Class: SernEmitter
Since
1.0.0
Hierarchy
-
EventEmitter↳
SernEmitter
Constructors
constructor
• new SernEmitter(): SernEmitter
Returns
Overrides
EventEmitter.constructor
Defined in
src/core/structures/sern-emitter.ts:10
Properties
captureRejectionSymbol
▪ Static Readonly captureRejectionSymbol: typeof captureRejectionSymbol
Inherited from
EventEmitter.captureRejectionSymbol
Defined in
node_modules/@types/node/events.d.ts:357
captureRejections
▪ Static captureRejections: boolean
Sets or gets the default captureRejection value for all emitters.
Inherited from
EventEmitter.captureRejections
Defined in
node_modules/@types/node/events.d.ts:362
defaultMaxListeners
▪ Static defaultMaxListeners: number
Inherited from
EventEmitter.defaultMaxListeners
Defined in
node_modules/@types/node/events.d.ts:363
errorMonitor
▪ Static Readonly 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.
Inherited from
EventEmitter.errorMonitor
Defined in
node_modules/@types/node/events.d.ts:356
Methods
addListener
▸ addListener(eventName, listener): SernEmitter
Alias for emitter.on(eventName, listener).
Parameters
| Name | Type |
|---|---|
eventName | string | symbol |
listener | (...args: any[]) => void |
Returns
Since
v0.1.26
Inherited from
EventEmitter.addListener
Defined in
node_modules/@types/node/events.d.ts:383
emit
▸ emit<T>(eventName, ...args): boolean
Listening to sern events with on. This event stays on until a crash or a normal exit
Type parameters
| Name | Type |
|---|---|
T | extends keyof SernEventsMapping |
Parameters
| Name | Type | Description |
|---|---|---|
eventName | T | |
...args | SernEventsMapping[T] | the arguments for emitting the eventName |
Returns
boolean
Overrides
EventEmitter.emit
Defined in
src/core/structures/sern-emitter.ts:40
eventNames
▸ eventNames(): (string | symbol)[]
Returns an array listing the events for which the emitter has registered
listeners. The values in the array are strings or Symbols.
const EventEmitter = require('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
Inherited from
EventEmitter.eventNames
Defined in
node_modules/@types/node/events.d.ts:702
getMaxListeners
▸ getMaxListeners(): number
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
Inherited from
EventEmitter.getMaxListeners
Defined in
node_modules/@types/node/events.d.ts:555
listenerCount
▸ listenerCount(eventName, listener?): number
Returns the number of listeners listening to 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
| Name | Type | Description |
|---|---|---|
eventName | string | symbol | The name of the event being listened for |
listener? | Function | The event handler function |
Returns
number
Since
v3.2.0
Inherited from
EventEmitter.listenerCount
Defined in
node_modules/@types/node/events.d.ts:649
listeners
▸ listeners(eventName): Function[]
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
| Name | Type |
|---|---|
eventName | string | symbol |
Returns
Function[]
Since
v0.1.26
Inherited from
EventEmitter.listeners
Defined in
node_modules/@types/node/events.d.ts:568
off
▸ off(eventName, listener): SernEmitter
Alias for emitter.removeListener().
Parameters
| Name | Type |
|---|---|
eventName | string | symbol |
listener | (...args: any[]) => void |
Returns
Since
v10.0.0
Inherited from
EventEmitter.off
Defined in
node_modules/@types/node/events.d.ts:528
on
▸ on<T>(eventName, listener): SernEmitter
Listening to sern events with on. This event stays on until a crash or a normal exit
Type parameters
| Name | Type |
|---|---|
T | extends keyof SernEventsMapping |
Parameters
| Name | Type | Description |
|---|---|---|
eventName | T | |
listener | (...args: SernEventsMapping[T][]) => void | what to do with the data |
Returns
Overrides
EventEmitter.on
Defined in
src/core/structures/sern-emitter.ts:18
once
▸ once<T>(eventName, listener): SernEmitter
Listening to sern events with on. This event stays on until a crash or a normal exit
Type parameters
| Name | Type |
|---|---|
T | extends keyof SernEventsMapping |
Parameters
| Name | Type | Description |
|---|---|---|
eventName | T | |
listener | (...args: SernEventsMapping[T][]) => void | what to do with the data |
Returns
Overrides
EventEmitter.once
Defined in
src/core/structures/sern-emitter.ts:29
prependListener
▸ prependListener(eventName, listener): SernEmitter
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
| Name | Type | Description |
|---|---|---|
eventName | string | symbol | The name of the event. |
listener | (...args: any[]) => void | The callback function |
Returns
Since
v6.0.0
Inherited from
EventEmitter.prependListener
Defined in
node_modules/@types/node/events.d.ts:667
prependOnceListener
▸ prependOnceListener(eventName, listener): SernEmitter
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
| Name | Type | Description |
|---|---|---|
eventName | string | symbol | The name of the event. |
listener | (...args: any[]) => void | The callback function |
Returns
Since
v6.0.0
Inherited from
EventEmitter.prependOnceListener
Defined in
node_modules/@types/node/events.d.ts:683
rawListeners
▸ rawListeners(eventName): Function[]
Returns a copy of the array of listeners for the event named eventName,
including any wrappers (such as those created by .once()).
