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
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
|
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<meta name="nodejs.org:node-version" content="v22.14.0">
<title>Zlib | Node.js v22.14.0 Documentation</title>
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Lato:400,700,400italic&display=fallback">
<link rel="stylesheet" href="assets/style.css">
<link rel="stylesheet" href="assets/hljs.css">
<link rel="canonical" href="https://nodejs.org/api/zlib.html">
<script async defer src="assets/api.js" type="text/javascript"></script>
<script>
const storedTheme = localStorage.getItem('theme');
// Follow operating system theme preference
if (storedTheme === null && window.matchMedia) {
const mq = window.matchMedia('(prefers-color-scheme: dark)');
if (mq.matches) {
document.documentElement.classList.add('dark-mode');
}
} else if (storedTheme === 'dark') {
document.documentElement.classList.add('dark-mode');
}
</script>
<style>@media(max-width:494px){.with-34-chars>.js-flavor-toggle{float:none;margin:0 0 1em auto;}}@media(max-width:374px){.with-19-chars>.js-flavor-toggle{float:none;margin:0 0 1em auto;}}@media(max-width:606px){.with-48-chars>.js-flavor-toggle{float:none;margin:0 0 1em auto;}}@media(max-width:518px){.with-37-chars>.js-flavor-toggle{float:none;margin:0 0 1em auto;}}@media(max-width:734px){.with-64-chars>.js-flavor-toggle{float:none;margin:0 0 1em auto;}}@media(max-width:558px){.with-42-chars>.js-flavor-toggle{float:none;margin:0 0 1em auto;}}</style>
</head>
<body class="alt apidoc" id="api-section-zlib">
<a href="#apicontent" class="skip-to-content">Skip to content</a>
<div id="content" class="clearfix">
<div role="navigation" id="column2" class="interior">
<div id="intro" class="interior">
<a href="/" title="Go back to the home page">
Node.js
</a>
</div>
<ul>
<li><a href="documentation.html" class="nav-documentation">About this documentation</a></li>
<li><a href="synopsis.html" class="nav-synopsis">Usage and example</a></li>
</ul>
<hr class="line">
<ul>
<li><a href="assert.html" class="nav-assert">Assertion testing</a></li>
<li><a href="async_context.html" class="nav-async_context">Asynchronous context tracking</a></li>
<li><a href="async_hooks.html" class="nav-async_hooks">Async hooks</a></li>
<li><a href="buffer.html" class="nav-buffer">Buffer</a></li>
<li><a href="addons.html" class="nav-addons">C++ addons</a></li>
<li><a href="n-api.html" class="nav-n-api">C/C++ addons with Node-API</a></li>
<li><a href="embedding.html" class="nav-embedding">C++ embedder API</a></li>
<li><a href="child_process.html" class="nav-child_process">Child processes</a></li>
<li><a href="cluster.html" class="nav-cluster">Cluster</a></li>
<li><a href="cli.html" class="nav-cli">Command-line options</a></li>
<li><a href="console.html" class="nav-console">Console</a></li>
<li><a href="corepack.html" class="nav-corepack">Corepack</a></li>
<li><a href="crypto.html" class="nav-crypto">Crypto</a></li>
<li><a href="debugger.html" class="nav-debugger">Debugger</a></li>
<li><a href="deprecations.html" class="nav-deprecations">Deprecated APIs</a></li>
<li><a href="diagnostics_channel.html" class="nav-diagnostics_channel">Diagnostics Channel</a></li>
<li><a href="dns.html" class="nav-dns">DNS</a></li>
<li><a href="domain.html" class="nav-domain">Domain</a></li>
<li><a href="errors.html" class="nav-errors">Errors</a></li>
<li><a href="events.html" class="nav-events">Events</a></li>
<li><a href="fs.html" class="nav-fs">File system</a></li>
<li><a href="globals.html" class="nav-globals">Globals</a></li>
<li><a href="http.html" class="nav-http">HTTP</a></li>
<li><a href="http2.html" class="nav-http2">HTTP/2</a></li>
<li><a href="https.html" class="nav-https">HTTPS</a></li>
<li><a href="inspector.html" class="nav-inspector">Inspector</a></li>
<li><a href="intl.html" class="nav-intl">Internationalization</a></li>
<li><a href="modules.html" class="nav-modules">Modules: CommonJS modules</a></li>
<li><a href="esm.html" class="nav-esm">Modules: ECMAScript modules</a></li>
<li><a href="module.html" class="nav-module">Modules: <code>node:module</code> API</a></li>
<li><a href="packages.html" class="nav-packages">Modules: Packages</a></li>
<li><a href="typescript.html" class="nav-typescript">Modules: TypeScript</a></li>
<li><a href="net.html" class="nav-net">Net</a></li>
<li><a href="os.html" class="nav-os">OS</a></li>
<li><a href="path.html" class="nav-path">Path</a></li>
<li><a href="perf_hooks.html" class="nav-perf_hooks">Performance hooks</a></li>
<li><a href="permissions.html" class="nav-permissions">Permissions</a></li>
<li><a href="process.html" class="nav-process">Process</a></li>
<li><a href="punycode.html" class="nav-punycode">Punycode</a></li>
<li><a href="querystring.html" class="nav-querystring">Query strings</a></li>
<li><a href="readline.html" class="nav-readline">Readline</a></li>
<li><a href="repl.html" class="nav-repl">REPL</a></li>
<li><a href="report.html" class="nav-report">Report</a></li>
<li><a href="single-executable-applications.html" class="nav-single-executable-applications">Single executable applications</a></li>
<li><a href="sqlite.html" class="nav-sqlite">SQLite</a></li>
<li><a href="stream.html" class="nav-stream">Stream</a></li>
<li><a href="string_decoder.html" class="nav-string_decoder">String decoder</a></li>
<li><a href="test.html" class="nav-test">Test runner</a></li>
<li><a href="timers.html" class="nav-timers">Timers</a></li>
<li><a href="tls.html" class="nav-tls">TLS/SSL</a></li>
<li><a href="tracing.html" class="nav-tracing">Trace events</a></li>
<li><a href="tty.html" class="nav-tty">TTY</a></li>
<li><a href="dgram.html" class="nav-dgram">UDP/datagram</a></li>
<li><a href="url.html" class="nav-url">URL</a></li>
<li><a href="util.html" class="nav-util">Utilities</a></li>
<li><a href="v8.html" class="nav-v8">V8</a></li>
<li><a href="vm.html" class="nav-vm">VM</a></li>
<li><a href="wasi.html" class="nav-wasi">WASI</a></li>
<li><a href="webcrypto.html" class="nav-webcrypto">Web Crypto API</a></li>
<li><a href="webstreams.html" class="nav-webstreams">Web Streams API</a></li>
<li><a href="worker_threads.html" class="nav-worker_threads">Worker threads</a></li>
<li><a href="zlib.html" class="nav-zlib active">Zlib</a></li>
</ul>
<hr class="line">
<ul>
<li><a href="https://github.com/nodejs/node" class="nav-https-github-com-nodejs-node">Code repository and issue tracker</a></li>
</ul>
</div>
<div id="column1" data-id="zlib" class="interior">
<header class="header">
<div class="header-container">
<h1>Node.js v22.14.0 documentation</h1>
<button class="theme-toggle-btn" id="theme-toggle-btn" title="Toggle dark mode/light mode" aria-label="Toggle dark mode/light mode" hidden>
<svg xmlns="http://www.w3.org/2000/svg" class="icon dark-icon" height="24" width="24">
<path fill="none" d="M0 0h24v24H0z" />
<path d="M11.1 12.08c-2.33-4.51-.5-8.48.53-10.07C6.27 2.2 1.98 6.59 1.98 12c0 .14.02.28.02.42.62-.27 1.29-.42 2-.42 1.66 0 3.18.83 4.1 2.15A4.01 4.01 0 0111 18c0 1.52-.87 2.83-2.12 3.51.98.32 2.03.5 3.11.5 3.5 0 6.58-1.8 8.37-4.52-2.36.23-6.98-.97-9.26-5.41z"/>
<path d="M7 16h-.18C6.4 14.84 5.3 14 4 14c-1.66 0-3 1.34-3 3s1.34 3 3 3h3c1.1 0 2-.9 2-2s-.9-2-2-2z"/>
</svg>
<svg xmlns="http://www.w3.org/2000/svg" class="icon light-icon" height="24" width="24">
<path d="M0 0h24v24H0z" fill="none" />
<path d="M6.76 4.84l-1.8-1.79-1.41 1.41 1.79 1.79 1.42-1.41zM4 10.5H1v2h3v-2zm9-9.95h-2V3.5h2V.55zm7.45 3.91l-1.41-1.41-1.79 1.79 1.41 1.41 1.79-1.79zm-3.21 13.7l1.79 1.8 1.41-1.41-1.8-1.79-1.4 1.4zM20 10.5v2h3v-2h-3zm-8-5c-3.31 0-6 2.69-6 6s2.69 6 6 6 6-2.69 6-6-2.69-6-6-6zm-1 16.95h2V19.5h-2v2.95zm-7.45-3.91l1.41 1.41 1.79-1.8-1.41-1.41-1.79 1.8z"/>
</svg>
</button>
</div>
<div id="gtoc">
<ul>
<li class="pinned-header">Node.js v22.14.0</li>
<li class="picker-header">
<a href="#toc-picker" aria-controls="toc-picker">
<span class="picker-arrow"></span>
Table of contents
</a>
<div class="picker" tabindex="-1"><div class="toc"><ul id="toc-picker">
<li><span class="stability_2"><a href="#zlib">Zlib</a></span>
<ul>
<li><a href="#threadpool-usage-and-performance-considerations">Threadpool usage and performance considerations</a></li>
<li><a href="#compressing-http-requests-and-responses">Compressing HTTP requests and responses</a></li>
<li><a href="#memory-usage-tuning">Memory usage tuning</a>
<ul>
<li><a href="#for-zlib-based-streams">For zlib-based streams</a></li>
<li><a href="#for-brotli-based-streams">For Brotli-based streams</a></li>
</ul>
</li>
<li><a href="#flushing">Flushing</a></li>
<li><a href="#constants">Constants</a>
<ul>
<li><a href="#zlib-constants">zlib constants</a></li>
<li><a href="#brotli-constants">Brotli constants</a>
<ul>
<li><a href="#flush-operations">Flush operations</a></li>
<li><a href="#compressor-options">Compressor options</a></li>
<li><a href="#decompressor-options">Decompressor options</a></li>
</ul>
</li>
</ul>
</li>
<li><a href="#class-options">Class: <code>Options</code></a></li>
<li><a href="#class-brotlioptions">Class: <code>BrotliOptions</code></a></li>
<li><a href="#class-zlibbrotlicompress">Class: <code>zlib.BrotliCompress</code></a></li>
<li><a href="#class-zlibbrotlidecompress">Class: <code>zlib.BrotliDecompress</code></a></li>
<li><a href="#class-zlibdeflate">Class: <code>zlib.Deflate</code></a></li>
<li><a href="#class-zlibdeflateraw">Class: <code>zlib.DeflateRaw</code></a></li>
<li><a href="#class-zlibgunzip">Class: <code>zlib.Gunzip</code></a></li>
<li><a href="#class-zlibgzip">Class: <code>zlib.Gzip</code></a></li>
<li><a href="#class-zlibinflate">Class: <code>zlib.Inflate</code></a></li>
<li><a href="#class-zlibinflateraw">Class: <code>zlib.InflateRaw</code></a></li>
<li><a href="#class-zlibunzip">Class: <code>zlib.Unzip</code></a></li>
<li><a href="#class-zlibzlibbase">Class: <code>zlib.ZlibBase</code></a>
<ul>
<li><span class="stability_0"><a href="#zlibbytesread"><code>zlib.bytesRead</code></a></span></li>
<li><a href="#zlibbyteswritten"><code>zlib.bytesWritten</code></a></li>
<li><a href="#zlibclosecallback"><code>zlib.close([callback])</code></a></li>
<li><a href="#zlibflushkind-callback"><code>zlib.flush([kind, ]callback)</code></a></li>
<li><a href="#zlibparamslevel-strategy-callback"><code>zlib.params(level, strategy, callback)</code></a></li>
<li><a href="#zlibreset"><code>zlib.reset()</code></a></li>
</ul>
</li>
<li><a href="#zlibconstants"><code>zlib.constants</code></a></li>
<li><a href="#zlibcrc32data-value"><code>zlib.crc32(data[, value])</code></a></li>
<li><a href="#zlibcreatebrotlicompressoptions"><code>zlib.createBrotliCompress([options])</code></a></li>
<li><a href="#zlibcreatebrotlidecompressoptions"><code>zlib.createBrotliDecompress([options])</code></a></li>
<li><a href="#zlibcreatedeflateoptions"><code>zlib.createDeflate([options])</code></a></li>
<li><a href="#zlibcreatedeflaterawoptions"><code>zlib.createDeflateRaw([options])</code></a></li>
<li><a href="#zlibcreategunzipoptions"><code>zlib.createGunzip([options])</code></a></li>
<li><a href="#zlibcreategzipoptions"><code>zlib.createGzip([options])</code></a></li>
<li><a href="#zlibcreateinflateoptions"><code>zlib.createInflate([options])</code></a></li>
<li><a href="#zlibcreateinflaterawoptions"><code>zlib.createInflateRaw([options])</code></a></li>
<li><a href="#zlibcreateunzipoptions"><code>zlib.createUnzip([options])</code></a></li>
<li><a href="#convenience-methods">Convenience methods</a>
<ul>
<li><a href="#zlibbrotlicompressbuffer-options-callback"><code>zlib.brotliCompress(buffer[, options], callback)</code></a></li>
<li><a href="#zlibbrotlicompresssyncbuffer-options"><code>zlib.brotliCompressSync(buffer[, options])</code></a></li>
<li><a href="#zlibbrotlidecompressbuffer-options-callback"><code>zlib.brotliDecompress(buffer[, options], callback)</code></a></li>
<li><a href="#zlibbrotlidecompresssyncbuffer-options"><code>zlib.brotliDecompressSync(buffer[, options])</code></a></li>
<li><a href="#zlibdeflatebuffer-options-callback"><code>zlib.deflate(buffer[, options], callback)</code></a></li>
<li><a href="#zlibdeflatesyncbuffer-options"><code>zlib.deflateSync(buffer[, options])</code></a></li>
<li><a href="#zlibdeflaterawbuffer-options-callback"><code>zlib.deflateRaw(buffer[, options], callback)</code></a></li>
<li><a href="#zlibdeflaterawsyncbuffer-options"><code>zlib.deflateRawSync(buffer[, options])</code></a></li>
<li><a href="#zlibgunzipbuffer-options-callback"><code>zlib.gunzip(buffer[, options], callback)</code></a></li>
<li><a href="#zlibgunzipsyncbuffer-options"><code>zlib.gunzipSync(buffer[, options])</code></a></li>
<li><a href="#zlibgzipbuffer-options-callback"><code>zlib.gzip(buffer[, options], callback)</code></a></li>
<li><a href="#zlibgzipsyncbuffer-options"><code>zlib.gzipSync(buffer[, options])</code></a></li>
<li><a href="#zlibinflatebuffer-options-callback"><code>zlib.inflate(buffer[, options], callback)</code></a></li>
<li><a href="#zlibinflatesyncbuffer-options"><code>zlib.inflateSync(buffer[, options])</code></a></li>
<li><a href="#zlibinflaterawbuffer-options-callback"><code>zlib.inflateRaw(buffer[, options], callback)</code></a></li>
<li><a href="#zlibinflaterawsyncbuffer-options"><code>zlib.inflateRawSync(buffer[, options])</code></a></li>
<li><a href="#zlibunzipbuffer-options-callback"><code>zlib.unzip(buffer[, options], callback)</code></a></li>
<li><a href="#zlibunzipsyncbuffer-options"><code>zlib.unzipSync(buffer[, options])</code></a></li>
</ul>
</li>
</ul>
</li>
</ul></div></div>
</li>
<li class="picker-header">
<a href="#gtoc-picker" aria-controls="gtoc-picker">
<span class="picker-arrow"></span>
Index
