HarmonyLink Documentation
- README
- Globals
- HarmonyLink
- Node
- Player
- Queue
- Track
- Response
- ConnectionHandler
- WebSocketClosedEvent
- TrackStuckEvent
- TrackStartEvent
- TrackExceptionEvent
- TrackEndEvent
- TrackDataInfo
- SetStateUpdate
- PlayerOptions
- PlayerEvents
- NodeStats
- NodeOption
- NodeInfo
- NodeGroup
- NodeEvents
- LavalinkNodeStatsPacket
- HarmonyLinkRequesterOptions
- HarmonyLinkEvents
- HarmonyLinkConfiguration
- FrequenCInfo
- FiltersOptions
- ErrorResponses
- FailingAddresses
- DistortionOptions
- ConnectionOptions
- Config
- ChannelMixOptions
- NodeType
- DiscordVoiceStates
- PlayerConnectionState
- PlayerLoop
- VoiceConnectionState
- AbstractPlugin
- DJSLibrary
- ErisJS
- OceanicJS
- CamelToSnake
- DefaultOptions
- GetDefaultConnectionOptions
- GetDefaultNodeStats
- LoadPlugins
- ParseHarmonyLinkConfig
- ParseOptions
- SnakeToCamel
- AnyOtherPacket
- Band
- IPBlockType
- LavalinkPlayerUpdatePacket
- LavalinkReadyPacket
- NoPlaylistInfo
- PacketVoiceServerUpdate
- PacketVoiceStateUpdate
- PlayerEvent
- PlayerObjectFromAPI
- PlayerState
- PlaylistInfoFound
- ResolveOptions
- RoutePlannerStatusBIRP
- RoutePlannerStatusBase
- RoutePlannerStatusNIRP
- RoutePlannerStatusRIRP
- RoutePlannerStatusRNIP
- TrackData
- TrackLoadResultEmpty
- TrackLoadResultPlaylist
- TrackLoadResultSearch
- TrackLoadResultTrack
- TrackLoadingResultException
- UpdatePlayerInfo
- UpdatePlayerOptions
- UpdatePlayerTrack
- VoiceServer
- KaraokeOptions
- LowPassOptions
- RotationOptions
- TimescaleOptions
- TremoloOptions
- VibratoOptions
- EventData
- LavaLinkLoadTypes
- LavalinkEventPacket
- LavalinkPackets
- LoadTrackResult
- NodeLinkV2LoadTypes
- NodeOptions
- Packet
- PartialNull
- PlayerEventType
- PlaylistInfo
- RequiredHarmonyLinkConfiguration
- RoutePlannerStatus
- RoutePlannerStatusDisabled
- Severity
- Snowflake
- TDateISO
- TDateISODate
- TDateISOTime
- TDay
- THours
- TMilliseconds
- TMinutes
- TMonth
- TSeconds
- TYear
- TrackEndReason
- Config
Player
harmonylink • Docs
harmonylink / Player
Class: Player
Extends
EventEmitter
Constructors
new Player()
new Player(
manager
,node
,options
):Player
Parameters
• manager: HarmonyLink
• node: Node
• options: PlayerOptions
Returns
Defined in
src/player/Player.ts:57
Properties
ConnectionHandler
readonly
ConnectionHandler:ConnectionHandler
Defined in
src/player/Player.ts:31
emit()
emit: <
K
>(event
, ...args
) =>boolean
Type Parameters
• K extends keyof PlayerEvents
Parameters
• event: K
• ...args: Parameters
<PlayerEvents
[K
]>
Returns
boolean
Defined in
src/player/Player.ts:21
filters
filters:
Filters
Defined in
src/player/Player.ts:33
guildId
guildId:
string
Defined in
src/player/Player.ts:37
isAutoplay
isAutoplay:
boolean
Defined in
src/player/Player.ts:45
isConnected
isConnected:
boolean
Defined in
src/player/Player.ts:39
isPaused
isPaused:
boolean
Defined in
src/player/Player.ts:41
isPlaying
isPlaying:
boolean
Defined in
src/player/Player.ts:40
loop
loop:
"NONE"
|"QUEUE"
|"TRACK"
|PlayerLoop
Defined in
src/player/Player.ts:44
manager
readonly
manager:HarmonyLink
Defined in
src/player/Player.ts:30
node
readonly
node:Node
Defined in
src/player/Player.ts:29
off()
off: <
K
>(event
,listener
) =>this
Type Parameters
• K extends keyof PlayerEvents
Parameters
• event: K
• listener: PlayerEvents
[K
]
Returns
this
Defined in
src/player/Player.ts:25
on()
on: <
K
>(event
,listener
) =>this
Type Parameters
• K extends keyof PlayerEvents
Parameters
• event: K
