WriteStream

Defined in: src/node/streams.ts:121

A WriteStream implementation that wraps an underlying global WritableStream.

Extends

Writable

Implements

WriteStream

Constructors

Constructor

new WriteStream(opts?, handleOrPromise): WriteStream

Defined in: src/node/streams.ts:128

Parameters

opts?

CreateWriteStreamOptions = {}

handleOrPromise

FileHandle | Promise<FileHandle>

Returns

WriteStream

Overrides

Writable.constructor

Properties

closed

readonly closed: boolean

Defined in: node_modules/@types/node/stream.d.ts:841

Is true after 'close' has been emitted.

Since

v18.0.0

Implementation of

fs.WriteStream.closed

Inherited from

Writable.closed

destroyed

destroyed: boolean

Defined in: node_modules/@types/node/stream.d.ts:836

Is true after writable.destroy() has been called.

Since

v8.0.0

Implementation of

fs.WriteStream.destroyed

Inherited from

Writable.destroyed

errored

readonly errored: Error | null

Defined in: node_modules/@types/node/stream.d.ts:846

Returns error if the stream has been destroyed with an error.

Since

v18.0.0

Implementation of

fs.WriteStream.errored

Inherited from

Writable.errored

pending

pending: boolean = true

Defined in: src/node/streams.ts:122

This property is true if the underlying file has not been opened yet, i.e. before the 'ready' event is emitted.

Since

v11.2.0

Implementation of

fs.WriteStream.pending

writable

writable: boolean

Defined in: node_modules/@types/node/stream.d.ts:792

Is true if it is safe to call writable.write(), which means the stream has not been destroyed, errored, or ended.

Since

v11.4.0

Implementation of

fs.WriteStream.writable

Inherited from

Writable.writable

writableAborted

readonly writableAborted: boolean

Defined in: node_modules/@types/node/stream.d.ts:797

Returns whether the stream was destroyed or errored before emitting 'finish'.

Since

v18.0.0, v16.17.0

Implementation of

fs.WriteStream.writableAborted

Inherited from

Writable.writableAborted

writableCorked

readonly writableCorked: number

Defined in: node_modules/@types/node/stream.d.ts:831

Number of times writable.uncork() needs to be called in order to fully uncork the stream.

Since

v13.2.0, v12.16.0

Implementation of

fs.WriteStream.writableCorked

Inherited from

Writable.writableCorked

writableEnded

readonly writableEnded: boolean

Defined in: node_modules/@types/node/stream.d.ts:803

Is true after writable.end() has been called. This property does not indicate whether the data has been flushed, for this use writable.writableFinished instead.

Since

v12.9.0

Implementation of

fs.WriteStream.writableEnded

Inherited from

Writable.writableEnded

writableFinished

readonly writableFinished: boolean

Defined in: node_modules/@types/node/stream.d.ts:808

Is set to true immediately before the 'finish' event is emitted.

Since

v12.6.0

Implementation of

fs.WriteStream.writableFinished

Inherited from

Writable.writableFinished

writableHighWaterMark

readonly writableHighWaterMark: number

Defined in: node_modules/@types/node/stream.d.ts:813

Return the value of highWaterMark passed when creating this Writable.

Since

v9.3.0

Implementation of

fs.WriteStream.writableHighWaterMark

Inherited from

Writable.writableHighWaterMark

writableLength

readonly writableLength: number

Defined in: node_modules/@types/node/stream.d.ts:820

This property contains the number of bytes (or objects) in the queue ready to be written. The value provides introspection data regarding the status of the highWaterMark.

Since

v9.4.0

Implementation of

fs.WriteStream.writableLength

Inherited from

Writable.writableLength

writableNeedDrain

readonly writableNeedDrain: boolean

Defined in: node_modules/@types/node/stream.d.ts:851

Is true if the stream’s buffer has been full and stream will emit 'drain'.

Since

v15.2.0, v14.17.0

Implementation of

fs.WriteStream.writableNeedDrain

Inherited from

Writable.writableNeedDrain

writableObjectMode

readonly writableObjectMode: boolean

Defined in: node_modules/@types/node/stream.d.ts:825

Getter for the property objectMode of a given Writable stream.

