Options
All
  • Public
  • Public/Protected
  • All
Menu

Class Context

Wrapper around dcn_context_t*

only acts as event emitter when created in standalone mode (without account manager) with Context.open

Hierarchy

  • EventEmitter
    • Context

Index

Interfaces

Constructors

Properties

Accessors

Methods

Constructors

constructor

Properties

Readonly account_id

account_id: number | null

Private inner_dcn_context

inner_dcn_context: NativeContext

Readonly manager

manager: AccountManager | null

Static Readonly captureRejectionSymbol

captureRejectionSymbol: keyof symbol

Static captureRejections

captureRejections: boolean

Sets or gets the default captureRejection value for all emitters.

Static defaultMaxListeners

defaultMaxListeners: number

Static Readonly errorMonitor

errorMonitor: keyof symbol

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.

Accessors

dcn_context

is_open

  • get is_open(): boolean

Methods

_getNextMedia

  • _getNextMedia(messageId: number, dir: number, msgType1: number, msgType2: number, msgType3: number): number
  • Parameters

    • messageId: number
    • dir: number
    • msgType1: number
    • msgType2: number
    • msgType3: number

    Returns number

acceptChat

  • acceptChat(chatId: number): void

addAddressBook

  • addAddressBook(addressBook: string): any

addContactToChat

  • addContactToChat(chatId: number, contactId: number): boolean

addDeviceMessage

  • addDeviceMessage(label: string, msg: Message | string): any

addListener

  • addListener(eventName: string | symbol, listener: (...args: any[]) => void): this
  • Alias for emitter.on(eventName, listener).

    since

    v0.1.26

    Parameters

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

          • Rest ...args: any[]

          Returns void

    Returns this

blockChat

  • blockChat(chatId: number): void

blockContact

  • blockContact(contactId: number, block: boolean): void

checkQrCode

  • checkQrCode(qrCode: string): null | { id: number }

configure

  • configure(opts: any): Promise<void>

continueKeyTransfer

  • continueKeyTransfer(messageId: number, setupCode: string): Promise<unknown>

createBroadcastList

  • createBroadcastList(): number

createChatByContactId

  • createChatByContactId(contactId: number): number

createContact

  • createContact(name: string, addr: string): number

createGroupChat

  • createGroupChat(chatName: string, is_protected?: boolean): number
  • Parameters

    • chatName: string

      The name of the chat that should be created

    • Default value is_protected: boolean = false

      Whether the chat should be protected at creation time

    Returns number

    chatId

deleteChat

  • deleteChat(chatId: number): void

deleteContact

  • deleteContact(contactId: number): boolean

deleteMessages

  • deleteMessages(messageIds: number[]): void

downloadFullMessage

  • downloadFullMessage(messageId: number): void

emit

  • emit(eventName: string | symbol, ...args: any[]): 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.

    const EventEmitter = require('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
    since

    v0.1.26

    Parameters

    • eventName: string | symbol
    • Rest ...args: any[]

    Returns boolean

estimateDeletionCount

  • estimateDeletionCount(fromServer: boolean, seconds: number): number

eventNames

  • eventNames(): Array<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 Array<string | symbol>

forwardMessages

  • forwardMessages(messageIds: number[], chatId: number): void

getBlobdir

  • getBlobdir(): string

getBlockedContacts

  • getBlockedContacts(): number[]

getBlockedCount

  • getBlockedCount(): number

getChat

  • getChat(chatId: number): null | Chat

getChatContacts

  • getChatContacts(chatId: number): number[]

getChatEncrytionInfo

  • getChatEncrytionInfo(chatId: number): string
  • Get encryption info for a chat. Get a multi-line encryption info, containing encryption preferences of all members. Can be used to find out why messages sent to group are not encrypted.

    Parameters

    • chatId: number

      ID of the chat to get the encryption info for.

    Returns string

    Multi-line text, must be released using dc_str_unref() after usage.

getChatEphemeralTimer

  • getChatEphemeralTimer(chatId: number): number

getChatIdByContactId

  • getChatIdByContactId(contactId: number): number

getChatList

  • getChatList(listFlags: number, queryStr: string, queryContactId: number): ChatList

getChatMedia

  • getChatMedia(chatId: number, msgType1: number, msgType2: number, msgType3: number): number[]
  • Parameters

    • chatId: number
    • msgType1: number
    • msgType2: number
    • msgType3: number

    Returns number[]

getChatMessages

  • getChatMessages(chatId: number, flags: number, marker1before: number): any

getChatlistItemSummary

  • getChatlistItemSummary(chatId: number, messageId: number): Lot

getChats

  • getChats(listFlags: number, queryStr: string, queryContactId: number): number[]
  • Parameters

