blackcat.js-discord - v1.0.10
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    Class Client<Ready>

    Client mở rộng từ DiscordClient.

    Đây là class trung tâm của framework bot, chịu trách nhiệm quản lý toàn bộ hệ thống:

    • Cấu hình (config)
    • Message commands
    • Slash commands
    • Events
    • Categories
    • Các manager tương ứng

    Client đóng vai trò như một orchestrator, kết nối các thành phần lại với nhau:

    • Các Manager chịu trách nhiệm load tài nguyên (commands, events, ...)
    • Các Collection lưu trữ dữ liệu runtime
    • config cung cấp thông tin cấu hình toàn cục

    Lifecycle khởi động:

    1. Khởi tạo instance với ClientOptions
    2. Gọi start để load toàn bộ hệ thống
    3. Đăng nhập Discord thông qua token
    const client = new Client({
    config: {
    botToken: process.env.TOKEN!
    },
    commandManager: new CommandManager({
    directory: "./commands",
    prefix: "!"
    }),
    eventManager: new EventManager({
    directory: "./events"
    }),
    slashCommandManager: new SlashCommandManager({
    directory: "./slashCommands"
    })
    });

    await client.start();

    Type Parameters

    • Ready extends boolean = boolean

    Hierarchy

    Index

    Constructors

    • Khởi tạo Client.

      Type Parameters

      • Ready extends boolean = boolean

      Parameters

      Returns Client<Ready>

      Constructor chỉ thực hiện:

      • Gán config
      • Khởi tạo các collection
      • Gán các manager

      Không thực hiện load hoặc login.

    Properties

    aliases: Collection<string, string>

    Danh sách aliases của command.

    Key: alias
    Value: command name chính

    Dùng để resolve command khi user gọi bằng alias.

    application: If<Ready, ClientApplication>
    categories: Collection<string, Collection<string, CommandBuilder>>

    Danh sách categories của command.

    Key: category name
    Value: collection các command thuộc category đó

    Hữu ích cho:

    • Tạo help command
    • Group command theo chức năng
    channels: ChannelManager
    commandManager: CommandManager | undefined

    Manager quản lý message commands.

    undefined
    

    Chịu trách nhiệm:

    • Load command từ file
    • Parse message theo prefix
    • Thực thi command
    commands: Collection<string, CommandBuilder>

    Danh sách message commands.

    Key: commandName
    Value: instance của CommandBuilder

    Collection này được populate bởi CommandManager trong quá trình load command.

    config: Config

    Cấu hình bot.

    Chứa các thông tin cần thiết như:

    • Token đăng nhập
    • Các config custom (API keys, prefix, flags, ...)
    undefined
    
    eventManager: EventManager | undefined

    Manager quản lý events.

    undefined
    

    Nếu được cung cấp, sẽ tự động load và đăng ký event khi gọi start.

    guilds: GuildManager
    options: Omit<ClientOptions, "intents"> & { intents: IntentsBitField }
    readyTimestamp: If<Ready, number>
    rest: REST
    shard: ShardClientUtil | null
    slashCommandManager: SlashCommandManager | undefined

    Manager quản lý slash commands.

    undefined
    

    Chịu trách nhiệm:

    • Load slash command
    • Đăng ký với Discord API
    • Đồng bộ command (global / guild)
    slashCommands: Collection<string, SlashCommandBuilder<any, {}, {}>>

    Danh sách slash commands.

