ServiceReceiver interface
- Extends
-
Receiver
Methods
abandon(Message, Callback<Message |
|
complete(Message, Callback<Message |
|
reject(Message, Callback<Message |
Inherited Methods
add |
Alias for |
emit<K>(string | symbol, Any |
Synchronously calls each of the listeners registered for the event named Returns
|
event |
Returns an array listing the events for which the emitter has registered
listeners. The values in the array are strings or
|
get |
Returns the current max listener value for the |
listener |
Returns the number of listeners listening for the event named |
listeners<K>(string | symbol) | Returns a copy of the array of listeners for the event named
|
off<K>(string | symbol, (args: any[]) => void) | Alias for |
on("error |
|
on("message", (msg: Message) => void) | |
on(string, Function) | |
once<K>(string | symbol, (args: any[]) => void) | Adds a one-time
Returns a reference to the By default, event listeners are invoked in the order they are added. The
|
prepend |
Adds the
Returns a reference to the |
prepend |
Adds a one-time
Returns a reference to the |
raw |
Returns a copy of the array of listeners for the event named
|
remove |
Removes all listeners, or those of the specified It is bad practice to remove listeners added elsewhere in the code,
particularly when the Returns a reference to the |
remove |
Removes the specified
Once an event is emitted, all listeners attached to it at the
time of emitting are called in order. This implies that any
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 When a single function has been added as a handler multiple times for a single
event (as in the example below),
Returns a reference to the |
set |
By default Returns a reference to the |
[capture |
Method Details
abandon(Message, Callback<MessageAbandoned>)
function abandon(message: Message, done?: Callback<MessageAbandoned>)
Parameters
- message
-
Message
- done
-
Callback<MessageAbandoned>
complete(Message, Callback<MessageCompleted>)
function complete(message: Message, done?: Callback<MessageCompleted>)
Parameters
- message
-
Message
- done
-
Callback<MessageCompleted>
reject(Message, Callback<MessageRejected>)
function reject(message: Message, done?: Callback<MessageRejected>)
Parameters
- message
-
Message
- done
-
Callback<MessageRejected>
Inherited Method Details
addListener<K>(string | symbol, (args: any[]) => void)
Alias for emitter.on(eventName, listener)
.
function addListener<K>(eventName: string | symbol, listener: (args: any[]) => void): ServiceReceiver
Parameters
- eventName
-
string | symbol
- listener
-
(args: any[]) => void
Returns
Inherited From Receiver.addListener
emit<K>(string | symbol, AnyRest)
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
function emit<K>(eventName: string | symbol, args: AnyRest): boolean
Parameters
- eventName
-
string | symbol
- args
-
AnyRest
Returns
boolean
Inherited From Receiver.emit
eventNames()
Returns an array listing the events for which the emitter has registered
listeners. The values in the array are strings or Symbol
s.
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) ]
function eventNames(): (string | symbol)[]
Returns
(string | symbol)[]
Inherited From Receiver.eventNames
getMaxListeners()
Returns the current max listener value for the EventEmitter
which is either
set by emitter.setMaxListeners(n)
or defaults to defaultMaxListeners.
function getMaxListeners(): number
Returns
number
Inherited From Receiver.getMaxListeners
listenerCount<K>(string | symbol, Function)
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.
function listenerCount<K>(eventName: string | symbol, listener?: Function): number
Parameters
- eventName
-
string | symbol
The name of the event being listened for
- listener
-
Function
The event handler function
Returns
number
Inherited From Receiver.listenerCount
listeners<K>(string | symbol)
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] ]
function listeners<K>(eventName: string | symbol): Function[]
Parameters
- eventName
-
string | symbol
Returns
Function[]
Inherited From Receiver.listeners
off<K>(string | symbol, (args: any[]) => void)
Alias for emitter.removeListener()
.
function off<K>(eventName: string | symbol, listener: (args: any[]) => void): ServiceReceiver
Parameters
- eventName
-
string | symbol
- listener
-
(args: any[]) => void
Returns
Inherited From Receiver.off
on("errorReceived", (err: Error) => void)
function on(type: "errorReceived", func: (err: Error) => void): ServiceReceiver
Parameters
- type
-
"errorReceived"
- func
-
(err: Error) => void
Returns
Inherited From Receiver.on
on("message", (msg: Message) => void)
function on(type: "message", func: (msg: Message) => void): ServiceReceiver
Parameters
- type
-
"message"
- func
-
(msg: Message) => void
Returns
Inherited From Receiver.on
on(string, Function)
function on(type: string, func: Function): ServiceReceiver
Parameters
- type
-
string
- func
-
Function
Returns
Inherited From Receiver.on
once<K>(string | symbol, (args: any[]) => void)
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
function once<K>(eventName: string | symbol, listener: (args: any[]) => void): ServiceReceiver
Parameters
- eventName
-
string | symbol
The name of the event.
- listener
-
(args: any[]) => void
The callback function
Returns
Inherited From Receiver.once
prependListener<K>(string | symbol, (args: any[]) => void)
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.
function prependListener<K>(eventName: string | symbol, listener: (args: any[]) => void): ServiceReceiver
Parameters
- eventName
-
string | symbol
The name of the event.
- listener
-
(args: any[]) => void
The callback function
Returns
Inherited From Receiver.prependListener
prependOnceListener<K>(string | symbol, (args: any[]) => void)
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.
function prependOnceListener<K>(eventName: string | symbol, listener: (args: any[]) => void): ServiceReceiver
Parameters
- eventName
-
string | symbol
The name of the event.
- listener
-
(args: any[]) => void
The callback function
Returns
Inherited From Receiver.prependOnceListener
rawListeners<K>(string | symbol)
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');
function rawListeners<K>(eventName: string | symbol): Function[]
Parameters
- eventName
-
string | symbol
Returns
Function[]
Inherited From Receiver.rawListeners
removeAllListeners(string | symbol)
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.
function removeAllListeners(eventName?: string | symbol): ServiceReceiver
Parameters
- eventName
-
string | symbol
Returns
Inherited From Receiver.removeAllListeners
removeListener<K>(string | symbol, (args: any[]) => void)
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.
function removeListener<K>(eventName: string | symbol, listener: (args: any[]) => void): ServiceReceiver
Parameters
- eventName
-
string | symbol
- listener
-
(args: any[]) => void
Returns
Inherited From Receiver.removeListener
setMaxListeners(number)
By default EventEmitter
s 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.
function setMaxListeners(n: number): ServiceReceiver
Parameters
- n
-
number
Returns
Inherited From Receiver.setMaxListeners
[captureRejectionSymbol]<K>(Error, string | symbol, AnyRest)
function [captureRejectionSymbol]<K>(error: Error, event: string | symbol, args: AnyRest)
Parameters
- error
-
Error
- event
-
string | symbol
- args
-
AnyRest
Inherited From Receiver.__@captureRejectionSymbol@118