This repository has been archived by the owner on Dec 15, 2022. It is now read-only.
-
Notifications
You must be signed in to change notification settings - Fork 11
/
stream.d.ts
1482 lines (1479 loc) · 57.8 KB
/
stream.d.ts
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/**
* A stream is an abstract interface for working with streaming data in Node.js.
* The `stream` module provides an API for implementing the stream interface.
*
* There are many stream objects provided by Node.js. For instance, a `request to an HTTP server` and `process.stdout` are both stream instances.
*
* Streams can be readable, writable, or both. All streams are instances of `EventEmitter`.
*
* To access the `stream` module:
*
* ```js
* const stream = require('stream');
* ```
*
* The `stream` module is useful for creating new types of stream instances. It is
* usually not necessary to use the `stream` module to consume streams.
* @see [source](https://github.com/nodejs/node/blob/v18.0.0/lib/stream.js)
*/
declare module "stream" {
import { EventEmitter, Abortable } from "node:events";
class internal extends EventEmitter {
pipe<T extends WritableStream>(
destination: T,
options?: {
end?: boolean | undefined;
}
): T;
}
namespace internal {
class Stream extends internal {
constructor(opts?: ReadableOptions);
}
interface StreamOptions<T extends Stream> extends Abortable {
emitClose?: boolean | undefined;
highWaterMark?: number | undefined;
objectMode?: boolean | undefined;
construct?(this: T, callback: (error?: Error | null) => void): void;
destroy?(
this: T,
error: Error | null,
callback: (error: Error | null) => void
): void;
autoDestroy?: boolean | undefined;
}
interface ReadableOptions extends StreamOptions<Readable> {
encoding?: BufferEncoding | undefined;
read?(this: Readable, size: number): void;
}
class Readable<R = any> extends Stream implements ReadableStream {
// TODO: improve type later
values: any;
readonly locked: boolean;
cancel(reason?: any): Promise<void>;
getReader(): ReadableStreamDefaultReader<R>;
pipeThrough<T>(
transform: ReadableWritablePair<T, R>,
options?: StreamPipeOptions
): ReadableStream<T>;
pipeTo(
destination: WritableStream<R>,
options?: StreamPipeOptions
): Promise<void>;
tee(): [ReadableStream<R>, ReadableStream<R>];
forEach(
callbackfn: (
value: any,
key: number,
parent: ReadableStream<R>
) => void,
thisArg?: any
): void;
/**
* A utility method for creating Readable Streams out of iterators.
*/
static from(
iterable: Iterable<any> | AsyncIterable<any>,
options?: ReadableOptions
): Readable;
/**
* Returns whether the stream has been read from or cancelled.
*/
static isDisturbed(stream: Readable | ReadableStream): boolean;
/**
* Returns whether the stream was destroyed or errored before emitting `'end'`.
* @experimental
*/
readonly readableAborted: boolean;
/**
* Is `true` if it is safe to call `readable.read()`, which means
* the stream has not been destroyed or emitted `'error'` or `'end'`.
*/
readable: boolean;
/**
* Getter for the property `encoding` of a given `Readable` stream. The `encoding`property can be set using the `readable.setEncoding()` method.
*/
readonly readableEncoding: BufferEncoding | null;
/**
* Becomes `true` when `'end'` event is emitted.
*/
readonly readableEnded: boolean;
/**
* This property reflects the current state of a `Readable` stream as described
* in the `Three states` section.
*/
readonly readableFlowing: boolean | null;
/**
* Returns the value of `highWaterMark` passed when creating this `Readable`.
*/
readonly readableHighWaterMark: number;
/**
* This property contains the number of bytes (or objects) in the queue
* ready to be read. The value provides introspection data regarding
* the status of the `highWaterMark`.
*/
readonly readableLength: number;
/**
* Getter for the property `objectMode` of a given `Readable` stream.
*/
readonly readableObjectMode: boolean;
/**
* Is `true` after `readable.destroy()` has been called.
*/
destroyed: boolean;
constructor(opts?: ReadableOptions);
_construct?(callback: (error?: Error | null) => void): void;
_read(size: number): void;
/**
* The `readable.read()` method reads data out of the internal buffer and
* returns it. If no data is available to be read, `null` is returned. By default,
* the data is returned as a `Buffer` object unless an encoding has been
* specified using the `readable.setEncoding()` method or the stream is operating
* in object mode.