• listener: PlayerEvents
[K
]
Returns
this
Defined in
src/player/Player.ts:19
once()
once: <
K
>(event
,listener
) =>this
Type Parameters
• K extends keyof PlayerEvents
Parameters
• event: K
• listener: PlayerEvents
[K
]
Returns
this
Defined in
src/player/Player.ts:20
ping
ping:
number
The ping of the node to the Discord voice server in milliseconds (-1 if not connected)
Defined in
src/player/Player.ts:51
position
position:
number
Defined in
src/player/Player.ts:55
queue
readonly
queue:Queue
Defined in
src/player/Player.ts:32
shardId
shardId:
string
Defined in
src/player/Player.ts:38
state
state:
PlayerConnectionState
Defined in
src/player/Player.ts:42
textChannelId
textChannelId:
string
Defined in
src/player/Player.ts:36
timestamp
timestamp:
number
Defined in
src/player/Player.ts:52
voiceChannelId
voiceChannelId:
string
Defined in
src/player/Player.ts:35
voiceState
voiceState:
VoiceConnectionState
Defined in
src/player/Player.ts:43
volume
volume:
number
Defined in
src/player/Player.ts:46
captureRejectionSymbol
readonly
static
captureRejectionSymbol: typeofcaptureRejectionSymbol
Value: Symbol.for('nodejs.rejection')
See how to write a custom rejection handler
.
Since
v13.4.0, v12.16.0
Defined in
node_modules/@types/node/events.d.ts:405
captureRejections
static
captureRejections:boolean
Value: boolean
Change the default captureRejections
option on all new EventEmitter
objects.
Since
v13.4.0, v12.16.0
Defined in
node_modules/@types/node/events.d.ts:412
defaultMaxListeners
static
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.defaultMaxListeners
property
can be used. If this value is not a positive number, a RangeError
is thrown.
Take caution when setting the events.defaultMaxListeners
because the
change affects all EventEmitter
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 single
EventEmitter
, 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
Defined in
node_modules/@types/node/events.d.ts:451
errorMonitor
readonly
static
errorMonitor: typeoferrorMonitor
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
Defined in
node_modules/@types/node/events.d.ts:398
Methods
[captureRejectionSymbol]()?
optional
[captureRejectionSymbol]<K
>(error
,event
, ...args
):void
Type Parameters
• K
Parameters
• error: Error
• event: string
| symbol
• ...args: AnyRest
Returns
void
Defined in
node_modules/@types/node/events.d.ts:115
addListener()
addListener<
K
>(eventName
,listener
):this
Alias for emitter.on(eventName, listener)
.
Type Parameters
• K
Parameters
• eventName: string
| symbol
• listener
Returns
this
Since
v0.1.26
Defined in
node_modules/@types/node/events.d.ts:550
autoplay()
autoplay(
previousTrack
?):Promise
<Player
>
Autoplays a track.
Parameters
• previousTrack?: null
| Track
= null
The previous track to use for autoplay
Returns
Promise
<Player
>
- A Promise that resolves to the Player instance.
Defined in
src/player/Player.ts:415
checkDestroyed()
protected
checkDestroyed():void
Returns
void
Defined in
src/player/Player.ts:503
connect()
connect():
Promise
<Player
>
Connects the player to the voice channel.
Returns
Promise
<Player
>
- A Promise that resolves to the Player instance.
Defined in
src/player/Player.ts:106
destroy()
destroy():
Promise
<boolean
>
Destroys the player and cleans up associated resources.
Returns
Promise
<boolean
>
- A Promise that resolves to a boolean which is true if an element in the Map existed and has been removed, or false if the element does not exist.