</a>
<div class="picker" tabindex="-1" id="gtoc-picker"><ul>
<li><a href="documentation.html" class="nav-documentation">About this documentation</a></li>
<li><a href="synopsis.html" class="nav-synopsis">Usage and example</a></li>
<li>
<a href="index.html">Index</a>
</li>
</ul>
<hr class="line">
<ul>
<li><a href="assert.html" class="nav-assert">Assertion testing</a></li>
<li><a href="async_context.html" class="nav-async_context">Asynchronous context tracking</a></li>
<li><a href="async_hooks.html" class="nav-async_hooks">Async hooks</a></li>
<li><a href="buffer.html" class="nav-buffer">Buffer</a></li>
<li><a href="addons.html" class="nav-addons">C++ addons</a></li>
<li><a href="n-api.html" class="nav-n-api">C/C++ addons with Node-API</a></li>
<li><a href="embedding.html" class="nav-embedding">C++ embedder API</a></li>
<li><a href="child_process.html" class="nav-child_process">Child processes</a></li>
<li><a href="cluster.html" class="nav-cluster">Cluster</a></li>
<li><a href="cli.html" class="nav-cli">Command-line options</a></li>
<li><a href="console.html" class="nav-console">Console</a></li>
<li><a href="corepack.html" class="nav-corepack">Corepack</a></li>
<li><a href="crypto.html" class="nav-crypto">Crypto</a></li>
<li><a href="debugger.html" class="nav-debugger">Debugger</a></li>
<li><a href="deprecations.html" class="nav-deprecations">Deprecated APIs</a></li>
<li><a href="diagnostics_channel.html" class="nav-diagnostics_channel">Diagnostics Channel</a></li>
<li><a href="dns.html" class="nav-dns">DNS</a></li>
<li><a href="domain.html" class="nav-domain">Domain</a></li>
<li><a href="errors.html" class="nav-errors">Errors</a></li>
<li><a href="events.html" class="nav-events">Events</a></li>
<li><a href="fs.html" class="nav-fs">File system</a></li>
<li><a href="globals.html" class="nav-globals">Globals</a></li>
<li><a href="http.html" class="nav-http">HTTP</a></li>
<li><a href="http2.html" class="nav-http2">HTTP/2</a></li>
<li><a href="https.html" class="nav-https">HTTPS</a></li>
<li><a href="inspector.html" class="nav-inspector">Inspector</a></li>
<li><a href="intl.html" class="nav-intl">Internationalization</a></li>
<li><a href="modules.html" class="nav-modules">Modules: CommonJS modules</a></li>
<li><a href="esm.html" class="nav-esm">Modules: ECMAScript modules</a></li>
<li><a href="module.html" class="nav-module">Modules: <code>node:module</code> API</a></li>
<li><a href="packages.html" class="nav-packages">Modules: Packages</a></li>
<li><a href="typescript.html" class="nav-typescript">Modules: TypeScript</a></li>
<li><a href="net.html" class="nav-net">Net</a></li>
<li><a href="os.html" class="nav-os">OS</a></li>
<li><a href="path.html" class="nav-path">Path</a></li>
<li><a href="perf_hooks.html" class="nav-perf_hooks">Performance hooks</a></li>
<li><a href="permissions.html" class="nav-permissions">Permissions</a></li>
<li><a href="process.html" class="nav-process">Process</a></li>
<li><a href="punycode.html" class="nav-punycode">Punycode</a></li>
<li><a href="querystring.html" class="nav-querystring">Query strings</a></li>
<li><a href="readline.html" class="nav-readline">Readline</a></li>
<li><a href="repl.html" class="nav-repl">REPL</a></li>
<li><a href="report.html" class="nav-report">Report</a></li>
<li><a href="single-executable-applications.html" class="nav-single-executable-applications">Single executable applications</a></li>
<li><a href="sqlite.html" class="nav-sqlite">SQLite</a></li>
<li><a href="stream.html" class="nav-stream">Stream</a></li>
<li><a href="string_decoder.html" class="nav-string_decoder">String decoder</a></li>
<li><a href="test.html" class="nav-test">Test runner</a></li>
<li><a href="timers.html" class="nav-timers">Timers</a></li>
<li><a href="tls.html" class="nav-tls">TLS/SSL</a></li>
<li><a href="tracing.html" class="nav-tracing">Trace events</a></li>
<li><a href="tty.html" class="nav-tty">TTY</a></li>
<li><a href="dgram.html" class="nav-dgram">UDP/datagram</a></li>
<li><a href="url.html" class="nav-url">URL</a></li>
<li><a href="util.html" class="nav-util">Utilities</a></li>
<li><a href="v8.html" class="nav-v8">V8</a></li>
<li><a href="vm.html" class="nav-vm">VM</a></li>
<li><a href="wasi.html" class="nav-wasi">WASI</a></li>
<li><a href="webcrypto.html" class="nav-webcrypto">Web Crypto API</a></li>
<li><a href="webstreams.html" class="nav-webstreams">Web Streams API</a></li>
<li><a href="worker_threads.html" class="nav-worker_threads">Worker threads</a></li>
<li><a href="zlib.html" class="nav-zlib active">Zlib</a></li>
</ul>
<hr class="line">
<ul>
<li><a href="https://github.com/nodejs/node" class="nav-https-github-com-nodejs-node">Code repository and issue tracker</a></li>
</ul></div>
</li>
<li class="picker-header">
<a href="#alt-docs" aria-controls="alt-docs">
<span class="picker-arrow"></span>
Other versions
</a>
<div class="picker" tabindex="-1"><ol id="alt-docs"><li><a href="https://nodejs.org/docs/latest-v23.x/api/zlib.html">23.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v22.x/api/zlib.html">22.x <b>LTS</b></a></li>
<li><a href="https://nodejs.org/docs/latest-v21.x/api/zlib.html">21.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v20.x/api/zlib.html">20.x <b>LTS</b></a></li>
<li><a href="https://nodejs.org/docs/latest-v19.x/api/zlib.html">19.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v18.x/api/zlib.html">18.x <b>LTS</b></a></li>
<li><a href="https://nodejs.org/docs/latest-v17.x/api/zlib.html">17.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v16.x/api/zlib.html">16.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v15.x/api/zlib.html">15.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v14.x/api/zlib.html">14.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v13.x/api/zlib.html">13.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v12.x/api/zlib.html">12.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v11.x/api/zlib.html">11.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v10.x/api/zlib.html">10.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v9.x/api/zlib.html">9.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v8.x/api/zlib.html">8.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v7.x/api/zlib.html">7.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v6.x/api/zlib.html">6.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v5.x/api/zlib.html">5.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v4.x/api/zlib.html">4.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v0.12.x/api/zlib.html">0.12.x</a></li>
<li><a href="https://nodejs.org/docs/latest-v0.10.x/api/zlib.html">0.10.x</a></li></ol></div>
</li>
<li class="picker-header">
<a href="#options-picker" aria-controls="options-picker">
<span class="picker-arrow"></span>
Options
</a>
<div class="picker" tabindex="-1">
<ul id="options-picker">
<li>
<a href="all.html">View on single page</a>
</li>
<li>
<a href="zlib.json">View as JSON</a>
</li>
<li class="edit_on_github"><a href="https://github.com/nodejs/node/edit/main/doc/api/zlib.md">Edit on GitHub</a></li>
</ul>
</div>
</li>
</ul>
</div>
<hr>
</header>
<details role="navigation" id="toc" open><summary>Table of contents</summary><ul>
<li><span class="stability_2"><a href="#zlib">Zlib</a></span>
<ul>
<li><a href="#threadpool-usage-and-performance-considerations">Threadpool usage and performance considerations</a></li>
<li><a href="#compressing-http-requests-and-responses">Compressing HTTP requests and responses</a></li>
<li><a href="#memory-usage-tuning">Memory usage tuning</a>
<ul>
<li><a href="#for-zlib-based-streams">For zlib-based streams</a></li>
<li><a href="#for-brotli-based-streams">For Brotli-based streams</a></li>
</ul>
</li>
<li><a href="#flushing">Flushing</a></li>
<li><a href="#constants">Constants</a>
<ul>
<li><a href="#zlib-constants">zlib constants</a></li>
<li><a href="#brotli-constants">Brotli constants</a>
<ul>
<li><a href="#flush-operations">Flush operations</a></li>
<li><a href="#compressor-options">Compressor options</a></li>
<li><a href="#decompressor-options">Decompressor options</a></li>
</ul>
</li>
</ul>
</li>
<li><a href="#class-options">Class: <code>Options</code></a></li>
<li><a href="#class-brotlioptions">Class: <code>BrotliOptions</code></a></li>
<li><a href="#class-zlibbrotlicompress">Class: <code>zlib.BrotliCompress</code></a></li>
<li><a href="#class-zlibbrotlidecompress">Class: <code>zlib.BrotliDecompress</code></a></li>
<li><a href="#class-zlibdeflate">Class: <code>zlib.Deflate</code></a></li>
<li><a href="#class-zlibdeflateraw">Class: <code>zlib.DeflateRaw</code></a></li>
<li><a href="#class-zlibgunzip">Class: <code>zlib.Gunzip</code></a></li>
<li><a href="#class-zlibgzip">Class: <code>zlib.Gzip</code></a></li>
<li><a href="#class-zlibinflate">Class: <code>zlib.Inflate</code></a></li>
<li><a href="#class-zlibinflateraw">Class: <code>zlib.InflateRaw</code></a></li>
<li><a href="#class-zlibunzip">Class: <code>zlib.Unzip</code></a></li>
<li><a href="#class-zlibzlibbase">Class: <code>zlib.ZlibBase</code></a>
<ul>
<li><span class="stability_0"><a href="#zlibbytesread"><code>zlib.bytesRead</code></a></span></li>
<li><a href="#zlibbyteswritten"><code>zlib.bytesWritten</code></a></li>
<li><a href="#zlibclosecallback"><code>zlib.close([callback])</code></a></li>
<li><a href="#zlibflushkind-callback"><code>zlib.flush([kind, ]callback)</code></a></li>
<li><a href="#zlibparamslevel-strategy-callback"><code>zlib.params(level, strategy, callback)</code></a></li>
<li><a href="#zlibreset"><code>zlib.reset()</code></a></li>
</ul>
</li>
<li><a href="#zlibconstants"><code>zlib.constants</code></a></li>
<li><a href="#zlibcrc32data-value"><code>zlib.crc32(data[, value])</code></a></li>
<li><a href="#zlibcreatebrotlicompressoptions"><code>zlib.createBrotliCompress([options])</code></a></li>
<li><a href="#zlibcreatebrotlidecompressoptions"><code>zlib.createBrotliDecompress([options])</code></a></li>
<li><a href="#zlibcreatedeflateoptions"><code>zlib.createDeflate([options])</code></a></li>
<li><a href="#zlibcreatedeflaterawoptions"><code>zlib.createDeflateRaw([options])</code></a></li>
<li><a href="#zlibcreategunzipoptions"><code>zlib.createGunzip([options])</code></a></li>
<li><a href="#zlibcreategzipoptions"><code>zlib.createGzip([options])</code></a></li>
<li><a href="#zlibcreateinflateoptions"><code>zlib.createInflate([options])</code></a></li>
<li><a href="#zlibcreateinflaterawoptions"><code>zlib.createInflateRaw([options])</code></a></li>
<li><a href="#zlibcreateunzipoptions"><code>zlib.createUnzip([options])</code></a></li>
<li><a href="#convenience-methods">Convenience methods</a>
<ul>
<li><a href="#zlibbrotlicompressbuffer-options-callback"><code>zlib.brotliCompress(buffer[, options], callback)</code></a></li>
<li><a href="#zlibbrotlicompresssyncbuffer-options"><code>zlib.brotliCompressSync(buffer[, options])</code></a></li>
<li><a href="#zlibbrotlidecompressbuffer-options-callback"><code>zlib.brotliDecompress(buffer[, options], callback)</code></a></li>
<li><a href="#zlibbrotlidecompresssyncbuffer-options"><code>zlib.brotliDecompressSync(buffer[, options])</code></a></li>
<li><a href="#zlibdeflatebuffer-options-callback"><code>zlib.deflate(buffer[, options], callback)</code></a></li>
<li><a href="#zlibdeflatesyncbuffer-options"><code>zlib.deflateSync(buffer[, options])</code></a></li>
<li><a href="#zlibdeflaterawbuffer-options-callback"><code>zlib.deflateRaw(buffer[, options], callback)</code></a></li>
<li><a href="#zlibdeflaterawsyncbuffer-options"><code>zlib.deflateRawSync(buffer[, options])</code></a></li>
<li><a href="#zlibgunzipbuffer-options-callback"><code>zlib.gunzip(buffer[, options], callback)</code></a></li>
<li><a href="#zlibgunzipsyncbuffer-options"><code>zlib.gunzipSync(buffer[, options])</code></a></li>
<li><a href="#zlibgzipbuffer-options-callback"><code>zlib.gzip(buffer[, options], callback)</code></a></li>
<li><a href="#zlibgzipsyncbuffer-options"><code>zlib.gzipSync(buffer[, options])</code></a></li>
<li><a href="#zlibinflatebuffer-options-callback"><code>zlib.inflate(buffer[, options], callback)</code></a></li>
<li><a href="#zlibinflatesyncbuffer-options"><code>zlib.inflateSync(buffer[, options])</code></a></li>
<li><a href="#zlibinflaterawbuffer-options-callback"><code>zlib.inflateRaw(buffer[, options], callback)</code></a></li>
<li><a href="#zlibinflaterawsyncbuffer-options"><code>zlib.inflateRawSync(buffer[, options])</code></a></li>
<li><a href="#zlibunzipbuffer-options-callback"><code>zlib.unzip(buffer[, options], callback)</code></a></li>
<li><a href="#zlibunzipsyncbuffer-options"><code>zlib.unzipSync(buffer[, options])</code></a></li>
</ul>
</li>
</ul>
</li>
</ul></details>
<div role="main" id="apicontent">
<h2>Zlib<span><a class="mark" href="#zlib" id="zlib">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib"></a></h2>
<p></p><div class="api_stability api_stability_2"><a href="documentation.html#stability-index">Stability: 2</a> - Stable</div><p></p>
<p><strong>Source Code:</strong> <a href="https://github.com/nodejs/node/blob/v22.14.0/lib/zlib.js">lib/zlib.js</a></p>
<p>The <code>node:zlib</code> module provides compression functionality implemented using
Gzip, Deflate/Inflate, and Brotli.</p>
<p>To access it:</p>
<pre class="with-34-chars"><input class="js-flavor-toggle" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> os <span class="hljs-keyword">from</span> <span class="hljs-string">'node:zlib'</span>;</code><code class="language-js cjs"><span class="hljs-keyword">const</span> zlib = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:zlib'</span>);</code><button class="copy-button">copy</button></pre>