*
* The optional `size` argument specifies a specific number of bytes to read. If`size` bytes are not available to be read, `null` will be returned _unless_the stream has ended, in which
* case all of the data remaining in the internal
* buffer will be returned.
*
* If the `size` argument is not specified, all of the data contained in the
* internal buffer will be returned.
*
* The `size` argument must be less than or equal to 1 GiB.
*
* The `readable.read()` method should only be called on `Readable` streams
* operating in paused mode. In flowing mode, `readable.read()` is called
* automatically until the internal buffer is fully drained.
*
* ```js
* const readable = getReadableStreamSomehow();
*
* // 'readable' may be triggered multiple times as data is buffered in
* readable.on('readable', () => {
* let chunk;
* console.log('Stream is readable (new data received in buffer)');
* // Use a loop to make sure we read all currently available data
* while (null !== (chunk = readable.read())) {
* console.log(`Read ${chunk.length} bytes of data...`);
* }
* });
*
* // 'end' will be triggered once when there is no more data available
* readable.on('end', () => {
* console.log('Reached end of stream.');
* });
* ```
*
* Each call to `readable.read()` returns a chunk of data, or `null`. The chunks
* are not concatenated. A `while` loop is necessary to consume all data
* currently in the buffer. When reading a large file `.read()` may return `null`,
* having consumed all buffered content so far, but there is still more data to
* come not yet buffered. In this case a new `'readable'` event will be emitted
* when there is more data in the buffer. Finally the `'end'` event will be
* emitted when there is no more data to come.
*
* Therefore to read a file's whole contents from a `readable`, it is necessary
* to collect chunks across multiple `'readable'` events:
*
* ```js
* const chunks = [];
*
* readable.on('readable', () => {
* let chunk;
* while (null !== (chunk = readable.read())) {
* chunks.push(chunk);
* }
* });
*
* readable.on('end', () => {
* const content = chunks.join('');
* });
* ```
*
* A `Readable` stream in object mode will always return a single item from
* a call to `readable.read(size)`, regardless of the value of the`size` argument.
*
* If the `readable.read()` method returns a chunk of data, a `'data'` event will
* also be emitted.
*
* Calling {@link read} after the `'end'` event has
* been emitted will return `null`. No runtime error will be raised.
* @param size Optional argument to specify how much data to read.
*/
read(size?: number): any;
/**
* The `readable.setEncoding()` method sets the character encoding for
* data read from the `Readable` stream.
*
* By default, no encoding is assigned and stream data will be returned as`Buffer` objects. Setting an encoding causes the stream data
* to be returned as strings of the specified encoding rather than as `Buffer`objects. For instance, calling `readable.setEncoding('utf8')` will cause the
* output data to be interpreted as UTF-8 data, and passed as strings. Calling`readable.setEncoding('hex')` will cause the data to be encoded in hexadecimal
* string format.
*
* The `Readable` stream will properly handle multi-byte characters delivered
* through the stream that would otherwise become improperly decoded if simply
* pulled from the stream as `Buffer` objects.
*
* ```js
* const readable = getReadableStreamSomehow();
* readable.setEncoding('utf8');
* readable.on('data', (chunk) => {
* assert.equal(typeof chunk, 'string');
* console.log('Got %d characters of string data:', chunk.length);
* });
* ```
* @param encoding The encoding to use.
*/
setEncoding(encoding: BufferEncoding): this;
/**
* The `readable.pause()` method will cause a stream in flowing mode to stop
* emitting `'data'` events, switching out of flowing mode. Any data that
* becomes available will remain in the internal buffer.
*
* ```js
* const readable = getReadableStreamSomehow();
* readable.on('data', (chunk) => {
* console.log(`Received ${chunk.length} bytes of data.`);
* readable.pause();
* console.log('There will be no additional data for 1 second.');
* setTimeout(() => {
* console.log('Now data will start flowing again.');
* readable.resume();
* }, 1000);
* });
* ```
*
* The `readable.pause()` method has no effect if there is a `'readable'`event listener.
*/
pause(): this;
/**
* The `readable.resume()` method causes an explicitly paused `Readable` stream to
* resume emitting `'data'` events, switching the stream into flowing mode.
*
* The `readable.resume()` method can be used to fully consume the data from a
* stream without actually processing any of that data:
*
* ```js
* getReadableStreamSomehow()
* .resume()
* .on('end', () => {
* console.log('Reached the end, but did not read anything.');
* });
* ```
*
* The `readable.resume()` method has no effect if there is a `'readable'`event listener.
