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Class: SapphireClient<Ready>

The base Client extension that makes Sapphire work. When building a Discord bot with the framework, the developer must either use this class, or extend it.

Sapphire also automatically detects the folders to scan for pieces, please read registerPath for reference. This method is called at the start of the login method.

See

SapphireClientOptions for all options available to the Sapphire Client. You can also provide all of discord.js' ClientOptions

Since

1.0.0

Example

const client = new SapphireClient({
presence: {
activity: {
name: 'for commands!',
type: 'LISTENING'
}
}
});

client.login(process.env.DISCORD_TOKEN)
.catch(console.error);

Example

// Automatically scan from a specific directory, e.g. the main
// file is at `/home/me/bot/index.js` and all your pieces are at
// `/home/me/bot/pieces` (e.g. `/home/me/bot/pieces/commands/MyCommand.js`):
const client = new SapphireClient({
baseUserDirectory: join(__dirname, 'pieces'),
// More options...
});

Example

// Opt-out automatic scanning:
const client = new SapphireClient({
baseUserDirectory: null,
// More options...
});

Type parameters

NameType
Readyextends boolean = boolean

Hierarchy

  • Client<Ready>

    SapphireClient

Constructors

constructor

new SapphireClient<Ready>(options)

Type parameters

NameType
Readyextends boolean = boolean

Parameters

NameType
optionsClientOptions

Overrides

Client<Ready\>.constructor

Defined in

projects/framework/src/lib/SapphireClient.ts:272

Properties

application

application: If<Ready, ClientApplication, null>

Inherited from

Client.application

Defined in

node_modules/discord.js/typings/index.d.ts:943


channels

channels: ChannelManager

Inherited from

Client.channels

Defined in

node_modules/discord.js/typings/index.d.ts:944


disableMentionPrefix

Optional disableMentionPrefix: boolean

Whether the bot has mention as a prefix disabled

Default

false

Example

client.disableMentionPrefix = false;

Defined in

projects/framework/src/lib/SapphireClient.ts:264


fetchPrefix

fetchPrefix: SapphirePrefixHook

The method to be overridden by the developer.

Since

1.0.0

Example

// Return always the same prefix (unconfigurable):
client.fetchPrefix = () => '!';

Example

// Retrieving the prefix from a SQL database:
client.fetchPrefix = async (message) => {
// note: driver is something generic and depends on how you connect to your database
const guild = await driver.getOne('SELECT prefix FROM public.guild WHERE id = $1', [message.guild.id]);
return guild?.prefix ?? '!';
};

Example

// Retrieving the prefix from an ORM:
client.fetchPrefix = async (message) => {
// note: driver is something generic and depends on how you connect to your database
const guild = await driver.getRepository(GuildEntity).findOne({ id: message.guild.id });
return guild?.prefix ?? '!';
};

Overrides

Client.fetchPrefix

Defined in

projects/framework/src/lib/SapphireClient.ts:247


guilds

guilds: GuildManager

Inherited from

Client.guilds

Defined in

node_modules/discord.js/typings/index.d.ts:946


id

id: null | string = null

The client's ID, used for the user prefix.

Since

1.0.0

Overrides

Client.id

Defined in

projects/framework/src/lib/SapphireClient.ts:217


logger

logger: ILogger

The logger to be used by the framework and plugins. By default, a Logger instance is used, which emits the messages to the console.

Since

1.0.0

Overrides

Client.logger

Defined in

projects/framework/src/lib/SapphireClient.ts:254


options

options: Omit<ClientOptions, "intents"> & { intents: IntentsBitField }

Inherited from

Client.options

Defined in

node_modules/discord.js/typings/index.d.ts:947


readyTimestamp

readyTimestamp: If<Ready, number, null>

Inherited from

Client.readyTimestamp

Defined in

node_modules/discord.js/typings/index.d.ts:949


rest

rest: REST

Inherited from

Client.rest

Defined in

node_modules/discord.js/typings/index.d.ts:502


shard

shard: null | ShardClientUtil

Inherited from

Client.shard

Defined in

node_modules/discord.js/typings/index.d.ts:951


stores

stores: StoreRegistry

The registered stores.