    Key: commandName
    Value: instance của SlashCommandBuilder

    Được sử dụng để map interaction với handler tương ứng.

    sweepers: Sweepers
    token: If<Ready, string, string | null>
    user: If<Ready, ClientUser>
    users: UserManager
    voice: ClientVoiceManager
    ws: WebSocketManager
    captureRejections: boolean

    Value: boolean

    Change the default captureRejections option on all new EventEmitter objects.

    v13.4.0, v12.16.0

    captureRejectionSymbol: typeof captureRejectionSymbol

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

    See how to write a custom rejection handler.

    v13.4.0, v12.16.0

    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.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'.

    v0.11.2

    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.

    v13.6.0, v12.17.0

    Accessors

    • get emojis(): BaseGuildEmojiManager

      Returns BaseGuildEmojiManager

    • get readyAt(): If<Ready, Date>

      Returns If<Ready, Date>

    • get uptime(): If<Ready, number>

      Returns If<Ready, number>

    Methods

    • Returns Promise<void>

    • Type Parameters

      • K

      Parameters

      • error: Error
      • event: string | symbol
      • ...args: AnyRest

      Returns void

    • Alias for emitter.on(eventName, listener).

      Type Parameters

      • K

      Parameters

      • eventName: string | symbol
      • listener: (...args: any[]) => void

      Returns this

      v0.1.26

    • Parameters

      • id: string
      • Optionaloptions: WebhookDeleteOptions

      Returns Promise<void>

    • Returns Promise<void>

    • 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

      • Event extends keyof ClientEvents

      Parameters

      Returns boolean

      v0.1.26

    • Type Parameters

      • Event extends string | symbol

      Parameters

      • event: Exclude<Event, keyof ClientEvents>
      • ...args: unknown[]

      Returns boolean

    • 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)[]

      v6.0.0

    • Parameters

      • guild: GuildResolvable

      Returns Promise<GuildPreview>

    • Parameters

      • template: string

      Returns Promise<GuildTemplate>

    • Parameters

      • guild: GuildResolvable

      Returns Promise<Widget>

    • Parameters

      • invite: string
      • Optionaloptions: ClientFetchInviteOptions

      Returns Promise<Invite>

    • Returns Promise<Collection<string, StickerPack>>

      Use Client.fetchStickerPacks instead.

    • Parameters

      • id: string

      Returns Promise<Sticker>

    • Parameters

      • options: { packId: string }

      Returns Promise<StickerPack>

    • Parameters

      • Optionaloptions: StickerPackFetchOptions

      Returns Promise<Collection<string, StickerPack>>

    • Returns Promise<Collection<string, VoiceRegion>>

    • Parameters

      • id: string
      • Optionaltoken: string

      Returns Promise<Webhook<WebhookType>>

    • Parameters

      • Optionaloptions: InviteGenerationOptions

      Returns string

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

      Returns number

      v1.0.0

    • Returns this is Client<true>

    • 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

      Parameters

      • eventName: string | symbol

        The name of the event being listened for

      • Optionallistener: Function

        The event handler function

      Returns number

      v3.2.0

    • 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

      Parameters

      • eventName: string | symbol

      Returns Function[]

      v0.1.26

    • Parameters

      • Optionaltoken: string

      Returns Promise<string>

    • Alias for emitter.removeListener().

      Type Parameters

      • Event extends keyof ClientEvents

      Parameters

      • event: Event
      • listener: (...args: ClientEvents[Event]) => void

      Returns this

      v10.0.0

    • Type Parameters

      • Event extends string | symbol

      Parameters

      • event: Exclude<Event, keyof ClientEvents>
      • listener: (...args: any[]) => void

      Returns this

    • 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 eventName and 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. The emitter.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

      Type Parameters

      • Event extends keyof ClientEvents

      Parameters

      • event: Event
      • listener: (...args: ClientEvents[Event]) => void

        The callback function

      Returns this

      v0.1.101

    • Type Parameters

      • Event extends string | symbol

      Parameters

      • event: Exclude<Event, keyof ClientEvents>
      • listener: (...args: any[]) => void

      Returns this

    • 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

      • Event extends keyof ClientEvents

      Parameters

      • event: Event
      • listener: (...args: ClientEvents[Event]) => void

        The callback function

      Returns this

      v0.3.0

    • Type Parameters

      • Event extends string | symbol

      Parameters

      • event: Exclude<Event, keyof ClientEvents>
      • listener: (...args: any[]) => void

      Returns this

    • 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

      Parameters

      • eventName: string | symbol

        The name of the event.