Since

v12.3.0

Implementation of

fs.WriteStream.writableObjectMode

Inherited from

Writable.writableObjectMode

Accessors

bytesWritten

Get Signature

get bytesWritten(): number

Defined in: src/node/streams.ts:185

The number of bytes written so far. Does not include data that is still queued for writing.

Since

v0.4.7

Returns

number

Implementation of

fs.WriteStream.bytesWritten

path

Get Signature

get path(): string

Defined in: src/node/streams.ts:181

The path to the file the stream is writing to as specified in the first argument to createWriteStream. If path is passed as a string, thenwriteStream.path will be a string. If path is passed as a Buffer, thenwriteStream.path will be a Buffer.

Since

v0.1.93

Returns

string

Implementation of

fs.WriteStream.path

Methods

_construct()?

optional _construct(callback): void

Defined in: node_modules/@types/node/stream.d.ts:860

Parameters

callback

(error?) => void

Returns

void

Implementation of

fs.WriteStream._construct

Inherited from

Writable._construct

_destroy()

_destroy(error, callback): void

Defined in: node_modules/@types/node/stream.d.ts:861

Parameters

error

Error | null

callback

(error?) => void

Returns

void

Implementation of

fs.WriteStream._destroy

Inherited from

Writable._destroy

_final()

_final(callback): Promise<void>

Defined in: src/node/streams.ts:158

Parameters

callback

(error?) => void

Returns

Promise<void>

Implementation of

fs.WriteStream._final

Overrides

Writable._final

_write()

_write(chunk, encoding, callback): Promise<void>

Defined in: src/node/streams.ts:141

Parameters

chunk

any

encoding

"buffer" | BufferEncoding

callback

(error?) => void

Returns

Promise<void>

Implementation of

fs.WriteStream._write

Overrides

Writable._write

_writev()?

optional _writev(chunks, callback): void

Defined in: node_modules/@types/node/stream.d.ts:853

Parameters

chunks

object[]

callback

(error?) => void

Returns

void

Implementation of

fs.WriteStream._writev

Inherited from

Writable._writev

[asyncDispose]()

[asyncDispose](): Promise<void>

Defined in: node_modules/@types/node/stream.d.ts:1046

Calls writable.destroy() with an AbortError and returns a promise that fulfills when the stream is finished.

Returns

Promise<void>

Since

v22.4.0, v20.16.0

Implementation of

fs.WriteStream.[asyncDispose]

Inherited from

Writable.[asyncDispose]

[captureRejectionSymbol]()?

optional [captureRejectionSymbol](error, event, …args): void

Defined in: node_modules/@types/node/events.d.ts:87

The Symbol.for('nodejs.rejection') method is called in case a promise rejection happens when emitting an event and captureRejections is enabled on the emitter. It is possible to use events.captureRejectionSymbol in place of Symbol.for('nodejs.rejection').

import { EventEmitter, captureRejectionSymbol } from 'node:events';

class MyClass extends EventEmitter {
  constructor() {
    super({ captureRejections: true });
  }

  [captureRejectionSymbol](err, event, ...args) {
    console.log('rejection happened for', event, 'with', err, ...args);
    this.destroy(err);
  }

  destroy(err) {
    // Tear the resource down here.
  }
}

Parameters

error

Error

event

string | symbol

args

…any[]

Returns

void

Since

v13.4.0, v12.16.0

Implementation of

fs.WriteStream.[captureRejectionSymbol]

Inherited from

Writable.[captureRejectionSymbol]

addListener()

Call Signature

addListener<E>(eventName, listener): this

Defined in: node_modules/@types/node/stream.d.ts:1048

Alias for emitter.on(eventName, listener).

Type Parameters

E

E extends keyof WritableEventMap

Parameters

eventName

E

listener

(…args) => void

Returns

this

Since

v0.1.26

Implementation of

fs.WriteStream.addListener

Inherited from

Writable.addListener

Call Signature

addListener(eventName, listener): this

Defined in: node_modules/@types/node/stream.d.ts:1052

Parameters

eventName

string | symbol

listener

(…args) => void

Returns

this

Implementation of

fs.WriteStream.addListener

Inherited from

Writable.addListener

close()

close(callback?): void

Defined in: src/node/streams.ts:171

Closes writeStream. Optionally accepts a callback that will be executed once the writeStreamis closed.

Parameters

callback?

Callback<[void]> = ...