Since

1.0.0

Overrides

Client.stores

Defined in

projects/framework/src/lib/SapphireClient.ts:270


sweepers

sweepers: Sweepers

Inherited from

Client.sweepers

Defined in

node_modules/discord.js/typings/index.d.ts:950


token

token: If<Ready, string, null | string>

Inherited from

Client.token

Defined in

node_modules/discord.js/typings/index.d.ts:952


user

user: If<Ready, ClientUser, null>

Inherited from

Client.user

Defined in

node_modules/discord.js/typings/index.d.ts:954


users

users: UserManager

Inherited from

Client.users

Defined in

node_modules/discord.js/typings/index.d.ts:955


voice

voice: ClientVoiceManager

Inherited from

Client.voice

Defined in

node_modules/discord.js/typings/index.d.ts:956


ws

ws: WebSocketManager

Inherited from

Client.ws

Defined in

node_modules/discord.js/typings/index.d.ts:957


captureRejectionSymbol

Static Readonly captureRejectionSymbol: typeof captureRejectionSymbol

Inherited from

Client.captureRejectionSymbol

Defined in

node_modules/@types/node/events.d.ts:328


captureRejections

Static captureRejections: boolean

Sets or gets the default captureRejection value for all emitters.

Inherited from

Client.captureRejections

Defined in

node_modules/@types/node/events.d.ts:333


defaultMaxListeners

Static defaultMaxListeners: number

Inherited from

Client.defaultMaxListeners

Defined in

node_modules/@types/node/events.d.ts:334


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.

Inherited from

Client.errorMonitor

Defined in

node_modules/@types/node/events.d.ts:327


plugins

Static plugins: PluginManager

Defined in

projects/framework/src/lib/SapphireClient.ts:359

Accessors

_censoredToken

Private get _censoredToken(): null | string

Returns

null | string

Inherited from

Client._censoredToken

Defined in

node_modules/discord.js/typings/index.d.ts:941


emojis

get emojis(): BaseGuildEmojiManager

Returns

BaseGuildEmojiManager

Inherited from

Client.emojis

Defined in

node_modules/discord.js/typings/index.d.ts:945


readyAt

get readyAt(): If<Ready, Date, null>

Returns

If<Ready, Date, null>

Inherited from

Client.readyAt

Defined in

node_modules/discord.js/typings/index.d.ts:948


uptime

get uptime(): If<Ready, number, null>

Returns

If<Ready, number, null>

Inherited from

Client.uptime

Defined in

node_modules/discord.js/typings/index.d.ts:953

Methods

addListener

addListener(eventName, listener): SapphireClient<Ready>

Alias for emitter.on(eventName, listener).

Since

v0.1.26

Parameters

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

Returns

SapphireClient<Ready>

Inherited from

Client.addListener

Defined in

node_modules/@types/node/events.d.ts:354


destroy

destroy(): void

Returns

void

Inherited from

Client.destroy

Defined in

node_modules/discord.js/typings/index.d.ts:958


emit

emit<K>(event, ...args): boolean

Type parameters

NameType
Kextends keyof ClientEvents

Parameters

NameType
eventK
...argsClientEvents[K]

Returns

boolean

Inherited from

Client.emit

Defined in

node_modules/discord.js/typings/index.d.ts:984

emit<S>(event, ...args): boolean

Type parameters

NameType
Sextends string | symbol

Parameters

NameType
eventExclude<S, keyof ClientEvents>
...argsunknown[]

Returns

boolean

Inherited from

Client.emit

Defined in

node_modules/discord.js/typings/index.d.ts:985


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.