    • listFlags: number
    • queryStr: string
    • queryContactId: number

    Returns number[]

getConfig

  • getConfig(key: string): string

getConnectivity

  • getConnectivity(): number

getConnectivityHTML

  • getConnectivityHTML(): String

getContact

  • getContact(contactId: number): null | Contact

getContactEncryptionInfo

  • getContactEncryptionInfo(contactId: number): any

getContacts

  • getContacts(listFlags: number, query: string): any

getDraft

  • getDraft(chatId: number): null | Message

getFreshMessageCount

  • getFreshMessageCount(chatId: number): number

getFreshMessages

  • getFreshMessages(): any

getInfo

  • getInfo(): {}

getLocations

  • getLocations(chatId: number, contactId: number, timestampFrom?: number, timestampTo?: number): { accuracy: number; chatId: number; contactId: number; isIndependent: boolean; latitude: number; longitude: number; marker: string; msgId: number; timestamp: number }[]
  • Parameters

    • chatId: number
    • contactId: number
    • Default value timestampFrom: number = 0
    • Default value timestampTo: number = 0

    Returns { accuracy: number; chatId: number; contactId: number; isIndependent: boolean; latitude: number; longitude: number; marker: string; msgId: number; timestamp: number }[]

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

getMessage

  • getMessage(messageId: number): null | Message

getMessageCount

  • getMessageCount(chatId: number): number

getMessageHTML

  • getMessageHTML(messageId: number): string

getMessageInfo

  • getMessageInfo(messageId: number): string

getMimeHeaders

  • getMimeHeaders(messageId: number): string

getNextMediaMessage

  • getNextMediaMessage(messageId: number, msgType1: number, msgType2: number, msgType3: number): number
  • Parameters

    • messageId: number
    • msgType1: number
    • msgType2: number
    • msgType3: number

    Returns number

getPreviousMediaMessage

  • getPreviousMediaMessage(messageId: number, msgType1: number, msgType2: number, msgType3: number): number
  • Parameters

    • messageId: number
    • msgType1: number
    • msgType2: number
    • msgType3: number

    Returns number

getProviderFromEmail

  • getProviderFromEmail(email: string): undefined | { before_login_hint: any; overview_page: any; status: any }
  • get information about the provider

    Parameters

    • email: string

    Returns undefined | { before_login_hint: any; overview_page: any; status: any }

getSecurejoinQrCode

  • getSecurejoinQrCode(chatId: number): string

getSecurejoinQrCodeSVG

  • getSecurejoinQrCodeSVG(chatId: number): string

getWebxdcBlob

  • getWebxdcBlob(message: Message, filename: string): Buffer | null
  • the string contains the binary data, it is an "u8 string", maybe we will use a more efficient type in the future.

    Parameters

    • message: Message
    • filename: string

    Returns Buffer | null

getWebxdcStatusUpdates

importExport

  • importExport(what: number, param1: string, param2?: string): void
  • Parameters

    • what: number
    • param1: string
    • Default value param2: string = ""

    Returns void

importExportHasBackup

  • importExportHasBackup(dir: string): any

initiateKeyTransfer

  • initiateKeyTransfer(): Promise<string>

isConfigured

  • isConfigured(): boolean

isContactInChat

  • isContactInChat(chatId: number, contactId: number): boolean

joinSecurejoin

  • joinSecurejoin(qrCode: string): number

listenerCount

  • listenerCount(eventName: string | symbol): number
  • Returns the number of listeners listening to the event named eventName.

    since

    v3.2.0

    Parameters

    • eventName: string | symbol

      The name of the event being listened for

    Returns number

listeners

  • listeners(eventName: string | symbol): 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

    • eventName: string | symbol

    Returns Function[]

lookupContactIdByAddr

  • lookupContactIdByAddr(addr: string): number

markNoticedChat

  • markNoticedChat(chatId: number): void

markSeenMessages

  • markSeenMessages(messageIds: number[]): void

maybeNetwork

  • maybeNetwork(): void

messageNew

off

  • off(eventName: string | symbol, listener: (...args: any[]) => void): this
  • Alias for emitter.removeListener().

    since

    v10.0.0

    Parameters

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

          • Rest ...args: any[]

          Returns void

    Returns this

on

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

    const myEE = new EventEmitter();
    myEE.on('foo', () => console.log('a'));
    myEE.prependListener('foo', () => console.log('b'));
    myEE.emit('foo');
    // Prints:
    //   b
    //   a
    since

    v0.1.101

    Parameters

    • eventName: string | symbol

      The name of the event.

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

      The callback function

        • (...args: any[]): void
        • Parameters

          • Rest ...args: any[]

          Returns void

    Returns this

once

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

    const myEE = new EventEmitter();
    myEE.once('foo', () => console.log('a'));
    myEE.prependOnceListener('foo', () => console.log('b'));
    myEE.emit('foo');
    // Prints:
    //   b
    //   a
    since

    v0.3.0

    Parameters

    • eventName: string | symbol

      The name of the event.

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

      The callback function

        • (...args: any[]): void
        • Parameters

          • Rest ...args: any[]

          Returns void

    Returns this

open

  • open(passphrase?: undefined | string): boolean

prependListener

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

    • eventName: string | symbol

      The name of the event.

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

      The callback function

        • (...args: any[]): void
        • Parameters

          • Rest ...args: any[]

          Returns void

    Returns this

prependOnceListener

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

    • eventName: string | symbol

      The name of the event.

