Encapsulates the datagram functionality.
New instances of dgram.Socket
are created using createSocket. The new
keyword is not to be used to create dgram.Socket
instances.
Node.js module
The 'node:dgram'
module provides an implementation of UDP datagram sockets. It allows sending and receiving UDP packets, creating both IPv4 and IPv6 sockets.
This module is used for lightweight, connectionless communication, such as DNS queries, syslog, and real-time streaming protocols that favor speed over reliability.
Fully implemented. > 90% of Node.js's test suite passes.
Encapsulates the datagram functionality.
New instances of dgram.Socket
are created using createSocket. The new
keyword is not to be used to create dgram.Socket
instances.
Value: boolean
Change the default captureRejections
option on all new EventEmitter
objects.
Value: Symbol.for('nodejs.rejection')
See how to write a custom rejection handler
.
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'
.
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.
Calls socket.close()
and returns a promise that fulfills when the socket has closed.
events.EventEmitter
events.EventEmitter
events.EventEmitter
events.EventEmitter
events.EventEmitter
events.EventEmitter
Tells the kernel to join a multicast group at the given multicastAddress
and multicastInterface
using the IP_ADD_MEMBERSHIP
socket option. If the multicastInterface
argument is not specified, the operating system will choose one interface and will add membership to it. To add membership to every available interface, call addMembership
multiple times, once per interface.
When called on an unbound socket, this method will implicitly bind to a random port, listening on all interfaces.
When sharing a UDP socket across multiple cluster
workers, thesocket.addMembership()
function must be called only once or anEADDRINUSE
error will occur:
import cluster from 'node:cluster';
import dgram from 'node:dgram';
if (cluster.isPrimary) {
cluster.fork(); // Works ok.
cluster.fork(); // Fails with EADDRINUSE.
} else {
const s = dgram.createSocket('udp4');
s.bind(1234, () => {
s.addMembership('224.0.0.114');
});
}
Returns an object containing the address information for a socket. For UDP sockets, this object will contain address
, family
, and port
properties.
This method throws EBADF
if called on an unbound socket.
Tells the kernel to join a source-specific multicast channel at the given sourceAddress
and groupAddress
, using the multicastInterface
with the IP_ADD_SOURCE_MEMBERSHIP
socket option. If the multicastInterface
argument is not specified, the operating system will choose one interface and will add membership to it. To add membership to every available interface, call socket.addSourceSpecificMembership()
multiple times, once per interface.
When called on an unbound socket, this method will implicitly bind to a random port, listening on all interfaces.
For UDP sockets, causes the dgram.Socket
to listen for datagram messages on a named port
and optional address
. If port
is not specified or is 0
, the operating system will attempt to bind to a random port. If address
is not specified, the operating system will attempt to listen on all addresses. Once binding is complete, a 'listening'
event is emitted and the optional callback
function is called.
Specifying both a 'listening'
event listener and passing a callback
to the socket.bind()
method is not harmful but not very useful.
A bound datagram socket keeps the Node.js process running to receive datagram messages.
If binding fails, an 'error'
event is generated. In rare case (e.g. attempting to bind with a closed socket), an Error
may be thrown.
Example of a UDP server listening on port 41234:
import dgram from 'node:dgram';
const server = dgram.createSocket('udp4');
server.on('error', (err) => {
console.error(`server error:\n${err.stack}`);
server.close();
});
server.on('message', (msg, rinfo) => {
console.log(`server got: ${msg} from ${rinfo.address}:${rinfo.port}`);
});
server.on('listening', () => {
const address = server.address();
console.log(`server listening ${address.address}:${address.port}`);
});
server.bind(41234);
// Prints: server listening 0.0.0.0:41234
with no parameters. Called when binding is complete.
For UDP sockets, causes the dgram.Socket
to listen for datagram messages on a named port
and optional address
. If port
is not specified or is 0
, the operating system will attempt to bind to a random port. If address
is not specified, the operating system will attempt to listen on all addresses. Once binding is complete, a 'listening'
event is emitted and the optional callback
function is called.
Specifying both a 'listening'
event listener and passing a callback
to the socket.bind()
method is not harmful but not very useful.
A bound datagram socket keeps the Node.js process running to receive datagram messages.