*/
resume(): this;
/**
* The `readable.isPaused()` method returns the current operating state of the`Readable`. This is used primarily by the mechanism that underlies the`readable.pipe()` method. In most
* typical cases, there will be no reason to
* use this method directly.
*
* ```js
* const readable = new stream.Readable();
*
* readable.isPaused(); // === false
* readable.pause();
* readable.isPaused(); // === true
* readable.resume();
* readable.isPaused(); // === false
* ```
*/
isPaused(): boolean;
/**
* The `readable.unpipe()` method detaches a `Writable` stream previously attached
* using the {@link pipe} method.
*
* If the `destination` is not specified, then _all_ pipes are detached.
*
* If the `destination` is specified, but no pipe is set up for it, then
* the method does nothing.
*
* ```js
* const fs = require('fs');
* const readable = getReadableStreamSomehow();
* const writable = fs.createWriteStream('file.txt');
* // All the data from readable goes into 'file.txt',
* // but only for the first second.
* readable.pipe(writable);
* setTimeout(() => {
* console.log('Stop writing to file.txt.');
* readable.unpipe(writable);
* console.log('Manually close the file stream.');
* writable.end();
* }, 1000);
* ```
* @param destination Optional specific stream to unpipe
*/
unpipe(destination?: WritableStream): this;
/**
* Passing `chunk` as `null` signals the end of the stream (EOF) and behaves the
* same as `readable.push(null)`, after which no more data can be written. The EOF
* signal is put at the end of the buffer and any buffered data will still be
* flushed.
*
* The `readable.unshift()` method pushes a chunk of data back into the internal
* buffer. This is useful in certain situations where a stream is being consumed by
* code that needs to "un-consume" some amount of data that it has optimistically
* pulled out of the source, so that the data can be passed on to some other party.
*
* The `stream.unshift(chunk)` method cannot be called after the `'end'` event
* has been emitted or a runtime error will be thrown.
*
* Developers using `stream.unshift()` often should consider switching to
* use of a `Transform` stream instead. See the `API for stream implementers` section for more information.
*
* ```js
* // Pull off a header delimited by \n\n.
* // Use unshift() if we get too much.
* // Call the callback with (error, header, stream).
* const { StringDecoder } = require('string_decoder');
* function parseHeader(stream, callback) {
* stream.on('error', callback);
* stream.on('readable', onReadable);
* const decoder = new StringDecoder('utf8');
* let header = '';
* function onReadable() {
* let chunk;
* while (null !== (chunk = stream.read())) {
* const str = decoder.write(chunk);
* if (str.includes('\n\n')) {
* // Found the header boundary.
* const split = str.split(/\n\n/);
* header += split.shift();
* const remaining = split.join('\n\n');
* const buf = Buffer.from(remaining, 'utf8');
* stream.removeListener('error', callback);
* // Remove the 'readable' listener before unshifting.
* stream.removeListener('readable', onReadable);
* if (buf.length)
* stream.unshift(buf);
* // Now the body of the message can be read from the stream.
* callback(null, header, stream);
* return;
* }
* // Still reading the header.
* header += str;
* }
* }
* }
* ```
*
* Unlike {@link push}, `stream.unshift(chunk)` will not
* end the reading process by resetting the internal reading state of the stream.
* This can cause unexpected results if `readable.unshift()` is called during a
* read (i.e. from within a {@link _read} implementation on a
* custom stream). Following the call to `readable.unshift()` with an immediate {@link push} will reset the reading state appropriately,
* however it is best to simply avoid calling `readable.unshift()` while in the
* process of performing a read.
* @param chunk Chunk of data to unshift onto the read queue. For streams not operating in object mode, `chunk` must be a string, `Buffer`, `Uint8Array` or `null`. For object mode
* streams, `chunk` may be any JavaScript value.
* @param encoding Encoding of string chunks. Must be a valid `Buffer` encoding, such as `'utf8'` or `'ascii'`.
*/
unshift(chunk: any, encoding?: BufferEncoding): void;
/**
* Prior to Node.js 0.10, streams did not implement the entire `stream` module API
* as it is currently defined. (See `Compatibility` for more information.)
*
* When using an older Node.js library that emits `'data'` events and has a {@link pause} method that is advisory only, the`readable.wrap()` method can be used to create a `Readable`
* stream that uses
* the old stream as its data source.
