Class SolidClientService

Solid client service

Hierarchy (view full)

Constructors

Properties

_clientAuthentication: default
_session: SolidSession
clientRegistrar: ClientRegistrar
driver: DataServiceDriver<string, string>
express: Express
localServices: Set<string>
model: Model<any, any>
nodes: Set<string>
promises: Map<string, {
    reject: ((ex?) => void);
    resolve: ((data?) => void);
}>

Type declaration

  • reject: ((ex?) => void)
      • (ex?): void
      • Parameters

        • Optional ex: any

        Returns void

  • resolve: ((data?) => void)
      • (data?): void
      • Parameters

        • Optional data: any

        Returns void

remoteServices: Set<string>
sessionManager: SessionManager
storage: default
storageUtility: default
uid: string

Service name

PREFIX: "OpenHPS:solid" = 'OpenHPS:solid'
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

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

Accessors

Methods

  • Type Parameters

    • K

    Parameters

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

    Returns void

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

    Type Parameters

    • K

    Parameters

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

          • Rest ...args: any[]

          Returns void

    Returns this

    Since

    v0.1.26

  • Create a Solid container

    Parameters

    • session: SolidSession

      Solid session to create a container with

    • url: `http://${string}` | `https://${string}`

      URL of the container

    Returns Promise<Readonly<{
        graphs: Readonly<Record<string, Readonly<Record<string, Readonly<{
            predicates: Readonly<(...)>;
            type: "Subject";
            url: string;
        }>>>> & {
            default: Readonly<Record<string, Readonly<{
                predicates: Readonly<(...)>;
                type: "Subject";
                url: string;
            }>>>;
        }>;
        type: "Dataset";
    }>>

    Promise of the container

  • Set a thing in a session Pod

    Parameters

    • session: SolidSession

      Solid session to set a thing to

    • thing: Readonly<{
          predicates: Readonly<Record<string, Readonly<Partial<{
              blankNodes: readonly (`_:${string}` | (Readonly<Record<string, Readonly<Partial<{ literals: Readonly<Record<string, readonly string[]>>; langStrings: Readonly<Record<string, readonly string[]>>; namedNodes: readonly string[]; blankNodes: readonly (`_:${string}` | Readonly<...>)[]; }>>>>))[];
              langStrings: Readonly<Record<string, readonly string[]>>;
              literals: Readonly<Record<string, readonly string[]>>;
              namedNodes: readonly string[];
          }>>>>;
          type: "Subject";
          url: string;
      }>

      Non-persisted thing to store in the Pod

    • Optional dataset: Readonly<{
          graphs: Readonly<Record<string, Readonly<Record<string, Readonly<{
              predicates: Readonly<Record<(...), (...)>>;
              type: "Subject";
              url: string;
          }>>>> & {
              default: Readonly<Record<string, Readonly<{
                  predicates: Readonly<Record<(...), (...)>>;
                  type: "Subject";
                  url: string;
              }>>>;
          }>;
          type: "Dataset";
      }>

    Returns Promise<Readonly<{
        graphs: Readonly<Record<string, Readonly<Record<string, Readonly<{
            predicates: Readonly<(...)>;
            type: "Subject";
            url: string;
        }>>>> & {
            default: Readonly<Record<string, Readonly<{
                predicates: Readonly<(...)>;
                type: "Subject";
                url: string;
            }>>>;
        }>;
        type: "Dataset";
    }>>

    Promise if stored

  • Parameters

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

    Returns boolean

  • Service ready

    Parameters

    • name: "ready"

      ready

    Returns boolean

  • Destroy the service

    Parameters

    • name: "destroy"

      destroy

    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)[]

    Since

    v6.0.0

  • Returns string

  • Get access control list for a specific resource

    Parameters

    • uri: `http://${string}` | `https://${string}`
    • webId: string = foaf.Agent

      WebID to get access control list for

    • Optional session: SolidSession

      Session to use

    Returns Promise<AccessModes>

    Access control list

  • Get a Solid dataset

    Parameters

    • session: SolidSession

      Solid session to get a thing from

    • uri: string

      URI of the thing in the Solid Pod

    Returns Promise<Readonly<{
        graphs: Readonly<Record<string, Readonly<Record<string, Readonly<{
            predicates: Readonly<(...)>;
            type: "Subject";
            url: string;
        }>>>> & {
            default: Readonly<Record<string, Readonly<{
                predicates: Readonly<(...)>;
                type: "Subject";
                url: string;
            }>>>;
        }>;
        type: "Dataset";
    }>>