If binding fails, an 'error'
event is generated. In rare case (e.g. attempting to bind with a closed socket), an Error
may be thrown.
Example of a UDP server listening on port 41234:
import dgram from 'node:dgram';
const server = dgram.createSocket('udp4');
server.on('error', (err) => {
console.error(`server error:\n${err.stack}`);
server.close();
});
server.on('message', (msg, rinfo) => {
console.log(`server got: ${msg} from ${rinfo.address}:${rinfo.port}`);
});
server.on('listening', () => {
const address = server.address();
console.log(`server listening ${address.address}:${address.port}`);
});
server.bind(41234);
// Prints: server listening 0.0.0.0:41234
with no parameters. Called when binding is complete.
For UDP sockets, causes the dgram.Socket
to listen for datagram messages on a named port
and optional address
. If port
is not specified or is 0
, the operating system will attempt to bind to a random port. If address
is not specified, the operating system will attempt to listen on all addresses. Once binding is complete, a 'listening'
event is emitted and the optional callback
function is called.
Specifying both a 'listening'
event listener and passing a callback
to the socket.bind()
method is not harmful but not very useful.
A bound datagram socket keeps the Node.js process running to receive datagram messages.
If binding fails, an 'error'
event is generated. In rare case (e.g. attempting to bind with a closed socket), an Error
may be thrown.
Example of a UDP server listening on port 41234:
import dgram from 'node:dgram';
const server = dgram.createSocket('udp4');
server.on('error', (err) => {
console.error(`server error:\n${err.stack}`);
server.close();
});
server.on('message', (msg, rinfo) => {
console.log(`server got: ${msg} from ${rinfo.address}:${rinfo.port}`);
});
server.on('listening', () => {
const address = server.address();
console.log(`server listening ${address.address}:${address.port}`);
});
server.bind(41234);
// Prints: server listening 0.0.0.0:41234
with no parameters. Called when binding is complete.
For UDP sockets, causes the dgram.Socket
to listen for datagram messages on a named port
and optional address
. If port
is not specified or is 0
, the operating system will attempt to bind to a random port. If address
is not specified, the operating system will attempt to listen on all addresses. Once binding is complete, a 'listening'
event is emitted and the optional callback
function is called.
Specifying both a 'listening'
event listener and passing a callback
to the socket.bind()
method is not harmful but not very useful.
A bound datagram socket keeps the Node.js process running to receive datagram messages.
If binding fails, an 'error'
event is generated. In rare case (e.g. attempting to bind with a closed socket), an Error
may be thrown.
Example of a UDP server listening on port 41234:
import dgram from 'node:dgram';
const server = dgram.createSocket('udp4');
server.on('error', (err) => {
console.error(`server error:\n${err.stack}`);
server.close();
});
server.on('message', (msg, rinfo) => {
console.log(`server got: ${msg} from ${rinfo.address}:${rinfo.port}`);
});
server.on('listening', () => {
const address = server.address();
console.log(`server listening ${address.address}:${address.port}`);
});
server.bind(41234);
// Prints: server listening 0.0.0.0:41234
with no parameters. Called when binding is complete.
Close the underlying socket and stop listening for data on it. If a callback is provided, it is added as a listener for the 'close'
event.
Called when the socket has been closed.
Associates the dgram.Socket
to a remote address and port. Every message sent by this handle is automatically sent to that destination. Also, the socket will only receive messages from that remote peer. Trying to call connect()
on an already connected socket will result in an ERR_SOCKET_DGRAM_IS_CONNECTED
exception. If address
is not provided, '127.0.0.1'
(for udp4
sockets) or '::1'
(for udp6
sockets) will be used by default. Once the connection is complete, a 'connect'
event is emitted and the optional callback
function is called. In case of failure, the callback
is called or, failing this, an 'error'
event is emitted.
Called when the connection is completed or on error.
Associates the dgram.Socket
to a remote address and port. Every message sent by this handle is automatically sent to that destination. Also, the socket will only receive messages from that remote peer. Trying to call connect()
on an already connected socket will result in an ERR_SOCKET_DGRAM_IS_CONNECTED
exception. If address
is not provided, '127.0.0.1'
(for udp4
sockets) or '::1'
(for udp6
sockets) will be used by default. Once the connection is complete, a 'connect'
event is emitted and the optional callback
function is called. In case of failure, the callback
is called or, failing this, an 'error'
event is emitted.