<p>Compression and decompression are built around the Node.js <a href="stream.html">Streams API</a>.</p>
<p>Compressing or decompressing a stream (such as a file) can be accomplished by
piping the source stream through a <code>zlib</code> <code>Transform</code> stream into a destination
stream:</p>
<pre class="with-19-chars"><input class="js-flavor-toggle" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> {
createReadStream,
createWriteStream,
} <span class="hljs-keyword">from</span> <span class="hljs-string">'node:fs'</span>;
<span class="hljs-keyword">import</span> process <span class="hljs-keyword">from</span> <span class="hljs-string">'node:process'</span>;
<span class="hljs-keyword">import</span> { createGzip } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:zlib'</span>;
<span class="hljs-keyword">import</span> { pipeline } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream'</span>;
<span class="hljs-keyword">const</span> gzip = <span class="hljs-title function_">createGzip</span>();
<span class="hljs-keyword">const</span> source = <span class="hljs-title function_">createReadStream</span>(<span class="hljs-string">'input.txt'</span>);
<span class="hljs-keyword">const</span> destination = <span class="hljs-title function_">createWriteStream</span>(<span class="hljs-string">'input.txt.gz'</span>);
<span class="hljs-title function_">pipeline</span>(source, gzip, destination, <span class="hljs-function">(<span class="hljs-params">err</span>) =></span> {
<span class="hljs-keyword">if</span> (err) {
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'An error occurred:'</span>, err);
process.<span class="hljs-property">exitCode</span> = <span class="hljs-number">1</span>;
}
});</code><code class="language-js cjs"><span class="hljs-keyword">const</span> {
createReadStream,
createWriteStream,
} = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:fs'</span>);
<span class="hljs-keyword">const</span> process = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:process'</span>);
<span class="hljs-keyword">const</span> { createGzip } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:zlib'</span>);
<span class="hljs-keyword">const</span> { pipeline } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream'</span>);
<span class="hljs-keyword">const</span> gzip = <span class="hljs-title function_">createGzip</span>();
<span class="hljs-keyword">const</span> source = <span class="hljs-title function_">createReadStream</span>(<span class="hljs-string">'input.txt'</span>);
<span class="hljs-keyword">const</span> destination = <span class="hljs-title function_">createWriteStream</span>(<span class="hljs-string">'input.txt.gz'</span>);
<span class="hljs-title function_">pipeline</span>(source, gzip, destination, <span class="hljs-function">(<span class="hljs-params">err</span>) =></span> {
<span class="hljs-keyword">if</span> (err) {
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'An error occurred:'</span>, err);
process.<span class="hljs-property">exitCode</span> = <span class="hljs-number">1</span>;
}
});</code><button class="copy-button">copy</button></pre>
<p>Or, using the promise <code>pipeline</code> API:</p>
<pre class="with-19-chars"><input class="js-flavor-toggle" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> {
createReadStream,
createWriteStream,
} <span class="hljs-keyword">from</span> <span class="hljs-string">'node:fs'</span>;
<span class="hljs-keyword">import</span> process <span class="hljs-keyword">from</span> <span class="hljs-string">'node:process'</span>;
<span class="hljs-keyword">import</span> { createGzip } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:zlib'</span>;
<span class="hljs-keyword">import</span> { pipeline } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream/promises'</span>;
<span class="hljs-keyword">async</span> <span class="hljs-keyword">function</span> <span class="hljs-title function_">do_gzip</span>(<span class="hljs-params">input, output</span>) {
<span class="hljs-keyword">const</span> gzip = <span class="hljs-title function_">createGzip</span>();
<span class="hljs-keyword">const</span> source = <span class="hljs-title function_">createReadStream</span>(input);
<span class="hljs-keyword">const</span> destination = <span class="hljs-title function_">createWriteStream</span>(output);
<span class="hljs-keyword">await</span> <span class="hljs-title function_">pipeline</span>(source, gzip, destination);
}
<span class="hljs-keyword">await</span> <span class="hljs-title function_">do_gzip</span>(<span class="hljs-string">'input.txt'</span>, <span class="hljs-string">'input.txt.gz'</span>);</code><code class="language-js cjs"><span class="hljs-keyword">const</span> {
createReadStream,
createWriteStream,
} = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:fs'</span>);
<span class="hljs-keyword">const</span> process = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:process'</span>);
<span class="hljs-keyword">const</span> { createGzip } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:zlib'</span>);
<span class="hljs-keyword">const</span> { pipeline } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream/promises'</span>);
<span class="hljs-keyword">async</span> <span class="hljs-keyword">function</span> <span class="hljs-title function_">do_gzip</span>(<span class="hljs-params">input, output</span>) {
<span class="hljs-keyword">const</span> gzip = <span class="hljs-title function_">createGzip</span>();
<span class="hljs-keyword">const</span> source = <span class="hljs-title function_">createReadStream</span>(input);
<span class="hljs-keyword">const</span> destination = <span class="hljs-title function_">createWriteStream</span>(output);
<span class="hljs-keyword">await</span> <span class="hljs-title function_">pipeline</span>(source, gzip, destination);
}
<span class="hljs-title function_">do_gzip</span>(<span class="hljs-string">'input.txt'</span>, <span class="hljs-string">'input.txt.gz'</span>)
.<span class="hljs-title function_">catch</span>(<span class="hljs-function">(<span class="hljs-params">err</span>) =></span> {
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'An error occurred:'</span>, err);
process.<span class="hljs-property">exitCode</span> = <span class="hljs-number">1</span>;
});</code><button class="copy-button">copy</button></pre>
<p>It is also possible to compress or decompress data in a single step:</p>
<pre class="with-48-chars"><input class="js-flavor-toggle" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> process <span class="hljs-keyword">from</span> <span class="hljs-string">'node:process'</span>;
<span class="hljs-keyword">import</span> { <span class="hljs-title class_">Buffer</span> } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:buffer'</span>;
<span class="hljs-keyword">import</span> { deflate, unzip } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:zlib'</span>;
<span class="hljs-keyword">const</span> input = <span class="hljs-string">'.................................'</span>;
<span class="hljs-title function_">deflate</span>(input, <span class="hljs-function">(<span class="hljs-params">err, buffer</span>) =></span> {
<span class="hljs-keyword">if</span> (err) {
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'An error occurred:'</span>, err);
process.<span class="hljs-property">exitCode</span> = <span class="hljs-number">1</span>;
}
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(buffer.<span class="hljs-title function_">toString</span>(<span class="hljs-string">'base64'</span>));
});
<span class="hljs-keyword">const</span> buffer = <span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>(<span class="hljs-string">'eJzT0yMAAGTvBe8='</span>, <span class="hljs-string">'base64'</span>);
<span class="hljs-title function_">unzip</span>(buffer, <span class="hljs-function">(<span class="hljs-params">err, buffer</span>) =></span> {
<span class="hljs-keyword">if</span> (err) {
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'An error occurred:'</span>, err);
process.<span class="hljs-property">exitCode</span> = <span class="hljs-number">1</span>;
}
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(buffer.<span class="hljs-title function_">toString</span>());
});
<span class="hljs-comment">// Or, Promisified</span>
<span class="hljs-keyword">import</span> { promisify } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:util'</span>;
<span class="hljs-keyword">const</span> do_unzip = <span class="hljs-title function_">promisify</span>(unzip);
<span class="hljs-keyword">const</span> unzippedBuffer = <span class="hljs-keyword">await</span> <span class="hljs-title function_">do_unzip</span>(buffer);
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(unzippedBuffer.<span class="hljs-title function_">toString</span>());</code><code class="language-js cjs"><span class="hljs-keyword">const</span> { deflate, unzip } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:zlib'</span>);
<span class="hljs-keyword">const</span> input = <span class="hljs-string">'.................................'</span>;
<span class="hljs-title function_">deflate</span>(input, <span class="hljs-function">(<span class="hljs-params">err, buffer</span>) =></span> {
<span class="hljs-keyword">if</span> (err) {
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'An error occurred:'</span>, err);
process.<span class="hljs-property">exitCode</span> = <span class="hljs-number">1</span>;
}
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(buffer.<span class="hljs-title function_">toString</span>(<span class="hljs-string">'base64'</span>));
});
<span class="hljs-keyword">const</span> buffer = <span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>(<span class="hljs-string">'eJzT0yMAAGTvBe8='</span>, <span class="hljs-string">'base64'</span>);
<span class="hljs-title function_">unzip</span>(buffer, <span class="hljs-function">(<span class="hljs-params">err, buffer</span>) =></span> {
<span class="hljs-keyword">if</span> (err) {
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'An error occurred:'</span>, err);
process.<span class="hljs-property">exitCode</span> = <span class="hljs-number">1</span>;
}
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(buffer.<span class="hljs-title function_">toString</span>());
});
<span class="hljs-comment">// Or, Promisified</span>
<span class="hljs-keyword">const</span> { promisify } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:util'</span>);
<span class="hljs-keyword">const</span> do_unzip = <span class="hljs-title function_">promisify</span>(unzip);
<span class="hljs-title function_">do_unzip</span>(buffer)
.<span class="hljs-title function_">then</span>(<span class="hljs-function">(<span class="hljs-params">buf</span>) =></span> <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(buf.<span class="hljs-title function_">toString</span>()))
.<span class="hljs-title function_">catch</span>(<span class="hljs-function">(<span class="hljs-params">err</span>) =></span> {
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'An error occurred:'</span>, err);
process.<span class="hljs-property">exitCode</span> = <span class="hljs-number">1</span>;
});</code><button class="copy-button">copy</button></pre>
<section><h3>Threadpool usage and performance considerations<span><a class="mark" href="#threadpool-usage-and-performance-considerations" id="threadpool-usage-and-performance-considerations">#</a></span><a aria-hidden="true" class="legacy" id="zlib_threadpool_usage_and_performance_considerations"></a></h3>
<p>All <code>zlib</code> APIs, except those that are explicitly synchronous, use the Node.js
internal threadpool. This can lead to surprising effects and performance
limitations in some applications.</p>
<p>Creating and using a large number of zlib objects simultaneously can cause
significant memory fragmentation.</p>
<pre class="with-37-chars"><input class="js-flavor-toggle" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> zlib <span class="hljs-keyword">from</span> <span class="hljs-string">'node:zlib'</span>;
<span class="hljs-keyword">import</span> { <span class="hljs-title class_">Buffer</span> } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:buffer'</span>;
<span class="hljs-keyword">const</span> payload = <span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>(<span class="hljs-string">'This is some data'</span>);
<span class="hljs-comment">// WARNING: DO NOT DO THIS!</span>
<span class="hljs-keyword">for</span> (<span class="hljs-keyword">let</span> i = <span class="hljs-number">0</span>; i < <span class="hljs-number">30000</span>; ++i) {
zlib.<span class="hljs-title function_">deflate</span>(payload, <span class="hljs-function">(<span class="hljs-params">err, buffer</span>) =></span> {});
}</code><code class="language-js cjs"><span class="hljs-keyword">const</span> zlib = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:zlib'</span>);
<span class="hljs-keyword">const</span> payload = <span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>(<span class="hljs-string">'This is some data'</span>);
<span class="hljs-comment">// WARNING: DO NOT DO THIS!</span>
<span class="hljs-keyword">for</span> (<span class="hljs-keyword">let</span> i = <span class="hljs-number">0</span>; i < <span class="hljs-number">30000</span>; ++i) {
zlib.<span class="hljs-title function_">deflate</span>(payload, <span class="hljs-function">(<span class="hljs-params">err, buffer</span>) =></span> {});
}</code><button class="copy-button">copy</button></pre>
<p>In the preceding example, 30,000 deflate instances are created concurrently.