    Promise of a solid dataset

  • Get a Solid dataset as an N3 Quads dataset

    Parameters

    • session: SolidSession

      Solid session to get a thing from

    • uri: string

      URI of the thing in the Solid Pod

    Returns Promise<Store<Quad, Quad, Quad, Quad>>

    Promise of a solid dataset store

  • 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

    • uuid: string

    Returns {
        reject: ((ex?) => void);
        resolve: ((data?) => void);
    }

    • reject: ((ex?) => void)
        • (ex?): void
        • Parameters

          • Optional ex: any

          Returns void

    • resolve: ((data?) => void)
        • (data?): void
        • Parameters

          • Optional data: any

          Returns void

  • Get a thing from a session Pod

    Parameters

    • session: SolidSession

      Solid session to get a thing from

    • uri: string

      URI of the thing in the Solid Pod

    Returns Promise<ThingPersisted>

    Persisted thing

  • Returns boolean

  • 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

    • 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] ]

    Type Parameters

    • K

    Parameters

    • eventName: string | symbol

    Returns Function[]

    Since

    v0.1.26

  • Local positioning model event

    Parameters

    • uid: string

      UID of the node

    • event: string

      Event name

    • Optional Rest ...args: any[]

      Argument

    Returns void

  • Local positioning model pull

    Parameters

    • uid: string

      UID of the node

    • Optional options: RemotePullOptions

      Pull options

    Returns void

  • Local positioning model push

    Parameters

    • uid: string

      UID of the node

    • frame: any

      Data frame

    • Optional options: RemotePushOptions

      Push options

    Returns void

  • Local service call

    Parameters

    • uid: string

      Service uid

    • method: string

      Method name

    • Optional Rest ...args: any[]

      optional arguments

    Returns any

    service call output

  • Parameters

    • level: "debug"
    • message: string
    • Optional data: any

    Returns void

  • Parameters

    • level: "info"
    • message: string
    • Optional data: any

    Returns void

  • Parameters

    • level: "warn"
    • message: string
    • Optional data: any

    Returns void

  • Parameters

    • level: "error"
    • message: string
    • Optional error: Error

    Returns void

  • Parameters

    • level: string

      Logging level

    • log: any

      Logging data or message

    Returns void

    Deprecated

  • Login a Solid user

    Parameters

    • oidcIssuer: string = ...

      OpenID Issuer

    • interactive: boolean = false

    Returns Promise<Session>

    Session promise

  • Alias for emitter.removeListener().

    Type Parameters

    • K

    Parameters

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

          • Rest ...args: any[]

          Returns void

    Returns this

    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

    Type Parameters

    • K

    Parameters

    • eventName: string | symbol

      The name of the event.

    • listener: ((...args) => void)

      The callback function

        • (...args): void
        • Parameters

          • Rest ...args: any[]

          Returns void

    Returns this

    Since

    v0.1.101

  • Parameters

    • req: Request<ParamsDictionary, any, any, ParsedQs, Record<string, any>>
    • res: Response<any, Record<string, any>>

    Returns void

  • Parameters

    • req: Request<ParamsDictionary, any, any, ParsedQs, Record<string, any>>
    • res: Response<any, Record<string, any>>

    Returns void

  • Parameters

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

          • Rest ...args: any[]

          Returns void

    Returns this

  • Event called when service is destroyed

    Parameters

    • name: "destroy"

      destroy

    • listener: (() => void | Promise<void>)

      Event callback

        • (): void | Promise<void>
        • Returns void | Promise<void>

    Returns this

  • Event called when service is build

    Parameters

    • name: "build"

      build

    • listener: (() => void | Promise<void>)

      Event callback

        • (): void | Promise<void>
        • Returns void | Promise<void>

    Returns this

  • Event called when service is ready

    Parameters

    • name: "ready"

      ready

    • listener: (() => void | Promise<void>)

      Event callback

        • (): void | Promise<void>
        • Returns void | Promise<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 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.