Called when the connection is completed or on error.
A synchronous function that disassociates a connected dgram.Socket
from its remote address. Trying to call disconnect()
on an unbound or already disconnected socket will result in an ERR_SOCKET_DGRAM_NOT_CONNECTED
exception.
Instructs the kernel to leave a multicast group at multicastAddress
using the IP_DROP_MEMBERSHIP
socket option. This method is automatically called by the kernel when the socket is closed or the process terminates, so most apps will never have reason to call this.
If multicastInterface
is not specified, the operating system will attempt to drop membership on all valid interfaces.
Instructs the kernel to leave a source-specific multicast channel at the given sourceAddress
and groupAddress
using the IP_DROP_SOURCE_MEMBERSHIP
socket option. This method is automatically called by the kernel when the socket is closed or the process terminates, so most apps will never have reason to call this.
If multicastInterface
is not specified, the operating system will attempt to drop membership on all valid interfaces.
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
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 the current max listener value for the EventEmitter
which is either set by emitter.setMaxListeners(n)
or defaults to EventEmitter.defaultMaxListeners.
This method throws ERR_SOCKET_BUFFER_SIZE
if called on an unbound socket.
the SO_RCVBUF
socket receive buffer size in bytes.
This method throws ERR_SOCKET_BUFFER_SIZE
if called on an unbound socket.
the SO_SNDBUF
socket send buffer size in bytes.
Number of send requests currently in the queue awaiting to be processed.
Number of bytes queued for sending.
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
The event handler 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] ]
Alias for emitter.removeListener()
.
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
The callback function
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
The callback function
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.
The callback function
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.
The callback 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');
By default, binding a socket will cause it to block the Node.js process from exiting as long as the socket is open. The socket.unref()
method can be used to exclude the socket from the reference counting that keeps the Node.js process active. The socket.ref()
method adds the socket back to the reference counting and restores the default behavior.
Calling socket.ref()
multiples times will have no additional effect.
The socket.ref()
method returns a reference to the socket so calls can be chained.
Returns an object containing the address
, family
, and port
of the remote endpoint. This method throws an ERR_SOCKET_DGRAM_NOT_CONNECTED
exception if the socket is not connected.
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.
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.
Broadcasts a datagram on the socket. For connectionless sockets, the destination port
and address
must be specified. Connected sockets, on the other hand, will use their associated remote endpoint, so the port
and address
arguments must not be set.
The msg
argument contains the message to be sent. Depending on its type, different behavior can apply. If msg
is a Buffer
, any TypedArray
or a DataView
, the offset
and length
specify the offset within the Buffer
where the message begins and the number of bytes in the message, respectively. If msg
is a String
, then it is automatically converted to a Buffer
with 'utf8'
encoding. With messages that contain multi-byte characters, offset
and length
will be calculated with respect to byte length
and not the character position. If msg
is an array, offset
and length
must not be specified.
The address
argument is a string. If the value of address
is a host name, DNS will be used to resolve the address of the host. If address
is not provided or otherwise nullish, '127.0.0.1'
(for udp4
sockets) or '::1'
(for udp6
sockets) will be used by default.
If the socket has not been previously bound with a call to bind
, the socket is assigned a random port number and is bound to the "all interfaces" address ('0.0.0.0'
for udp4
sockets, '::0'
for udp6
sockets.)
An optional callback
function may be specified to as a way of reporting DNS errors or for determining when it is safe to reuse the buf
object. DNS lookups delay the time to send for at least one tick of the Node.js event loop.
The only way to know for sure that the datagram has been sent is by using a callback
. If an error occurs and a callback
is given, the error will be passed as the first argument to the callback
. If a callback
is not given, the error is emitted as an 'error'
event on the socket
object.
Offset and length are optional but both must be set if either are used. They are supported only when the first argument is a Buffer
, a TypedArray
, or a DataView
.
This method throws ERR_SOCKET_BAD_PORT
if called on an unbound socket.
