | symbol

Returns

Function[]

Since

v0.1.26

Inherited from

EventEmitter.listeners

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:735


off

off(eventName, listener): CommandClient

Alias for emitter.removeListener().

Parameters

NameType
eventNamestring | symbol
listener(...args: any[]) => void

Returns

CommandClient

Since

v10.0.0

Inherited from

EventEmitter.off

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:695


on

on(eventName, listener): CommandClient

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

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

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

By default, event listeners are invoked in the order they are added. Theemitter.prependListener() 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.on('foo', () => console.log('a'));
myEE.prependListener('foo', () => console.log('b'));
myEE.emit('foo');
// Prints:
//   b
//   a

Parameters

NameTypeDescription
eventNamestring | symbolThe name of the event.
listener(...args: any[]) => voidThe callback function

Returns

CommandClient

Since

v0.1.101

Inherited from

EventEmitter.on

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:577


once

once(eventName, listener): CommandClient

Adds a one-timelistener 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. Theemitter.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

Parameters

NameTypeDescription
eventNamestring | symbolThe name of the event.
listener(...args: any[]) => voidThe callback function

Returns

CommandClient

Since

v0.3.0

Inherited from

EventEmitter.once

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:607


prependListener

prependListener(eventName, listener): CommandClient

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 eventNameand 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.

Parameters

NameTypeDescription
eventNamestring | symbolThe name of the event.
listener(...args: any[]) => voidThe callback function

Returns

CommandClient

Since

v6.0.0

Inherited from

EventEmitter.prependListener

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:834


prependOnceListener

prependOnceListener(eventName, listener): CommandClient

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.

Parameters

NameTypeDescription
eventNamestring | symbolThe name of the event.
listener(...args: any[]) => voidThe callback function

Returns

CommandClient

Since

v6.0.0

Inherited from

EventEmitter.prependOnceListener

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:850


rawListeners

rawListeners(eventName): Function[]

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');

Parameters

NameType
eventNamestring | symbol

Returns

Function[]

Since

v9.4.0

Inherited from

EventEmitter.rawListeners

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:766


removeAllListeners

removeAllListeners(event?): CommandClient

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

NameType
event?string | symbol

Returns

CommandClient

Since

v0.1.26

Inherited from

EventEmitter.removeAllListeners

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:706


removeListener

removeListener(eventName, listener): CommandClient

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

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 anyremoveListener() 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.

Parameters

NameType
eventNamestring | symbol
listener(...args: any[]) => void

Returns

CommandClient

Since

v0.1.26

Inherited from

EventEmitter.removeListener

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:690


setMaxListeners

setMaxListeners(n): CommandClient

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 toInfinity (or 0) to indicate an unlimited number of listeners.

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

Parameters

NameType
nnumber

Returns

CommandClient

Since

v0.3.5

Inherited from

EventEmitter.setMaxListeners

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:716


addAbortListener

addAbortListener(signal, resource): Disposable

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

NameType
signalAbortSignal
resource(event: Event) => void

Returns

Disposable

Disposable that removes the abort listener.

Since

v20.5.0

Inherited from

EventEmitter.addAbortListener

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:387


getEventListeners

getEventListeners(emitter, name): Function[]

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

NameType
emitterEventEmitter | _DOMEventTarget
namestring | symbol

Returns

Function[]

Since

v15.2.0, v14.17.0

Inherited from

EventEmitter.getEventListeners

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:308


getFromModule

getFromModule(ext): CommandClient

Parameters

NameType
extobject

Returns

CommandClient

Defined in

src/core/structures/CommandClient.ts:81 (opens in a new tab)


getMaxListeners

getMaxListeners(emitter): number

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

NameType
emitterEventEmitter | _DOMEventTarget

Returns

number

Since

v19.9.0

Inherited from

EventEmitter.getMaxListeners

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:337


listenerCount

listenerCount(emitter, eventName): number

A class method that returns the number of listeners for the given eventNameregistered 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

NameTypeDescription
emitterEventEmitterThe emitter to query
eventNamestring | symbolThe event name

Returns

number

Since

v0.9.12

Deprecated

Since v3.2.0 - Use listenerCount instead.

Inherited from

EventEmitter.listenerCount

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:280


on

on(emitter, eventName, options?): AsyncIterableIterator<any>

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());

Parameters

NameTypeDescription
emitterEventEmitter-
eventNamestringThe name of the event being listened for
options?StaticEventEmitterOptions-

Returns

AsyncIterableIterator<any>

that iterates eventName events emitted by the emitter

Since

v13.6.0, v12.16.0

Inherited from

EventEmitter.on

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:258

on<Emitter, Events>(eventEmitter, eventName): AsyncIterableIterator<Emitter extends Client<boolean> ? ClientEvents[Events] : any>

Type parameters

NameType
Emitterextends __module
Eventsextends keyof ClientEvents

Parameters

NameType
eventEmitterEmitter
eventNameEmitter extends Client<boolean> ? Events : string

Returns

AsyncIterableIterator<Emitter extends Client<boolean> ? ClientEvents[Events] : any>

Inherited from

EventEmitter.on

Defined in

node_modules/.pnpm/discord.js@14.14.1/node_modules/discord.js/typings/index.d.ts:243


once

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

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 (opens in a new tab) 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

NameType
emitter_NodeEventTarget
eventNamestring | symbol
options?StaticEventEmitterOptions

Returns

Promise<any[]>

Since

v11.13.0, v10.16.0

Inherited from

EventEmitter.once

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:193

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

Parameters

NameType
emitter_DOMEventTarget
eventNamestring
options?StaticEventEmitterOptions

Returns

Promise<any[]>

Inherited from

EventEmitter.once

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:198

once<Emitter, Event>(eventEmitter, eventName): Promise<Emitter extends Client<boolean> ? ClientEvents[Event] : any[]>

Type parameters

NameType
Emitterextends __module
Eventextends keyof ClientEvents

Parameters

NameType
eventEmitterEmitter
eventNameEmitter extends Client<boolean> ? Event : string

Returns

Promise<Emitter extends Client<boolean> ? ClientEvents[Event] : any[]>

Inherited from

EventEmitter.once

Defined in

node_modules/.pnpm/discord.js@14.14.1/node_modules/discord.js/typings/index.d.ts:239


setMaxListeners

setMaxListeners(n?, ...eventTargets): void

import { setMaxListeners, EventEmitter } from 'node:events';
 
const target = new EventTarget();
const emitter = new EventEmitter();
 
setMaxListeners(5, target, emitter);

Parameters

NameTypeDescription
n?numberA non-negative number. The maximum number of listeners per EventTarget event.
...eventTargets(EventEmitter | _DOMEventTarget)[]-

Returns

void

Since

v15.4.0

Inherited from

EventEmitter.setMaxListeners

Defined in

node_modules/.pnpm/@types+node@20.10.5/node_modules/@types/node/events.d.ts:352