Because of how some operating systems handle memory allocation and
deallocation, this may lead to significant memory fragmentation.</p>
<p>It is strongly recommended that the results of compression
operations be cached to avoid duplication of effort.</p>
</section><section><h3>Compressing HTTP requests and responses<span><a class="mark" href="#compressing-http-requests-and-responses" id="compressing-http-requests-and-responses">#</a></span><a aria-hidden="true" class="legacy" id="zlib_compressing_http_requests_and_responses"></a></h3>
<p>The <code>node:zlib</code> module can be used to implement support for the <code>gzip</code>, <code>deflate</code>
and <code>br</code> content-encoding mechanisms defined by
<a href="https://tools.ietf.org/html/rfc7230#section-4.2">HTTP</a>.</p>
<p>The HTTP <a href="https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.3"><code>Accept-Encoding</code></a> header is used within an HTTP request to identify
the compression encodings accepted by the client. The <a href="https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.11"><code>Content-Encoding</code></a>
header is used to identify the compression encodings actually applied to a
message.</p>
<p>The examples given below are drastically simplified to show the basic concept.
Using <code>zlib</code> encoding can be expensive, and the results ought to be cached.
See <a href="#memory-usage-tuning">Memory usage tuning</a> for more information on the speed/memory/compression
tradeoffs involved in <code>zlib</code> usage.</p>
<pre class="with-34-chars"><input class="js-flavor-toggle" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-comment">// Client request example</span>
<span class="hljs-keyword">import</span> fs <span class="hljs-keyword">from</span> <span class="hljs-string">'node:fs'</span>;
<span class="hljs-keyword">import</span> zlib <span class="hljs-keyword">from</span> <span class="hljs-string">'node:zlib'</span>;
<span class="hljs-keyword">import</span> http <span class="hljs-keyword">from</span> <span class="hljs-string">'node:http'</span>;
<span class="hljs-keyword">import</span> process <span class="hljs-keyword">from</span> <span class="hljs-string">'node:process'</span>;
<span class="hljs-keyword">import</span> { pipeline } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream'</span>;
<span class="hljs-keyword">const</span> request = http.<span class="hljs-title function_">get</span>({ <span class="hljs-attr">host</span>: <span class="hljs-string">'example.com'</span>,
<span class="hljs-attr">path</span>: <span class="hljs-string">'/'</span>,
<span class="hljs-attr">port</span>: <span class="hljs-number">80</span>,
<span class="hljs-attr">headers</span>: { <span class="hljs-string">'Accept-Encoding'</span>: <span class="hljs-string">'br,gzip,deflate'</span> } });
request.<span class="hljs-title function_">on</span>(<span class="hljs-string">'response'</span>, <span class="hljs-function">(<span class="hljs-params">response</span>) =></span> {
<span class="hljs-keyword">const</span> output = fs.<span class="hljs-title function_">createWriteStream</span>(<span class="hljs-string">'example.com_index.html'</span>);
<span class="hljs-keyword">const</span> <span class="hljs-title function_">onError</span> = (<span class="hljs-params">err</span>) => {
<span class="hljs-keyword">if</span> (err) {
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'An error occurred:'</span>, err);
process.<span class="hljs-property">exitCode</span> = <span class="hljs-number">1</span>;
}
};
<span class="hljs-keyword">switch</span> (response.<span class="hljs-property">headers</span>[<span class="hljs-string">'content-encoding'</span>]) {
<span class="hljs-keyword">case</span> <span class="hljs-string">'br'</span>:
<span class="hljs-title function_">pipeline</span>(response, zlib.<span class="hljs-title function_">createBrotliDecompress</span>(), output, onError);
<span class="hljs-keyword">break</span>;
<span class="hljs-comment">// Or, just use zlib.createUnzip() to handle both of the following cases:</span>
<span class="hljs-keyword">case</span> <span class="hljs-string">'gzip'</span>:
<span class="hljs-title function_">pipeline</span>(response, zlib.<span class="hljs-title function_">createGunzip</span>(), output, onError);
<span class="hljs-keyword">break</span>;
<span class="hljs-keyword">case</span> <span class="hljs-string">'deflate'</span>:
<span class="hljs-title function_">pipeline</span>(response, zlib.<span class="hljs-title function_">createInflate</span>(), output, onError);
<span class="hljs-keyword">break</span>;
<span class="hljs-attr">default</span>:
<span class="hljs-title function_">pipeline</span>(response, output, onError);
<span class="hljs-keyword">break</span>;
}
});</code><code class="language-js cjs"><span class="hljs-comment">// Client request example</span>
<span class="hljs-keyword">const</span> zlib = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:zlib'</span>);
<span class="hljs-keyword">const</span> http = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:http'</span>);
<span class="hljs-keyword">const</span> fs = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:fs'</span>);
<span class="hljs-keyword">const</span> { pipeline } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream'</span>);
<span class="hljs-keyword">const</span> request = http.<span class="hljs-title function_">get</span>({ <span class="hljs-attr">host</span>: <span class="hljs-string">'example.com'</span>,
<span class="hljs-attr">path</span>: <span class="hljs-string">'/'</span>,
<span class="hljs-attr">port</span>: <span class="hljs-number">80</span>,
<span class="hljs-attr">headers</span>: { <span class="hljs-string">'Accept-Encoding'</span>: <span class="hljs-string">'br,gzip,deflate'</span> } });
request.<span class="hljs-title function_">on</span>(<span class="hljs-string">'response'</span>, <span class="hljs-function">(<span class="hljs-params">response</span>) =></span> {
<span class="hljs-keyword">const</span> output = fs.<span class="hljs-title function_">createWriteStream</span>(<span class="hljs-string">'example.com_index.html'</span>);
<span class="hljs-keyword">const</span> <span class="hljs-title function_">onError</span> = (<span class="hljs-params">err</span>) => {
<span class="hljs-keyword">if</span> (err) {
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'An error occurred:'</span>, err);
process.<span class="hljs-property">exitCode</span> = <span class="hljs-number">1</span>;
}
};
<span class="hljs-keyword">switch</span> (response.<span class="hljs-property">headers</span>[<span class="hljs-string">'content-encoding'</span>]) {
<span class="hljs-keyword">case</span> <span class="hljs-string">'br'</span>:
<span class="hljs-title function_">pipeline</span>(response, zlib.<span class="hljs-title function_">createBrotliDecompress</span>(), output, onError);
<span class="hljs-keyword">break</span>;
<span class="hljs-comment">// Or, just use zlib.createUnzip() to handle both of the following cases:</span>
<span class="hljs-keyword">case</span> <span class="hljs-string">'gzip'</span>:
<span class="hljs-title function_">pipeline</span>(response, zlib.<span class="hljs-title function_">createGunzip</span>(), output, onError);
<span class="hljs-keyword">break</span>;
<span class="hljs-keyword">case</span> <span class="hljs-string">'deflate'</span>:
<span class="hljs-title function_">pipeline</span>(response, zlib.<span class="hljs-title function_">createInflate</span>(), output, onError);
<span class="hljs-keyword">break</span>;
<span class="hljs-attr">default</span>:
<span class="hljs-title function_">pipeline</span>(response, output, onError);
<span class="hljs-keyword">break</span>;
}
});</code><button class="copy-button">copy</button></pre>
<pre class="with-64-chars"><input class="js-flavor-toggle" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-comment">// server example</span>
<span class="hljs-comment">// Running a gzip operation on every request is quite expensive.</span>
<span class="hljs-comment">// It would be much more efficient to cache the compressed buffer.</span>
<span class="hljs-keyword">import</span> zlib <span class="hljs-keyword">from</span> <span class="hljs-string">'node:zlib'</span>;
<span class="hljs-keyword">import</span> http <span class="hljs-keyword">from</span> <span class="hljs-string">'node:http'</span>;
<span class="hljs-keyword">import</span> fs <span class="hljs-keyword">from</span> <span class="hljs-string">'node:fs'</span>;
<span class="hljs-keyword">import</span> { pipeline } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream'</span>;
http.<span class="hljs-title function_">createServer</span>(<span class="hljs-function">(<span class="hljs-params">request, response</span>) =></span> {
<span class="hljs-keyword">const</span> raw = fs.<span class="hljs-title function_">createReadStream</span>(<span class="hljs-string">'index.html'</span>);
<span class="hljs-comment">// Store both a compressed and an uncompressed version of the resource.</span>
response.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Vary'</span>, <span class="hljs-string">'Accept-Encoding'</span>);
<span class="hljs-keyword">const</span> acceptEncoding = request.<span class="hljs-property">headers</span>[<span class="hljs-string">'accept-encoding'</span>] || <span class="hljs-string">''</span>;
<span class="hljs-keyword">const</span> <span class="hljs-title function_">onError</span> = (<span class="hljs-params">err</span>) => {
<span class="hljs-keyword">if</span> (err) {
<span class="hljs-comment">// If an error occurs, there's not much we can do because</span>
<span class="hljs-comment">// the server has already sent the 200 response code and</span>
<span class="hljs-comment">// some amount of data has already been sent to the client.</span>
<span class="hljs-comment">// The best we can do is terminate the response immediately</span>
<span class="hljs-comment">// and log the error.</span>
response.<span class="hljs-title function_">end</span>();
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'An error occurred:'</span>, err);
}
};
<span class="hljs-comment">// Note: This is not a conformant accept-encoding parser.</span>
<span class="hljs-comment">// See https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.3</span>
<span class="hljs-keyword">if</span> (<span class="hljs-regexp">/\bdeflate\b/</span>.<span class="hljs-title function_">test</span>(acceptEncoding)) {
response.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'Content-Encoding'</span>: <span class="hljs-string">'deflate'</span> });
<span class="hljs-title function_">pipeline</span>(raw, zlib.<span class="hljs-title function_">createDeflate</span>(), response, onError);
} <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> (<span class="hljs-regexp">/\bgzip\b/</span>.<span class="hljs-title function_">test</span>(acceptEncoding)) {
response.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'Content-Encoding'</span>: <span class="hljs-string">'gzip'</span> });
<span class="hljs-title function_">pipeline</span>(raw, zlib.<span class="hljs-title function_">createGzip</span>(), response, onError);
} <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> (<span class="hljs-regexp">/\bbr\b/</span>.<span class="hljs-title function_">test</span>(acceptEncoding)) {
response.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'Content-Encoding'</span>: <span class="hljs-string">'br'</span> });
<span class="hljs-title function_">pipeline</span>(raw, zlib.<span class="hljs-title function_">createBrotliCompress</span>(), response, onError);
} <span class="hljs-keyword">else</span> {
response.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, {});
<span class="hljs-title function_">pipeline</span>(raw, response, onError);
}
}).<span class="hljs-title function_">listen</span>(<span class="hljs-number">1337</span>);</code><code class="language-js cjs"><span class="hljs-comment">// server example</span>
<span class="hljs-comment">// Running a gzip operation on every request is quite expensive.</span>
<span class="hljs-comment">// It would be much more efficient to cache the compressed buffer.</span>
<span class="hljs-keyword">const</span> zlib = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:zlib'</span>);
<span class="hljs-keyword">const</span> http = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:http'</span>);
<span class="hljs-keyword">const</span> fs = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:fs'</span>);
<span class="hljs-keyword">const</span> { pipeline } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream'</span>);
http.<span class="hljs-title function_">createServer</span>(<span class="hljs-function">(<span class="hljs-params">request, response</span>) =></span> {
<span class="hljs-keyword">const</span> raw = fs.<span class="hljs-title function_">createReadStream</span>(<span class="hljs-string">'index.html'</span>);
<span class="hljs-comment">// Store both a compressed and an uncompressed version of the resource.</span>
response.<span class="hljs-title function_">setHeader</span>(<span class="hljs-string">'Vary'</span>, <span class="hljs-string">'Accept-Encoding'</span>);
<span class="hljs-keyword">const</span> acceptEncoding = request.<span class="hljs-property">headers</span>[<span class="hljs-string">'accept-encoding'</span>] || <span class="hljs-string">''</span>;
<span class="hljs-keyword">const</span> <span class="hljs-title function_">onError</span> = (<span class="hljs-params">err</span>) => {
<span class="hljs-keyword">if</span> (err) {
<span class="hljs-comment">// If an error occurs, there's not much we can do because</span>
<span class="hljs-comment">// the server has already sent the 200 response code and</span>
<span class="hljs-comment">// some amount of data has already been sent to the client.</span>
