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href="#example-readablestream">Example <code>ReadableStream</code></a></li> 128</ul> 129</li> 130<li><a href="#api">API</a> 131<ul> 132<li><a href="#class-readablestream">Class: <code>ReadableStream</code></a> 133<ul> 134<li><a href="#new-readablestreamunderlyingsource--strategy"><code>new ReadableStream([underlyingSource [, strategy]])</code></a></li> 135<li><a href="#readablestreamlocked"><code>readableStream.locked</code></a></li> 136<li><a href="#readablestreamcancelreason"><code>readableStream.cancel([reason])</code></a></li> 137<li><a href="#readablestreamgetreaderoptions"><code>readableStream.getReader([options])</code></a></li> 138<li><a href="#readablestreampipethroughtransform-options"><code>readableStream.pipeThrough(transform[, options])</code></a></li> 139<li><a href="#readablestreampipetodestination-options"><code>readableStream.pipeTo(destination[, options])</code></a></li> 140<li><a href="#readablestreamtee"><code>readableStream.tee()</code></a></li> 141<li><a href="#readablestreamvaluesoptions"><code>readableStream.values([options])</code></a></li> 142<li><a href="#async-iteration">Async Iteration</a></li> 143<li><a href="#transferring-with-postmessage">Transferring with <code>postMessage()</code></a></li> 144</ul> 145</li> 146<li><a href="#class-readablestreamdefaultreader">Class: <code>ReadableStreamDefaultReader</code></a> 147<ul> 148<li><a href="#new-readablestreamdefaultreaderstream"><code>new ReadableStreamDefaultReader(stream)</code></a></li> 149<li><a href="#readablestreamdefaultreadercancelreason"><code>readableStreamDefaultReader.cancel([reason])</code></a></li> 150<li><a href="#readablestreamdefaultreaderclosed"><code>readableStreamDefaultReader.closed</code></a></li> 151<li><a href="#readablestreamdefaultreaderread"><code>readableStreamDefaultReader.read()</code></a></li> 152<li><a href="#readablestreamdefaultreaderreleaselock"><code>readableStreamDefaultReader.releaseLock()</code></a></li> 153</ul> 154</li> 155<li><a href="#class-readablestreambyobreader">Class: <code>ReadableStreamBYOBReader</code></a> 156<ul> 157<li><a href="#new-readablestreambyobreaderstream"><code>new ReadableStreamBYOBReader(stream)</code></a></li> 158<li><a href="#readablestreambyobreadercancelreason"><code>readableStreamBYOBReader.cancel([reason])</code></a></li> 159<li><a href="#readablestreambyobreaderclosed"><code>readableStreamBYOBReader.closed</code></a></li> 160<li><a href="#readablestreambyobreaderreadview"><code>readableStreamBYOBReader.read(view)</code></a></li> 161<li><a href="#readablestreambyobreaderreleaselock"><code>readableStreamBYOBReader.releaseLock()</code></a></li> 162</ul> 163</li> 164<li><a href="#class-readablestreamdefaultcontroller">Class: <code>ReadableStreamDefaultController</code></a> 165<ul> 166<li><a href="#readablestreamdefaultcontrollerclose"><code>readableStreamDefaultController.close()</code></a></li> 167<li><a href="#readablestreamdefaultcontrollerdesiredsize"><code>readableStreamDefaultController.desiredSize</code></a></li> 168<li><a href="#readablestreamdefaultcontrollerenqueuechunk"><code>readableStreamDefaultController.enqueue([chunk])</code></a></li> 169<li><a href="#readablestreamdefaultcontrollererrorerror"><code>readableStreamDefaultController.error([error])</code></a></li> 170</ul> 171</li> 172<li><a href="#class-readablebytestreamcontroller">Class: <code>ReadableByteStreamController</code></a> 173<ul> 174<li><a href="#readablebytestreamcontrollerbyobrequest"><code>readableByteStreamController.byobRequest</code></a></li> 175<li><a href="#readablebytestreamcontrollerclose"><code>readableByteStreamController.close()</code></a></li> 176<li><a href="#readablebytestreamcontrollerdesiredsize"><code>readableByteStreamController.desiredSize</code></a></li> 177<li><a href="#readablebytestreamcontrollerenqueuechunk"><code>readableByteStreamController.enqueue(chunk)</code></a></li> 178<li><a href="#readablebytestreamcontrollererrorerror"><code>readableByteStreamController.error([error])</code></a></li> 179</ul> 180</li> 181<li><a href="#class-readablestreambyobrequest">Class: <code>ReadableStreamBYOBRequest</code></a> 182<ul> 183<li><a href="#readablestreambyobrequestrespondbyteswritten"><code>readableStreamBYOBRequest.respond(bytesWritten)</code></a></li> 184<li><a href="#readablestreambyobrequestrespondwithnewviewview"><code>readableStreamBYOBRequest.respondWithNewView(view)</code></a></li> 185<li><a href="#readablestreambyobrequestview"><code>readableStreamBYOBRequest.view</code></a></li> 186</ul> 187</li> 188<li><a href="#class-writablestream">Class: <code>WritableStream</code></a> 189<ul> 190<li><a href="#new-writablestreamunderlyingsink-strategy"><code>new WritableStream([underlyingSink[, strategy]])</code></a></li> 191<li><a href="#writablestreamabortreason"><code>writableStream.abort([reason])</code></a></li> 192<li><a href="#writablestreamclose"><code>writableStream.close()</code></a></li> 193<li><a href="#writablestreamgetwriter"><code>writableStream.getWriter()</code></a></li> 194<li><a href="#writablestreamlocked"><code>writableStream.locked</code></a></li> 195<li><a href="#transferring-with-postmessage_1">Transferring with postMessage()</a></li> 196</ul> 197</li> 198<li><a href="#class-writablestreamdefaultwriter">Class: <code>WritableStreamDefaultWriter</code></a> 199<ul> 200<li><a href="#new-writablestreamdefaultwriterstream"><code>new WritableStreamDefaultWriter(stream)</code></a></li> 201<li><a href="#writablestreamdefaultwriterabortreason"><code>writableStreamDefaultWriter.abort([reason])</code></a></li> 202<li><a href="#writablestreamdefaultwriterclose"><code>writableStreamDefaultWriter.close()</code></a></li> 203<li><a href="#writablestreamdefaultwriterclosed"><code>writableStreamDefaultWriter.closed</code></a></li> 204<li><a href="#writablestreamdefaultwriterdesiredsize"><code>writableStreamDefaultWriter.desiredSize</code></a></li> 205<li><a href="#writablestreamdefaultwriterready"><code>writableStreamDefaultWriter.ready</code></a></li> 206<li><a href="#writablestreamdefaultwriterreleaselock"><code>writableStreamDefaultWriter.releaseLock()</code></a></li> 207<li><a href="#writablestreamdefaultwriterwritechunk"><code>writableStreamDefaultWriter.write([chunk])</code></a></li> 208</ul> 209</li> 210<li><a href="#class-writablestreamdefaultcontroller">Class: <code>WritableStreamDefaultController</code></a> 211<ul> 212<li><a href="#writablestreamdefaultcontrollererrorerror"><code>writableStreamDefaultController.error([error])</code></a></li> 213<li><a href="#writablestreamdefaultcontrollersignal"><code>writableStreamDefaultController.signal</code></a></li> 214</ul> 215</li> 216<li><a href="#class-transformstream">Class: <code>TransformStream</code></a> 217<ul> 218<li><a href="#new-transformstreamtransformer-writablestrategy-readablestrategy"><code>new TransformStream([transformer[, writableStrategy[, readableStrategy]]])</code></a></li> 219<li><a href="#transformstreamreadable"><code>transformStream.readable</code></a></li> 220<li><a href="#transformstreamwritable"><code>transformStream.writable</code></a></li> 221<li><a href="#transferring-with-postmessage_2">Transferring with postMessage()</a></li> 222</ul> 223</li> 224<li><a href="#class-transformstreamdefaultcontroller">Class: <code>TransformStreamDefaultController</code></a> 225<ul> 226<li><a href="#transformstreamdefaultcontrollerdesiredsize"><code>transformStreamDefaultController.desiredSize</code></a></li> 227<li><a href="#transformstreamdefaultcontrollerenqueuechunk"><code>transformStreamDefaultController.enqueue([chunk])</code></a></li> 228<li><a href="#transformstreamdefaultcontrollererrorreason"><code>transformStreamDefaultController.error([reason])</code></a></li> 