*
* It will rarely be necessary to use `readable.wrap()` but the method has been
* provided as a convenience for interacting with older Node.js applications and
* libraries.
*
* ```js
* const { OldReader } = require('./old-api-module.js');
* const { Readable } = require('stream');
* const oreader = new OldReader();
* const myReader = new Readable().wrap(oreader);
*
* myReader.on('readable', () => {
* myReader.read(); // etc.
* });
* ```
* @param stream An "old style" readable stream
*/
wrap(stream: ReadableStream): this;
push(chunk: any, encoding?: BufferEncoding): boolean;
_destroy(
error: Error | null,
callback: (error?: Error | null) => void
): void;
/**
* Destroy the stream. Optionally emit an `'error'` event, and emit a `'close'`event (unless `emitClose` is set to `false`). After this call, the readable
* stream will release any internal resources and subsequent calls to `push()`will be ignored.
*
* 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 `readable._destroy()`.
* @param error Error which will be passed as payload in `'error'` event
*/
destroy(error?: Error): this;
/**
* Event emitter
* The defined events on documents including:
* 1. close
* 2. data
* 3. end
* 4. error
* 5. pause
* 6. readable
* 7. resume
*/
addListener(event: "close", listener: () => void): this;
addListener(event: "data", listener: (chunk: any) => void): this;
addListener(event: "end", listener: () => void): this;
addListener(event: "error", listener: (err: Error) => void): this;
addListener(event: "pause", listener: () => void): this;
addListener(event: "readable", listener: () => void): this;
addListener(event: "resume", listener: () => void): this;
addListener(
event: string | symbol,
listener: (...args: any[]) => void
): this;
emit(event: "close"): boolean;
emit(event: "data", chunk: any): boolean;
emit(event: "end"): boolean;
emit(event: "error", err: Error): boolean;
emit(event: "pause"): boolean;
emit(event: "readable"): boolean;
emit(event: "resume"): boolean;
emit(event: string | symbol, ...args: any[]): boolean;
on(event: "close", listener: () => void): this;
on(event: "data", listener: (chunk: any) => void): this;
on(event: "end", listener: () => void): this;
on(event: "error", listener: (err: Error) => void): this;
on(event: "pause", listener: () => void): this;
on(event: "readable", listener: () => void): this;
on(event: "resume", listener: () => void): this;
on(event: string | symbol, listener: (...args: any[]) => void): this;
once(event: "close", listener: () => void): this;
once(event: "data", listener: (chunk: any) => void): this;
once(event: "end", listener: () => void): this;
once(event: "error", listener: (err: Error) => void): this;
once(event: "pause", listener: () => void): this;
once(event: "readable", listener: () => void): this;
once(event: "resume", listener: () => void): this;
once(event: string | symbol, listener: (...args: any[]) => void): this;
prependListener(event: "close", listener: () => void): this;
prependListener(event: "data", listener: (chunk: any) => void): this;
prependListener(event: "end", listener: () => void): this;
prependListener(event: "error", listener: (err: Error) => void): this;
prependListener(event: "pause", listener: () => void): this;
prependListener(event: "readable", listener: () => void): this;
prependListener(event: "resume", listener: () => void): this;
prependListener(
event: string | symbol,
listener: (...args: any[]) => void
): this;
prependOnceListener(event: "close", listener: () => void): this;
prependOnceListener(event: "data", listener: (chunk: any) => void): this;
prependOnceListener(event: "end", listener: () => void): this;
prependOnceListener(event: "error", listener: (err: Error) => void): this;
prependOnceListener(event: "pause", listener: () => void): this;
prependOnceListener(event: "readable", listener: () => void): this;
prependOnceListener(event: "resume", listener: () => void): this;
prependOnceListener(
event: string | symbol,
listener: (...args: any[]) => void
): this;
removeListener(event: "close", listener: () => void): this;
removeListener(event: "data", listener: (chunk: any) => void): this;
removeListener(event: "end", listener: () => void): this;
removeListener(event: "error", listener: (err: Error) => void): this;
removeListener(event: "pause", listener: () => void): this;
removeListener(event: "readable", listener: () => void): this;
removeListener(event: "resume", listener: () => void): this;
removeListener(
event: string | symbol,
listener: (...args: any[]) => void
): this;
[Symbol.asyncIterator](): AsyncIterableIterator<any>;
}
interface WritableOptions extends StreamOptions<Writable> {
decodeStrings?: boolean | undefined;
defaultEncoding?: BufferEncoding | undefined;
write?(
this: Writable,
chunk: any,
encoding: BufferEncoding,
callback: (error?: Error | null) => void
): void;
writev?(
this: Writable,
chunks: Array<{
chunk: any;
encoding: BufferEncoding;
}>,
callback: (error?: Error | null) => void
): void;
final?(this: Writable, callback: (error?: Error | null) => void): void;
}
class Writable<W = any> extends Stream implements WritableStream {
readonly locked: boolean;
abort(reason?: any): Promise<void>;
close(): Promise<void>;
getWriter(): WritableStreamDefaultWriter<W>;
/**
* Is `true` if it is safe to call `writable.write()`, which means
* the stream has not been destroyed, errored or ended.