<span class="hljs-comment">// The best we can do is terminate the response immediately</span>
<span class="hljs-comment">// and log the error.</span>
response.<span class="hljs-title function_">end</span>();
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'An error occurred:'</span>, err);
}
};
<span class="hljs-comment">// Note: This is not a conformant accept-encoding parser.</span>
<span class="hljs-comment">// See https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.3</span>
<span class="hljs-keyword">if</span> (<span class="hljs-regexp">/\bdeflate\b/</span>.<span class="hljs-title function_">test</span>(acceptEncoding)) {
response.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'Content-Encoding'</span>: <span class="hljs-string">'deflate'</span> });
<span class="hljs-title function_">pipeline</span>(raw, zlib.<span class="hljs-title function_">createDeflate</span>(), response, onError);
} <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> (<span class="hljs-regexp">/\bgzip\b/</span>.<span class="hljs-title function_">test</span>(acceptEncoding)) {
response.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'Content-Encoding'</span>: <span class="hljs-string">'gzip'</span> });
<span class="hljs-title function_">pipeline</span>(raw, zlib.<span class="hljs-title function_">createGzip</span>(), response, onError);
} <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> (<span class="hljs-regexp">/\bbr\b/</span>.<span class="hljs-title function_">test</span>(acceptEncoding)) {
response.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'Content-Encoding'</span>: <span class="hljs-string">'br'</span> });
<span class="hljs-title function_">pipeline</span>(raw, zlib.<span class="hljs-title function_">createBrotliCompress</span>(), response, onError);
} <span class="hljs-keyword">else</span> {
response.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, {});
<span class="hljs-title function_">pipeline</span>(raw, response, onError);
}
}).<span class="hljs-title function_">listen</span>(<span class="hljs-number">1337</span>);</code><button class="copy-button">copy</button></pre>
<p>By default, the <code>zlib</code> methods will throw an error when decompressing
truncated data. However, if it is known that the data is incomplete, or
the desire is to inspect only the beginning of a compressed file, it is
possible to suppress the default error handling by changing the flushing
method that is used to decompress the last chunk of input data:</p>
<pre><code class="language-js"><span class="hljs-comment">// This is a truncated version of the buffer from the above examples</span>
<span class="hljs-keyword">const</span> buffer = <span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>(<span class="hljs-string">'eJzT0yMA'</span>, <span class="hljs-string">'base64'</span>);
zlib.<span class="hljs-title function_">unzip</span>(
buffer,
<span class="hljs-comment">// For Brotli, the equivalent is zlib.constants.BROTLI_OPERATION_FLUSH.</span>
{ <span class="hljs-attr">finishFlush</span>: zlib.<span class="hljs-property">constants</span>.<span class="hljs-property">Z_SYNC_FLUSH</span> },
<span class="hljs-function">(<span class="hljs-params">err, buffer</span>) =></span> {
<span class="hljs-keyword">if</span> (err) {
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'An error occurred:'</span>, err);
process.<span class="hljs-property">exitCode</span> = <span class="hljs-number">1</span>;
}
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(buffer.<span class="hljs-title function_">toString</span>());
});</code> <button class="copy-button">copy</button></pre>
<p>This will not change the behavior in other error-throwing situations, e.g.
when the input data has an invalid format. Using this method, it will not be
possible to determine whether the input ended prematurely or lacks the
integrity checks, making it necessary to manually check that the
decompressed result is valid.</p>
</section><section><h3>Memory usage tuning<span><a class="mark" href="#memory-usage-tuning" id="memory-usage-tuning">#</a></span><a aria-hidden="true" class="legacy" id="zlib_memory_usage_tuning"></a></h3>
<h4>For zlib-based streams<span><a class="mark" href="#for-zlib-based-streams" id="for-zlib-based-streams">#</a></span><a aria-hidden="true" class="legacy" id="zlib_for_zlib_based_streams"></a></h4>
<p>From <code>zlib/zconf.h</code>, modified for Node.js usage:</p>
<p>The memory requirements for deflate are (in bytes):</p>
<!-- eslint-disable @stylistic/js/semi -->
<pre><code class="language-js">(<span class="hljs-number">1</span> << (windowBits + <span class="hljs-number">2</span>)) + (<span class="hljs-number">1</span> << (memLevel + <span class="hljs-number">9</span>))</code> <button class="copy-button">copy</button></pre>
<p>That is: 128K for <code>windowBits</code> = 15 + 128K for <code>memLevel</code> = 8
(default values) plus a few kilobytes for small objects.</p>
<p>For example, to reduce the default memory requirements from 256K to 128K, the
options should be set to:</p>
<pre><code class="language-js"><span class="hljs-keyword">const</span> options = { <span class="hljs-attr">windowBits</span>: <span class="hljs-number">14</span>, <span class="hljs-attr">memLevel</span>: <span class="hljs-number">7</span> };</code> <button class="copy-button">copy</button></pre>
<p>This will, however, generally degrade compression.</p>
<p>The memory requirements for inflate are (in bytes) <code>1 << windowBits</code>.
That is, 32K for <code>windowBits</code> = 15 (default value) plus a few kilobytes
for small objects.</p>
<p>This is in addition to a single internal output slab buffer of size
<code>chunkSize</code>, which defaults to 16K.</p>
<p>The speed of <code>zlib</code> compression is affected most dramatically by the
<code>level</code> setting. A higher level will result in better compression, but
will take longer to complete. A lower level will result in less
compression, but will be much faster.</p>
<p>In general, greater memory usage options will mean that Node.js has to make
fewer calls to <code>zlib</code> because it will be able to process more data on
each <code>write</code> operation. So, this is another factor that affects the
speed, at the cost of memory usage.</p>
<h4>For Brotli-based streams<span><a class="mark" href="#for-brotli-based-streams" id="for-brotli-based-streams">#</a></span><a aria-hidden="true" class="legacy" id="zlib_for_brotli_based_streams"></a></h4>
<p>There are equivalents to the zlib options for Brotli-based streams, although
these options have different ranges than the zlib ones:</p>
<ul>
<li>zlib's <code>level</code> option matches Brotli's <code>BROTLI_PARAM_QUALITY</code> option.</li>
<li>zlib's <code>windowBits</code> option matches Brotli's <code>BROTLI_PARAM_LGWIN</code> option.</li>
</ul>
<p>See <a href="#brotli-constants">below</a> for more details on Brotli-specific options.</p>
</section><section><h3>Flushing<span><a class="mark" href="#flushing" id="flushing">#</a></span><a aria-hidden="true" class="legacy" id="zlib_flushing"></a></h3>
<p>Calling <a href="#zlibflushkind-callback"><code>.flush()</code></a> on a compression stream will make <code>zlib</code> return as much
output as currently possible. This may come at the cost of degraded compression
quality, but can be useful when data needs to be available as soon as possible.</p>
<p>In the following example, <code>flush()</code> is used to write a compressed partial
HTTP response to the client:</p>
<pre class="with-34-chars"><input class="js-flavor-toggle" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> zlib <span class="hljs-keyword">from</span> <span class="hljs-string">'node:zlib'</span>;
<span class="hljs-keyword">import</span> http <span class="hljs-keyword">from</span> <span class="hljs-string">'node:http'</span>;
<span class="hljs-keyword">import</span> { pipeline } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream'</span>;
http.<span class="hljs-title function_">createServer</span>(<span class="hljs-function">(<span class="hljs-params">request, response</span>) =></span> {
<span class="hljs-comment">// For the sake of simplicity, the Accept-Encoding checks are omitted.</span>
response.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'content-encoding'</span>: <span class="hljs-string">'gzip'</span> });
<span class="hljs-keyword">const</span> output = zlib.<span class="hljs-title function_">createGzip</span>();
<span class="hljs-keyword">let</span> i;
<span class="hljs-title function_">pipeline</span>(output, response, <span class="hljs-function">(<span class="hljs-params">err</span>) =></span> {
<span class="hljs-keyword">if</span> (err) {
<span class="hljs-comment">// If an error occurs, there's not much we can do because</span>
<span class="hljs-comment">// the server has already sent the 200 response code and</span>
<span class="hljs-comment">// some amount of data has already been sent to the client.</span>
<span class="hljs-comment">// The best we can do is terminate the response immediately</span>
<span class="hljs-comment">// and log the error.</span>
<span class="hljs-built_in">clearInterval</span>(i);
response.<span class="hljs-title function_">end</span>();
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'An error occurred:'</span>, err);
}
});
i = <span class="hljs-built_in">setInterval</span>(<span class="hljs-function">() =></span> {
output.<span class="hljs-title function_">write</span>(<span class="hljs-string">`The current time is <span class="hljs-subst">${<span class="hljs-built_in">Date</span>()}</span>\n`</span>, <span class="hljs-function">() =></span> {
<span class="hljs-comment">// The data has been passed to zlib, but the compression algorithm may</span>
<span class="hljs-comment">// have decided to buffer the data for more efficient compression.</span>
<span class="hljs-comment">// Calling .flush() will make the data available as soon as the client</span>
<span class="hljs-comment">// is ready to receive it.</span>
output.<span class="hljs-title function_">flush</span>();
});
}, <span class="hljs-number">1000</span>);
}).<span class="hljs-title function_">listen</span>(<span class="hljs-number">1337</span>);</code><code class="language-js cjs"><span class="hljs-keyword">const</span> zlib = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:zlib'</span>);
<span class="hljs-keyword">const</span> http = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:http'</span>);
<span class="hljs-keyword">const</span> { pipeline } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream'</span>);
http.<span class="hljs-title function_">createServer</span>(<span class="hljs-function">(<span class="hljs-params">request, response</span>) =></span> {
<span class="hljs-comment">// For the sake of simplicity, the Accept-Encoding checks are omitted.</span>
response.<span class="hljs-title function_">writeHead</span>(<span class="hljs-number">200</span>, { <span class="hljs-string">'content-encoding'</span>: <span class="hljs-string">'gzip'</span> });
<span class="hljs-keyword">const</span> output = zlib.<span class="hljs-title function_">createGzip</span>();
<span class="hljs-keyword">let</span> i;
<span class="hljs-title function_">pipeline</span>(output, response, <span class="hljs-function">(<span class="hljs-params">err</span>) =></span> {
<span class="hljs-keyword">if</span> (err) {
<span class="hljs-comment">// If an error occurs, there's not much we can do because</span>
<span class="hljs-comment">// the server has already sent the 200 response code and</span>
<span class="hljs-comment">// some amount of data has already been sent to the client.</span>
<span class="hljs-comment">// The best we can do is terminate the response immediately</span>
<span class="hljs-comment">// and log the error.</span>
<span class="hljs-built_in">clearInterval</span>(i);
response.<span class="hljs-title function_">end</span>();
<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">error</span>(<span class="hljs-string">'An error occurred:'</span>, err);
}
});
i = <span class="hljs-built_in">setInterval</span>(<span class="hljs-function">() =></span> {
output.<span class="hljs-title function_">write</span>(<span class="hljs-string">`The current time is <span class="hljs-subst">${<span class="hljs-built_in">Date</span>()}</span>\n`</span>, <span class="hljs-function">() =></span> {
<span class="hljs-comment">// The data has been passed to zlib, but the compression algorithm may</span>
<span class="hljs-comment">// have decided to buffer the data for more efficient compression.</span>
<span class="hljs-comment">// Calling .flush() will make the data available as soon as the client</span>
<span class="hljs-comment">// is ready to receive it.</span>
output.<span class="hljs-title function_">flush</span>();
});
}, <span class="hljs-number">1000</span>);
}).<span class="hljs-title function_">listen</span>(<span class="hljs-number">1337</span>);</code><button class="copy-button">copy</button></pre>
</section><section><h3>Constants<span><a class="mark" href="#constants" id="constants">#</a></span><a aria-hidden="true" class="legacy" id="zlib_constants"></a></h3>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<h4>zlib constants<span><a class="mark" href="#zlib-constants" id="zlib-constants">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_constants"></a></h4>
<p>All of the constants defined in <code>zlib.h</code> are also defined on
<code>require('node:zlib').constants</code>. In the normal course of operations, it will
not be necessary to use these constants. They are documented so that their
presence is not surprising. This section is taken almost directly from the
<a href="https://zlib.net/manual.html#Constants">zlib documentation</a>.</p>
<p>Previously, the constants were available directly from <code>require('node:zlib')</code>,
for instance <code>zlib.Z_NO_FLUSH</code>. Accessing the constants directly from the module