Returns

void

Since

v0.9.4

Implementation of

fs.WriteStream.close

cork()

cork(): void

Defined in: node_modules/@types/node/stream.d.ts:989

The writable.cork() method forces all written data to be buffered in memory. The buffered data will be flushed when either the uncork or end methods are called.

The primary intent of writable.cork() is to accommodate a situation in which several small chunks are written to the stream in rapid succession. Instead of immediately forwarding them to the underlying destination, writable.cork() buffers all the chunks until writable.uncork() is called, which will pass them all to writable._writev(), if present. This prevents a head-of-line blocking situation where data is being buffered while waiting for the first small chunk to be processed. However, use of writable.cork() without implementing writable._writev() may have an adverse effect on throughput.

See also: writable.uncork(), writable._writev().

Returns

void

Since

v0.11.2

Implementation of

fs.WriteStream.cork

Inherited from

Writable.cork

destroy()

destroy(error?): this

Defined in: node_modules/@types/node/stream.d.ts:1040

Destroy the stream. Optionally emit an 'error' event, and emit a 'close' event (unless emitClose is set to false). After this call, the writable stream has ended and subsequent calls to write() or end() will result in an ERR_STREAM_DESTROYED error. This is a destructive and immediate way to destroy a stream. Previous calls to write() may not have drained, and may trigger an ERR_STREAM_DESTROYED error. Use end() instead of destroy if data should flush before close, or wait for the 'drain' event before destroying the stream.

Once destroy() has been called any further calls will be a no-op and no further errors except from _destroy() may be emitted as 'error'.

Implementors should not override this method, but instead implement writable._destroy().

Parameters

error?

Error

Optional, an error to emit with 'error' event.

Returns

this

Since

v8.0.0

Implementation of

fs.WriteStream.destroy

Inherited from

Writable.destroy

emit()

Call Signature

emit<E>(eventName, …args): boolean

Defined in: node_modules/@types/node/stream.d.ts:1053

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

Type Parameters

E

E extends keyof WritableEventMap

Parameters

eventName

E

args

…WritableEventMap[E]

Returns

boolean

Since

v0.1.26

Implementation of

fs.WriteStream.emit

Inherited from

Writable.emit

Call Signature

emit(eventName, …args): boolean

Defined in: node_modules/@types/node/stream.d.ts:1054

Parameters

eventName

string | symbol

args

…any[]

Returns

boolean

Implementation of

fs.WriteStream.emit

Inherited from

Writable.emit

end()

Call Signature

end(cb?): this

Defined in: node_modules/@types/node/stream.d.ts:955

Calling the writable.end() method signals that no more data will be written to the Writable. The optional chunk and encoding arguments allow one final additional chunk of data to be written immediately before closing the stream.

Calling the write method after calling end will raise an error.

// Write 'hello, ' and then end with 'world!'.
import fs from 'node:fs';
const file = fs.createWriteStream('example.txt');
file.write('hello, ');
file.end('world!');
// Writing more now is not allowed!

Parameters

cb?

() => void

Callback for when the stream is finished.

Returns

this

Since

v0.9.4

Implementation of

fs.WriteStream.end

Inherited from

Writable.end

Call Signature

end(chunk, cb?): this

Defined in: node_modules/@types/node/stream.d.ts:964

Signals that no more data will be written, with one final chunk of data.

Parameters

chunk

any

Optional data to write. For streams not operating in object mode, chunk must be a {string}, {Buffer}, {TypedArray} or {DataView}. For object mode streams, chunk may be any JavaScript value other than null.

cb?

() => void

Callback for when the stream is finished.

Returns

this

See

Writable.end for full details.

Since

v0.9.4

Implementation of

fs.WriteStream.end

Inherited from

Writable.end

Call Signature

end(chunk, encoding, cb?): this

Defined in: node_modules/@types/node/stream.d.ts:974

Signals that no more data will be written, with one final chunk of data.

Parameters

chunk

any

encoding

BufferEncoding

The encoding if chunk is a string

cb?

() => void

Callback for when the stream is finished.

Returns

this

See

Writable.end for full details.

Since

v0.9.4

Implementation of

fs.WriteStream.end

Inherited from

Writable.end

eventNames()

eventNames(): (string | symbol)[]

Defined in: node_modules/@types/node/events.d.ts:154

Returns an array listing the events for which the emitter has registered listeners.