*/
readonly writable: boolean;
/**
* 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.
*/
readonly writableEnded: boolean;
/**
* Is set to `true` immediately before the `'finish'` event is emitted.
*/
readonly writableFinished: boolean;
/**
* Return the value of `highWaterMark` passed when creating this `Writable`.
*/
readonly writableHighWaterMark: number;
/**
* 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`.
*/
readonly writableLength: number;
/**
* Getter for the property `objectMode` of a given `Writable` stream.
*/
readonly writableObjectMode: boolean;
/**
* Number of times `writable.uncork()` needs to be
* called in order to fully uncork the stream.
*/
readonly writableCorked: number;
/**
* Is `true` after `writable.destroy()` has been called.
*/
destroyed: boolean;
constructor(opts?: WritableOptions);
_write(
chunk: any,
encoding: BufferEncoding,
callback: (error?: Error | null) => void
): void;
_writev?(
chunks: Array<{
chunk: any;
encoding: BufferEncoding;
}>,
callback: (error?: Error | null) => void
): void;
_construct?(callback: (error?: Error | null) => void): void;
_destroy(
error: Error | null,
callback: (error?: Error | null) => void
): void;
_final(callback: (error?: Error | null) => void): void;
/**
* 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 {@link pipe}. However, if calling `write()` is preferred, it is
* possible to respect backpressure and avoid memory issues using the `'drain'` event:
*
* ```js
* 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.
* @param chunk Optional data to write. For streams not operating in object mode, `chunk` must be a string, `Buffer` or `Uint8Array`. For object mode streams, `chunk` may be any
* JavaScript value other than `null`.
* @param [encoding='utf8'] The encoding, if `chunk` is a string.
* @param callback Callback for when this chunk of data is flushed.
* @return `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`.
*/
write(
chunk: any,
callback?: (error: Error | null | undefined) => void
): boolean;
write(
chunk: any,
encoding: BufferEncoding,
callback?: (error: Error | null | undefined) => void
): boolean;
/**
* The `writable.setDefaultEncoding()` method sets the default `encoding` for a `Writable` stream.
* @param encoding The new default encoding
*/
setDefaultEncoding(encoding: BufferEncoding): this;
/**
* 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 {@link write} method after calling {@link end} will raise an error.
*
* ```js
* // Write 'hello, ' and then end with 'world!'.
* const fs = require('fs');
* const file = fs.createWriteStream('example.txt');
* file.write('hello, ');
* file.end('world!');
* // Writing more now is not allowed!
* ```
* @param chunk Optional data to write. For streams not operating in object mode, `chunk` must be a string, `Buffer` or `Uint8Array`. For object mode streams, `chunk` may be any
* JavaScript value other than `null`.
* @param encoding The encoding if `chunk` is a string
* @param callback Callback for when the stream is finished.
*/
end(cb?: () => void): this;
end(chunk: any, cb?: () => void): this;
end(chunk: any, encoding: BufferEncoding, cb?: () => void): this;
/**
* The `writable.cork()` method forces all written data to be buffered in memory.
* The buffered data will be flushed when either the {@link uncork} or {@link 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()`.
*/
cork(): void;
/**
* The `writable.uncork()` method flushes all data buffered since {@link 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.
*
* ```js
* 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.
*
* ```js
* 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();
* });
* ```
*
* See also: `writable.cork()`.
*/
uncork(): void;
/**
* 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()`.
* @param error Optional, an error to emit with `'error'` event.