229<li><a href="#transformstreamdefaultcontrollerterminate"><code>transformStreamDefaultController.terminate()</code></a></li> 230</ul> 231</li> 232<li><a href="#class-bytelengthqueuingstrategy">Class: <code>ByteLengthQueuingStrategy</code></a> 233<ul> 234<li><a href="#new-bytelengthqueuingstrategyoptions"><code>new ByteLengthQueuingStrategy(options)</code></a></li> 235<li><a href="#bytelengthqueuingstrategyhighwatermark"><code>byteLengthQueuingStrategy.highWaterMark</code></a></li> 236<li><a href="#bytelengthqueuingstrategysize"><code>byteLengthQueuingStrategy.size</code></a></li> 237</ul> 238</li> 239<li><a href="#class-countqueuingstrategy">Class: <code>CountQueuingStrategy</code></a> 240<ul> 241<li><a href="#new-countqueuingstrategyoptions"><code>new CountQueuingStrategy(options)</code></a></li> 242<li><a href="#countqueuingstrategyhighwatermark"><code>countQueuingStrategy.highWaterMark</code></a></li> 243<li><a href="#countqueuingstrategysize"><code>countQueuingStrategy.size</code></a></li> 244</ul> 245</li> 246<li><a href="#class-textencoderstream">Class: <code>TextEncoderStream</code></a> 247<ul> 248<li><a href="#new-textencoderstream"><code>new TextEncoderStream()</code></a></li> 249<li><a href="#textencoderstreamencoding"><code>textEncoderStream.encoding</code></a></li> 250<li><a href="#textencoderstreamreadable"><code>textEncoderStream.readable</code></a></li> 251<li><a href="#textencoderstreamwritable"><code>textEncoderStream.writable</code></a></li> 252</ul> 253</li> 254<li><a href="#class-textdecoderstream">Class: <code>TextDecoderStream</code></a> 255<ul> 256<li><a href="#new-textdecoderstreamencoding-options"><code>new TextDecoderStream([encoding[, options]])</code></a></li> 257<li><a href="#textdecoderstreamencoding"><code>textDecoderStream.encoding</code></a></li> 258<li><a href="#textdecoderstreamfatal"><code>textDecoderStream.fatal</code></a></li> 259<li><a href="#textdecoderstreamignorebom"><code>textDecoderStream.ignoreBOM</code></a></li> 260<li><a href="#textdecoderstreamreadable"><code>textDecoderStream.readable</code></a></li> 261<li><a href="#textdecoderstreamwritable"><code>textDecoderStream.writable</code></a></li> 262</ul> 263</li> 264<li><a href="#class-compressionstream">Class: <code>CompressionStream</code></a> 265<ul> 266<li><a href="#new-compressionstreamformat"><code>new CompressionStream(format)</code></a></li> 267<li><a href="#compressionstreamreadable"><code>compressionStream.readable</code></a></li> 268<li><a href="#compressionstreamwritable"><code>compressionStream.writable</code></a></li> 269</ul> 270</li> 271<li><a href="#class-decompressionstream">Class: <code>DecompressionStream</code></a> 272<ul> 273<li><a href="#new-decompressionstreamformat"><code>new DecompressionStream(format)</code></a></li> 274<li><a href="#decompressionstreamreadable"><code>decompressionStream.readable</code></a></li> 275<li><a href="#decompressionstreamwritable"><code>decompressionStream.writable</code></a></li> 276</ul> 277</li> 278<li><a href="#utility-consumers">Utility Consumers</a> 279<ul> 280<li><a href="#streamconsumersarraybufferstream"><code>streamConsumers.arrayBuffer(stream)</code></a></li> 281<li><a href="#streamconsumersblobstream"><code>streamConsumers.blob(stream)</code></a></li> 282<li><a href="#streamconsumersbufferstream"><code>streamConsumers.buffer(stream)</code></a></li> 283<li><a href="#streamconsumersjsonstream"><code>streamConsumers.json(stream)</code></a></li> 284<li><a href="#streamconsumerstextstream"><code>streamConsumers.text(stream)</code></a></li> 285</ul> 286</li> 287</ul> 288</li> 289</ul> 290</li> 291</ul></div></div> 292 </li> 293 294 295 <li class="picker-header"> 296 <a href="#"> 297 <span class="collapsed-arrow">►</span><span class="expanded-arrow">▼</span> 298 Index 299 </a> 300 301 <div class="picker"><ul> 302<li><a href="documentation.html" class="nav-documentation">About this documentation</a></li> 303<li><a href="synopsis.html" class="nav-synopsis">Usage and 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class="nav-readline">Readline</a></li> 352<li><a href="repl.html" class="nav-repl">REPL</a></li> 353<li><a href="report.html" class="nav-report">Report</a></li> 354<li><a href="single-executable-applications.html" class="nav-single-executable-applications">Single executable applications</a></li> 355<li><a href="stream.html" class="nav-stream">Stream</a></li> 356<li><a href="string_decoder.html" class="nav-string_decoder">String decoder</a></li> 357<li><a href="test.html" class="nav-test">Test runner</a></li> 358<li><a href="timers.html" class="nav-timers">Timers</a></li> 359<li><a href="tls.html" class="nav-tls">TLS/SSL</a></li> 360<li><a href="tracing.html" class="nav-tracing">Trace events</a></li> 361<li><a href="tty.html" class="nav-tty">TTY</a></li> 362<li><a href="dgram.html" class="nav-dgram">UDP/datagram</a></li> 363<li><a href="url.html" class="nav-url">URL</a></li> 364<li><a href="util.html" class="nav-util">Utilities</a></li> 365<li><a href="v8.html" class="nav-v8">V8</a></li> 366<li><a href="vm.html" class="nav-vm">VM</a></li> 367<li><a href="wasi.html" class="nav-wasi">WASI</a></li> 368<li><a href="webcrypto.html" class="nav-webcrypto">Web Crypto API</a></li> 369<li><a href="webstreams.html" class="nav-webstreams active">Web Streams API</a></li> 370<li><a href="worker_threads.html" class="nav-worker_threads">Worker threads</a></li> 371<li><a href="zlib.html" class="nav-zlib">Zlib</a></li> 372</ul> 373<hr class="line"> 374<ul> 375<li><a href="https://github.com/nodejs/node" class="nav-https-github-com-nodejs-node">Code repository and issue tracker</a></li> 376</ul></div> 377 </li> 378 379 380 <li class="picker-header"> 381 <a href="#"> 382 <span class="collapsed-arrow">►</span><span class="expanded-arrow">▼</span> 383 Other versions 384 </a> 385 <div class="picker"><ol id="alt-docs"><li><a href="https://nodejs.org/docs/latest-v20.x/api/webstreams.html">20.x</a></li> 386<li><a href="https://nodejs.org/docs/latest-v19.x/api/webstreams.html">19.x</a></li> 387<li><a href="https://nodejs.org/docs/latest-v18.x/api/webstreams.html">18.x <b>LTS</b></a></li> 388<li><a href="https://nodejs.org/docs/latest-v17.x/api/webstreams.html">17.x</a></li> 389<li><a href="https://nodejs.org/docs/latest-v16.x/api/webstreams.html">16.x</a></li></ol></div> 390 </li> 391 392 <li class="picker-header"> 393 <a href="#"> 394 <span class="collapsed-arrow">►</span><span class="expanded-arrow">▼</span> 395 Options 396 </a> 397 398 <div class="picker"> 399 <ul> 400 <li> 401 <a href="all.html">View on single page</a> 402 </li> 403 <li> 404 <a href="webstreams.json">View as JSON</a> 405 </li> 406 <li class="edit_on_github"><a href="https://github.com/nodejs/node/edit/main/doc/api/webstreams.md">Edit on GitHub</a></li> 407 </ul> 408 </div> 409 </li> 410 </ul> 411 </div> 412 <hr> 413 </header> 414 415 <details id="toc" open><summary>Table of contents</summary><ul> 416<li><span class="stability_1"><a href="#web-streams-api">Web Streams API</a></span> 417<ul> 418<li><a href="#overview">Overview</a> 419<ul> 420<li><a href="#example-readablestream">Example <code>ReadableStream</code></a></li> 421</ul> 422</li> 423<li><a href="#api">API</a> 424<ul> 425<li><a href="#class-readablestream">Class: <code>ReadableStream</code></a> 426<ul> 427<li><a href="#new-readablestreamunderlyingsource--strategy"><code>new ReadableStream([underlyingSource [, strategy]])</code></a></li> 428<li><a href="#readablestreamlocked"><code>readableStream.locked</code></a></li> 429<li><a href="#readablestreamcancelreason"><code>readableStream.cancel([reason])</code></a></li> 430<li><a