    Type Parameters

    • K

    Parameters

    • eventName: string | symbol

      The name of the event.

    • listener: ((...args) => void)

      The callback function

        • (...args): void
        • Parameters

          • Rest ...args: any[]

          Returns void

    Returns this

    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.

    Type Parameters

    • K

    Parameters

    • eventName: string | symbol

      The name of the event.

    • listener: ((...args) => void)

      The callback function

        • (...args): void
        • Parameters

          • Rest ...args: any[]

          Returns void

    Returns this

    Since

    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[]

    Since

    v9.4.0

  • Register a node as a remotely available node

    Parameters

    • node: string | Node<any, any>

      Node to register

    Returns Promise<void>

    Promise of registration

  • Parameters

    • resolve: ((data?) => void)
        • (data?): void
        • Parameters

          • Optional data: any

          Returns void

    • reject: ((ex?) => void)
        • (ex?): void
        • Parameters

          • Optional ex: any

          Returns void

    • Optional id: string

    Returns string

  • Register a service to be remotely available

    Parameters

    • service: Service

      Service to register

    Returns Promise<void>

    Promise of registration

  • Send an error to a remote node

    Parameters

    • uid: string

      Remote Node UID

    • event: string

      Event to send

    • Optional Rest ...args: any[]

      Event argument

    Returns Promise<void>

  • Send a pull request to a specific remote node

    Parameters

    • uid: string

      Remote Node UID

    • Optional options: PullOptions

      Pull options

    Returns Promise<void>

  • Send a push to a specific remote node

    Type Parameters

    • T extends DataFrame | DataFrame[]

    Parameters

    • uid: string

      Remote Node UID

    • frame: T

      Data frame to push

    • Optional options: PushOptions

      Push options

    Returns Promise<void>

  • Send a remote service call

    Parameters

    • uid: string

      Service uid

    • method: string

      Method to call

    • Optional Rest ...args: any[]

      Optional set of arguments

    Returns Promise<any>

  • 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 eventName: string | symbol

    Returns this

    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.

    Type Parameters

    • K

    Parameters

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

          • Rest ...args: any[]

          Returns void

    Returns this

    Since

    v0.1.26

  • Save a Solid dataset

    Parameters

    • session: SolidSession

      Solid session to get a thing from

    • uri: string

      URI of the thing in the Solid Pod

    • Optional dataset: Readonly<{
          graphs: Readonly<Record<string, Readonly<Record<string, Readonly<{
              predicates: Readonly<Record<(...), (...)>>;
              type: "Subject";
              url: string;
          }>>>> & {
              default: Readonly<Record<string, Readonly<{
                  predicates: Readonly<Record<(...), (...)>>;
                  type: "Subject";
                  url: string;
              }>>>;
          }>;
          type: "Dataset";
      }>

      Dataset to save at the uri

    Returns Promise<Readonly<{
        graphs: Readonly<Record<string, Readonly<Record<string, Readonly<{
            predicates: Readonly<(...)>;
            type: "Subject";
            url: string;
        }>>>> & {
            default: Readonly<Record<string, Readonly<{
                predicates: Readonly<(...)>;
                type: "Subject";
                url: string;
            }>>>;
        }>;
        type: "Dataset";
    }>>

    Promise of a solid dataset

  • Set access control list for a specific object

    Parameters

    • uri: `http://${string}` | `https://${string}`

      URI of the object

    • acces: Partial<AccessModes>

      Access modes

    • Optional webId: string = foaf.Agent

      WebID to set access for

    • Optional session: SolidSession

      Session to use

    Returns Promise<void>

  • 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 this

    Since

    v0.3.5

  • Parameters

    • uid: string

    Returns this

  • 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) => void)
        • (event): void
        • Parameters

          • event: Event

          Returns void

    Returns Disposable

    Disposable that removes the abort listener.

    Since

    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> | _DOMEventTarget
    • name: string | symbol

    Returns Function[]

    Since

    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> | _DOMEventTarget

    Returns number

    Since

    v19.9.0

  • 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<DefaultEventMap>

      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<DefaultEventMap>
    • 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: EventEmitter<DefaultEventMap>
    • 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<DefaultEventMap> | _DOMEventTarget)[]

    Returns void

    Since

    v15.4.0