Example of sending a UDP packet to a port on localhost
;
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const message = Buffer.from('Some bytes');
const client = dgram.createSocket('udp4');
client.send(message, 41234, 'localhost', (err) => {
client.close();
});
Example of sending a UDP packet composed of multiple buffers to a port on127.0.0.1
;
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const buf1 = Buffer.from('Some ');
const buf2 = Buffer.from('bytes');
const client = dgram.createSocket('udp4');
client.send([buf1, buf2], 41234, (err) => {
client.close();
});
Sending multiple buffers might be faster or slower depending on the application and operating system. Run benchmarks to determine the optimal strategy on a case-by-case basis. Generally speaking, however, sending multiple buffers is faster.
Example of sending a UDP packet using a socket connected to a port on localhost
:
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const message = Buffer.from('Some bytes');
const client = dgram.createSocket('udp4');
client.connect(41234, 'localhost', (err) => {
client.send(message, (err) => {
client.close();
});
});
Message to be sent.
Destination port.
Destination host name or IP address.
Called when the message has been sent.
Broadcasts a datagram on the socket. For connectionless sockets, the destination port
and address
must be specified. Connected sockets, on the other hand, will use their associated remote endpoint, so the port
and address
arguments must not be set.
The msg
argument contains the message to be sent. Depending on its type, different behavior can apply. If msg
is a Buffer
, any TypedArray
or a DataView
, the offset
and length
specify the offset within the Buffer
where the message begins and the number of bytes in the message, respectively. If msg
is a String
, then it is automatically converted to a Buffer
with 'utf8'
encoding. With messages that contain multi-byte characters, offset
and length
will be calculated with respect to byte length
and not the character position. If msg
is an array, offset
and length
must not be specified.
The address
argument is a string. If the value of address
is a host name, DNS will be used to resolve the address of the host. If address
is not provided or otherwise nullish, '127.0.0.1'
(for udp4
sockets) or '::1'
(for udp6
sockets) will be used by default.
If the socket has not been previously bound with a call to bind
, the socket is assigned a random port number and is bound to the "all interfaces" address ('0.0.0.0'
for udp4
sockets, '::0'
for udp6
sockets.)
An optional callback
function may be specified to as a way of reporting DNS errors or for determining when it is safe to reuse the buf
object. DNS lookups delay the time to send for at least one tick of the Node.js event loop.
The only way to know for sure that the datagram has been sent is by using a callback
. If an error occurs and a callback
is given, the error will be passed as the first argument to the callback
. If a callback
is not given, the error is emitted as an 'error'
event on the socket
object.
Offset and length are optional but both must be set if either are used. They are supported only when the first argument is a Buffer
, a TypedArray
, or a DataView
.
This method throws ERR_SOCKET_BAD_PORT
if called on an unbound socket.
Example of sending a UDP packet to a port on localhost
;
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const message = Buffer.from('Some bytes');
const client = dgram.createSocket('udp4');
client.send(message, 41234, 'localhost', (err) => {
client.close();
});
Example of sending a UDP packet composed of multiple buffers to a port on127.0.0.1
;
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const buf1 = Buffer.from('Some ');
const buf2 = Buffer.from('bytes');
const client = dgram.createSocket('udp4');
client.send([buf1, buf2], 41234, (err) => {
client.close();
});
Sending multiple buffers might be faster or slower depending on the application and operating system. Run benchmarks to determine the optimal strategy on a case-by-case basis. Generally speaking, however, sending multiple buffers is faster.
Example of sending a UDP packet using a socket connected to a port on localhost
:
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const message = Buffer.from('Some bytes');
const client = dgram.createSocket('udp4');
client.connect(41234, 'localhost', (err) => {
client.send(message, (err) => {
client.close();
});
});
Message to be sent.
Destination port.
Called when the message has been sent.
Broadcasts a datagram on the socket. For connectionless sockets, the destination port
and address
must be specified. Connected sockets, on the other hand, will use their associated remote endpoint, so the port
and address
arguments must not be set.
The msg
argument contains the message to be sent. Depending on its type, different behavior can apply. If msg
is a Buffer
, any TypedArray
or a DataView
, the offset
and length
specify the offset within the Buffer
where the message begins and the number of bytes in the message, respectively. If msg
is a String
, then it is automatically converted to a Buffer
with 'utf8'
encoding. With messages that contain multi-byte characters, offset
and length
will be calculated with respect to byte length
and not the character position. If msg
is an array, offset
and length
must not be specified.