href="#readablestreamgetreaderoptions"><code>readableStream.getReader([options])</code></a></li> 431<li><a href="#readablestreampipethroughtransform-options"><code>readableStream.pipeThrough(transform[, options])</code></a></li> 432<li><a href="#readablestreampipetodestination-options"><code>readableStream.pipeTo(destination[, options])</code></a></li> 433<li><a href="#readablestreamtee"><code>readableStream.tee()</code></a></li> 434<li><a href="#readablestreamvaluesoptions"><code>readableStream.values([options])</code></a></li> 435<li><a href="#async-iteration">Async Iteration</a></li> 436<li><a href="#transferring-with-postmessage">Transferring with <code>postMessage()</code></a></li> 437</ul> 438</li> 439<li><a href="#class-readablestreamdefaultreader">Class: <code>ReadableStreamDefaultReader</code></a> 440<ul> 441<li><a href="#new-readablestreamdefaultreaderstream"><code>new ReadableStreamDefaultReader(stream)</code></a></li> 442<li><a href="#readablestreamdefaultreadercancelreason"><code>readableStreamDefaultReader.cancel([reason])</code></a></li> 443<li><a href="#readablestreamdefaultreaderclosed"><code>readableStreamDefaultReader.closed</code></a></li> 444<li><a href="#readablestreamdefaultreaderread"><code>readableStreamDefaultReader.read()</code></a></li> 445<li><a href="#readablestreamdefaultreaderreleaselock"><code>readableStreamDefaultReader.releaseLock()</code></a></li> 446</ul> 447</li> 448<li><a href="#class-readablestreambyobreader">Class: <code>ReadableStreamBYOBReader</code></a> 449<ul> 450<li><a href="#new-readablestreambyobreaderstream"><code>new ReadableStreamBYOBReader(stream)</code></a></li> 451<li><a href="#readablestreambyobreadercancelreason"><code>readableStreamBYOBReader.cancel([reason])</code></a></li> 452<li><a href="#readablestreambyobreaderclosed"><code>readableStreamBYOBReader.closed</code></a></li> 453<li><a href="#readablestreambyobreaderreadview"><code>readableStreamBYOBReader.read(view)</code></a></li> 454<li><a href="#readablestreambyobreaderreleaselock"><code>readableStreamBYOBReader.releaseLock()</code></a></li> 455</ul> 456</li> 457<li><a href="#class-readablestreamdefaultcontroller">Class: <code>ReadableStreamDefaultController</code></a> 458<ul> 459<li><a href="#readablestreamdefaultcontrollerclose"><code>readableStreamDefaultController.close()</code></a></li> 460<li><a href="#readablestreamdefaultcontrollerdesiredsize"><code>readableStreamDefaultController.desiredSize</code></a></li> 461<li><a href="#readablestreamdefaultcontrollerenqueuechunk"><code>readableStreamDefaultController.enqueue([chunk])</code></a></li> 462<li><a href="#readablestreamdefaultcontrollererrorerror"><code>readableStreamDefaultController.error([error])</code></a></li> 463</ul> 464</li> 465<li><a href="#class-readablebytestreamcontroller">Class: <code>ReadableByteStreamController</code></a> 466<ul> 467<li><a href="#readablebytestreamcontrollerbyobrequest"><code>readableByteStreamController.byobRequest</code></a></li> 468<li><a href="#readablebytestreamcontrollerclose"><code>readableByteStreamController.close()</code></a></li> 469<li><a href="#readablebytestreamcontrollerdesiredsize"><code>readableByteStreamController.desiredSize</code></a></li> 470<li><a href="#readablebytestreamcontrollerenqueuechunk"><code>readableByteStreamController.enqueue(chunk)</code></a></li> 471<li><a href="#readablebytestreamcontrollererrorerror"><code>readableByteStreamController.error([error])</code></a></li> 472</ul> 473</li> 474<li><a href="#class-readablestreambyobrequest">Class: <code>ReadableStreamBYOBRequest</code></a> 475<ul> 476<li><a href="#readablestreambyobrequestrespondbyteswritten"><code>readableStreamBYOBRequest.respond(bytesWritten)</code></a></li> 477<li><a href="#readablestreambyobrequestrespondwithnewviewview"><code>readableStreamBYOBRequest.respondWithNewView(view)</code></a></li> 478<li><a href="#readablestreambyobrequestview"><code>readableStreamBYOBRequest.view</code></a></li> 479</ul> 480</li> 481<li><a href="#class-writablestream">Class: <code>WritableStream</code></a> 482<ul> 483<li><a href="#new-writablestreamunderlyingsink-strategy"><code>new WritableStream([underlyingSink[, strategy]])</code></a></li> 484<li><a href="#writablestreamabortreason"><code>writableStream.abort([reason])</code></a></li> 485<li><a href="#writablestreamclose"><code>writableStream.close()</code></a></li> 486<li><a href="#writablestreamgetwriter"><code>writableStream.getWriter()</code></a></li> 487<li><a href="#writablestreamlocked"><code>writableStream.locked</code></a></li> 488<li><a href="#transferring-with-postmessage_1">Transferring with postMessage()</a></li> 489</ul> 490</li> 491<li><a href="#class-writablestreamdefaultwriter">Class: <code>WritableStreamDefaultWriter</code></a> 492<ul> 493<li><a href="#new-writablestreamdefaultwriterstream"><code>new WritableStreamDefaultWriter(stream)</code></a></li> 494<li><a href="#writablestreamdefaultwriterabortreason"><code>writableStreamDefaultWriter.abort([reason])</code></a></li> 495<li><a href="#writablestreamdefaultwriterclose"><code>writableStreamDefaultWriter.close()</code></a></li> 496<li><a href="#writablestreamdefaultwriterclosed"><code>writableStreamDefaultWriter.closed</code></a></li> 497<li><a href="#writablestreamdefaultwriterdesiredsize"><code>writableStreamDefaultWriter.desiredSize</code></a></li> 498<li><a href="#writablestreamdefaultwriterready"><code>writableStreamDefaultWriter.ready</code></a></li> 499<li><a href="#writablestreamdefaultwriterreleaselock"><code>writableStreamDefaultWriter.releaseLock()</code></a></li> 500<li><a href="#writablestreamdefaultwriterwritechunk"><code>writableStreamDefaultWriter.write([chunk])</code></a></li> 501</ul> 502</li> 503<li><a href="#class-writablestreamdefaultcontroller">Class: <code>WritableStreamDefaultController</code></a> 504<ul> 505<li><a href="#writablestreamdefaultcontrollererrorerror"><code>writableStreamDefaultController.error([error])</code></a></li> 506<li><a href="#writablestreamdefaultcontrollersignal"><code>writableStreamDefaultController.signal</code></a></li> 507</ul> 508</li> 509<li><a href="#class-transformstream">Class: <code>TransformStream</code></a> 510<ul> 511<li><a href="#new-transformstreamtransformer-writablestrategy-readablestrategy"><code>new TransformStream([transformer[, writableStrategy[, readableStrategy]]])</code></a></li> 512<li><a href="#transformstreamreadable"><code>transformStream.readable</code></a></li> 513<li><a href="#transformstreamwritable"><code>transformStream.writable</code></a></li> 514<li><a href="#transferring-with-postmessage_2">Transferring with postMessage()</a></li> 515</ul> 516</li> 517<li><a href="#class-transformstreamdefaultcontroller">Class: <code>TransformStreamDefaultController</code></a> 518<ul> 519<li><a href="#transformstreamdefaultcontrollerdesiredsize"><code>transformStreamDefaultController.desiredSize</code></a></li> 520<li><a href="#transformstreamdefaultcontrollerenqueuechunk"><code>transformStreamDefaultController.enqueue([chunk])</code></a></li> 521<li><a href="#transformstreamdefaultcontrollererrorreason"><code>transformStreamDefaultController.error([reason])</code></a></li> 522<li><a href="#transformstreamdefaultcontrollerterminate"><code>transformStreamDefaultController.terminate()</code></a></li> 523</ul> 524</li> 525<li><a href="#class-bytelengthqueuingstrategy">Class: <code>ByteLengthQueuingStrategy</code></a> 526<ul> 527<li><a href="#new-bytelengthqueuingstrategyoptions"><code>new ByteLengthQueuingStrategy(options)</code></a></li> 528<li><a href="#bytelengthqueuingstrategyhighwatermark"><code>byteLengthQueuingStrategy.highWaterMark</code></a></li> 529<li><a href="#bytelengthqueuingstrategysize"><code>byteLengthQueuingStrategy.size</code></a></li> 