Interface IWorkerNode<Worker, Data>Internal

Worker node interface.

interface IWorkerNode<Worker, Data> {
    clearTasksQueue: (() => void);
    deleteTaskFunctionWorkerUsage: ((name: string) => boolean);
    dequeueLastPrioritizedTask: (() => undefined | Task<Data>);
    dequeueTask: ((bucket?: number) => undefined | Task<Data>);
    enqueueTask: ((task: Task<Data>) => number);
    getTaskFunctionWorkerUsage: ((name: string) => undefined | WorkerUsage);
    info: WorkerInfo;
    messageChannel?: MessageChannel;
    registerOnceWorkerEventHandler: ((event: string, handler: EventHandler<Worker>) => void);
    registerWorkerEventHandler: ((event: string, handler: EventHandler<Worker>) => void);
    setTasksQueuePriority: ((enablePriority: boolean) => void);
    strategyData?: StrategyData;
    tasksQueueBackPressureSize: number;
    tasksQueueSize: (() => number);
    terminate: (() => Promise<void>);
    usage: WorkerUsage;
    worker: Worker;
    [captureRejectionSymbol]?<K>(error: Error, event: string | symbol, ...args: AnyRest): void;
    addListener<K>(eventName: string | symbol, listener: ((...args: any[]) => void)): this;
    emit<K>(eventName: string | symbol, ...args: AnyRest): boolean;
    eventNames(): (string | symbol)[];
    getMaxListeners(): number;
    listenerCount<K>(eventName: string | symbol, listener?: Function): number;
    listeners<K>(eventName: string | symbol): Function[];
    off<K>(eventName: string | symbol, listener: ((...args: any[]) => void)): this;
    on<K>(eventName: string | symbol, listener: ((...args: any[]) => void)): this;
    once<K>(eventName: string | symbol, listener: ((...args: any[]) => void)): this;
    prependListener<K>(eventName: string | symbol, listener: ((...args: any[]) => void)): this;
    prependOnceListener<K>(eventName: string | symbol, listener: ((...args: any[]) => void)): this;
    rawListeners<K>(eventName: string | symbol): Function[];
    removeAllListeners(eventName?: string | symbol): this;
    removeListener<K>(eventName: string | symbol, listener: ((...args: any[]) => void)): this;
    setMaxListeners(n: number): this;
}

Type Parameters

  • Worker extends IWorker

    Type of worker.

  • Data = unknown

    Type of data sent to the worker. This can only be structured-cloneable data.

Hierarchy

  • EventEmitter
    • IWorkerNode

Properties

clearTasksQueue: (() => void)

Clears tasks queue.

deleteTaskFunctionWorkerUsage: ((name: string) => boolean)

Deletes task function worker usage statistics.

Type declaration

    • (name): boolean
    • Parameters

      • name: string

        The task function name.

      Returns boolean

      true if the task function worker usage statistics were deleted, false otherwise.

dequeueLastPrioritizedTask: (() => undefined | Task<Data>)

Dequeue last prioritized task.

Type declaration

dequeueTask: ((bucket?: number) => undefined | Task<Data>)

Dequeue task.

Type declaration

    • (bucket?): undefined | Task<Data>
    • Parameters

      • Optionalbucket: number

        The prioritized bucket to dequeue from.

      Returns undefined | Task<Data>

      The dequeued task.

0
enqueueTask: ((task: Task<Data>) => number)

Enqueue task.

Type declaration

    • (task): number
    • Parameters

      Returns number

      The tasks queue size.

getTaskFunctionWorkerUsage: ((name: string) => undefined | WorkerUsage)

Gets task function worker usage statistics.

Type declaration

    • (name): undefined | WorkerUsage
    • Parameters

      • name: string

        The task function name.

      Returns undefined | WorkerUsage

      The task function worker usage statistics if the task function worker usage statistics are initialized, undefined otherwise.

Worker info.

messageChannel?: MessageChannel

Message channel (worker thread only).

registerOnceWorkerEventHandler: ((event: string, handler: EventHandler<Worker>) => void)

Registers once a worker event handler.

Type declaration

    • (event, handler): void
    • Parameters

      Returns void

registerWorkerEventHandler: ((event: string, handler: EventHandler<Worker>) => void)

Registers a worker event handler.

Type declaration

    • (event, handler): void
    • Parameters

      Returns void

setTasksQueuePriority: ((enablePriority: boolean) => void)

Sets tasks queue priority.

Type declaration

    • (enablePriority): void
    • Parameters

      • enablePriority: boolean

        Whether to enable tasks queue priority.