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
| Name | Type |
|---|---|
eventName | string | symbol |
Returns
Function[]
Since
v9.4.0
Inherited from
EventEmitter.rawListeners
Defined in
node_modules/@types/node/events.d.ts:598
removeAllListeners
▸ removeAllListeners(event?): SernEmitter
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
| Name | Type |
|---|---|
event? | string | symbol |
Returns
Since
v0.1.26
Inherited from
EventEmitter.removeAllListeners
Defined in
node_modules/@types/node/events.d.ts:539
removeListener
▸ removeListener(eventName, listener): SernEmitter
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.
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:
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
| Name | Type |
|---|---|
eventName | string | symbol |
listener | (...args: any[]) => void |
Returns
Since
v0.1.26
Inherited from
EventEmitter.removeListener
Defined in
node_modules/@types/node/events.d.ts:523
setMaxListeners
▸ setMaxListeners(n): SernEmitter
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
| Name | Type |
|---|---|
n | number |
Returns
Since
v0.3.5
Inherited from
EventEmitter.setMaxListeners
Defined in
node_modules/@types/node/events.d.ts:549
failure
▸ failure(module?, reason?): Object
Creates a compliant SernEmitter failure payload
Parameters
| Name | Type |
|---|---|
module? | Module |
reason? | unknown |
Returns
Object
| Name | Type |
|---|---|
module? | AnyModule |
reason | string | Error |
type | Failure |
Defined in
src/core/structures/sern-emitter.ts:59
getEventListeners
▸ getEventListeners(emitter, name): Function[]
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.
const { getEventListeners, EventEmitter } = require('events');
{
const ee = new EventEmitter();
const listener = () => console.log('Events are fun');
ee.on('foo', listener);
getEventListeners(ee, 'foo'); // [listener]
}
{
const et = new EventTarget();
const listener = () => console.log('Events are fun');
et.addEventListener('foo', listener);
getEventListeners(et, 'foo'); // [listener]
}
Parameters
| Name | Type |
|---|---|
emitter | EventEmitter | _DOMEventTarget |
name | string | symbol |
Returns
Function[]
Since
v15.2.0, v14.17.0
Inherited from
EventEmitter.getEventListeners
Defined in
node_modules/@types/node/events.d.ts:299
getMaxListeners
▸ getMaxListeners(emitter): number
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
| Name | Type |
|---|---|
emitter | EventEmitter | _DOMEventTarget |
Returns
number
Since
v18.17.0
Inherited from
EventEmitter.getMaxListeners
Defined in
node_modules/@types/node/events.d.ts:328
listenerCount
▸ listenerCount(emitter, eventName): number
A class method that returns the number of listeners for the given eventNameregistered on the given emitter.
const { EventEmitter, listenerCount } = require('events');
const myEmitter = new EventEmitter();
myEmitter.on('event', () => {});
myEmitter.on('event', () => {});
console.log(listenerCount(myEmitter, 'event'));
// Prints: 2
Parameters
| Name | Type | Description |
|---|---|---|
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.