530</ul> 531</li> 532<li><a href="#class-countqueuingstrategy">Class: <code>CountQueuingStrategy</code></a> 533<ul> 534<li><a href="#new-countqueuingstrategyoptions"><code>new CountQueuingStrategy(options)</code></a></li> 535<li><a href="#countqueuingstrategyhighwatermark"><code>countQueuingStrategy.highWaterMark</code></a></li> 536<li><a href="#countqueuingstrategysize"><code>countQueuingStrategy.size</code></a></li> 537</ul> 538</li> 539<li><a href="#class-textencoderstream">Class: <code>TextEncoderStream</code></a> 540<ul> 541<li><a href="#new-textencoderstream"><code>new TextEncoderStream()</code></a></li> 542<li><a href="#textencoderstreamencoding"><code>textEncoderStream.encoding</code></a></li> 543<li><a href="#textencoderstreamreadable"><code>textEncoderStream.readable</code></a></li> 544<li><a href="#textencoderstreamwritable"><code>textEncoderStream.writable</code></a></li> 545</ul> 546</li> 547<li><a href="#class-textdecoderstream">Class: <code>TextDecoderStream</code></a> 548<ul> 549<li><a href="#new-textdecoderstreamencoding-options"><code>new TextDecoderStream([encoding[, options]])</code></a></li> 550<li><a href="#textdecoderstreamencoding"><code>textDecoderStream.encoding</code></a></li> 551<li><a href="#textdecoderstreamfatal"><code>textDecoderStream.fatal</code></a></li> 552<li><a href="#textdecoderstreamignorebom"><code>textDecoderStream.ignoreBOM</code></a></li> 553<li><a href="#textdecoderstreamreadable"><code>textDecoderStream.readable</code></a></li> 554<li><a href="#textdecoderstreamwritable"><code>textDecoderStream.writable</code></a></li> 555</ul> 556</li> 557<li><a href="#class-compressionstream">Class: <code>CompressionStream</code></a> 558<ul> 559<li><a href="#new-compressionstreamformat"><code>new CompressionStream(format)</code></a></li> 560<li><a href="#compressionstreamreadable"><code>compressionStream.readable</code></a></li> 561<li><a href="#compressionstreamwritable"><code>compressionStream.writable</code></a></li> 562</ul> 563</li> 564<li><a href="#class-decompressionstream">Class: <code>DecompressionStream</code></a> 565<ul> 566<li><a href="#new-decompressionstreamformat"><code>new DecompressionStream(format)</code></a></li> 567<li><a href="#decompressionstreamreadable"><code>decompressionStream.readable</code></a></li> 568<li><a href="#decompressionstreamwritable"><code>decompressionStream.writable</code></a></li> 569</ul> 570</li> 571<li><a href="#utility-consumers">Utility Consumers</a> 572<ul> 573<li><a href="#streamconsumersarraybufferstream"><code>streamConsumers.arrayBuffer(stream)</code></a></li> 574<li><a href="#streamconsumersblobstream"><code>streamConsumers.blob(stream)</code></a></li> 575<li><a href="#streamconsumersbufferstream"><code>streamConsumers.buffer(stream)</code></a></li> 576<li><a href="#streamconsumersjsonstream"><code>streamConsumers.json(stream)</code></a></li> 577<li><a href="#streamconsumerstextstream"><code>streamConsumers.text(stream)</code></a></li> 578</ul> 579</li> 580</ul> 581</li> 582</ul> 583</li> 584</ul></details> 585 586 <div id="apicontent"> 587 <h2>Web Streams API<span><a class="mark" href="#web-streams-api" id="web-streams-api">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_web_streams_api"></a></h2> 588 589<div class="api_metadata"> 590<details class="changelog"><summary>History</summary> 591<table> 592<tbody><tr><th>Version</th><th>Changes</th></tr> 593<tr><td>v18.0.0</td> 594<td><p>Use of this API no longer emit a runtime warning.</p></td></tr> 595<tr><td>v16.5.0</td> 596<td><p><span>Added in: v16.5.0</span></p></td></tr> 597</tbody></table> 598</details> 599</div> 600<p></p><div class="api_stability api_stability_1"><a href="documentation.html#stability-index">Stability: 1</a> - Experimental.</div><p></p> 601<p>An implementation of the <a href="https://streams.spec.whatwg.org/">WHATWG Streams Standard</a>.</p> 602<section><h3>Overview<span><a class="mark" href="#overview" id="overview">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_overview"></a></h3> 603<p>The <a href="https://streams.spec.whatwg.org/">WHATWG Streams Standard</a> (or "web streams") defines an API for handling 604streaming data. It is similar to the Node.js <a href="stream.html">Streams</a> API but emerged later 605and has become the "standard" API for streaming data across many JavaScript 606environments.</p> 607<p>There are three primary types of objects:</p> 608<ul> 609<li><code>ReadableStream</code> - Represents a source of streaming data.</li> 610<li><code>WritableStream</code> - Represents a destination for streaming data.</li> 611<li><code>TransformStream</code> - Represents an algorithm for transforming streaming data.</li> 612</ul> 613<h4>Example <code>ReadableStream</code><span><a class="mark" href="#example-readablestream" id="example-readablestream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_example_readablestream"></a></h4> 614<p>This example creates a simple <code>ReadableStream</code> that pushes the current 615<code>performance.now()</code> timestamp once every second forever. An async iterable 616is used to read the data from the stream.</p> 617 618<pre class="with-17-chars"><input class="js-flavor-selector" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> { 619 <span class="hljs-title class_">ReadableStream</span>, 620} <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream/web'</span>; 621 622<span class="hljs-keyword">import</span> { 623 <span class="hljs-built_in">setInterval</span> <span class="hljs-keyword">as</span> every, 624} <span class="hljs-keyword">from</span> <span class="hljs-string">'node:timers/promises'</span>; 625 626<span class="hljs-keyword">import</span> { 627 performance, 628} <span class="hljs-keyword">from</span> <span class="hljs-string">'node:perf_hooks'</span>; 629 630<span class="hljs-keyword">const</span> <span class="hljs-variable constant_">SECOND</span> = <span class="hljs-number">1000</span>; 631 632<span class="hljs-keyword">const</span> stream = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ReadableStream</span>({ 633 <span class="hljs-keyword">async</span> <span class="hljs-title function_">start</span>(<span class="hljs-params">controller</span>) { 634 <span class="hljs-keyword">for</span> <span class="hljs-keyword">await</span> (<span class="hljs-keyword">const</span> _ <span class="hljs-keyword">of</span> <span class="hljs-title function_">every</span>(<span class="hljs-variable constant_">SECOND</span>)) 635 controller.<span class="hljs-title function_">enqueue</span>(performance.<span class="hljs-title function_">now</span>()); 636 }, 637}); 638 639<span class="hljs-keyword">for</span> <span class="hljs-keyword">await</span> (<span class="hljs-keyword">const</span> value <span class="hljs-keyword">of</span> stream) 640 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(value);</code><code class="language-js cjs"><span class="hljs-keyword">const</span> { 641 <span class="hljs-title class_">ReadableStream</span>, 642} = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream/web'</span>); 643 644<span class="hljs-keyword">const</span> { 645 <span class="hljs-attr">setInterval</span>: every, 646} = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:timers/promises'</span>); 647 648<span class="hljs-keyword">const</span> { 649 performance, 650} = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:perf_hooks'</span>); 651 652<span class="hljs-keyword">const</span> <span class="hljs-variable constant_">SECOND</span> = <span class="hljs-number">1000</span>; 653 654<span class="hljs-keyword">const</span> stream = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ReadableStream</span>({ 655 <span class="hljs-keyword">async</span> <span class="hljs-title function_">start</span>(<span class="hljs-params">controller</span>) { 656 <span class="hljs-keyword">for</span> <span class="hljs-keyword">await</span> (<span class="hljs-keyword">const</span> _ <span class="hljs-keyword">of</span> <span class="hljs-title function_">every</span>(<span class="hljs-variable constant_">SECOND</span>)) 657 controller.