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

Implementation of

fs.WriteStream.eventNames

Inherited from

Writable.eventNames

getMaxListeners()

getMaxListeners(): number

Defined in: node_modules/@types/node/events.d.ts:161

Returns the current max listener value for the EventEmitter which is either set by emitter.setMaxListeners(n) or defaults to events.defaultMaxListeners.

Returns

number

Since

v1.0.0

Implementation of

fs.WriteStream.getMaxListeners

Inherited from

Writable.getMaxListeners

listenerCount()

Call Signature

listenerCount<E>(eventName, listener?): number

Defined in: node_modules/@types/node/stream.d.ts:1055

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

E

E extends keyof WritableEventMap

Parameters

eventName

E

The name of the event being listened for

listener?

(…args) => void

The event handler function

Returns

number

Since

v3.2.0

Implementation of

fs.WriteStream.listenerCount

Inherited from

Writable.listenerCount

Call Signature

listenerCount(eventName, listener?): number

Defined in: node_modules/@types/node/stream.d.ts:1059

Parameters

eventName

string | symbol

listener?

(…args) => void

Returns

number

Implementation of

fs.WriteStream.listenerCount

Inherited from

Writable.listenerCount

listeners()

Call Signature

listeners<E>(eventName): (…args) => void[]

Defined in: node_modules/@types/node/stream.d.ts:1060

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

E

E extends keyof WritableEventMap

Parameters

eventName

E

Returns

(…args) => void[]

Since

v0.1.26

Implementation of

fs.WriteStream.listeners

Inherited from

Writable.listeners

Call Signature

listeners(eventName): (…args) => void[]

Defined in: node_modules/@types/node/stream.d.ts:1061

Parameters

eventName

string | symbol

Returns

(…args) => void[]

Implementation of

fs.WriteStream.listeners

Inherited from

Writable.listeners

off()

Call Signature

off<E>(eventName, listener): this

Defined in: node_modules/@types/node/stream.d.ts:1062

Alias for emitter.removeListener().

Type Parameters

E

E extends keyof WritableEventMap

Parameters

eventName

E

listener

(…args) => void

Returns

this

Since

v10.0.0

Implementation of

fs.WriteStream.off

Inherited from

Writable.off

Call Signature

off(eventName, listener): this

Defined in: node_modules/@types/node/stream.d.ts:1063

Parameters

eventName

string | symbol

listener

(…args) => void

Returns

this

Implementation of

fs.WriteStream.off

Inherited from

Writable.off

on()

Call Signature

on<E>(eventName, listener): this

Defined in: node_modules/@types/node/stream.d.ts:1064

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

Type Parameters

E

E extends keyof WritableEventMap

Parameters

eventName

E

The name of the event.

listener

(…args) => void

The callback function

Returns

this

Since

v0.1.101

Implementation of

fs.WriteStream.on

Inherited from

Writable.on

Call Signature

on(eventName, listener): this

Defined in: node_modules/@types/node/stream.d.ts:1065

Parameters

eventName

string | symbol

listener

(…args) => void

Returns

this

Implementation of

fs.WriteStream.on

Inherited from

Writable.on

once()

Call Signature

once<E>(eventName, listener): this

Defined in: node_modules/@types/node/stream.d.ts:1066

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

Type Parameters

E

E extends keyof WritableEventMap

Parameters

eventName

E

The name of the event.

listener

(…args) => void

The callback function

Returns

this

Since

v0.3.0

Implementation of

fs.WriteStream.once

Inherited from

Writable.once

Call Signature

once(eventName, listener): this

Defined in: node_modules/@types/node/stream.d.ts:1070

Parameters

eventName

string | symbol

listener

(…args) => void

Returns

this

Implementation of

fs.WriteStream.once

Inherited from

Writable.once

pipe()

pipe<T>(destination, options?): T

Defined in: node_modules/@types/node/stream.d.ts:11

Type Parameters

T

T extends WritableStream

Parameters

destination

T

options?