The address
argument is a string. If the value of address
is a host name, DNS will be used to resolve the address of the host. If address
is not provided or otherwise nullish, '127.0.0.1'
(for udp4
sockets) or '::1'
(for udp6
sockets) will be used by default.
If the socket has not been previously bound with a call to bind
, the socket is assigned a random port number and is bound to the "all interfaces" address ('0.0.0.0'
for udp4
sockets, '::0'
for udp6
sockets.)
An optional callback
function may be specified to as a way of reporting DNS errors or for determining when it is safe to reuse the buf
object. DNS lookups delay the time to send for at least one tick of the Node.js event loop.
The only way to know for sure that the datagram has been sent is by using a callback
. If an error occurs and a callback
is given, the error will be passed as the first argument to the callback
. If a callback
is not given, the error is emitted as an 'error'
event on the socket
object.
Offset and length are optional but both must be set if either are used. They are supported only when the first argument is a Buffer
, a TypedArray
, or a DataView
.
This method throws ERR_SOCKET_BAD_PORT
if called on an unbound socket.
Example of sending a UDP packet to a port on localhost
;
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const message = Buffer.from('Some bytes');
const client = dgram.createSocket('udp4');
client.send(message, 41234, 'localhost', (err) => {
client.close();
});
Example of sending a UDP packet composed of multiple buffers to a port on127.0.0.1
;
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const buf1 = Buffer.from('Some ');
const buf2 = Buffer.from('bytes');
const client = dgram.createSocket('udp4');
client.send([buf1, buf2], 41234, (err) => {
client.close();
});
Sending multiple buffers might be faster or slower depending on the application and operating system. Run benchmarks to determine the optimal strategy on a case-by-case basis. Generally speaking, however, sending multiple buffers is faster.
Example of sending a UDP packet using a socket connected to a port on localhost
:
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const message = Buffer.from('Some bytes');
const client = dgram.createSocket('udp4');
client.connect(41234, 'localhost', (err) => {
client.send(message, (err) => {
client.close();
});
});
Message to be sent.
Called when the message has been sent.
Broadcasts a datagram on the socket. For connectionless sockets, the destination port
and address
must be specified. Connected sockets, on the other hand, will use their associated remote endpoint, so the port
and address
arguments must not be set.
The msg
argument contains the message to be sent. Depending on its type, different behavior can apply. If msg
is a Buffer
, any TypedArray
or a DataView
, the offset
and length
specify the offset within the Buffer
where the message begins and the number of bytes in the message, respectively. If msg
is a String
, then it is automatically converted to a Buffer
with 'utf8'
encoding. With messages that contain multi-byte characters, offset
and length
will be calculated with respect to byte length
and not the character position. If msg
is an array, offset
and length
must not be specified.
The address
argument is a string. If the value of address
is a host name, DNS will be used to resolve the address of the host. If address
is not provided or otherwise nullish, '127.0.0.1'
(for udp4
sockets) or '::1'
(for udp6
sockets) will be used by default.
If the socket has not been previously bound with a call to bind
, the socket is assigned a random port number and is bound to the "all interfaces" address ('0.0.0.0'
for udp4
sockets, '::0'
for udp6
sockets.)
An optional callback
function may be specified to as a way of reporting DNS errors or for determining when it is safe to reuse the buf
object. DNS lookups delay the time to send for at least one tick of the Node.js event loop.
The only way to know for sure that the datagram has been sent is by using a callback
. If an error occurs and a callback
is given, the error will be passed as the first argument to the callback
. If a callback
is not given, the error is emitted as an 'error'
event on the socket
object.
Offset and length are optional but both must be set if either are used. They are supported only when the first argument is a Buffer
, a TypedArray
, or a DataView
.
This method throws ERR_SOCKET_BAD_PORT
if called on an unbound socket.
Example of sending a UDP packet to a port on localhost
;
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const message = Buffer.from('Some bytes');
const client = dgram.createSocket('udp4');
client.send(message, 41234, 'localhost', (err) => {
client.close();
});
Example of sending a UDP packet composed of multiple buffers to a port on127.0.0.1
;
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const buf1 = Buffer.from('Some ');
const buf2 = Buffer.from('bytes');
const client = dgram.createSocket('udp4');
client.send([buf1, buf2], 41234, (err) => {
client.close();
});
Sending multiple buffers might be faster or slower depending on the application and operating system. Run benchmarks to determine the optimal strategy on a case-by-case basis. Generally speaking, however, sending multiple buffers is faster.