Defined in
src/player/Player.ts:341
disconnect()
protected
disconnect(cleanQueue
):Promise
<Player
>
Parameters
• cleanQueue: boolean
= false
Returns
Promise
<Player
>
Defined in
src/player/Player.ts:484
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 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) ]
Returns
(string
| symbol
)[]
Since
v6.0.0
Defined in
node_modules/@types/node/events.d.ts:875
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
Defined in
node_modules/@types/node/events.d.ts:727
listenerCount()
listenerCount<
K
>(eventName
,listener
?):number
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
• listener?: Function
The event handler function
Returns
number
Since
v3.2.0
Defined in
node_modules/@types/node/events.d.ts:821
listeners()
listeners<
K
>(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] ]
Type Parameters
• K
Parameters
• eventName: string
| symbol
Returns
Function
[]
Since
v0.1.26
Defined in
node_modules/@types/node/events.d.ts:740
pause()
pause(
toggle
?):Promise
<Player
>
Pauses the current track.
Parameters
• toggle?: boolean
= true
Whether to pause or resume the track.
Returns
Promise
<Player
>
- A Promise that resolves to the Player instance.
Defined in
src/player/Player.ts:384
play()
play():
Promise
<Player
>
Plays the current track in the queue.
Returns
Promise
<Player
>
- A Promise that resolves to the Player instance.
Defined in
src/player/Player.ts:315
prependListener()
prependListener<
K
>(eventName
,listener
):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 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
The callback function
Returns
this
Since
v6.0.0
Defined in
node_modules/@types/node/events.d.ts:839
prependOnceListener()
prependOnceListener<
K
>(eventName
,listener
):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!');
});
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
The callback function
Returns
this
Since
v6.0.0
Defined in
node_modules/@types/node/events.d.ts:855
rawListeners()
rawListeners<
K
>(eventName
):Function
[]
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
Defined in
node_modules/@types/node/events.d.ts:771
reconnect()
reconnect(
restartSong
?):Promise
<Player
>
Reconnects the player to the voice channel.
Parameters
• restartSong?: boolean
= true
Whether to restart the current song or not.
Returns
Promise
<Player
>
- A Promise that resolves to the Player instance.
Defined in
src/player/Player.ts:161
removeAllListeners()
removeAllListeners(
eventName
?):this
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
• eventName?: string
| symbol
Returns
this
Since
v0.1.26
Defined in
node_modules/@types/node/events.d.ts:711
removeListener()
removeListener<
K
>(eventName
,listener
):this
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
Returns
this
Since
v0.1.26
Defined in
node_modules/@types/node/events.d.ts:695
resolve()
resolve(
options
?,node
?):Promise
<Response
>
Resolves a track.
Parameters
• options?: ResolveOptions
Options for resolving tracks.
• node?: Node
Node to use for resolution.
Returns
Promise
<Response
>
The response containing resolved tracks.
Defined in
src/player/Player.ts:404
seekTo()
seekTo(
position
):Promise
<Player
>
Seeks to a position in the current track.
Parameters
• position: number
The position to seek to in milliseconds. Must be between 0 and <Track>.info.length
Returns
Promise
<Player
>
- A Promise that resolves to the Player instance.
Defined in
src/player/Player.ts:290
setAutoplay()
setAutoplay(
toggle
?):Promise
<Player
>
Sets the autoplay mode for the player.
Parameters
• toggle?: boolean
Whether to enable or disable autoplay.
Returns
Promise
<Player
>
- A Promise that resolves to the Player instance.
Defined in
src/player/Player.ts:256
setDeaf()
setDeaf(
deaf
):Promise
<Player
>
Sets the deaf state for the player.
Parameters
• deaf: boolean
Whether to deafen or undeafen the player in the voice channel.
Returns
Promise
<Player
>
- A Promise that resolves to the Player instance.
Defined in
src/player/Player.ts:475
setLoop()
setLoop(
mode
?):Promise
<Player
>
Sets the loop mode for the player.
Parameters
• mode?: "NONE"
| "QUEUE"
| "TRACK"
| PlayerLoop
The loop mode to set.
Returns
Promise
<Player
>
- A Promise that resolves to the Player instance.
Defined in
src/player/Player.ts:195
setMaxListeners()
setMaxListeners(
n
):this
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.