is currently still possible but is deprecated.</p>
<p>Allowed flush values.</p>
<ul>
<li><code>zlib.constants.Z_NO_FLUSH</code></li>
<li><code>zlib.constants.Z_PARTIAL_FLUSH</code></li>
<li><code>zlib.constants.Z_SYNC_FLUSH</code></li>
<li><code>zlib.constants.Z_FULL_FLUSH</code></li>
<li><code>zlib.constants.Z_FINISH</code></li>
<li><code>zlib.constants.Z_BLOCK</code></li>
<li><code>zlib.constants.Z_TREES</code></li>
</ul>
<p>Return codes for the compression/decompression functions. Negative
values are errors, positive values are used for special but normal
events.</p>
<ul>
<li><code>zlib.constants.Z_OK</code></li>
<li><code>zlib.constants.Z_STREAM_END</code></li>
<li><code>zlib.constants.Z_NEED_DICT</code></li>
<li><code>zlib.constants.Z_ERRNO</code></li>
<li><code>zlib.constants.Z_STREAM_ERROR</code></li>
<li><code>zlib.constants.Z_DATA_ERROR</code></li>
<li><code>zlib.constants.Z_MEM_ERROR</code></li>
<li><code>zlib.constants.Z_BUF_ERROR</code></li>
<li><code>zlib.constants.Z_VERSION_ERROR</code></li>
</ul>
<p>Compression levels.</p>
<ul>
<li><code>zlib.constants.Z_NO_COMPRESSION</code></li>
<li><code>zlib.constants.Z_BEST_SPEED</code></li>
<li><code>zlib.constants.Z_BEST_COMPRESSION</code></li>
<li><code>zlib.constants.Z_DEFAULT_COMPRESSION</code></li>
</ul>
<p>Compression strategy.</p>
<ul>
<li><code>zlib.constants.Z_FILTERED</code></li>
<li><code>zlib.constants.Z_HUFFMAN_ONLY</code></li>
<li><code>zlib.constants.Z_RLE</code></li>
<li><code>zlib.constants.Z_FIXED</code></li>
<li><code>zlib.constants.Z_DEFAULT_STRATEGY</code></li>
</ul>
<h4>Brotli constants<span><a class="mark" href="#brotli-constants" id="brotli-constants">#</a></span><a aria-hidden="true" class="legacy" id="zlib_brotli_constants"></a></h4>
<div class="api_metadata">
<span>Added in: v11.7.0, v10.16.0</span>
</div>
<p>There are several options and other constants available for Brotli-based
streams:</p>
<h5>Flush operations<span><a class="mark" href="#flush-operations" id="flush-operations">#</a></span><a aria-hidden="true" class="legacy" id="zlib_flush_operations"></a></h5>
<p>The following values are valid flush operations for Brotli-based streams:</p>
<ul>
<li><code>zlib.constants.BROTLI_OPERATION_PROCESS</code> (default for all operations)</li>
<li><code>zlib.constants.BROTLI_OPERATION_FLUSH</code> (default when calling <code>.flush()</code>)</li>
<li><code>zlib.constants.BROTLI_OPERATION_FINISH</code> (default for the last chunk)</li>
<li><code>zlib.constants.BROTLI_OPERATION_EMIT_METADATA</code>
<ul>
<li>This particular operation may be hard to use in a Node.js context,
as the streaming layer makes it hard to know which data will end up
in this frame. Also, there is currently no way to consume this data through
the Node.js API.</li>
</ul>
</li>
</ul>
<h5>Compressor options<span><a class="mark" href="#compressor-options" id="compressor-options">#</a></span><a aria-hidden="true" class="legacy" id="zlib_compressor_options"></a></h5>
<p>There are several options that can be set on Brotli encoders, affecting
compression efficiency and speed. Both the keys and the values can be accessed
as properties of the <code>zlib.constants</code> object.</p>
<p>The most important options are:</p>
<ul>
<li><code>BROTLI_PARAM_MODE</code>
<ul>
<li><code>BROTLI_MODE_GENERIC</code> (default)</li>
<li><code>BROTLI_MODE_TEXT</code>, adjusted for UTF-8 text</li>
<li><code>BROTLI_MODE_FONT</code>, adjusted for WOFF 2.0 fonts</li>
</ul>
</li>
<li><code>BROTLI_PARAM_QUALITY</code>
<ul>
<li>Ranges from <code>BROTLI_MIN_QUALITY</code> to <code>BROTLI_MAX_QUALITY</code>,
with a default of <code>BROTLI_DEFAULT_QUALITY</code>.</li>
</ul>
</li>
<li><code>BROTLI_PARAM_SIZE_HINT</code>
<ul>
<li>Integer value representing the expected input size;
defaults to <code>0</code> for an unknown input size.</li>
</ul>
</li>
</ul>
<p>The following flags can be set for advanced control over the compression
algorithm and memory usage tuning:</p>
<ul>
<li><code>BROTLI_PARAM_LGWIN</code>
<ul>
<li>Ranges from <code>BROTLI_MIN_WINDOW_BITS</code> to <code>BROTLI_MAX_WINDOW_BITS</code>,
with a default of <code>BROTLI_DEFAULT_WINDOW</code>, or up to
<code>BROTLI_LARGE_MAX_WINDOW_BITS</code> if the <code>BROTLI_PARAM_LARGE_WINDOW</code> flag
is set.</li>
</ul>
</li>
<li><code>BROTLI_PARAM_LGBLOCK</code>
<ul>
<li>Ranges from <code>BROTLI_MIN_INPUT_BLOCK_BITS</code> to <code>BROTLI_MAX_INPUT_BLOCK_BITS</code>.</li>
</ul>
</li>
<li><code>BROTLI_PARAM_DISABLE_LITERAL_CONTEXT_MODELING</code>
<ul>
<li>Boolean flag that decreases compression ratio in favour of
decompression speed.</li>
</ul>
</li>
<li><code>BROTLI_PARAM_LARGE_WINDOW</code>
<ul>
<li>Boolean flag enabling “Large Window Brotli” mode (not compatible with the
Brotli format as standardized in <a href="https://www.rfc-editor.org/rfc/rfc7932.txt">RFC 7932</a>).</li>
</ul>
</li>
<li><code>BROTLI_PARAM_NPOSTFIX</code>
<ul>
<li>Ranges from <code>0</code> to <code>BROTLI_MAX_NPOSTFIX</code>.</li>
</ul>
</li>
<li><code>BROTLI_PARAM_NDIRECT</code>
<ul>
<li>Ranges from <code>0</code> to <code>15 << NPOSTFIX</code> in steps of <code>1 << NPOSTFIX</code>.</li>
</ul>
</li>
</ul>
<h5>Decompressor options<span><a class="mark" href="#decompressor-options" id="decompressor-options">#</a></span><a aria-hidden="true" class="legacy" id="zlib_decompressor_options"></a></h5>
<p>These advanced options are available for controlling decompression:</p>
<ul>
<li><code>BROTLI_DECODER_PARAM_DISABLE_RING_BUFFER_REALLOCATION</code>
<ul>
<li>Boolean flag that affects internal memory allocation patterns.</li>
</ul>
</li>
<li><code>BROTLI_DECODER_PARAM_LARGE_WINDOW</code>
<ul>
<li>Boolean flag enabling “Large Window Brotli” mode (not compatible with the
Brotli format as standardized in <a href="https://www.rfc-editor.org/rfc/rfc7932.txt">RFC 7932</a>).</li>
</ul>
</li>
</ul>
</section><section><h3>Class: <code>Options</code><span><a class="mark" href="#class-options" id="class-options">#</a></span><a aria-hidden="true" class="legacy" id="zlib_class_options"></a></h3>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v14.5.0, v12.19.0</td>
<td><p>The <code>maxOutputLength</code> option is supported now.</p></td></tr>
<tr><td>v9.4.0</td>
<td><p>The <code>dictionary</code> option can be an <code>ArrayBuffer</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>dictionary</code> option can be an <code>Uint8Array</code> now.</p></td></tr>
<tr><td>v5.11.0</td>
<td><p>The <code>finishFlush</code> option is supported now.</p></td></tr>
<tr><td>v0.11.1</td>
<td><p><span>Added in: v0.11.1</span></p></td></tr>
</tbody></table>
</details>
</div>
<p>Each zlib-based class takes an <code>options</code> object. No options are required.</p>
<p>Some options are only relevant when compressing and are
ignored by the decompression classes.</p>
<ul>
<li><code>flush</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a> <strong>Default:</strong> <code>zlib.constants.Z_NO_FLUSH</code></li>
<li><code>finishFlush</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a> <strong>Default:</strong> <code>zlib.constants.Z_FINISH</code></li>
<li><code>chunkSize</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a> <strong>Default:</strong> <code>16 * 1024</code></li>
<li><code>windowBits</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a></li>
<li><code>level</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a> (compression only)</li>
<li><code>memLevel</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a> (compression only)</li>
<li><code>strategy</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a> (compression only)</li>
<li><code>dictionary</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> (deflate/inflate only,
empty dictionary by default)</li>
<li><code>info</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> (If <code>true</code>, returns an object with <code>buffer</code> and <code>engine</code>.)</li>
<li><code>maxOutputLength</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a> Limits output size when using
<a href="#convenience-methods">convenience methods</a>. <strong>Default:</strong> <a href="buffer.html#bufferkmaxlength"><code>buffer.kMaxLength</code></a></li>
</ul>
<p>See the <a href="https://zlib.net/manual.html#Advanced"><code>deflateInit2</code> and <code>inflateInit2</code></a> documentation for more
information.</p>
</section><section><h3>Class: <code>BrotliOptions</code><span><a class="mark" href="#class-brotlioptions" id="class-brotlioptions">#</a></span><a aria-hidden="true" class="legacy" id="zlib_class_brotlioptions"></a></h3>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v14.5.0, v12.19.0</td>
<td><p>The <code>maxOutputLength</code> option is supported now.</p></td></tr>
<tr><td>v11.7.0</td>
<td><p><span>Added in: v11.7.0</span></p></td></tr>
</tbody></table>
</details>
</div>
<p>Each Brotli-based class takes an <code>options</code> object. All options are optional.</p>
<ul>
<li><code>flush</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a> <strong>Default:</strong> <code>zlib.constants.BROTLI_OPERATION_PROCESS</code></li>
<li><code>finishFlush</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a> <strong>Default:</strong> <code>zlib.constants.BROTLI_OPERATION_FINISH</code></li>
<li><code>chunkSize</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a> <strong>Default:</strong> <code>16 * 1024</code></li>
<li><code>params</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> Key-value object containing indexed <a href="#brotli-constants">Brotli parameters</a>.</li>
<li><code>maxOutputLength</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a> Limits output size when using
<a href="#convenience-methods">convenience methods</a>. <strong>Default:</strong> <a href="buffer.html#bufferkmaxlength"><code>buffer.kMaxLength</code></a></li>
</ul>
<p>For example:</p>
<pre><code class="language-js"><span class="hljs-keyword">const</span> stream = zlib.<span class="hljs-title function_">createBrotliCompress</span>({
<span class="hljs-attr">chunkSize</span>: <span class="hljs-number">32</span> * <span class="hljs-number">1024</span>,
<span class="hljs-attr">params</span>: {
[zlib.<span class="hljs-property">constants</span>.<span class="hljs-property">BROTLI_PARAM_MODE</span>]: zlib.<span class="hljs-property">constants</span>.<span class="hljs-property">BROTLI_MODE_TEXT</span>,
[zlib.<span class="hljs-property">constants</span>.<span class="hljs-property">BROTLI_PARAM_QUALITY</span>]: <span class="hljs-number">4</span>,
[zlib.<span class="hljs-property">constants</span>.<span class="hljs-property">BROTLI_PARAM_SIZE_HINT</span>]: fs.<span class="hljs-title function_">statSync</span>(inputFile).<span class="hljs-property">size</span>,
},
});</code> <button class="copy-button">copy</button></pre>
</section><section><h3>Class: <code>zlib.BrotliCompress</code><span><a class="mark" href="#class-zlibbrotlicompress" id="class-zlibbrotlicompress">#</a></span><a aria-hidden="true" class="legacy" id="zlib_class_zlib_brotlicompress"></a></h3>
<div class="api_metadata">
<span>Added in: v11.7.0, v10.16.0</span>
</div>
<p>Compress data using the Brotli algorithm.</p>
</section><section><h3>Class: <code>zlib.BrotliDecompress</code><span><a class="mark" href="#class-zlibbrotlidecompress" id="class-zlibbrotlidecompress">#</a></span><a aria-hidden="true" class="legacy" id="zlib_class_zlib_brotlidecompress"></a></h3>
<div class="api_metadata">
<span>Added in: v11.7.0, v10.16.0</span>
</div>
<p>Decompress data using the Brotli algorithm.</p>
</section><section><h3>Class: <code>zlib.Deflate</code><span><a class="mark" href="#class-zlibdeflate" id="class-zlibdeflate">#</a></span><a aria-hidden="true" class="legacy" id="zlib_class_zlib_deflate"></a></h3>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<p>Compress data using deflate.</p>
</section><section><h3>Class: <code>zlib.DeflateRaw</code><span><a class="mark" href="#class-zlibdeflateraw" id="class-zlibdeflateraw">#</a></span><a aria-hidden="true" class="legacy" id="zlib_class_zlib_deflateraw"></a></h3>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<p>Compress data using deflate, and do not append a <code>zlib</code> header.</p>
</section><section><h3>Class: <code>zlib.Gunzip</code><span><a class="mark" href="#class-zlibgunzip" id="class-zlibgunzip">#</a></span><a aria-hidden="true" class="legacy" id="zlib_class_zlib_gunzip"></a></h3>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v6.0.0</td>
<td><p>Trailing garbage at the end of the input stream will now result in an <code>'error'</code> event.</p></td></tr>
<tr><td>v5.9.0</td>
<td><p>Multiple concatenated gzip file members are supported now.</p></td></tr>
<tr><td>v5.0.0</td>
<td><p>A truncated input stream will now result in an <code>'error'</code> event.</p></td></tr>
<tr><td>v0.5.8</td>
<td><p><span>Added in: v0.5.8</span></p></td></tr>
</tbody></table>
</details>
</div>
<p>Decompress a gzip stream.</p>
</section><section><h3>Class: <code>zlib.Gzip</code><span><a class="mark" href="#class-zlibgzip" id="class-zlibgzip">#</a></span><a aria-hidden="true" class="legacy" id="zlib_class_zlib_gzip"></a></h3>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<p>Compress data using gzip.</p>
</section><section><h3>Class: <code>zlib.Inflate</code><span><a class="mark" href="#class-zlibinflate" id="class-zlibinflate">#</a></span><a aria-hidden="true" class="legacy" id="zlib_class_zlib_inflate"></a></h3>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v5.0.0</td>
<td><p>A truncated input stream will now result in an <code>'error'</code> event.</p></td></tr>
<tr><td>v0.5.8</td>
<td><p><span>Added in: v0.5.8</span></p></td></tr>
</tbody></table>
</details>
</div>
<p>Decompress a deflate stream.</p>
</section><section><h3>Class: <code>zlib.InflateRaw</code><span><a class="mark" href="#class-zlibinflateraw" id="class-zlibinflateraw">#</a></span><a aria-hidden="true" class="legacy" id="zlib_class_zlib_inflateraw"></a></h3>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v6.8.0</td>