Example of sending a UDP packet using a socket connected to a port on localhost
:
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const message = Buffer.from('Some bytes');
const client = dgram.createSocket('udp4');
client.connect(41234, 'localhost', (err) => {
client.send(message, (err) => {
client.close();
});
});
Message to be sent.
Offset in the buffer where the message starts.
Number of bytes in the message.
Destination port.
Destination host name or IP address.
Called when the message has been sent.
Broadcasts a datagram on the socket. For connectionless sockets, the destination port
and address
must be specified. Connected sockets, on the other hand, will use their associated remote endpoint, so the port
and address
arguments must not be set.
The msg
argument contains the message to be sent. Depending on its type, different behavior can apply. If msg
is a Buffer
, any TypedArray
or a DataView
, the offset
and length
specify the offset within the Buffer
where the message begins and the number of bytes in the message, respectively. If msg
is a String
, then it is automatically converted to a Buffer
with 'utf8'
encoding. With messages that contain multi-byte characters, offset
and length
will be calculated with respect to byte length
and not the character position. If msg
is an array, offset
and length
must not be specified.
The address
argument is a string. If the value of address
is a host name, DNS will be used to resolve the address of the host. If address
is not provided or otherwise nullish, '127.0.0.1'
(for udp4
sockets) or '::1'
(for udp6
sockets) will be used by default.
If the socket has not been previously bound with a call to bind
, the socket is assigned a random port number and is bound to the "all interfaces" address ('0.0.0.0'
for udp4
sockets, '::0'
for udp6
sockets.)
An optional callback
function may be specified to as a way of reporting DNS errors or for determining when it is safe to reuse the buf
object. DNS lookups delay the time to send for at least one tick of the Node.js event loop.
The only way to know for sure that the datagram has been sent is by using a callback
. If an error occurs and a callback
is given, the error will be passed as the first argument to the callback
. If a callback
is not given, the error is emitted as an 'error'
event on the socket
object.
Offset and length are optional but both must be set if either are used. They are supported only when the first argument is a Buffer
, a TypedArray
, or a DataView
.
This method throws ERR_SOCKET_BAD_PORT
if called on an unbound socket.
Example of sending a UDP packet to a port on localhost
;
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const message = Buffer.from('Some bytes');
const client = dgram.createSocket('udp4');
client.send(message, 41234, 'localhost', (err) => {
client.close();
});
Example of sending a UDP packet composed of multiple buffers to a port on127.0.0.1
;
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const buf1 = Buffer.from('Some ');
const buf2 = Buffer.from('bytes');
const client = dgram.createSocket('udp4');
client.send([buf1, buf2], 41234, (err) => {
client.close();
});
Sending multiple buffers might be faster or slower depending on the application and operating system. Run benchmarks to determine the optimal strategy on a case-by-case basis. Generally speaking, however, sending multiple buffers is faster.
Example of sending a UDP packet using a socket connected to a port on localhost
:
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const message = Buffer.from('Some bytes');
const client = dgram.createSocket('udp4');
client.connect(41234, 'localhost', (err) => {
client.send(message, (err) => {
client.close();
});
});
Message to be sent.
Offset in the buffer where the message starts.
Number of bytes in the message.
Destination port.
Called when the message has been sent.
Broadcasts a datagram on the socket. For connectionless sockets, the destination port
and address
must be specified. Connected sockets, on the other hand, will use their associated remote endpoint, so the port
and address
arguments must not be set.
The msg
argument contains the message to be sent. Depending on its type, different behavior can apply. If msg
is a Buffer
, any TypedArray
or a DataView
, the offset
and length
specify the offset within the Buffer
where the message begins and the number of bytes in the message, respectively. If msg
is a String
, then it is automatically converted to a Buffer
with 'utf8'
encoding. With messages that contain multi-byte characters, offset
and length
will be calculated with respect to byte length
and not the character position. If msg
is an array, offset
and length
must not be specified.