      Returns void

strategyData?: StrategyData

Worker choice strategy data. This is used to store data that are specific to the worker choice strategy.

tasksQueueBackPressureSize: number

Tasks queue back pressure size. This is the number of tasks that can be enqueued before the worker node has back pressure.

tasksQueueSize: (() => number)

Tasks queue size.

Type declaration

    • (): number
    • Returns number

      The tasks queue size.

terminate: (() => Promise<void>)

Terminates the worker node.

Worker usage statistics.

worker: Worker

Worker.

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

          • Rest...args: any[]

          Returns void

    Returns this

    v0.1.26

  • Synchronously calls each of the listeners registered for the event named eventName, in the order they were registered, passing the supplied arguments to each.

    Returns true if the event had listeners, false otherwise.

    import { EventEmitter } from 'node:events';
    const myEmitter = new EventEmitter();

    // First listener
    myEmitter.on('event', function firstListener() {
    console.log('Helloooo! first listener');
    });
    // Second listener
    myEmitter.on('event', function secondListener(arg1, arg2) {
    console.log(`event with parameters ${arg1}, ${arg2} in second listener`);
    });
    // Third listener
    myEmitter.on('event', function thirdListener(...args) {
    const parameters = args.join(', ');
    console.log(`event with parameters ${parameters} in third listener`);
    });

    console.log(myEmitter.listeners('event'));

    myEmitter.emit('event', 1, 2, 3, 4, 5);

    // Prints:
    // [
    // [Function: firstListener],
    // [Function: secondListener],
    // [Function: thirdListener]
    // ]
    // Helloooo! first listener
    // event with parameters 1, 2 in second listener
    // event with parameters 1, 2, 3, 4, 5 in third listener

    Type Parameters

    • K

    Parameters

    • eventName: string | symbol
    • Rest...args: AnyRest

    Returns boolean

    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)[]

    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

    v1.0.0

  • Returns the number of listeners listening for the event named eventName. If listener is provided, it will return how many times the listener is found in the list of the listeners of the event.

    Type Parameters

    • K

    Parameters

    • eventName: string | symbol

      The name of the event being listened for

    • Optionallistener: Function

      The event handler function

    Returns number

    v3.2.0

  • Returns a copy of the array of listeners for the event named eventName.

    server.on('connection', (stream) => {
    console.log('someone connected!');
    });
    console.log(util.inspect(server.listeners('connection')));
    // Prints: [ [Function] ]

    Type Parameters

    • K

    Parameters

    • eventName: string | symbol

    Returns Function[]

    v0.1.26

  • Alias for emitter.removeListener().

    Type Parameters

    • K

    Parameters

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

          • Rest...args: any[]

          Returns void

    Returns this

    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 eventName and listener will result in the listener being added, and called, multiple times.

    server.on('connection', (stream) => {
    console.log('someone connected!');
    });

    Returns a reference to the EventEmitter, so that calls can be chained.

    By default, event listeners are invoked in the order they are added. The emitter.prependListener() method can be used as an alternative to add the event listener to the beginning of the listeners array.

    import { EventEmitter } from 'node:events';
    const myEE = new EventEmitter();
    myEE.on('foo', () => console.log('a'));
    myEE.prependListener('foo', () => console.log('b'));
    myEE.emit('foo');
    // Prints:
    // b
    // a

    Type Parameters

    • K

    Parameters

    • eventName: string | symbol

      The name of the event.

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

      The callback function

        • (...args): void
        • Parameters

          • Rest...args: any[]

          Returns void

    Returns this

    v0.1.101

  • Adds a one-time listener function for the event named eventName. The next time eventName is triggered, this listener is removed and then invoked.

    server.once('connection', (stream) => {
    console.log('Ah, we have our first user!');
    });

    Returns a reference to the EventEmitter, so that calls can be chained.

    By default, event listeners are invoked in the order they are added. The emitter.prependOnceListener() method can be used as an alternative to add the event listener to the beginning of the listeners array.

    import { EventEmitter } from 'node:events';
    const myEE = new EventEmitter();
    myEE.once('foo', () => console.log('a'));
    myEE.prependOnceListener('foo', () => console.log('b'));
    myEE.emit('foo');
    // Prints:
    // b
    // a

    Type Parameters

    • K

    Parameters

    • eventName: string | symbol

      The name of the event.

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

      The callback function

        • (...args): void
        • Parameters

          • Rest...args: any[]

          Returns void

    Returns this

    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 eventName and listener will result in the listener being added, and called, multiple times.

    server.prependListener('connection', (stream) => {
    console.log('someone connected!');
    });

    Returns a reference to the EventEmitter, so that calls can be chained.

    Type Parameters

    • K

    Parameters

    • eventName: string | symbol

      The name of the event.