<span class="hljs-title function_">enqueue</span>(performance.<span class="hljs-title function_">now</span>()); 658 }, 659}); 660 661(<span class="hljs-keyword">async</span> () => { 662 <span class="hljs-keyword">for</span> <span class="hljs-keyword">await</span> (<span class="hljs-keyword">const</span> value <span class="hljs-keyword">of</span> stream) 663 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(value); 664})();</code><button class="copy-button">copy</button></pre> 665</section><section><h3>API<span><a class="mark" href="#api" id="api">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_api"></a></h3> 666<h4>Class: <code>ReadableStream</code><span><a class="mark" href="#class-readablestream" id="class-readablestream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_readablestream"></a></h4> 667<div class="api_metadata"> 668<details class="changelog"><summary>History</summary> 669<table> 670<tbody><tr><th>Version</th><th>Changes</th></tr> 671<tr><td>v18.0.0</td> 672<td><p>This class is now exposed on the global object.</p></td></tr> 673<tr><td>v16.5.0</td> 674<td><p><span>Added in: v16.5.0</span></p></td></tr> 675</tbody></table> 676</details> 677</div> 678<h5><code>new ReadableStream([underlyingSource [, strategy]])</code><span><a class="mark" href="#new-readablestreamunderlyingsource--strategy" id="new-readablestreamunderlyingsource--strategy">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_new_readablestream_underlyingsource_strategy"></a></h5> 679<div class="api_metadata"> 680<span>Added in: v16.5.0</span> 681</div> 682<!--lint disable maximum-line-length remark-lint--> 683<ul> 684<li><code>underlyingSource</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 685<ul> 686<li><code>start</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> A user-defined function that is invoked immediately when 687the <code>ReadableStream</code> is created. 688<ul> 689<li><code>controller</code> <a href="webstreams.html#class-readablestreamdefaultcontroller" class="type"><ReadableStreamDefaultController></a> | <a href="webstreams.html#class-readablebytestreamcontroller" class="type"><ReadableByteStreamController></a></li> 690<li>Returns: <code>undefined</code> or a promise fulfilled with <code>undefined</code>.</li> 691</ul> 692</li> 693<li><code>pull</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> A user-defined function that is called repeatedly when the 694<code>ReadableStream</code> internal queue is not full. The operation may be sync or 695async. If async, the function will not be called again until the previously 696returned promise is fulfilled. 697<ul> 698<li><code>controller</code> <a href="webstreams.html#class-readablestreamdefaultcontroller" class="type"><ReadableStreamDefaultController></a> | <a href="webstreams.html#class-readablebytestreamcontroller" class="type"><ReadableByteStreamController></a></li> 699<li>Returns: A promise fulfilled with <code>undefined</code>.</li> 700</ul> 701</li> 702<li><code>cancel</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> A user-defined function that is called when the 703<code>ReadableStream</code> is canceled. 704<ul> 705<li><code>reason</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 706<li>Returns: A promise fulfilled with <code>undefined</code>.</li> 707</ul> 708</li> 709<li><code>type</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Must be <code>'bytes'</code> or <code>undefined</code>.</li> 710<li><code>autoAllocateChunkSize</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Used only when <code>type</code> is equal to 711<code>'bytes'</code>. When set to a non-zero value a view buffer is automatically 712allocated to <code>ReadableByteStreamController.byobRequest</code>. When not set 713one must use stream's internal queues to transfer data via the default 714reader <code>ReadableStreamDefaultReader</code>.</li> 715</ul> 716</li> 717<li><code>strategy</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 718<ul> 719<li><code>highWaterMark</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> The maximum internal queue size before backpressure 720is applied.</li> 721<li><code>size</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> A user-defined function used to identify the size of each 722chunk of data. 723<ul> 724<li><code>chunk</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 725<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 726</ul> 727</li> 728</ul> 729</li> 730</ul> 731<!--lint enable maximum-line-length remark-lint--> 732<h5><code>readableStream.locked</code><span><a class="mark" href="#readablestreamlocked" id="readablestreamlocked">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestream_locked"></a></h5> 733<div class="api_metadata"> 734<span>Added in: v16.5.0</span> 735</div> 736<ul> 737<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> Set to <code>true</code> if there is an active reader for this 738<a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a>.</li> 739</ul> 740<p>The <code>readableStream.locked</code> property is <code>false</code> by default, and is 741switched to <code>true</code> while there is an active reader consuming the 742stream's data.</p> 743<h5><code>readableStream.cancel([reason])</code><span><a class="mark" href="#readablestreamcancelreason" id="readablestreamcancelreason">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestream_cancel_reason"></a></h5> 744<div class="api_metadata"> 745<span>Added in: v16.5.0</span> 746</div> 747<ul> 748<li><code>reason</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 749<li>Returns: A promise fulfilled with <code>undefined</code> once cancelation has 750been completed.</li> 751</ul> 752<h5><code>readableStream.getReader([options])</code><span><a class="mark" href="#readablestreamgetreaderoptions" id="readablestreamgetreaderoptions">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestream_getreader_options"></a></h5> 753<div class="api_metadata"> 754<span>Added in: v16.5.0</span> 755</div> 756<ul> 757<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 758<ul> 759<li><code>mode</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> <code>'byob'</code> or <code>undefined</code></li> 760</ul> 761</li> 762<li>Returns: <a href="webstreams.html#class-readablestreamdefaultreader" class="type"><ReadableStreamDefaultReader></a> | <a href="webstreams.html#class-readablestreambyobreader" class="type"><ReadableStreamBYOBReader></a></li> 763</ul> 764 765<pre class="with-54-chars"><input class="js-flavor-selector" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> { <span class="hljs-title class_">ReadableStream</span> } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream/web'</span>; 766 767<span class="hljs-keyword">const</span> stream = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ReadableStream</span>(); 768 769<span class="hljs-keyword">const</span> reader = stream.<span class="hljs-title function_">getReader</span>(); 770 771<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-keyword">await</span> reader.<span class="hljs-title function_">read</span>());</code><code class="language-js cjs"><span class="hljs-keyword">const</span> { <span class="hljs-title class_">ReadableStream</span> } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream/web'</span>); 772 773<span class="hljs-keyword">const</span> stream = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ReadableStream</span>(); 774 775<span class="hljs-keyword">const</span> reader = stream.