The address
argument is a string. If the value of address
is a host name, DNS will be used to resolve the address of the host. If address
is not provided or otherwise nullish, '127.0.0.1'
(for udp4
sockets) or '::1'
(for udp6
sockets) will be used by default.
If the socket has not been previously bound with a call to bind
, the socket is assigned a random port number and is bound to the "all interfaces" address ('0.0.0.0'
for udp4
sockets, '::0'
for udp6
sockets.)
An optional callback
function may be specified to as a way of reporting DNS errors or for determining when it is safe to reuse the buf
object. DNS lookups delay the time to send for at least one tick of the Node.js event loop.
The only way to know for sure that the datagram has been sent is by using a callback
. If an error occurs and a callback
is given, the error will be passed as the first argument to the callback
. If a callback
is not given, the error is emitted as an 'error'
event on the socket
object.
Offset and length are optional but both must be set if either are used. They are supported only when the first argument is a Buffer
, a TypedArray
, or a DataView
.
This method throws ERR_SOCKET_BAD_PORT
if called on an unbound socket.
Example of sending a UDP packet to a port on localhost
;
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const message = Buffer.from('Some bytes');
const client = dgram.createSocket('udp4');
client.send(message, 41234, 'localhost', (err) => {
client.close();
});
Example of sending a UDP packet composed of multiple buffers to a port on127.0.0.1
;
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const buf1 = Buffer.from('Some ');
const buf2 = Buffer.from('bytes');
const client = dgram.createSocket('udp4');
client.send([buf1, buf2], 41234, (err) => {
client.close();
});
Sending multiple buffers might be faster or slower depending on the application and operating system. Run benchmarks to determine the optimal strategy on a case-by-case basis. Generally speaking, however, sending multiple buffers is faster.
Example of sending a UDP packet using a socket connected to a port on localhost
:
import dgram from 'node:dgram';
import { Buffer } from 'node:buffer';
const message = Buffer.from('Some bytes');
const client = dgram.createSocket('udp4');
client.connect(41234, 'localhost', (err) => {
client.send(message, (err) => {
client.close();
});
});
Message to be sent.
Offset in the buffer where the message starts.
Number of bytes in the message.
Called when the message has been sent.
Sets or clears the SO_BROADCAST
socket option. When set to true
, UDP packets may be sent to a local interface's broadcast address.
This method throws EBADF
if called on an unbound socket.
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.
All references to scope in this section are referring to IPv6 Zone Indices, which are defined by RFC 4007. In string form, an IP with a scope index is written as 'IP%scope'
where scope is an interface name or interface number.
Sets the default outgoing multicast interface of the socket to a chosen interface or back to system interface selection. The multicastInterface
must be a valid string representation of an IP from the socket's family.
For IPv4 sockets, this should be the IP configured for the desired physical interface. All packets sent to multicast on the socket will be sent on the interface determined by the most recent successful use of this call.
For IPv6 sockets, multicastInterface
should include a scope to indicate the interface as in the examples that follow. In IPv6, individual send
calls can also use explicit scope in addresses, so only packets sent to a multicast address without specifying an explicit scope are affected by the most recent successful use of this call.
This method throws EBADF
if called on an unbound socket.
On most systems, where scope format uses the interface name:
const socket = dgram.createSocket('udp6');
socket.bind(1234, () => {
socket.setMulticastInterface('::%eth1');
});
On Windows, where scope format uses an interface number:
const socket = dgram.createSocket('udp6');
socket.bind(1234, () => {
socket.setMulticastInterface('::%2');
});
All systems use an IP of the host on the desired physical interface:
const socket = dgram.createSocket('udp4');
socket.bind(1234, () => {
socket.setMulticastInterface('10.0.0.2');
});
Sets or clears the IP_MULTICAST_LOOP
socket option. When set to true
, multicast packets will also be received on the local interface.
This method throws EBADF
if called on an unbound socket.
Sets the IP_MULTICAST_TTL
socket option. While TTL generally stands for "Time to Live", in this context it specifies the number of IP hops that a packet is allowed to travel through, specifically for multicast traffic. Each router or gateway that forwards a packet decrements the TTL. If the TTL is decremented to 0 by a router, it will not be forwarded.