*/
destroy(error?: Error): this;
/**
* Event emitter
* The defined events on documents including:
* 1. close
* 2. drain
* 3. error
* 4. finish
* 5. pipe
* 6. unpipe
*/
addListener(event: "close", listener: () => void): this;
addListener(event: "drain", listener: () => void): this;
addListener(event: "error", listener: (err: Error) => void): this;
addListener(event: "finish", listener: () => void): this;
addListener(event: "pipe", listener: (src: Readable) => void): this;
addListener(event: "unpipe", listener: (src: Readable) => void): this;
addListener(
event: string | symbol,
listener: (...args: any[]) => void
): this;
emit(event: "close"): boolean;
emit(event: "drain"): boolean;
emit(event: "error", err: Error): boolean;
emit(event: "finish"): boolean;
emit(event: "pipe", src: Readable): boolean;
emit(event: "unpipe", src: Readable): boolean;
emit(event: string | symbol, ...args: any[]): boolean;
on(event: "close", listener: () => void): this;
on(event: "drain", listener: () => void): this;
on(event: "error", listener: (err: Error) => void): this;
on(event: "finish", listener: () => void): this;
on(event: "pipe", listener: (src: Readable) => void): this;
on(event: "unpipe", listener: (src: Readable) => void): this;
on(event: string | symbol, listener: (...args: any[]) => void): this;
once(event: "close", listener: () => void): this;
once(event: "drain", listener: () => void): this;
once(event: "error", listener: (err: Error) => void): this;
once(event: "finish", listener: () => void): this;
once(event: "pipe", listener: (src: Readable) => void): this;
once(event: "unpipe", listener: (src: Readable) => void): this;
once(event: string | symbol, listener: (...args: any[]) => void): this;
prependListener(event: "close", listener: () => void): this;
prependListener(event: "drain", listener: () => void): this;
prependListener(event: "error", listener: (err: Error) => void): this;
prependListener(event: "finish", listener: () => void): this;
prependListener(event: "pipe", listener: (src: Readable) => void): this;
prependListener(event: "unpipe", listener: (src: Readable) => void): this;
prependListener(
event: string | symbol,
listener: (...args: any[]) => void
): this;
prependOnceListener(event: "close", listener: () => void): this;
prependOnceListener(event: "drain", listener: () => void): this;
prependOnceListener(event: "error", listener: (err: Error) => void): this;
prependOnceListener(event: "finish", listener: () => void): this;
prependOnceListener(
event: "pipe",
listener: (src: Readable) => void
): this;
prependOnceListener(
event: "unpipe",
listener: (src: Readable) => void
): this;
prependOnceListener(
event: string | symbol,
listener: (...args: any[]) => void
): this;
removeListener(event: "close", listener: () => void): this;
removeListener(event: "drain", listener: () => void): this;
removeListener(event: "error", listener: (err: Error) => void): this;
removeListener(event: "finish", listener: () => void): this;
removeListener(event: "pipe", listener: (src: Readable) => void): this;
removeListener(event: "unpipe", listener: (src: Readable) => void): this;
removeListener(
event: string | symbol,
listener: (...args: any[]) => void
): this;
}
interface DuplexOptions extends ReadableOptions, WritableOptions {
allowHalfOpen?: boolean | undefined;
readableObjectMode?: boolean | undefined;
writableObjectMode?: boolean | undefined;
readableHighWaterMark?: number | undefined;
writableHighWaterMark?: number | undefined;
writableCorked?: number | undefined;
construct?(this: Duplex, callback: (error?: Error | null) => void): void;
read?(this: Duplex, size: number): void;
write?(
this: Duplex,
chunk: any,
encoding: BufferEncoding,
callback: (error?: Error | null) => void
): void;
writev?(
this: Duplex,
chunks: Array<{
chunk: any;
encoding: BufferEncoding;
}>,
callback: (error?: Error | null) => void
): void;
final?(this: Duplex, callback: (error?: Error | null) => void): void;
destroy?(
this: Duplex,
error: Error | null,
callback: (error: Error | null) => void
): void;
}
/**
* Duplex streams are streams that implement both the `Readable` and `Writable` interfaces.
*
* Examples of `Duplex` streams include:
*
* * `TCP sockets`
* * `zlib streams`
* * `crypto streams`
*/
class Duplex extends Readable implements Writable {
readonly writable: boolean;
readonly writableEnded: boolean;
readonly writableFinished: boolean;
readonly writableHighWaterMark: number;
readonly writableLength: number;
readonly writableObjectMode: boolean;
readonly writableCorked: number;
/**
* If `false` then the stream will automatically end the writable side when the
* readable side ends. Set initially by the `allowHalfOpen` constructor option,
* which defaults to `false`.