PipeOptions

Returns

T

Since

v0.9.4

Implementation of

fs.WriteStream.pipe

Inherited from

Writable.pipe

prependListener()

Call Signature

prependListener<E>(eventName, listener): this

Defined in: node_modules/@types/node/stream.d.ts:1071

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

E

E extends keyof WritableEventMap

Parameters

eventName

E

The name of the event.

listener

(…args) => void

The callback function

Returns

this

Since

v6.0.0

Implementation of

fs.WriteStream.prependListener

Inherited from

Writable.prependListener

Call Signature

prependListener(eventName, listener): this

Defined in: node_modules/@types/node/stream.d.ts:1075

Parameters

eventName

string | symbol

listener

(…args) => void

Returns

this

Implementation of

fs.WriteStream.prependListener

Inherited from

Writable.prependListener

prependOnceListener()

Call Signature

prependOnceListener<E>(eventName, listener): this

Defined in: node_modules/@types/node/stream.d.ts:1076

Adds a one-time listener 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

E

E extends keyof WritableEventMap

Parameters

eventName

E

The name of the event.

listener

(…args) => void

The callback function

Returns

this

Since

v6.0.0

Implementation of

fs.WriteStream.prependOnceListener

Inherited from

Writable.prependOnceListener

Call Signature

prependOnceListener(eventName, listener): this

Defined in: node_modules/@types/node/stream.d.ts:1080

Parameters

eventName

string | symbol

listener

(…args) => void

Returns

this

Implementation of

fs.WriteStream.prependOnceListener

Inherited from

Writable.prependOnceListener

rawListeners()

Call Signature

rawListeners<E>(eventName): (…args) => void[]

Defined in: node_modules/@types/node/stream.d.ts:1081

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

E

E extends keyof WritableEventMap

Parameters

eventName

E

Returns

(…args) => void[]

Since

v9.4.0

Implementation of

fs.WriteStream.rawListeners

Inherited from

Writable.rawListeners

Call Signature

rawListeners(eventName): (…args) => void[]

Defined in: node_modules/@types/node/stream.d.ts:1082

Parameters

eventName

string | symbol

Returns

(…args) => void[]

Implementation of

fs.WriteStream.rawListeners

Inherited from

Writable.rawListeners

removeAllListeners()

Call Signature

removeAllListeners<E>(eventName?): this

Defined in: node_modules/@types/node/stream.d.ts:1084

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.

Type Parameters

E

E extends keyof WritableEventMap

Parameters

eventName?

E

Returns

this

Since

v0.1.26

Implementation of

fs.WriteStream.removeAllListeners

Inherited from

Writable.removeAllListeners

Call Signature

removeAllListeners(eventName?): this

Defined in: node_modules/@types/node/stream.d.ts:1085

Parameters

eventName?

string | symbol

Returns

this

Implementation of

fs.WriteStream.removeAllListeners

Inherited from

Writable.removeAllListeners

removeListener()

Call Signature

removeListener<E>(eventName, listener): this

Defined in: node_modules/@types/node/stream.d.ts:1086

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 from emit() 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 indexes 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

E

E extends keyof WritableEventMap

Parameters

eventName

E

listener

(…args) => void

Returns

this

Since

v0.1.26

Implementation of

fs.WriteStream.removeListener

Inherited from

Writable.removeListener

Call Signature

removeListener(eventName, listener): this

Defined in: node_modules/@types/node/stream.d.ts:1090

Parameters

eventName

string | symbol

listener

(…args) => void

Returns

this

Implementation of

fs.WriteStream.removeListener

Inherited from

Writable.removeListener

setDefaultEncoding()

setDefaultEncoding(encoding): this

Defined in: node_modules/@types/node/stream.d.ts:935

The writable.setDefaultEncoding() method sets the default encoding for a Writable stream.

Parameters

encoding

BufferEncoding

The new default encoding

Returns

this

Since

v0.11.15

Implementation of

fs.WriteStream.setDefaultEncoding

Inherited from

Writable.setDefaultEncoding

setMaxListeners()

setMaxListeners(n): this

Defined in: node_modules/@types/node/events.d.ts:436

By default EventEmitters will print a warning if more than 10 listeners are added for a particular event. This is a useful default that helps finding memory leaks. The emitter.setMaxListeners() method allows the limit to be modified for this specific EventEmitter instance. The value can be set to Infinity (or 0) to indicate an unlimited number of listeners.

Returns a reference to the EventEmitter, so that calls can be chained.

Parameters

n

number

Returns

this

Since

v0.3.5

Implementation of

fs.WriteStream.setMaxListeners

Inherited from

Writable.setMaxListeners

uncork()

uncork(): void

Defined in: node_modules/@types/node/stream.d.ts:1023

The writable.uncork() method flushes all data buffered since cork was called.