<span class="hljs-title function_">getReader</span>(); 776 777reader.<span class="hljs-title function_">read</span>().<span class="hljs-title function_">then</span>(<span class="hljs-variable language_">console</span>.<span class="hljs-property">log</span>);</code><button class="copy-button">copy</button></pre> 778<p>Causes the <code>readableStream.locked</code> to be <code>true</code>.</p> 779<h5><code>readableStream.pipeThrough(transform[, options])</code><span><a class="mark" href="#readablestreampipethroughtransform-options" id="readablestreampipethroughtransform-options">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestream_pipethrough_transform_options"></a></h5> 780<div class="api_metadata"> 781<span>Added in: v16.5.0</span> 782</div> 783<ul> 784<li><code>transform</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 785<ul> 786<li><code>readable</code> <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> The <code>ReadableStream</code> to which 787<code>transform.writable</code> will push the potentially modified data 788is receives from this <code>ReadableStream</code>.</li> 789<li><code>writable</code> <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a> The <code>WritableStream</code> to which this 790<code>ReadableStream</code>'s data will be written.</li> 791</ul> 792</li> 793<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 794<ul> 795<li><code>preventAbort</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> When <code>true</code>, errors in this <code>ReadableStream</code> 796will not cause <code>transform.writable</code> to be aborted.</li> 797<li><code>preventCancel</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> When <code>true</code>, errors in the destination 798<code>transform.writable</code> do not cause this <code>ReadableStream</code> to be 799canceled.</li> 800<li><code>preventClose</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> When <code>true</code>, closing this <code>ReadableStream</code> 801does not cause <code>transform.writable</code> to be closed.</li> 802<li><code>signal</code> <a href="globals.html#class-abortsignal" class="type"><AbortSignal></a> Allows the transfer of data to be canceled 803using an <a href="globals.html#class-abortcontroller" class="type"><AbortController></a>.</li> 804</ul> 805</li> 806<li>Returns: <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> From <code>transform.readable</code>.</li> 807</ul> 808<p>Connects this <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> to the pair of <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> and 809<a href="webstreams.html#class-writablestream" class="type"><WritableStream></a> provided in the <code>transform</code> argument such that the 810data from this <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> is written in to <code>transform.writable</code>, 811possibly transformed, then pushed to <code>transform.readable</code>. Once the 812pipeline is configured, <code>transform.readable</code> is returned.</p> 813<p>Causes the <code>readableStream.locked</code> to be <code>true</code> while the pipe operation 814is active.</p> 815 816<pre class="with-17-chars"><input class="js-flavor-selector" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> { 817 <span class="hljs-title class_">ReadableStream</span>, 818 <span class="hljs-title class_">TransformStream</span>, 819} <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream/web'</span>; 820 821<span class="hljs-keyword">const</span> stream = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ReadableStream</span>({ 822 <span class="hljs-title function_">start</span>(<span class="hljs-params">controller</span>) { 823 controller.<span class="hljs-title function_">enqueue</span>(<span class="hljs-string">'a'</span>); 824 }, 825}); 826 827<span class="hljs-keyword">const</span> transform = <span class="hljs-keyword">new</span> <span class="hljs-title class_">TransformStream</span>({ 828 <span class="hljs-title function_">transform</span>(<span class="hljs-params">chunk, controller</span>) { 829 controller.<span class="hljs-title function_">enqueue</span>(chunk.<span class="hljs-title function_">toUpperCase</span>()); 830 }, 831}); 832 833<span class="hljs-keyword">const</span> transformedStream = stream.<span class="hljs-title function_">pipeThrough</span>(transform); 834 835<span class="hljs-keyword">for</span> <span class="hljs-keyword">await</span> (<span class="hljs-keyword">const</span> chunk <span class="hljs-keyword">of</span> transformedStream) 836 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(chunk);</code><code class="language-js cjs"><span class="hljs-keyword">const</span> { 837 <span class="hljs-title class_">ReadableStream</span>, 838 <span class="hljs-title class_">TransformStream</span>, 839} = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream/web'</span>); 840 841<span class="hljs-keyword">const</span> stream = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ReadableStream</span>({ 842 <span class="hljs-title function_">start</span>(<span class="hljs-params">controller</span>) { 843 controller.<span class="hljs-title function_">enqueue</span>(<span class="hljs-string">'a'</span>); 844 }, 845}); 846 847<span class="hljs-keyword">const</span> transform = <span class="hljs-keyword">new</span> <span class="hljs-title class_">TransformStream</span>({ 848 <span class="hljs-title function_">transform</span>(<span class="hljs-params">chunk, controller</span>) { 849 controller.<span class="hljs-title function_">enqueue</span>(chunk.<span class="hljs-title function_">toUpperCase</span>()); 850 }, 851}); 852 853<span class="hljs-keyword">const</span> transformedStream = stream.<span class="hljs-title function_">pipeThrough</span>(transform); 854 855(<span class="hljs-keyword">async</span> () => { 856 <span class="hljs-keyword">for</span> <span class="hljs-keyword">await</span> (<span class="hljs-keyword">const</span> chunk <span class="hljs-keyword">of</span> transformedStream) 857 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(chunk); 858})();</code><button class="copy-button">copy</button></pre> 859<h5><code>readableStream.pipeTo(destination[, options])</code><span><a class="mark" href="#readablestreampipetodestination-options" id="readablestreampipetodestination-options">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestream_pipeto_destination_options"></a></h5> 860<div class="api_metadata"> 861<span>Added in: v16.5.0</span> 862</div> 863<ul> 864<li><code>destination</code> <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a> A <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a> to which this 865<code>ReadableStream</code>'s data will be written.</li> 866<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 867<ul> 868<li><code>preventAbort</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> When <code>true</code>, errors in this <code>ReadableStream</code> 869will not cause <code>destination</code> to be aborted.</li> 870<li><code>preventCancel</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> When <code>true</code>, errors in the <code>destination</code> 871will not cause this <code>ReadableStream</code> to be canceled.</li> 872<li><code>preventClose</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> When <code>true</code>, closing this <code>ReadableStream</code> 873does not cause <code>destination</code> to be closed.