<td><p>Custom dictionaries are now supported by <code>InflateRaw</code>.</p></td></tr>
<tr><td>v5.0.0</td>
<td><p>A truncated input stream will now result in an <code>'error'</code> event.</p></td></tr>
<tr><td>v0.5.8</td>
<td><p><span>Added in: v0.5.8</span></p></td></tr>
</tbody></table>
</details>
</div>
<p>Decompress a raw deflate stream.</p>
</section><section><h3>Class: <code>zlib.Unzip</code><span><a class="mark" href="#class-zlibunzip" id="class-zlibunzip">#</a></span><a aria-hidden="true" class="legacy" id="zlib_class_zlib_unzip"></a></h3>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<p>Decompress either a Gzip- or Deflate-compressed stream by auto-detecting
the header.</p>
</section><section><h3>Class: <code>zlib.ZlibBase</code><span><a class="mark" href="#class-zlibzlibbase" id="class-zlibzlibbase">#</a></span><a aria-hidden="true" class="legacy" id="zlib_class_zlib_zlibbase"></a></h3>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v11.7.0, v10.16.0</td>
<td><p>This class was renamed from <code>Zlib</code> to <code>ZlibBase</code>.</p></td></tr>
<tr><td>v0.5.8</td>
<td><p><span>Added in: v0.5.8</span></p></td></tr>
</tbody></table>
</details>
</div>
<p>Not exported by the <code>node:zlib</code> module. It is documented here because it is the
base class of the compressor/decompressor classes.</p>
<p>This class inherits from <a href="stream.html#class-streamtransform"><code>stream.Transform</code></a>, allowing <code>node:zlib</code> objects to
be used in pipes and similar stream operations.</p>
<h4><code>zlib.bytesRead</code><span><a class="mark" href="#zlibbytesread" id="zlibbytesread">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_bytesread"></a></h4>
<div class="api_metadata">
<span>Added in: v8.1.0</span><span>Deprecated since: v10.0.0</span>
</div>
<p></p><div class="api_stability api_stability_0"><a href="documentation.html#stability-index">Stability: 0</a> - Deprecated: Use <a href="#zlibbyteswritten"><code>zlib.bytesWritten</code></a> instead.</div><p></p>
<ul>
<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li>
</ul>
<p>Deprecated alias for <a href="#zlibbyteswritten"><code>zlib.bytesWritten</code></a>. This original name was chosen
because it also made sense to interpret the value as the number of bytes
read by the engine, but is inconsistent with other streams in Node.js that
expose values under these names.</p>
<h4><code>zlib.bytesWritten</code><span><a class="mark" href="#zlibbyteswritten" id="zlibbyteswritten">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_byteswritten"></a></h4>
<div class="api_metadata">
<span>Added in: v10.0.0</span>
</div>
<ul>
<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li>
</ul>
<p>The <code>zlib.bytesWritten</code> property specifies the number of bytes written to
the engine, before the bytes are processed (compressed or decompressed,
as appropriate for the derived class).</p>
<h4><code>zlib.close([callback])</code><span><a class="mark" href="#zlibclosecallback" id="zlibclosecallback">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_close_callback"></a></h4>
<div class="api_metadata">
<span>Added in: v0.9.4</span>
</div>
<ul>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li>
</ul>
<p>Close the underlying handle.</p>
<h4><code>zlib.flush([kind, ]callback)</code><span><a class="mark" href="#zlibflushkind-callback" id="zlibflushkind-callback">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_flush_kind_callback"></a></h4>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<ul>
<li><code>kind</code> <strong>Default:</strong> <code>zlib.constants.Z_FULL_FLUSH</code> for zlib-based streams,
<code>zlib.constants.BROTLI_OPERATION_FLUSH</code> for Brotli-based streams.</li>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li>
</ul>
<p>Flush pending data. Don't call this frivolously, premature flushes negatively
impact the effectiveness of the compression algorithm.</p>
<p>Calling this only flushes data from the internal <code>zlib</code> state, and does not
perform flushing of any kind on the streams level. Rather, it behaves like a
normal call to <code>.write()</code>, i.e. it will be queued up behind other pending
writes and will only produce output when data is being read from the stream.</p>
<h4><code>zlib.params(level, strategy, callback)</code><span><a class="mark" href="#zlibparamslevel-strategy-callback" id="zlibparamslevel-strategy-callback">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_params_level_strategy_callback"></a></h4>
<div class="api_metadata">
<span>Added in: v0.11.4</span>
</div>
<ul>
<li><code>level</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a></li>
<li><code>strategy</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a></li>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li>
</ul>
<p>This function is only available for zlib-based streams, i.e. not Brotli.</p>
<p>Dynamically update the compression level and compression strategy.
Only applicable to deflate algorithm.</p>
<h4><code>zlib.reset()</code><span><a class="mark" href="#zlibreset" id="zlibreset">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_reset"></a></h4>
<div class="api_metadata">
<span>Added in: v0.7.0</span>
</div>
<p>Reset the compressor/decompressor to factory defaults. Only applicable to
the inflate and deflate algorithms.</p>
</section><section><h3><code>zlib.constants</code><span><a class="mark" href="#zlibconstants" id="zlibconstants">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_constants_1"></a></h3>
<div class="api_metadata">
<span>Added in: v7.0.0</span>
</div>
<p>Provides an object enumerating Zlib-related constants.</p>
</section><section><h3><code>zlib.crc32(data[, value])</code><span><a class="mark" href="#zlibcrc32data-value" id="zlibcrc32data-value">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_crc32_data_value"></a></h3>
<div class="api_metadata">
<span>Added in: v22.2.0</span>
</div>
<ul>
<li><code>data</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> | <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> When <code>data</code> is a string,
it will be encoded as UTF-8 before being used for computation.</li>
<li><code>value</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a> An optional starting value. It must be a 32-bit unsigned
integer. <strong>Default:</strong> <code>0</code></li>
<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><integer></a> A 32-bit unsigned integer containing the checksum.</li>
</ul>
<p>Computes a 32-bit <a href="https://en.wikipedia.org/wiki/Cyclic_redundancy_check">Cyclic Redundancy Check</a> checksum of <code>data</code>. If
<code>value</code> is specified, it is used as the starting value of the checksum,
otherwise, 0 is used as the starting value.</p>
<p>The CRC algorithm is designed to compute checksums and to detect error
in data transmission. It's not suitable for cryptographic authentication.</p>
<p>To be consistent with other APIs, if the <code>data</code> is a string, it will
be encoded with UTF-8 before being used for computation. If users only
use Node.js to compute and match the checksums, this works well with
other APIs that uses the UTF-8 encoding by default.</p>
<p>Some third-party JavaScript libraries compute the checksum on a
string based on <code>str.charCodeAt()</code> so that it can be run in browsers.
If users want to match the checksum computed with this kind of library
in the browser, it's better to use the same library in Node.js
if it also runs in Node.js. If users have to use <code>zlib.crc32()</code> to
match the checksum produced by such a third-party library:</p>
<ol>
<li>If the library accepts <code>Uint8Array</code> as input, use <code>TextEncoder</code>
in the browser to encode the string into a <code>Uint8Array</code> with UTF-8
encoding, and compute the checksum based on the UTF-8 encoded string
in the browser.</li>
<li>If the library only takes a string and compute the data based on
<code>str.charCodeAt()</code>, on the Node.js side, convert the string into
a buffer using <code>Buffer.from(str, 'utf16le')</code>.</li>
</ol>
<pre class="with-42-chars"><input class="js-flavor-toggle" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> zlib <span class="hljs-keyword">from</span> <span class="hljs-string">'node:zlib'</span>;
<span class="hljs-keyword">import</span> { <span class="hljs-title class_">Buffer</span> } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:buffer'</span>;
<span class="hljs-keyword">let</span> crc = zlib.<span class="hljs-title function_">crc32</span>(<span class="hljs-string">'hello'</span>); <span class="hljs-comment">// 907060870</span>
crc = zlib.<span class="hljs-title function_">crc32</span>(<span class="hljs-string">'world'</span>, crc); <span class="hljs-comment">// 4192936109</span>
crc = zlib.<span class="hljs-title function_">crc32</span>(<span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>(<span class="hljs-string">'hello'</span>, <span class="hljs-string">'utf16le'</span>)); <span class="hljs-comment">// 1427272415</span>
crc = zlib.<span class="hljs-title function_">crc32</span>(<span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>(<span class="hljs-string">'world'</span>, <span class="hljs-string">'utf16le'</span>), crc); <span class="hljs-comment">// 4150509955</span></code><code class="language-js cjs"><span class="hljs-keyword">const</span> zlib = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:zlib'</span>);
<span class="hljs-keyword">const</span> { <span class="hljs-title class_">Buffer</span> } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:buffer'</span>);
<span class="hljs-keyword">let</span> crc = zlib.<span class="hljs-title function_">crc32</span>(<span class="hljs-string">'hello'</span>); <span class="hljs-comment">// 907060870</span>
crc = zlib.<span class="hljs-title function_">crc32</span>(<span class="hljs-string">'world'</span>, crc); <span class="hljs-comment">// 4192936109</span>
crc = zlib.<span class="hljs-title function_">crc32</span>(<span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>(<span class="hljs-string">'hello'</span>, <span class="hljs-string">'utf16le'</span>)); <span class="hljs-comment">// 1427272415</span>
crc = zlib.<span class="hljs-title function_">crc32</span>(<span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>(<span class="hljs-string">'world'</span>, <span class="hljs-string">'utf16le'</span>), crc); <span class="hljs-comment">// 4150509955</span></code><button class="copy-button">copy</button></pre>
</section><section><h3><code>zlib.createBrotliCompress([options])</code><span><a class="mark" href="#zlibcreatebrotlicompressoptions" id="zlibcreatebrotlicompressoptions">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_createbrotlicompress_options"></a></h3>
<div class="api_metadata">
<span>Added in: v11.7.0, v10.16.0</span>
</div>
<ul>
<li><code>options</code> <a href="zlib.html#class-brotlioptions" class="type"><brotli options></a></li>
</ul>
<p>Creates and returns a new <a href="#class-zlibbrotlicompress"><code>BrotliCompress</code></a> object.</p>
</section><section><h3><code>zlib.createBrotliDecompress([options])</code><span><a class="mark" href="#zlibcreatebrotlidecompressoptions" id="zlibcreatebrotlidecompressoptions">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_createbrotlidecompress_options"></a></h3>
<div class="api_metadata">
<span>Added in: v11.7.0, v10.16.0</span>
</div>
<ul>
<li><code>options</code> <a href="zlib.html#class-brotlioptions" class="type"><brotli options></a></li>
</ul>
<p>Creates and returns a new <a href="#class-zlibbrotlidecompress"><code>BrotliDecompress</code></a> object.</p>
</section><section><h3><code>zlib.createDeflate([options])</code><span><a class="mark" href="#zlibcreatedeflateoptions" id="zlibcreatedeflateoptions">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_createdeflate_options"></a></h3>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<ul>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
</ul>
<p>Creates and returns a new <a href="#class-zlibdeflate"><code>Deflate</code></a> object.</p>
</section><section><h3><code>zlib.createDeflateRaw([options])</code><span><a class="mark" href="#zlibcreatedeflaterawoptions" id="zlibcreatedeflaterawoptions">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_createdeflateraw_options"></a></h3>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<ul>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
</ul>
<p>Creates and returns a new <a href="#class-zlibdeflateraw"><code>DeflateRaw</code></a> object.</p>
<p>An upgrade of zlib from 1.2.8 to 1.2.11 changed behavior when <code>windowBits</code>
is set to 8 for raw deflate streams. zlib would automatically set <code>windowBits</code>
to 9 if was initially set to 8. Newer versions of zlib will throw an exception,
so Node.js restored the original behavior of upgrading a value of 8 to 9,
since passing <code>windowBits = 9</code> to zlib actually results in a compressed stream
that effectively uses an 8-bit window only.</p>
</section><section><h3><code>zlib.createGunzip([options])</code><span><a class="mark" href="#zlibcreategunzipoptions" id="zlibcreategunzipoptions">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_creategunzip_options"></a></h3>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<ul>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
</ul>
<p>Creates and returns a new <a href="#class-zlibgunzip"><code>Gunzip</code></a> object.</p>
</section><section><h3><code>zlib.createGzip([options])</code><span><a class="mark" href="#zlibcreategzipoptions" id="zlibcreategzipoptions">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_creategzip_options"></a></h3>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<ul>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
</ul>
<p>Creates and returns a new <a href="#class-zlibgzip"><code>Gzip</code></a> object.