When using writable.cork() and writable.uncork() to manage the buffering of writes to a stream, defer calls to writable.uncork() using process.nextTick(). Doing so allows batching of all writable.write() calls that occur within a given Node.js event loop phase.

stream.cork();
stream.write('some ');
stream.write('data ');
process.nextTick(() => stream.uncork());

If the writable.cork() method is called multiple times on a stream, the same number of calls to writable.uncork() must be called to flush the buffered data.

stream.cork();
stream.write('some ');
stream.cork();
stream.write('data ');
process.nextTick(() => {
  stream.uncork();
  // The data will not be flushed until uncork() is called a second time.
  stream.uncork();
});

Returns

void

Since

v0.11.2

Implementation of

fs.WriteStream.uncork

Inherited from

Writable.uncork

write()

Call Signature

write(chunk, callback?): boolean

Defined in: node_modules/@types/node/stream.d.ts:918

The writable.write() method writes some data to the stream, and calls the supplied callback once the data has been fully handled. If an error occurs, the callback will be called with the error as its first argument. The callback is called asynchronously and before 'error' is emitted.

The return value is true if the internal buffer is less than the highWaterMark configured when the stream was created after admitting chunk. If false is returned, further attempts to write data to the stream should stop until the 'drain' event is emitted.

While a stream is not draining, calls to write() will buffer chunk, and return false. Once all currently buffered chunks are drained (accepted for delivery by the operating system), the 'drain' event will be emitted. Once write() returns false, do not write more chunks until the 'drain' event is emitted. While calling write() on a stream that is not draining is allowed, Node.js will buffer all written chunks until maximum memory usage occurs, at which point it will abort unconditionally. Even before it aborts, high memory usage will cause poor garbage collector performance and high RSS (which is not typically released back to the system, even after the memory is no longer required). Since TCP sockets may never drain if the remote peer does not read the data, writing a socket that is not draining may lead to a remotely exploitable vulnerability.

Writing data while the stream is not draining is particularly problematic for a Transform, because the Transform streams are paused by default until they are piped or a 'data' or 'readable' event handler is added.

If the data to be written can be generated or fetched on demand, it is recommended to encapsulate the logic into a Readable and use pipe. However, if calling write() is preferred, it is possible to respect backpressure and avoid memory issues using the 'drain' event:

function write(data, cb) {
  if (!stream.write(data)) {
    stream.once('drain', cb);
  } else {
    process.nextTick(cb);
  }
}

// Wait for cb to be called before doing any other write.
write('hello', () => {
  console.log('Write completed, do more writes now.');
});

A Writable stream in object mode will always ignore the encoding argument.

Parameters

chunk

any

callback?

(error) => void

Callback for when this chunk of data is flushed.

Returns

boolean

false if the stream wishes for the calling code to wait for the 'drain' event to be emitted before continuing to write additional data; otherwise true.

Since

v0.9.4

Implementation of

fs.WriteStream.write

Inherited from

Writable.write

Call Signature

write(chunk, encoding, callback?): boolean

Defined in: node_modules/@types/node/stream.d.ts:929

Writes data to the stream, with an explicit encoding for string data.

Parameters

chunk

any

encoding

BufferEncoding

The encoding, if chunk is a string.

callback?

(error) => void

Callback for when this chunk of data is flushed.

Returns

boolean

false if the stream wishes for the calling code to wait for the 'drain' event to be emitted before continuing to write additional data; otherwise true.

See

Writable.write for full details.

Since

v0.9.4

Implementation of

fs.WriteStream.write

Inherited from

Writable.write

fromWeb()

static fromWeb(writableStream, options?): Writable

Defined in: node_modules/@types/node/stream.d.ts:778

A utility method for creating a Writable from a web WritableStream.

Parameters

writableStream

WritableStream

options?

Pick<WritableOptions<Writable>, "highWaterMark" | "objectMode" | "signal" | "decodeStrings">

Returns

Writable

Since

v17.0.0

Inherited from

Writable.fromWeb

toWeb()

static toWeb(streamWritable): WritableStream

Defined in: node_modules/@types/node/stream.d.ts:786

A utility method for creating a web WritableStream from a Writable.

Parameters

streamWritable

WritableStream

Returns

WritableStream

Since

v17.0.0

Inherited from

Writable.toWeb

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