Salesforce connection decorator that extends the base JSForce connection

Hierarchy

Constructors

Properties

_refreshDelegate: RefreshDelegate
_transport: Transport
accessToken: string
analytics: Analytics
apex: Apex
bulk: Bulk
cache: Cache
chatter: Chatter
describe$: {
    clear() => void;
    (type, callback?): DescribeSObjectResult;
}

Type declaration

  • clear:function
    • Returns void

describeGlobal$: {
    clear() => void;
    (callback?): DescribeGlobalResult;
}

Type declaration

  • clear:function
    • Returns void

enableFeedTracking: boolean

When true feed tracking is enabled improving decreasing overall performance by generating feed notifications on changes.

Default

false
instanceUrl: string
limitInfo?: LimitInfo
logger: Logger

Internal logger for the connection, is adapted into a JSforce logger as well

metadata: MetadataApi & Metadata
refreshToken?: string
soap: SoapApi
streaming: Streaming
tooling: Tooling
userInfo?: UserInfo
version: string
captureRejectionSymbol: typeof captureRejectionSymbol

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

See how to write a custom rejection handler.

Since

v13.4.0, v12.16.0

captureRejections: boolean

Value: boolean

Change the default captureRejections option on all new EventEmitter objects.

Since

v13.4.0, v12.16.0

clientConnectionId: string = ...

The client ID used in the request headers

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

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

maxRetries: number = 5

Max number of times a request is retried before throwing an error to the caller.

retryInterval: number = 1000

The retry interval after which a failed http request is retried. The retry interval is multiplied by the retry number to gradually increase the interval between each retry up until the maxRetries is reached.

Methods

  • Returns string

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

    Parameters

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

          • Rest ...args: any[]

          Returns void

    Returns SalesforceConnection

    Since

    v0.1.26

  • Parameters

    • code: string
    • Optional callback: ((err, res) => void)
        • (err, res): void
        • Parameters

          • err: Error
          • res: UserInfo

          Returns void

    Returns Promise<UserInfo>

  • Executes up to 25 subrequests in a single request. The response bodies and HTTP statuses of the subrequests in the batch are returned in a single response body. Each subrequest counts against rate limits.

    Note all requests are executed against the connections API version. URLs that do contain a version number such as /services/data/v33.0/sobjects/Account/describe are normalized to a format without a concrete API version such as, i.e: {apiVersion}/sobjects/Account/describe.

    Note only the following APIs are supported:

    • limits
    • query
    • queryAll
    • search
    • connect
    • chatter
    • actions
    • sobjects

    Format of requests:

    const requests = [{
    method: 'GET',
    url: 'sobjects/Account/describe'
    }, {
    method: 'POST',
    url: 'sobjects/Account',
    richInput: { Name: 'CB Corp.' }
    }]

    Type Parameters

    • T = any

    Parameters

    • requests: readonly Subrequest[]
    • Optional haltOnError: boolean

      Controls whether a batch continues to process after a subrequest fails. The default is false. If the value is false and a subrequest in the batch doesn’t complete, Salesforce attempts to execute the subsequent subrequests in the batch. If the value is true and a subrequest in the batch doesn’t complete due to an HTTP response in the 400 or 500 range, Salesforce halts execution. It returns an HTTP 412 status code and a BATCH_PROCESSING_HALTED error message for each subsequent subrequest. The top-level request to /composite/batch returns HTTP 200, and the hasErrors property in the response is set to true. This setting is only applied during subrequest processing, and not during initial request deserialization. If an error is detected during deserialization, such as a syntax error in the Subrequest request data, Salesforce returns an HTTP 400 Bad Request error without processing any subrequests, regardless of the value of haltOnError. An example where this could occur is if a subrequest has an invalid method or url field.

    Returns Promise<T>[]

    Array of promises that reflect the batch requests; each promise can be rejected or resolved individually

  • Type Parameters

    • T

    Parameters

    • type: string
    • records: Record<T> | Record<T>[]
    • Optional options: RestApiOptions
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: RecordResult | RecordResult[]

          Returns void

    Returns Promise<RecordResult | RecordResult[]>

  • Type Parameters

    • T

    Parameters

    • records: Record<T> | Record<T>[]
    • Optional options: RestApiOptions
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: RecordResult | RecordResult[]

          Returns void

    Returns Promise<RecordResult | RecordResult[]>

  • Type Parameters

    • T

    Parameters

    • type: string
    • ids: string | string[]
    • Optional options: RestApiOptions
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: RecordResult | RecordResult[]

          Returns void

    Returns Promise<RecordResult | RecordResult[]>

  • Type Parameters

    • T

    Parameters

    • type: string
    • ids: string | string[]
    • Optional options: RestApiOptions
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: RecordResult | RecordResult[]