const EventEmitter = require('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) ]

Since

v6.0.0

Returns

(string | symbol)[]

Inherited from

Client.eventNames

Defined in

node_modules/@types/node/events.d.ts:673


fetchGuildPreview

fetchGuildPreview(guild): Promise<GuildPreview>

Parameters

NameType
guildGuildResolvable

Returns

Promise<GuildPreview>

Inherited from

Client.fetchGuildPreview

Defined in

node_modules/discord.js/typings/index.d.ts:959


fetchGuildTemplate

fetchGuildTemplate(template): Promise<GuildTemplate>

Parameters

NameType
templatestring

Returns

Promise<GuildTemplate>

Inherited from

Client.fetchGuildTemplate

Defined in

node_modules/discord.js/typings/index.d.ts:961


fetchGuildWidget

fetchGuildWidget(guild): Promise<Widget>

Parameters

NameType
guildGuildResolvable

Returns

Promise<Widget>

Inherited from

Client.fetchGuildWidget

Defined in

node_modules/discord.js/typings/index.d.ts:966


fetchInvite

fetchInvite(invite, options?): Promise<Invite>

Parameters

NameType
invitestring
options?ClientFetchInviteOptions

Returns

Promise<Invite>

Inherited from

Client.fetchInvite

Defined in

node_modules/discord.js/typings/index.d.ts:960


fetchPremiumStickerPacks

fetchPremiumStickerPacks(): Promise<Collection<string, StickerPack>>

Returns

Promise<Collection<string, StickerPack>>

Inherited from

Client.fetchPremiumStickerPacks

Defined in

node_modules/discord.js/typings/index.d.ts:964


fetchSticker

fetchSticker(id): Promise<Sticker>

Parameters

NameType
idstring

Returns

Promise<Sticker>

Inherited from

Client.fetchSticker

Defined in

node_modules/discord.js/typings/index.d.ts:963


fetchVoiceRegions

fetchVoiceRegions(): Promise<Collection<string, VoiceRegion>>

Returns

Promise<Collection<string, VoiceRegion>>

Inherited from

Client.fetchVoiceRegions

Defined in

node_modules/discord.js/typings/index.d.ts:962


fetchWebhook

fetchWebhook(id, token?): Promise<Webhook>

Parameters

NameType
idstring
token?string

Returns

Promise<Webhook>

Inherited from

Client.fetchWebhook

Defined in

node_modules/discord.js/typings/index.d.ts:965


generateInvite

generateInvite(options?): string

Parameters

NameType
options?InviteGenerationOptions

Returns

string

Inherited from

Client.generateInvite

Defined in

node_modules/discord.js/typings/index.d.ts:967


getMaxListeners

getMaxListeners(): number

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

Since

v1.0.0

Returns

number

Inherited from

Client.getMaxListeners

Defined in

node_modules/@types/node/events.d.ts:526


isReady

isReady(): this is Client<true>

Returns

this is Client<true>

Inherited from

Client.isReady

Defined in

node_modules/discord.js/typings/index.d.ts:969


listenerCount

listenerCount(eventName, listener?): number

Returns the number of listeners listening to 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.

Since

v3.2.0

Parameters

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

Returns

number

Inherited from

Client.listenerCount

Defined in

node_modules/@types/node/events.d.ts:620


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] ]

Since

v0.1.26

Parameters

NameType
eventNamestring | symbol

Returns

Function[]

Inherited from

Client.listeners

Defined in

node_modules/@types/node/events.d.ts:539


login

login(token?): Promise<string>

Loads all pieces, then logs the client in, establishing a websocket connection to Discord.

Since

1.0.0

Parameters

NameTypeDescription
token?stringToken of the account to log in with.

Returns

Promise<string>

Token of the account used.