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

      The callback function

        • (...args): void
        • Parameters

          • Rest...args: any[]

          Returns void

    Returns this

    v6.0.0

  • Adds a one-timelistener function for the event named eventName to the beginning of the listeners array. The next time eventName is triggered, this listener is removed, and then invoked.

    server.prependOnceListener('connection', (stream) => {
    console.log('Ah, we have our first user!');
    });

    Returns a reference to the EventEmitter, so that calls can be chained.

    Type Parameters

    • K

    Parameters

    • eventName: string | symbol

      The name of the event.

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

      The callback function

        • (...args): void
        • Parameters

          • Rest...args: any[]

          Returns void

    Returns this

    v6.0.0

  • Returns a copy of the array of listeners for the event named eventName, including any wrappers (such as those created by .once()).

    import { EventEmitter } from 'node:events';
    const emitter = new EventEmitter();
    emitter.once('log', () => console.log('log once'));

    // Returns a new Array with a function `onceWrapper` which has a property
    // `listener` which contains the original listener bound above
    const listeners = emitter.rawListeners('log');
    const logFnWrapper = listeners[0];

    // Logs "log once" to the console and does not unbind the `once` event
    logFnWrapper.listener();

    // Logs "log once" to the console and removes the listener
    logFnWrapper();

    emitter.on('log', () => console.log('log persistently'));
    // Will return a new Array with a single function bound by `.on()` above
    const newListeners = emitter.rawListeners('log');

    // Logs "log persistently" twice
    newListeners[0]();
    emitter.emit('log');

    Type Parameters

    • K

    Parameters

    • eventName: string | symbol

    Returns Function[]

    v9.4.0

  • Removes all listeners, or those of the specified eventName.

    It is bad practice to remove listeners added elsewhere in the code, particularly when the EventEmitter instance was created by some other component or module (e.g. sockets or file streams).

    Returns a reference to the EventEmitter, so that calls can be chained.

    Parameters

    • OptionaleventName: string | symbol

    Returns this

    v0.1.26

  • Removes the specified listener from the listener array for the event named eventName.

    const callback = (stream) => {
    console.log('someone connected!');
    };
    server.on('connection', callback);
    // ...
    server.removeListener('connection', callback);

    removeListener() will remove, at most, one instance of a listener from the listener array. If any single listener has been added multiple times to the listener array for the specified eventName, then removeListener() must be called multiple times to remove each instance.

    Once an event is emitted, all listeners attached to it at the time of emitting are called in order. This implies that any removeListener() or removeAllListeners() calls after emitting and before the last listener finishes execution will not remove them fromemit() in progress. Subsequent events behave as expected.

    import { EventEmitter } from 'node:events';
    class MyEmitter extends EventEmitter {}
    const myEmitter = new MyEmitter();

    const callbackA = () => {
    console.log('A');
    myEmitter.removeListener('event', callbackB);
    };

    const callbackB = () => {
    console.log('B');
    };

    myEmitter.on('event', callbackA);

    myEmitter.on('event', callbackB);

    // callbackA removes listener callbackB but it will still be called.
    // Internal listener array at time of emit [callbackA, callbackB]
    myEmitter.emit('event');
    // Prints:
    // A
    // B

    // callbackB is now removed.
    // Internal listener array [callbackA]
    myEmitter.emit('event');
    // Prints:
    // A

    Because listeners are managed using an internal array, calling this will change the position indices of any listener registered after the listener being removed. This will not impact the order in which listeners are called, but it means that any copies of the listener array as returned by the emitter.listeners() method will need to be recreated.

    When a single function has been added as a handler multiple times for a single event (as in the example below), removeListener() will remove the most recently added instance. In the example the once('ping') listener is removed:

    import { EventEmitter } from 'node:events';
    const ee = new EventEmitter();

    function pong() {
    console.log('pong');
    }

    ee.on('ping', pong);
    ee.once('ping', pong);
    ee.removeListener('ping', pong);

    ee.emit('ping');
    ee.emit('ping');

    Returns a reference to the EventEmitter, so that calls can be chained.

    Type Parameters

    • K

    Parameters

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

          • Rest...args: any[]

          Returns void

    Returns this

    v0.1.26

  • By default EventEmitters will print a warning if more than 10 listeners are added for a particular event. This is a useful default that helps finding memory leaks. The emitter.setMaxListeners() method allows the limit to be modified for this specific EventEmitter instance. The value can be set to Infinity (or 0) to indicate an unlimited number of listeners.

    Returns a reference to the EventEmitter, so that calls can be chained.

    Parameters

    • n: number

    Returns this

    v0.3.5