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

      The callback function

        • (...args: any[]): void
        • Parameters

          • Rest ...args: any[]

          Returns void

    Returns this

rawListeners

  • rawListeners(eventName: string | symbol): 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

    • eventName: string | symbol

    Returns Function[]

removeAllListeners

  • removeAllListeners(event?: string | symbol): this
  • 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.

    since

    v0.1.26

    Parameters

    • Optional event: string | symbol

    Returns this

removeContactFromChat

  • removeContactFromChat(chatId: number, contactId: number): boolean

removeListener

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

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

          • Rest ...args: any[]

          Returns void

    Returns this

searchMessages

  • searchMessages(chatId: number, query: string): number[]
  • Parameters

    • chatId: number

      ID of the chat to search messages in. Set this to 0 for a global search.

    • query: string

      The query to search for.

    Returns number[]

sendMessage

  • sendMessage(chatId: number, msg: string | Message): any

sendVideochatInvitation

  • sendVideochatInvitation(chatId: number): Promise<number>
  • Parameters

    • chatId: number

    Returns Promise<number>

    Promise that resolves into the resulting message id

sendWebxdcStatusUpdate

setChatEphemeralTimer

  • setChatEphemeralTimer(chatId: number, timer: number): boolean

setChatMuteDuration

  • setChatMuteDuration(chatId: number, duration: number): boolean
  • Parameters

    • chatId: number
    • duration: number

      The duration (0 for no mute, -1 for forever mute, everything else is is the relative mute duration from now in seconds)

    Returns boolean

setChatName

  • setChatName(chatId: number, name: string): boolean

setChatProfileImage

  • setChatProfileImage(chatId: number, image: string): boolean

setChatProtection

  • setChatProtection(chatId: number, protect: boolean): boolean

setChatVisibility

setConfig

  • setConfig(key: string, value: string | boolean | number): number

setConfigFromQr

  • setConfigFromQr(qrcodeContent: string): boolean

setDraft

  • setDraft(chatId: number, msg: Message | null): void

setLocation

  • setLocation(latitude: number, longitude: number, accuracy: number): void

setMaxListeners

  • setMaxListeners(n: number): this
  • 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

    • n: number

    Returns this

setStockTranslation

  • setStockTranslation(stockId: number, stockMsg: string): boolean

startIO

  • startIO(): void

stopIO

  • stopIO(): void

stopOngoingProcess

  • stopOngoingProcess(): void

unref

  • unref(): void

wasDeviceMessageEverAdded

  • wasDeviceMessageEverAdded(label: string): boolean

Static getEventListeners

  • getEventListeners(emitter: DOMEventTarget | EventEmitter, name: string | symbol): 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

    Parameters

    • emitter: DOMEventTarget | EventEmitter
    • name: string | symbol

    Returns Function[]

Static getSystemInfo

  • getSystemInfo(): { arch: string; compile_date: string; deltachat_core_version: string; libetpan_version: string; openssl_version: string; sqlite_thread_safe: string; sqlite_version: string }
  • deprectated

    please use AccountManager.getSystemInfo() instead

    Returns { arch: string; compile_date: string; deltachat_core_version: string; libetpan_version: string; openssl_version: string; sqlite_thread_safe: string; sqlite_version: string }

    • arch: string
    • compile_date: string
    • deltachat_core_version: string
    • libetpan_version: string
    • openssl_version: string
    • sqlite_thread_safe: string
    • sqlite_version: string

Static listenerCount

  • listenerCount(emitter: EventEmitter, eventName: string | symbol): 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

    • emitter: EventEmitter

      The emitter to query

    • eventName: string | symbol

      The event name

    Returns number

Static on

  • on(emitter: EventEmitter, eventName: string, options?: StaticEventEmitterOptions): AsyncIterableIterator<any>
  • ```js 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:
    
    ```js
    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

    • emitter: EventEmitter
    • eventName: string

      The name of the event being listened for

    • Optional options: StaticEventEmitterOptions

    Returns AsyncIterableIterator<any>

    that iterates eventName events emitted by the emitter

Static once

  • once(emitter: NodeEventTarget, eventName: string | symbol, options?: StaticEventEmitterOptions): 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

    • emitter: NodeEventTarget
    • eventName: string | symbol
    • Optional options: StaticEventEmitterOptions

    Returns Promise<any[]>

Static open

  • Opens a stanalone context (without an account manager) automatically starts the event handler

    Parameters

    • cwd: string

    Returns Context

Static setMaxListeners

  • setMaxListeners(n?: undefined | number, ...eventTargets: Array<DOMEventTarget | EventEmitter>): void
  • ```js const { setMaxListeners, EventEmitter } = require('events');

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

    setMaxListeners(5, target, emitter); ```

    since

    v15.4.0

    Parameters

    • Optional n: undefined | number

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

    • Rest ...eventTargets: Array<DOMEventTarget | EventEmitter>

    Returns void

Generated using TypeDoc