See <a href="#zlib">example</a>.</p>
</section><section><h3><code>zlib.createInflate([options])</code><span><a class="mark" href="#zlibcreateinflateoptions" id="zlibcreateinflateoptions">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_createinflate_options"></a></h3>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<ul>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
</ul>
<p>Creates and returns a new <a href="#class-zlibinflate"><code>Inflate</code></a> object.</p>
</section><section><h3><code>zlib.createInflateRaw([options])</code><span><a class="mark" href="#zlibcreateinflaterawoptions" id="zlibcreateinflaterawoptions">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_createinflateraw_options"></a></h3>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<ul>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
</ul>
<p>Creates and returns a new <a href="#class-zlibinflateraw"><code>InflateRaw</code></a> object.</p>
</section><section><h3><code>zlib.createUnzip([options])</code><span><a class="mark" href="#zlibcreateunzipoptions" id="zlibcreateunzipoptions">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_createunzip_options"></a></h3>
<div class="api_metadata">
<span>Added in: v0.5.8</span>
</div>
<ul>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
</ul>
<p>Creates and returns a new <a href="#class-zlibunzip"><code>Unzip</code></a> object.</p>
</section><section><h3>Convenience methods<span><a class="mark" href="#convenience-methods" id="convenience-methods">#</a></span><a aria-hidden="true" class="legacy" id="zlib_convenience_methods"></a></h3>
<p>All of these take a <a href="buffer.html#class-buffer"><code>Buffer</code></a>, <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray"><code>TypedArray</code></a>, <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView"><code>DataView</code></a>,
<a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer"><code>ArrayBuffer</code></a> or string as the first argument, an optional second argument
to supply options to the <code>zlib</code> classes and will call the supplied callback
with <code>callback(error, result)</code>.</p>
<p>Every method has a <code>*Sync</code> counterpart, which accept the same arguments, but
without a callback.</p>
<h4><code>zlib.brotliCompress(buffer[, options], callback)</code><span><a class="mark" href="#zlibbrotlicompressbuffer-options-callback" id="zlibbrotlicompressbuffer-options-callback">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_brotlicompress_buffer_options_callback"></a></h4>
<div class="api_metadata">
<span>Added in: v11.7.0, v10.16.0</span>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-brotlioptions" class="type"><brotli options></a></li>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li>
</ul>
<h4><code>zlib.brotliCompressSync(buffer[, options])</code><span><a class="mark" href="#zlibbrotlicompresssyncbuffer-options" id="zlibbrotlicompresssyncbuffer-options">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_brotlicompresssync_buffer_options"></a></h4>
<div class="api_metadata">
<span>Added in: v11.7.0, v10.16.0</span>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-brotlioptions" class="type"><brotli options></a></li>
</ul>
<p>Compress a chunk of data with <a href="#class-zlibbrotlicompress"><code>BrotliCompress</code></a>.</p>
<h4><code>zlib.brotliDecompress(buffer[, options], callback)</code><span><a class="mark" href="#zlibbrotlidecompressbuffer-options-callback" id="zlibbrotlidecompressbuffer-options-callback">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_brotlidecompress_buffer_options_callback"></a></h4>
<div class="api_metadata">
<span>Added in: v11.7.0, v10.16.0</span>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-brotlioptions" class="type"><brotli options></a></li>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li>
</ul>
<h4><code>zlib.brotliDecompressSync(buffer[, options])</code><span><a class="mark" href="#zlibbrotlidecompresssyncbuffer-options" id="zlibbrotlidecompresssyncbuffer-options">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_brotlidecompresssync_buffer_options"></a></h4>
<div class="api_metadata">
<span>Added in: v11.7.0, v10.16.0</span>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-brotlioptions" class="type"><brotli options></a></li>
</ul>
<p>Decompress a chunk of data with <a href="#class-zlibbrotlidecompress"><code>BrotliDecompress</code></a>.</p>
<h4><code>zlib.deflate(buffer[, options], callback)</code><span><a class="mark" href="#zlibdeflatebuffer-options-callback" id="zlibdeflatebuffer-options-callback">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_deflate_buffer_options_callback"></a></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v9.4.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>ArrayBuffer</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be any <code>TypedArray</code> or <code>DataView</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>Uint8Array</code> now.</p></td></tr>
<tr><td>v0.6.0</td>
<td><p><span>Added in: v0.6.0</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li>
</ul>
<h4><code>zlib.deflateSync(buffer[, options])</code><span><a class="mark" href="#zlibdeflatesyncbuffer-options" id="zlibdeflatesyncbuffer-options">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_deflatesync_buffer_options"></a></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v9.4.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>ArrayBuffer</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be any <code>TypedArray</code> or <code>DataView</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>Uint8Array</code> now.</p></td></tr>
<tr><td>v0.11.12</td>
<td><p><span>Added in: v0.11.12</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
</ul>
<p>Compress a chunk of data with <a href="#class-zlibdeflate"><code>Deflate</code></a>.</p>
<h4><code>zlib.deflateRaw(buffer[, options], callback)</code><span><a class="mark" href="#zlibdeflaterawbuffer-options-callback" id="zlibdeflaterawbuffer-options-callback">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_deflateraw_buffer_options_callback"></a></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be any <code>TypedArray</code> or <code>DataView</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>Uint8Array</code> now.</p></td></tr>
<tr><td>v0.6.0</td>
<td><p><span>Added in: v0.6.0</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li>
</ul>
<h4><code>zlib.deflateRawSync(buffer[, options])</code><span><a class="mark" href="#zlibdeflaterawsyncbuffer-options" id="zlibdeflaterawsyncbuffer-options">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_deflaterawsync_buffer_options"></a></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v9.4.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>ArrayBuffer</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be any <code>TypedArray</code> or <code>DataView</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>Uint8Array</code> now.</p></td></tr>
<tr><td>v0.11.12</td>
<td><p><span>Added in: v0.11.12</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
</ul>
<p>Compress a chunk of data with <a href="#class-zlibdeflateraw"><code>DeflateRaw</code></a>.</p>
<h4><code>zlib.gunzip(buffer[, options], callback)</code><span><a class="mark" href="#zlibgunzipbuffer-options-callback" id="zlibgunzipbuffer-options-callback">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_gunzip_buffer_options_callback"></a></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v9.4.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>ArrayBuffer</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be any <code>TypedArray</code> or <code>DataView</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>Uint8Array</code> now.</p></td></tr>
<tr><td>v0.6.0</td>
<td><p><span>Added in: v0.6.0</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li>
</ul>
<h4><code>zlib.gunzipSync(buffer[, options])</code><span><a class="mark" href="#zlibgunzipsyncbuffer-options" id="zlibgunzipsyncbuffer-options">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_gunzipsync_buffer_options"></a></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v9.4.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>ArrayBuffer</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be any <code>TypedArray</code> or <code>DataView</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>Uint8Array</code> now.</p></td></tr>
<tr><td>v0.11.12</td>
<td><p><span>Added in: v0.11.12</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
</ul>
<p>Decompress a chunk of data with <a href="#class-zlibgunzip"><code>Gunzip</code></a>.</p>
<h4><code>zlib.gzip(buffer[, options], callback)</code><span><a class="mark" href="#zlibgzipbuffer-options-callback" id="zlibgzipbuffer-options-callback">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_gzip_buffer_options_callback"></a></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v9.4.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>ArrayBuffer</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be any <code>TypedArray</code> or <code>DataView</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>Uint8Array</code> now.</p></td></tr>
<tr><td>v0.6.0</td>
<td><p><span>Added in: v0.6.0</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li>
</ul>
<h4><code>zlib.gzipSync(buffer[, options])</code><span><a class="mark" href="#zlibgzipsyncbuffer-options" id="zlibgzipsyncbuffer-options">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_gzipsync_buffer_options"></a></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v9.4.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>ArrayBuffer</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be any <code>TypedArray</code> or <code>DataView</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>Uint8Array</code> now.</p></td></tr>
<tr><td>v0.11.12</td>
<td><p><span>Added in: v0.11.12</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
</ul>
<p>Compress a chunk of data with <a href="#class-zlibgzip"><code>Gzip</code></a>.</p>
<h4><code>zlib.inflate(buffer[, options], callback)</code><span><a class="mark" href="#zlibinflatebuffer-options-callback" id="zlibinflatebuffer-options-callback">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_inflate_buffer_options_callback"></a></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v9.4.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>ArrayBuffer</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be any <code>TypedArray</code> or <code>DataView</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>Uint8Array</code> now.</p></td></tr>
<tr><td>v0.6.0</td>
<td><p><span>Added in: v0.6.0</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li>
</ul>
<h4><code>zlib.inflateSync(buffer[, options])</code><span><a class="mark" href="#zlibinflatesyncbuffer-options" id="zlibinflatesyncbuffer-options">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_inflatesync_buffer_options"></a></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v9.4.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>ArrayBuffer</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be any <code>TypedArray</code> or <code>DataView</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>Uint8Array</code> now.</p></td></tr>
<tr><td>v0.11.12</td>
<td><p><span>Added in: v0.11.12</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
</ul>
<p>Decompress a chunk of data with <a href="#class-zlibinflate"><code>Inflate</code></a>.</p>
<h4><code>zlib.inflateRaw(buffer[, options], callback)</code><span><a class="mark" href="#zlibinflaterawbuffer-options-callback" id="zlibinflaterawbuffer-options-callback">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_inflateraw_buffer_options_callback"></a></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v9.4.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>ArrayBuffer</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be any <code>TypedArray</code> or <code>DataView</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>Uint8Array</code> now.</p></td></tr>
<tr><td>v0.6.0</td>
<td><p><span>Added in: v0.6.0</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li>
</ul>
<h4><code>zlib.inflateRawSync(buffer[, options])</code><span><a class="mark" href="#zlibinflaterawsyncbuffer-options" id="zlibinflaterawsyncbuffer-options">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_inflaterawsync_buffer_options"></a></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v9.4.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>ArrayBuffer</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be any <code>TypedArray</code> or <code>DataView</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>Uint8Array</code> now.</p></td></tr>
<tr><td>v0.11.12</td>
<td><p><span>Added in: v0.11.12</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
</ul>
<p>Decompress a chunk of data with <a href="#class-zlibinflateraw"><code>InflateRaw</code></a>.</p>
<h4><code>zlib.unzip(buffer[, options], callback)</code><span><a class="mark" href="#zlibunzipbuffer-options-callback" id="zlibunzipbuffer-options-callback">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_unzip_buffer_options_callback"></a></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v9.4.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>ArrayBuffer</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be any <code>TypedArray</code> or <code>DataView</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>Uint8Array</code> now.</p></td></tr>
<tr><td>v0.6.0</td>
<td><p><span>Added in: v0.6.0</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li>
</ul>
<h4><code>zlib.unzipSync(buffer[, options])</code><span><a class="mark" href="#zlibunzipsyncbuffer-options" id="zlibunzipsyncbuffer-options">#</a></span><a aria-hidden="true" class="legacy" id="zlib_zlib_unzipsync_buffer_options"></a></h4>
<div class="api_metadata">
<details class="changelog"><summary>History</summary>
<table>
<tbody><tr><th>Version</th><th>Changes</th></tr>
<tr><td>v9.4.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>ArrayBuffer</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be any <code>TypedArray</code> or <code>DataView</code>.</p></td></tr>
<tr><td>v8.0.0</td>
<td><p>The <code>buffer</code> parameter can be an <code>Uint8Array</code> now.</p></td></tr>
<tr><td>v0.11.12</td>
<td><p><span>Added in: v0.11.12</span></p></td></tr>
</tbody></table>
</details>
</div>
<ul>
<li><code>buffer</code> <a href="buffer.html#class-buffer" class="type"><Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li>
<li><code>options</code> <a href="zlib.html#class-options" class="type"><zlib options></a></li>
</ul>
<p>Decompress a chunk of data with <a href="#class-zlibunzip"><code>Unzip</code></a>.</p></section>
<!-- API END -->
</div>
</div>
</div>
</body>
</html>
|