          Returns void

    Returns Promise<RecordResult | RecordResult[]>

  • Type Parameters

    • T

    Parameters

    • Optional callback: ((err, result) => void)

    Returns Promise<DescribeGlobalResult>

  • Type Parameters

    • T

    Parameters

    • type: string
    • ids: string | string[]
    • Optional options: RestApiOptions
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: RecordResult | RecordResult[]

          Returns void

    Returns Promise<RecordResult | RecordResult[]>

  • 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

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

    Returns boolean

    Since

    v0.1.26

  • 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

  • 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

  • Parameters

    • Optional callback: ((err, res) => void)
        • (err, res): void
        • Parameters

          • err: Error
          • res: IdentityInfo

          Returns void

    Returns Promise<IdentityInfo>

  • Parameters

    • Optional options: ConnectionOptions

    Returns void

  • Type Parameters

    • T

    Parameters

    • type: string
    • records: Record<T> | Record<T>[]
    • Optional options: RestApiOptions
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: RecordResult | RecordResult[]

          Returns void

    Returns Promise<RecordResult | RecordResult[]>

  • Determine if an error can be retried; if returns true the error is retried before being thrown to the caller. The number of retries is limited by the maxRetries configured.

    Parameters

    Returns err is Error & {
        code: undefined | string;
        errorCode: undefined | string;
    }

    true if the error is retryable otherwise false

  • Parameters

    • Optional callback: ((err, res) => void)
        • (err, res): void
        • Parameters

          • err: Error
          • res: undefined

          Returns void

    Returns Promise<LimitsInfo>

  • 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

    • eventName: string | symbol

      The name of the event being listened for

    • Optional listener: Function

      The event handler function

    Returns number

    Since

    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] ]

    Parameters

    • eventName: string | symbol

    Returns Function[]

    Since

    v0.1.26

  • Parameters

    • user: string
    • password: string
    • Optional callback: ((err, res) => void)
        • (err, res): void
        • Parameters

          • err: Error
          • res: UserInfo

          Returns void

    Returns Promise<UserInfo>

  • Parameters

    • user: string
    • password: string
    • Optional callback: ((err, res) => void)
        • (err, res): void
        • Parameters

          • err: Error
          • res: UserInfo

          Returns void

    Returns Promise<UserInfo>

  • Parameters

    • user: string
    • password: string
    • Optional callback: ((err, res) => void)
        • (err, res): void
        • Parameters

          • err: Error
          • res: UserInfo

          Returns void

    Returns Promise<UserInfo>

  • Parameters

    • revoke: boolean
    • Optional callback: ((err, res) => void)
        • (err, res): void
        • Parameters

          • err: Error
          • res: undefined

          Returns void

    Returns Promise<void>

  • Parameters

    • Optional callback: ((err, res) => void)
        • (err, res): void
        • Parameters

          • err: Error
          • res: undefined

          Returns void

    Returns Promise<void>

  • Parameters

    • revoke: boolean
    • Optional callback: ((err, res) => void)
        • (err, res): void
        • Parameters

          • err: Error
          • res: undefined

          Returns void

    Returns Promise<void>

  • Parameters

    • Optional callback: ((err, res) => void)
        • (err, res): void
        • Parameters

          • err: Error
          • res: undefined

          Returns void

    Returns Promise<void>

  • Parameters

    • revoke: boolean
    • Optional callback: ((err, res) => void)
        • (err, res): void
        • Parameters

          • err: Error
          • res: undefined

          Returns void

    Returns Promise<void>

  • Parameters

    • Optional callback: ((err, res) => void)
        • (err, res): void
        • Parameters

          • err: Error
          • res: undefined

          Returns void

    Returns Promise<void>

  • Alias for emitter.removeListener().

    Parameters

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

          • Rest ...args: any[]

          Returns void

    Returns SalesforceConnection

    Since

    v10.0.0

  • 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

    • eventName: string | symbol

      The name of the event.

    • listener: ((...args) => void)

      The callback function

        • (...args): void
        • Parameters

          • Rest ...args: any[]

          Returns void

    Returns SalesforceConnection

    Since

    v0.1.101

  • 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

    • eventName: string | symbol

      The name of the event.

    • listener: ((...args) => void)

      The callback function

        • (...args): void
        • Parameters

          • Rest ...args: any[]

          Returns void

    Returns SalesforceConnection

    Since

    v0.3.0

  • 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

    • eventName: string | symbol

      The name of the event.

    • listener: ((...args) => void)

      The callback function

        • (...args): void
        • Parameters

          • Rest ...args: any[]

          Returns void

    Returns SalesforceConnection

    Since

    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.