</li> 874<li><code>signal</code> <a href="globals.html#class-abortsignal" class="type"><AbortSignal></a> Allows the transfer of data to be canceled 875using an <a href="globals.html#class-abortcontroller" class="type"><AbortController></a>.</li> 876</ul> 877</li> 878<li>Returns: A promise fulfilled with <code>undefined</code></li> 879</ul> 880<p>Causes the <code>readableStream.locked</code> to be <code>true</code> while the pipe operation 881is active.</p> 882<h5><code>readableStream.tee()</code><span><a class="mark" href="#readablestreamtee" id="readablestreamtee">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestream_tee"></a></h5> 883<div class="api_metadata"> 884<details class="changelog"><summary>History</summary> 885<table> 886<tbody><tr><th>Version</th><th>Changes</th></tr> 887<tr><td>v18.10.0</td> 888<td><p>Support teeing a readable byte stream.</p></td></tr> 889<tr><td>v16.5.0</td> 890<td><p><span>Added in: v16.5.0</span></p></td></tr> 891</tbody></table> 892</details> 893</div> 894<ul> 895<li>Returns: <a href="webstreams.html#class-readablestream" class="type"><ReadableStream[]></a></li> 896</ul> 897<p>Returns a pair of new <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> instances to which this 898<code>ReadableStream</code>'s data will be forwarded. Each will receive the 899same data.</p> 900<p>Causes the <code>readableStream.locked</code> to be <code>true</code>.</p> 901<h5><code>readableStream.values([options])</code><span><a class="mark" href="#readablestreamvaluesoptions" id="readablestreamvaluesoptions">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestream_values_options"></a></h5> 902<div class="api_metadata"> 903<span>Added in: v16.5.0</span> 904</div> 905<ul> 906<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 907<ul> 908<li><code>preventCancel</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> When <code>true</code>, prevents the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> 909from being closed when the async iterator abruptly terminates. 910<strong>Default</strong>: <code>false</code>.</li> 911</ul> 912</li> 913</ul> 914<p>Creates and returns an async iterator usable for consuming this 915<code>ReadableStream</code>'s data.</p> 916<p>Causes the <code>readableStream.locked</code> to be <code>true</code> while the async iterator 917is active.</p> 918<pre><code class="language-js mjs"><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>; 919 920<span class="hljs-keyword">const</span> stream = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ReadableStream</span>(<span class="hljs-title function_">getSomeSource</span>()); 921 922<span class="hljs-keyword">for</span> <span class="hljs-keyword">await</span> (<span class="hljs-keyword">const</span> chunk <span class="hljs-keyword">of</span> stream.<span class="hljs-title function_">values</span>({ <span class="hljs-attr">preventCancel</span>: <span class="hljs-literal">true</span> })) 923 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>(chunk).<span class="hljs-title function_">toString</span>());</code> <button class="copy-button">copy</button></pre> 924<h5>Async Iteration<span><a class="mark" href="#async-iteration" id="async-iteration">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_async_iteration"></a></h5> 925<p>The <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> object supports the async iterator protocol using 926<code>for await</code> syntax.</p> 927<pre><code class="language-js mjs"><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>; 928 929<span class="hljs-keyword">const</span> stream = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ReadableStream</span>(<span class="hljs-title function_">getSomeSource</span>()); 930 931<span class="hljs-keyword">for</span> <span class="hljs-keyword">await</span> (<span class="hljs-keyword">const</span> chunk <span class="hljs-keyword">of</span> stream) 932 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>(chunk).<span class="hljs-title function_">toString</span>());</code> <button class="copy-button">copy</button></pre> 933<p>The async iterator will consume the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> until it terminates.</p> 934<p>By default, if the async iterator exits early (via either a <code>break</code>, 935<code>return</code>, or a <code>throw</code>), the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> will be closed. To prevent 936automatic closing of the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a>, use the <code>readableStream.values()</code> 937method to acquire the async iterator and set the <code>preventCancel</code> option to 938<code>true</code>.</p> 939<p>The <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> must not be locked (that is, it must not have an existing 940active reader). During the async iteration, the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> will be locked.</p> 941<h5>Transferring with <code>postMessage()</code><span><a class="mark" href="#transferring-with-postmessage" id="transferring-with-postmessage">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_transferring_with_postmessage"></a></h5> 942<p>A <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> instance can be transferred using a <a href="worker_threads.html#class-messageport" class="type"><MessagePort></a>.</p> 943<pre><code class="language-js"><span class="hljs-keyword">const</span> stream = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ReadableStream</span>(<span class="hljs-title function_">getReadableSourceSomehow</span>()); 944 945<span class="hljs-keyword">const</span> { port1, port2 } = <span class="hljs-keyword">new</span> <span class="hljs-title class_">MessageChannel</span>(); 946 947port1.<span class="hljs-property">onmessage</span> = <span class="hljs-function">(<span class="hljs-params">{ data }</span>) =></span> { 948 data.<span class="hljs-title function_">getReader</span>().<span class="hljs-title function_">read</span>().<span class="hljs-title function_">then</span>(<span class="hljs-function">(<span class="hljs-params">chunk</span>) =></span> { 949 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(chunk); 950 }); 951}; 952 953port2.<span class="hljs-title function_">postMessage</span>(stream, [stream]);</code> <button class="copy-button">copy</button></pre> 954<h4>Class: <code>ReadableStreamDefaultReader</code><span><a class="mark" href="#class-readablestreamdefaultreader" id="class-readablestreamdefaultreader">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_readablestreamdefaultreader"></a></h4> 955<div class="api_metadata"> 956<details class="changelog"><summary>History</summary> 957<table> 958<tbody><tr><th>Version</th><th>Changes</th></tr> 959<tr><td>v18.0.0</td> 960<td><p>This class is now exposed on the global object.</p></td></tr> 961<tr><td>v16.5.0</td> 962<td><p><span>Added in: v16.5.0</span></p></td></tr> 963</tbody></table> 964</details> 965</div> 966<p>By default, calling <code>readableStream.getReader()</code> with no arguments 967will return an instance of <code>ReadableStreamDefaultReader</code>. The default 968reader treats the chunks of data passed through the stream as opaque 969values, which allows the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> to work with generally any 970JavaScript value.</p> 971<h5><code>new ReadableStreamDefaultReader(stream)</code><span><a class="mark" href="#new-readablestreamdefaultreaderstream" id="new-readablestreamdefaultreaderstream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_new_readablestreamdefaultreader_stream"></a></h5> 972<div class="api_metadata"> 973<span>Added in: v16.5.0</span> 974</div> 975<ul> 976<li><code>stream</code> <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a></li> 977</ul> 978<p>Creates a new <a href="webstreams.html#class-readablestreamdefaultreader" class="type"><ReadableStreamDefaultReader></a> that is locked to the 979given <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a>.