Inherited from
EventEmitter.listenerCount
Defined in
node_modules/@types/node/events.d.ts:271
on
▸ on(emitter, eventName, options?): AsyncIterableIterator<any>
const { on, EventEmitter } = require('events');
(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')) {
// 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:
const { on, EventEmitter } = require('events');
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
| Name | Type | Description |
|---|---|---|
emitter | EventEmitter | - |
eventName | string | The name of the event being listened for |
options? | StaticEventEmitterOptions | - |
Returns
AsyncIterableIterator<any>
that iterates eventName events emitted by the emitter
Since
v13.6.0, v12.16.0
Inherited from
EventEmitter.on
Defined in
node_modules/@types/node/events.d.ts:254
▸ on<Emitter, Events>(eventEmitter, eventName): AsyncIterableIterator<Emitter extends Client<boolean> ? ClientEvents[Events] : any>
Type parameters
| Name | Type |
|---|---|
Emitter | extends __module |
Events | extends keyof ClientEvents |
Parameters
| Name | Type |
|---|---|
eventEmitter | Emitter |
eventName | Emitter extends Client<boolean> ? Events : string |
Returns
AsyncIterableIterator<Emitter extends Client<boolean> ? ClientEvents[Events] : any>
Inherited from
EventEmitter.on
Defined in
node_modules/discord.js/typings/index.d.ts:243
once
▸ once(emitter, eventName, options?): Promise<any[]>
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.
const { once, EventEmitter } = require('events');
async function run() {
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.log('error happened', err);
}
}
run();
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:
const { EventEmitter, once } = require('events');
const ee = new EventEmitter();
once(ee, 'error')
.then(([err]) => console.log('ok', err.message))
.catch((err) => console.log('error', err.message));
ee.emit('error', new Error('boom'));
// Prints: ok boom
An AbortSignal can be used to cancel waiting for the event:
const { EventEmitter, once } = require('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
| Name | Type |
|---|---|
emitter | _NodeEventTarget |
eventName | string | symbol |
options? | StaticEventEmitterOptions |
Returns
Promise<any[]>
Since
v11.13.0, v10.16.0
Inherited from
EventEmitter.once
Defined in
node_modules/@types/node/events.d.ts:194
▸ once(emitter, eventName, options?): Promise<any[]>
Parameters
| Name | Type |
|---|---|
emitter | _DOMEventTarget |
eventName | string |
options? | StaticEventEmitterOptions |
Returns
Promise<any[]>
Inherited from
EventEmitter.once
Defined in
node_modules/@types/node/events.d.ts:195
▸ once<Emitter, Event>(eventEmitter, eventName): Promise<Emitter extends Client<boolean> ? ClientEvents[Event] : any[]>
Type parameters
| Name | Type |
|---|---|
Emitter | extends __module |
Event | extends keyof ClientEvents |
Parameters
| Name | Type |
|---|---|
eventEmitter | Emitter |
eventName | Emitter extends Client<boolean> ? Event : string |
Returns
Promise<Emitter extends Client<boolean> ? ClientEvents[Event] : any[]>
Inherited from
EventEmitter.once
Defined in
node_modules/discord.js/typings/index.d.ts:239
payload
▸ payload<T>(type, module?, reason?): T
Type parameters
| Name | Type |
|---|---|
T | extends Payload |
Parameters
| Name | Type |
|---|---|
type | PayloadType |
module? | Module |
reason? | unknown |
Returns
T
Defined in
src/core/structures/sern-emitter.ts:46
setMaxListeners
▸ setMaxListeners(n?, ...eventTargets): void
const {
setMaxListeners,
EventEmitter
} = require('events');
const target = new EventTarget();
const emitter = new EventEmitter();
setMaxListeners(5, target, emitter);
Parameters
| Name | Type | Description |
|---|---|---|
n? | number | A non-negative number. The maximum number of listeners per EventTarget event. |
...eventTargets | (EventEmitter | _DOMEventTarget)[] | - |
Returns
void
Since
v15.4.0
Inherited from
EventEmitter.setMaxListeners
Defined in
node_modules/@types/node/events.d.ts:346
success
▸ success(module): Object
Creates a compliant SernEmitter module success payload
Parameters
| Name | Type |
|---|---|
module | Module |
Returns
Object
| Name | Type |
|---|---|
module | AnyModule |
type | Success |
Defined in
src/core/structures/sern-emitter.ts:72
warning
▸ warning(reason): Object
Creates a compliant SernEmitter module warning payload
Parameters
| Name | Type |
|---|---|
reason | unknown |
Returns
Object
| Name | Type |
|---|---|
reason | string |
type | Warning |