Internal Type of worker.
+Internal Worker node interface.
+Type of worker.
Type of data sent to the worker. This can only be structured-cloneable data.
-Readonly clearClears tasks queue.
-Readonly deleteDeletes task function worker usage statistics.
+Readonly deleteDeletes task function worker usage statistics.
The task function name.
true if the task function worker usage statistics were deleted, false otherwise.
Readonly dequeueDequeue task.
-Optional bucket: numberThe prioritized bucket to dequeue from.
+Readonly dequeueDequeue last prioritized task.
+The dequeued task.
+Readonly dequeueDequeue task.
+0
The dequeued task.
-Readonly enqueueEnqueue task.
-The task to queue.
+Readonly enqueueEnqueue task.
+The tasks queue size.
-Readonly getGets task function worker usage statistics.
-The task function name.
+Readonly getGets task function worker usage statistics.
+The task function name.
The task function worker usage statistics if the task function worker usage statistics are initialized, undefined otherwise.
Readonly hasWhether the worker node has back pressure (i.e. its tasks queue is full).
-true if the worker node has back pressure, false otherwise.
Readonly infoWorker info.
-Optional Readonly messageMessage channel (worker thread only).
-Readonly registerRegisters once a worker event handler.
-The event.
+Readonly hasWhether the worker node has back pressure (i.e. its tasks queue is full).
+true if the worker node has back pressure, false otherwise.
Readonly infoWorker info.
+Optional Readonly messageMessage channel (worker thread only).
+Readonly registerRegisters once a worker event handler.
+The event.
The event handler.
-Readonly registerRegisters a worker event handler.
-The event.
+Readonly registerRegisters a worker event handler.
+The event.
The event handler.
-Optional strategyWorker choice strategy data. +
Optional strategyWorker choice strategy data. This is used to store data that are specific to the worker choice strategy.
-Tasks queue back pressure size. +
Tasks queue back pressure size. This is the number of tasks that can be enqueued before the worker node has back pressure.
-Readonly tasksTasks queue size.
-The tasks queue size.
-Readonly terminateTerminates the worker node.
-Readonly usageWorker usage statistics.
-Readonly workerWorker.
-Optional [captureRest ...args: AnyRestAlias for emitter.on(eventName, listener).
Readonly tasksTasks queue size.
+The tasks queue size.
+Readonly terminateTerminates the worker node.
+Readonly usageWorker usage statistics.
+Readonly workerWorker.
+Optional [captureRest ...args: AnyRestAlias for emitter.on(eventName, listener).
Rest ...args: any[]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
+
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
Rest ...args: AnyRestv0.1.26
-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) ]
v6.0.0
-Returns the number of listeners listening for the event named eventName.
+
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.
The name of the event being listened for
Optional listener: FunctionThe event handler function
v3.2.0
-Returns a copy of the array of listeners for the event named eventName.
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] ]
v0.1.26
-Alias for emitter.removeListener().
Alias for emitter.removeListener().
Rest ...args: any[]v10.0.0
-Adds the listener function to the end of the listeners array for the event
+
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.
The name of the event.
The callback function
Rest ...args: any[]v0.1.101
-Adds a one-time listener function for the event named eventName. The
+
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!');
});
The name of the event.
The callback function
Rest ...args: any[]v0.3.0
-Adds the listener function to the beginning of the listeners array for the
+
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.
listener will result in the listener being added,
The name of the event.
The callback function
Rest ...args: any[]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
+
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!');
});
The name of the event.
The callback function
Rest ...args: any[]v6.0.0
-Returns a copy of the array of listeners for the event named eventName,
+
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');
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.
Optional eventName: string | symbolv0.1.26
-Removes the specified listener from the listener array for the event named eventName.
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
@@ -174,10 +177,10 @@ recently added instance. In the example the once('ping') li
Returns a reference to the EventEmitter, so that calls can be chained.
Rest ...args: any[]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.
v0.3.5
-
Worker node interface.
-