Overrides

Client.login

Defined in

projects/framework/src/lib/SapphireClient.ts:334


off

off<K>(event, listener): SapphireClient<Ready>

Type parameters

NameType
Kextends keyof ClientEvents

Parameters

NameType
eventK
listener(...args: ClientEvents[K]) => Awaitable<void>

Returns

SapphireClient<Ready>

Inherited from

Client.off

Defined in

node_modules/discord.js/typings/index.d.ts:987

off<S>(event, listener): SapphireClient<Ready>

Type parameters

NameType
Sextends string | symbol

Parameters

NameType
eventExclude<S, keyof ClientEvents>
listener(...args: any[]) => Awaitable<void>

Returns

SapphireClient<Ready>

Inherited from

Client.off

Defined in

node_modules/discord.js/typings/index.d.ts:988


on

on<K>(event, listener): SapphireClient<Ready>

Type parameters

NameType
Kextends keyof ClientEvents

Parameters

NameType
eventK
listener(...args: ClientEvents[K]) => Awaitable<void>

Returns

SapphireClient<Ready>

Inherited from

Client.on

Defined in

node_modules/discord.js/typings/index.d.ts:972

on<S>(event, listener): SapphireClient<Ready>

Type parameters

NameType
Sextends string | symbol

Parameters

NameType
eventExclude<S, keyof ClientEvents>
listener(...args: any[]) => Awaitable<void>

Returns

SapphireClient<Ready>

Inherited from

Client.on

Defined in

node_modules/discord.js/typings/index.d.ts:973


once

once<K>(event, listener): SapphireClient<Ready>

Type parameters

NameType
Kextends keyof ClientEvents

Parameters

NameType
eventK
listener(...args: ClientEvents[K]) => Awaitable<void>

Returns

SapphireClient<Ready>

Inherited from

Client.once

Defined in

node_modules/discord.js/typings/index.d.ts:978

once<S>(event, listener): SapphireClient<Ready>

Type parameters

NameType
Sextends string | symbol

Parameters

NameType
eventExclude<S, keyof ClientEvents>
listener(...args: any[]) => Awaitable<void>

Returns

SapphireClient<Ready>

Inherited from

Client.once

Defined in

node_modules/discord.js/typings/index.d.ts:979


prependListener

prependListener(eventName, listener): SapphireClient<Ready>

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.

Since

v6.0.0

Parameters

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

Returns

SapphireClient<Ready>

Inherited from

Client.prependListener

Defined in

node_modules/@types/node/events.d.ts:638


prependOnceListener

prependOnceListener(eventName, listener): SapphireClient<Ready>

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.

Since

v6.0.0

Parameters

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

Returns

SapphireClient<Ready>

Inherited from

Client.prependOnceListener

Defined in

node_modules/@types/node/events.d.ts:654


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()).

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');

Since

v9.4.0

Parameters

NameType
eventNamestring | symbol

Returns

Function[]

Inherited from

Client.rawListeners

Defined in

node_modules/@types/node/events.d.ts:569


removeAllListeners

removeAllListeners<K>(event?): SapphireClient<Ready>

Type parameters

NameType
Kextends keyof ClientEvents

Parameters

NameType
event?K

Returns

SapphireClient<Ready>

Inherited from

Client.removeAllListeners

Defined in

node_modules/discord.js/typings/index.d.ts:993

removeAllListeners<S>(event?): SapphireClient<Ready>

Type parameters

NameType
Sextends string | symbol

Parameters

NameType
event?Exclude<S, keyof ClientEvents>

Returns

SapphireClient<Ready>

Inherited from

Client.removeAllListeners

Defined in

node_modules/discord.js/typings/index.d.ts:994


removeListener

removeListener(eventName, listener): SapphireClient<Ready>

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.

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:

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.

Since

v0.1.26

Parameters

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

Returns

SapphireClient<Ready>

Inherited from

Client.removeListener

Defined in

node_modules/@types/node/events.d.ts:494


setMaxListeners

setMaxListeners(n): SapphireClient<Ready>

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.