The ttl
argument may be between 0 and 255. The default on most systems is 1
.
This method throws EBADF
if called on an unbound socket.
Sets the SO_RCVBUF
socket option. Sets the maximum socket receive buffer in bytes.
This method throws ERR_SOCKET_BUFFER_SIZE
if called on an unbound socket.
Sets the SO_SNDBUF
socket option. Sets the maximum socket send buffer in bytes.
This method throws ERR_SOCKET_BUFFER_SIZE
if called on an unbound socket.
Sets the IP_TTL
socket option. While TTL generally stands for "Time to Live", in this context it specifies the number of IP hops that a packet is allowed to travel through. Each router or gateway that forwards a packet decrements the TTL. If the TTL is decremented to 0 by a router, it will not be forwarded. Changing TTL values is typically done for network probes or when multicasting.
The ttl
argument may be between 1 and 255. The default on most systems is 64.
This method throws EBADF
if called on an unbound socket.
By default, binding a socket will cause it to block the Node.js process from exiting as long as the socket is open. The socket.unref()
method can be used to exclude the socket from the reference counting that keeps the Node.js process active, allowing the process to exit even if the socket is still listening.
Calling socket.unref()
multiple times will have no additional effect.
The socket.unref()
method returns a reference to the socket so calls can be chained.
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]();
}
}
Disposable that removes the abort
listener.
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] ]
}
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
}
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());
Use the close
option to specify an array of event names that will end the iteration:
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);
ee.emit('close');
});
for await (const event of on(ee, 'foo', { close: ['close'] })) {
console.log(event); // prints ['bar'] [42]
}
// the loop will exit after 'close' is emitted
console.log('done'); // prints 'done'
An AsyncIterator
that iterates eventName
events emitted by the emitter
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());
Use the close
option to specify an array of event names that will end the iteration:
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);
ee.emit('close');
});
for await (const event of on(ee, 'foo', { close: ['close'] })) {
console.log(event); // prints ['bar'] [42]
}
// the loop will exit after 'close' is emitted
console.log('done'); // prints 'done'
An AsyncIterator
that iterates eventName
events emitted by the emitter
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!
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!
import { setMaxListeners, EventEmitter } from 'node:events';
const target = new EventTarget();
const emitter = new EventEmitter();
setMaxListeners(5, target, emitter);
A non-negative number. The maximum number of listeners per EventTarget
event.
Zero or more {EventTarget} or {EventEmitter} instances. If none are specified, n
is set as the default max for all newly created {EventTarget} and {EventEmitter} objects.
Creates a dgram.Socket
object. Once the socket is created, calling socket.bind()
will instruct the socket to begin listening for datagram messages. When address
and port
are not passed to socket.bind()
the method will bind the socket to the "all interfaces" address on a random port (it does the right thing for both udp4
and udp6
sockets). The bound address and port can be retrieved using socket.address().address
and socket.address().port
.
If the signal
option is enabled, calling .abort()
on the corresponding AbortController
is similar to calling .close()
on the socket:
const controller = new AbortController();
const { signal } = controller;
const server = dgram.createSocket({ type: 'udp4', signal });
server.on('message', (msg, rinfo) => {
console.log(`server got: ${msg} from ${rinfo.address}:${rinfo.port}`);
});
// Later, when you want to close the server.
controller.abort();
Attached as a listener for 'message'
events. Optional.
Creates a dgram.Socket
object. Once the socket is created, calling socket.bind()
will instruct the socket to begin listening for datagram messages. When address
and port
are not passed to socket.bind()
the method will bind the socket to the "all interfaces" address on a random port (it does the right thing for both udp4
and udp6
sockets). The bound address and port can be retrieved using socket.address().address
and socket.address().port
.
If the signal
option is enabled, calling .abort()
on the corresponding AbortController
is similar to calling .close()
on the socket:
const controller = new AbortController();
const { signal } = controller;
const server = dgram.createSocket({ type: 'udp4', signal });
server.on('message', (msg, rinfo) => {
console.log(`server got: ${msg} from ${rinfo.address}:${rinfo.port}`);
});
// Later, when you want to close the server.
controller.abort();
Available options are:
Attached as a listener for 'message'
events. Optional.
When provided the corresponding AbortController
can be used to cancel an asynchronous action.