*
* This can be changed manually to change the half-open behavior of an existing`Duplex` stream instance, but must be changed before the `'end'` event is
* emitted.
* @since v0.9.4
*/
allowHalfOpen: boolean;
constructor(opts?: DuplexOptions);
abort(reason?: any): Promise<void>;
close(): Promise<void>;
getWriter(): WritableStreamDefaultWriter<any>;
/**
* A utility method for creating duplex streams.
*
* - `Stream` converts writable stream into writable `Duplex` and readable stream
* to `Duplex`.
* - `Blob` converts into readable `Duplex`.
* - `string` converts into readable `Duplex`.
* - `ArrayBuffer` converts into readable `Duplex`.
* - `AsyncIterable` converts into a readable `Duplex`. Cannot yield `null`.
* - `AsyncGeneratorFunction` converts into a readable/writable transform
* `Duplex`. Must take a source `AsyncIterable` as first parameter. Cannot yield
* `null`.
* - `AsyncFunction` converts into a writable `Duplex`. Must return
* either `null` or `undefined`
* - `Object ({ writable, readable })` converts `readable` and
* `writable` into `Stream` and then combines them into `Duplex` where the
* `Duplex` will write to the `writable` and read from the `readable`.
* - `Promise` converts into readable `Duplex`. Value `null` is ignored.
*
* @since v16.8.0
*/
static from(
src:
| Stream
| Blob
| ArrayBuffer
| string
| Iterable<any>
| AsyncIterable<any>
| AsyncGeneratorFunction
| Promise<any>
| Object
): Duplex;
_write(
chunk: any,
encoding: BufferEncoding,
callback: (error?: Error | null) => void
): void;
_writev?(
chunks: Array<{
chunk: any;
encoding: BufferEncoding;
}>,
callback: (error?: Error | null) => void
): void;
_destroy(
error: Error | null,
callback: (error: Error | null) => void
): void;
_final(callback: (error?: Error | null) => void): void;
write(
chunk: any,
encoding?: BufferEncoding,
cb?: (error: Error | null | undefined) => void
): boolean;
write(
chunk: any,
cb?: (error: Error | null | undefined) => void
): boolean;
setDefaultEncoding(encoding: BufferEncoding): this;
end(cb?: () => void): this;
end(chunk: any, cb?: () => void): this;
end(chunk: any, encoding?: BufferEncoding, cb?: () => void): this;
cork(): void;
uncork(): void;
}
type TransformCallback = (error?: Error | null, data?: any) => void;
interface TransformOptions extends DuplexOptions {
construct?(
this: Transform,
callback: (error?: Error | null) => void
): void;
read?(this: Transform, size: number): void;
write?(
this: Transform,
chunk: any,
encoding: BufferEncoding,
callback: (error?: Error | null) => void
): void;
writev?(
this: Transform,
chunks: Array<{
chunk: any;
encoding: BufferEncoding;
}>,
callback: (error?: Error | null) => void
): void;
final?(this: Transform, callback: (error?: Error | null) => void): void;
destroy?(
this: Transform,
error: Error | null,
callback: (error: Error | null) => void
): void;
transform?(
this: Transform,
chunk: any,
encoding: BufferEncoding,
callback: TransformCallback
): void;
flush?(this: Transform, callback: TransformCallback): void;
}
/**
* Transform streams are `Duplex` streams where the output is in some way
* related to the input. Like all `Duplex` streams, `Transform` streams
* implement both the `Readable` and `Writable` interfaces.
*
* Examples of `Transform` streams include:
*
* * `zlib streams`
* * `crypto streams`
* @since v0.9.4
*/
class Transform extends Duplex {
constructor(opts?: TransformOptions);
_transform(
chunk: any,
encoding: BufferEncoding,
callback: TransformCallback
): void;
_flush(callback: TransformCallback): void;
}
/**
* The `stream.PassThrough` class is a trivial implementation of a `Transform` stream that simply passes the input bytes across to the output. Its purpose is
* primarily for examples and testing, but there are some use cases where`stream.PassThrough` is useful as a building block for novel sorts of streams.
*/
class PassThrough extends Transform {}
/**
* Attaches an AbortSignal to a readable or writeable stream. This lets code
* control stream destruction using an `AbortController`.
*