    Parameters

    • eventName: string | symbol

      The name of the event.

    • listener: ((...args) => void)

      The callback function

        • (...args): void
        • Parameters

          • Rest ...args: any[]

          Returns void

    Returns SalesforceConnection

    Since

    v6.0.0

  • Type Parameters

    • T

    Parameters

    • soql: string
    • Optional options: ExecuteOptions
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: QueryResult<T>

          Returns void

    Returns Query<QueryResult<T>>

  • Type Parameters

    • T

    Parameters

    • soql: string
    • Optional options: object
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: QueryResult<T>

          Returns void

    Returns Query<QueryResult<T>>

  • Type Parameters

    • T

    Parameters

    • locator: string
    • Optional options: ExecuteOptions
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: QueryResult<T>

          Returns void

    Returns Promise<QueryResult<T>>

  • 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

    • eventName: string | symbol

    Returns Function[]

    Since

    v9.4.0

  • Parameters

    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: RecordResult[]

          Returns void

    Returns Promise<RecordResult[]>

  • Parameters

    • param: string | number
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: RecordResult[]

          Returns void

    Returns Promise<RecordResult[]>

  • Parameters

    • type: string
    • limit: number
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: RecordResult[]

          Returns void

    Returns Promise<RecordResult[]>

  • 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

    • Optional event: string | symbol

    Returns SalesforceConnection

    Since

    v0.1.26

  • 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

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

          • Rest ...args: any[]

          Returns void

    Returns SalesforceConnection

    Since

    v0.1.26

  • Type Parameters

    • T = object

    Parameters

    • url: string
    • body: object
    • Optional options_callback: HttpApiOptions | ((err, Object) => void)

    Returns Promise<T>

  • Type Parameters

    • T = object

    Parameters

    • url: string
    • body: object
    • Optional options: HttpApiOptions
    • Optional callback: ((err, Object) => void)
        • (err, Object): void
        • Parameters

          • err: Error
          • Object: T

          Returns void

    Returns Promise<T>

  • Type Parameters

    • T

    Parameters

    • type: string
    • ids: string | string[]
    • Optional options: RestApiOptions
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: Record<T> | Record<T>[]

          Returns void

    Returns Promise<Record<T> | Record<T>[]>

  • Type Parameters

    • T

    Parameters

    • sosl: string
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: SearchResult<T>

          Returns void

    Returns Promise<SearchResult<T>>

  • 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

    • n: number

    Returns SalesforceConnection

    Since

    v0.3.5

  • Type Parameters

    • T = object

    Parameters

    • resource: string

    Returns SObject<T>

  • Type Parameters

    • T

    Parameters

    • type: string
    • records: Record<T> | Record<T>[]
    • Optional options: RestApiOptions
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: RecordResult | Record<T>[]

          Returns void

    Returns Promise<RecordResult | RecordResult[]>

  • Type Parameters

    • T

    Parameters

    • records: Record<T> | Record<T>[]
    • Optional options: RestApiOptions
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: RecordResult | Record<T>[]

          Returns void

    Returns Promise<RecordResult | RecordResult[]>

  • Type Parameters

    • T

    Parameters

    • type: string
    • records: Record<T> | Record<T>[]
    • extIdField: string
    • Optional options: RestApiOptions
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: RecordResult | RecordResult[]

          Returns void

    Returns Promise<RecordResult | RecordResult[]>

  • Type Parameters

    • T

    Parameters

    • records: Record<T> | Record<T>[]
    • extIdField: string
    • Optional options: RestApiOptions
    • Optional callback: ((err, result) => void)
        • (err, result): void
        • Parameters

          • err: Error
          • result: RecordResult | RecordResult[]

          Returns void

    Returns Promise<RecordResult | RecordResult[]>

  • 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 | _DOMEventTarget
    • name: string | symbol

    Returns Function[]

    Since

    v15.2.0, v14.17.0

  • 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

    • emitter: EventEmitter

      The emitter to query

    • eventName: string | symbol

      The event name

    Returns number

    Since

    v0.9.12

    Deprecated

    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());

    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

    Since

    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!

    Parameters

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

    Returns Promise<any[]>

    Since

    v11.13.0, v10.16.0

  • Parameters

    • emitter: _DOMEventTarget
    • eventName: string
    • Optional options: StaticEventEmitterOptions

    Returns Promise<any[]>

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

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

    setMaxListeners(5, target, emitter);

    Parameters

    • Optional n: number

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

    • Rest ...eventTargets: (EventEmitter | _DOMEventTarget)[]

    Returns void

    Since

    v15.4.0