Parameters
• n: number
Returns
this
Since
v0.3.5
Defined in
node_modules/@types/node/events.d.ts:721
setMute()
setMute(
mute
):Promise
<Player
>
Sets the mute state for the player.
Parameters
• mute: boolean
Whether to mute or unmute the player in the voice channel.
Returns
Promise
<Player
>
- A Promise that resolves to the Player instance.
Defined in
src/player/Player.ts:461
setTextChannel()
setTextChannel(
channelId
):Promise
<Player
>
Sets the voice channel for the player.
Parameters
• channelId: string
The channel ID to set for the player.
Returns
Promise
<Player
>
- A Promise that resolves to the Player instance.
Defined in
src/player/Player.ts:229
setVoiceChannel()
setVoiceChannel(
channelId
):Promise
<Player
>
Sets a new voice channel for the player.
Parameters
• channelId: string
The channel ID to set for the player.
Returns
Promise
<Player
>
- A Promise that resolves to the Player instance.
Defined in
src/player/Player.ts:241
setVolume()
setVolume(
volume
):Promise
<Player
>
Sets the volume for the player.
Parameters
• volume: number
The volume to set. Must be between 0 and 1000.
Returns
Promise
<Player
>
- A Promise that resolves to the Player instance.
Defined in
src/player/Player.ts:270
skip()
skip():
Promise
<Player
>
Skips the current track.
Returns
Promise
<Player
>
- A Promise that resolves to the Player instance.
Defined in
src/player/Player.ts:357
addAbortListener()
static
addAbortListener(signal
,resource
):Disposable
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 AbortSignal
s 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
Returns
Disposable
Disposable that removes the abort
listener.
Since
v20.5.0
Defined in
node_modules/@types/node/events.d.ts:390
getEventListeners()
static
getEventListeners(emitter
,name
):Function
[]
Returns a copy of the array of listeners for the event named eventName
.
For EventEmitter
s this behaves exactly the same as calling .listeners
on
the emitter.
For EventTarget
s 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
> | EventTarget
• name: string
| symbol
Returns
Function
[]
Since
v15.2.0, v14.17.0
Defined in
node_modules/@types/node/events.d.ts:311
getMaxListeners()
static
getMaxListeners(emitter
):number
Returns the currently set max amount of listeners.
For EventEmitter
s this behaves exactly the same as calling .getMaxListeners
on
the emitter.
For EventTarget
s 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
> | EventTarget
Returns
number
Since
v19.9.0
Defined in
node_modules/@types/node/events.d.ts:340
listenerCount()
static
listenerCount(emitter
,eventName
):number
A class method that returns the number of listeners for the given eventName
registered 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.
Defined in
node_modules/@types/node/events.d.ts:283
on()
static
on(emitter
,eventName
,options
?):AsyncIterableIterator
<any
>
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
• options?: StaticEventEmitterOptions
Returns
AsyncIterableIterator
<any
>
An AsyncIterator
that iterates eventName
events emitted by the emitter
Since
v13.6.0, v12.16.0
Defined in
node_modules/@types/node/events.d.ts:261
once()
once(emitter, eventName, options)
static
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.
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
• options?: StaticEventEmitterOptions
Returns
Promise
<any
[]>
Since
v11.13.0, v10.16.0
Defined in
node_modules/@types/node/events.d.ts:196
once(emitter, eventName, options)
static
once(emitter
,eventName
,options
?):Promise
<any
[]>
Parameters
• emitter: EventTarget
• eventName: string
• options?: StaticEventEmitterOptions
Returns
Promise
<any
[]>
Defined in
node_modules/@types/node/events.d.ts:201
setMaxListeners()
static
setMaxListeners(n
?, ...eventTargets
?):void
import { setMaxListeners, EventEmitter } from 'node:events';
const target = new EventTarget();
const emitter = new EventEmitter();
setMaxListeners(5, target, emitter);
Parameters
• n?: number
A non-negative number. The maximum number of listeners per EventTarget
event.
• ...eventTargets?: (EventEmitter
<DefaultEventMap
> | EventTarget
)[]
Returns
void
Since
v15.4.0
Defined in
node_modules/@types/node/events.d.ts:355