      • listener: (...args: any[]) => void

        The callback function

      Returns this

      v6.0.0

    • 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

      Parameters

      • eventName: string | symbol

        The name of the event.

      • listener: (...args: any[]) => void

        The callback function

      Returns this

      v6.0.0

    • 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

      Parameters

      • eventName: string | symbol

      Returns Function[]

      v9.4.0

    • 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.

      Type Parameters

      • Event extends keyof ClientEvents

      Parameters

      Returns this

      v0.1.26

    • Type Parameters

      • Event extends string | symbol

      Parameters

      • Optionalevent: Exclude<Event, keyof ClientEvents>

      Returns this

    • 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

      Parameters

      • eventName: string | symbol
      • listener: (...args: any[]) => void

      Returns this

      v0.1.26

    • Thiết lập hoặc cập nhật cấu hình bot.

      Phương thức này cho phép:

      • Gán mới toàn bộ config
      • Hoặc merge thêm config vào config hiện tại

      Parameters

      • config: Partial<Config>

        Cấu hình mới hoặc một phần cấu hình

      • Optionaloptions: { merge?: boolean }

        Tùy chọn cập nhật

        • Optionalmerge?: boolean

          Có merge với config hiện tại hay không

      Returns Config

      Config sau khi đã được cập nhật

      • Nếu merge = true: → config mới sẽ được merge vào config hiện tại (shallow merge)
      • Nếu merge = false (mặc định): → config cũ sẽ bị ghi đè hoàn toàn

      Lưu ý:

      • Không tự động gọi lại login
      • Nếu thay đổi botToken, bạn cần gọi lại start hoặc login
      client.setConfig({
      botToken: "new-token"
      });
      // Merge thêm config
      client.setConfig({
      debug: true
      }, { merge: true });
    • 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

      v0.3.5

    • Thiết lập token cho bot.

      Phương thức này cho phép override token runtime, thay thế cho giá trị trong config.

      Parameters

      • token: string

        Token Discord bot

      Returns string

      Token đã được thiết lập

      client.setToken(process.env.TOKEN!);
      
    • Khởi động bot.

      Quy trình:

      1. Load slash commands
      2. Load message commands
      3. Load events
      4. Đăng nhập Discord

      Returns Promise<string>

      Promise resolve với token sau khi login thành công

      Error nếu token chưa được thiết lập

      Token được resolve theo thứ tự ưu tiên:

      1. Token đã set bằng setToken
      2. config.botToken

      Nếu không có → throw error

      await client.start();
      
    • Returns unknown

    • Experimental

      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: Event) => void

      Returns Disposable

      Disposable that removes the abort listener.

      v20.5.0

    • 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[]

      v15.2.0, v14.17.0

    • 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

      v19.9.0

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

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

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

      Parameters

      • emitter: EventEmitter

        The emitter to query

      • eventName: string | symbol

        The event name

      Returns number

      v0.9.12

      Since v3.2.0 - Use listenerCount instead.

    • 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'

      Type Parameters

      • Emitter extends EventEmitter<DefaultEventMap>
      • Event extends keyof ClientEvents

      Parameters

      • eventEmitter: Emitter
      • eventName: Emitter extends Client<boolean> ? Event : string | symbol
      • Optionaloptions: { signal?: AbortSignal }

      Returns AsyncEventIterator<
          Emitter extends Client<boolean> ? ClientEvents[Event] : any[],
      >

      An AsyncIterator that iterates eventName events emitted by the emitter

      v13.6.0, v12.16.0

    • 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!

      Type Parameters

      • Emitter extends EventEmitter<DefaultEventMap>
      • Event extends keyof ClientEvents

      Parameters

      • eventEmitter: Emitter
      • eventName: Emitter extends Client<boolean> ? Event : string | symbol
      • Optionaloptions: { signal?: AbortSignal }

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

      v11.13.0, v10.16.0

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

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

      setMaxListeners(5, target, emitter);

      Parameters

      • Optionaln: 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

      v15.4.0