Since

v0.3.5

Parameters

NameType
nnumber

Returns

SapphireClient<Ready>

Inherited from

Client.setMaxListeners

Defined in

node_modules/@types/node/events.d.ts:520


toJSON

toJSON(): unknown

Returns

unknown

Inherited from

Client.toJSON

Defined in

node_modules/discord.js/typings/index.d.ts:970


getEventListeners

Static 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.

const { getEventListeners, EventEmitter } = require('events');

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

Since

v15.2.0, v14.17.0

Parameters

NameType
emitterEventEmitter | _DOMEventTarget
namestring | symbol

Returns

Function[]

Inherited from

Client.getEventListeners

Defined in

node_modules/@types/node/events.d.ts:299


listenerCount

Static listenerCount(emitter, eventName): number

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

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

Since

v0.9.12

Deprecated

Since v3.2.0 - Use listenerCount instead.

Parameters

NameTypeDescription
emitterEventEmitterThe emitter to query
eventNamestring | symbolThe event name

Returns

number

Inherited from

Client.listenerCount

Defined in

node_modules/@types/node/events.d.ts:271


on

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

const { on, EventEmitter } = require('events');

(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')) {
// 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:

const { on, EventEmitter } = require('events');
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());

Since

v13.6.0, v12.16.0

Parameters

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

Returns

AsyncIterableIterator<any>

that iterates eventName events emitted by the emitter

Inherited from

Client.on

Defined in

node_modules/@types/node/events.d.ts:254

Static on<E, K>(eventEmitter, eventName): AsyncIterableIterator<E extends Client<boolean> ? ClientEvents[K] : any>

Type parameters

NameType
Eextends __module
Kextends keyof ClientEvents

Parameters

NameType
eventEmitterE
eventNameE extends Client<boolean> ? K : string

Returns

AsyncIterableIterator<E extends Client<boolean> ? ClientEvents[K] : any>

Inherited from

Client.on

Defined in

node_modules/discord.js/typings/index.d.ts:229


once

Static 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 interface, which has no special'error' event semantics and does not listen to the 'error' event.

const { once, EventEmitter } = require('events');

async function run() {
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.log('error happened', err);
}
}

run();

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:

const { EventEmitter, once } = require('events');

const ee = new EventEmitter();

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

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

// Prints: ok boom

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

const { EventEmitter, once } = require('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!

Since

v11.13.0, v10.16.0

Parameters

NameType
emitter_NodeEventTarget
eventNamestring | symbol
options?StaticEventEmitterOptions

Returns

Promise<any[]>

Inherited from

Client.once

Defined in

node_modules/@types/node/events.d.ts:194

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

Parameters

NameType
emitter_DOMEventTarget
eventNamestring
options?StaticEventEmitterOptions

Returns

Promise<any[]>

Inherited from

Client.once

Defined in

node_modules/@types/node/events.d.ts:195

Static once<E, K>(eventEmitter, eventName): Promise<E extends Client<boolean> ? ClientEvents[K] : any[]>

Type parameters

NameType
Eextends __module
Kextends keyof ClientEvents

Parameters

NameType
eventEmitterE
eventNameE extends Client<boolean> ? K : string

Returns

Promise<E extends Client<boolean> ? ClientEvents[K] : any[]>

Inherited from

Client.once

Defined in

node_modules/discord.js/typings/index.d.ts:225


setMaxListeners

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

const {
setMaxListeners,
EventEmitter
} = require('events');

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

setMaxListeners(5, target, emitter);

Since

v15.4.0

Parameters

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

Returns

void

Inherited from

Client.setMaxListeners

Defined in

node_modules/@types/node/events.d.ts:317


use

Static use(plugin): typeof SapphireClient

Parameters

NameType
plugintypeof Plugin

Returns

typeof SapphireClient

Defined in

projects/framework/src/lib/SapphireClient.ts:361