</p> 980<h5><code>readableStreamDefaultReader.cancel([reason])</code><span><a class="mark" href="#readablestreamdefaultreadercancelreason" id="readablestreamdefaultreadercancelreason">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestreamdefaultreader_cancel_reason"></a></h5> 981<div class="api_metadata"> 982<span>Added in: v16.5.0</span> 983</div> 984<ul> 985<li><code>reason</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 986<li>Returns: A promise fulfilled with <code>undefined</code>.</li> 987</ul> 988<p>Cancels the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> and returns a promise that is fulfilled 989when the underlying stream has been canceled.</p> 990<h5><code>readableStreamDefaultReader.closed</code><span><a class="mark" href="#readablestreamdefaultreaderclosed" id="readablestreamdefaultreaderclosed">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestreamdefaultreader_closed"></a></h5> 991<div class="api_metadata"> 992<span>Added in: v16.5.0</span> 993</div> 994<ul> 995<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise" class="type"><Promise></a> Fulfilled with <code>undefined</code> when the associated 996<a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> is closed or rejected if the stream errors or the reader's 997lock is released before the stream finishes closing.</li> 998</ul> 999<h5><code>readableStreamDefaultReader.read()</code><span><a class="mark" href="#readablestreamdefaultreaderread" id="readablestreamdefaultreaderread">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestreamdefaultreader_read"></a></h5> 1000<div class="api_metadata"> 1001<span>Added in: v16.5.0</span> 1002</div> 1003<ul> 1004<li>Returns: A promise fulfilled with an object: 1005<ul> 1006<li><code>value</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a></li> 1007<li><code>done</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a></li> 1008</ul> 1009</li> 1010</ul> 1011<p>Requests the next chunk of data from the underlying <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> 1012and returns a promise that is fulfilled with the data once it is 1013available.</p> 1014<h5><code>readableStreamDefaultReader.releaseLock()</code><span><a class="mark" href="#readablestreamdefaultreaderreleaselock" id="readablestreamdefaultreaderreleaselock">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestreamdefaultreader_releaselock"></a></h5> 1015<div class="api_metadata"> 1016<span>Added in: v16.5.0</span> 1017</div> 1018<p>Releases this reader's lock on the underlying <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a>.</p> 1019<h4>Class: <code>ReadableStreamBYOBReader</code><span><a class="mark" href="#class-readablestreambyobreader" id="class-readablestreambyobreader">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_readablestreambyobreader"></a></h4> 1020<div class="api_metadata"> 1021<details class="changelog"><summary>History</summary> 1022<table> 1023<tbody><tr><th>Version</th><th>Changes</th></tr> 1024<tr><td>v18.0.0</td> 1025<td><p>This class is now exposed on the global object.</p></td></tr> 1026<tr><td>v16.5.0</td> 1027<td><p><span>Added in: v16.5.0</span></p></td></tr> 1028</tbody></table> 1029</details> 1030</div> 1031<p>The <code>ReadableStreamBYOBReader</code> is an alternative consumer for 1032byte-oriented <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a>s (those that are created with 1033<code>underlyingSource.type</code> set equal to <code>'bytes'</code> when the 1034<code>ReadableStream</code> was created).</p> 1035<p>The <code>BYOB</code> is short for "bring your own buffer". This is a 1036pattern that allows for more efficient reading of byte-oriented 1037data that avoids extraneous copying.</p> 1038<pre><code class="language-js mjs"><span class="hljs-keyword">import</span> { 1039 open, 1040} <span class="hljs-keyword">from</span> <span class="hljs-string">'node:fs/promises'</span>; 1041 1042<span class="hljs-keyword">import</span> { 1043 <span class="hljs-title class_">ReadableStream</span>, 1044} <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream/web'</span>; 1045 1046<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>; 1047 1048<span class="hljs-keyword">class</span> <span class="hljs-title class_">Source</span> { 1049 type = <span class="hljs-string">'bytes'</span>; 1050 autoAllocateChunkSize = <span class="hljs-number">1024</span>; 1051 1052 <span class="hljs-keyword">async</span> <span class="hljs-title function_">start</span>(<span class="hljs-params">controller</span>) { 1053 <span class="hljs-variable language_">this</span>.<span class="hljs-property">file</span> = <span class="hljs-keyword">await</span> <span class="hljs-title function_">open</span>(<span class="hljs-keyword">new</span> <span class="hljs-title function_">URL</span>(<span class="hljs-keyword">import</span>.<span class="hljs-property">meta</span>.<span class="hljs-property">url</span>)); 1054 <span class="hljs-variable language_">this</span>.<span class="hljs-property">controller</span> = controller; 1055 } 1056 1057 <span class="hljs-keyword">async</span> <span class="hljs-title function_">pull</span>(<span class="hljs-params">controller</span>) { 1058 <span class="hljs-keyword">const</span> view = controller.<span class="hljs-property">byobRequest</span>?.<span class="hljs-property">view</span>; 1059 <span class="hljs-keyword">const</span> { 1060 bytesRead, 1061 } = <span class="hljs-keyword">await</span> <span class="hljs-variable language_">this</span>.<span class="hljs-property">file</span>.<span class="hljs-title function_">read</span>({ 1062 <span class="hljs-attr">buffer</span>: view, 1063 <span class="hljs-attr">offset</span>: view.<span class="hljs-property">byteOffset</span>, 1064 <span class="hljs-attr">length</span>: view.<span class="hljs-property">byteLength</span>, 1065 }); 1066 1067 <span class="hljs-keyword">if</span> (bytesRead === <span class="hljs-number">0</span>) { 1068 <span class="hljs-keyword">await</span> <span class="hljs-variable language_">this</span>.<span class="hljs-property">file</span>.<span class="hljs-title function_">close</span>(); 1069 <span class="hljs-variable language_">this</span>.<span class="hljs-property">controller</span>.<span class="hljs-title function_">close</span>(); 1070 } 1071 controller.<span class="hljs-property">byobRequest</span>.<span class="hljs-title function_">respond</span>(bytesRead); 1072 } 1073} 1074 1075<span class="hljs-keyword">const</span> stream = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ReadableStream</span>(<span class="hljs-keyword">new</span> <span class="hljs-title class_">Source</span>()); 1076 1077<span class="hljs-keyword">async</span> <span class="hljs-keyword">function</span> <span class="hljs-title function_">read</span>(<span class="hljs-params">stream</span>) { 1078 <span class="hljs-keyword">const</span> reader = stream.<span class="hljs-title function_">getReader</span>({ <span class="hljs-attr">mode</span>: <span class="hljs-string">'byob'</span> }); 1079 1080 <span class="hljs-keyword">const</span> chunks = []; 1081 <span class="hljs-keyword">let</span> result; 1082 <span class="hljs-keyword">do</span> { 1083 result = <span class="hljs-keyword">await</span> reader.<span class="hljs-title function_">read</span>(<span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">alloc</span>(<span class="hljs-number">100</span>)); 1084 <span class="hljs-keyword">if</span> (result.<span class="hljs-property">value</span> !== <span class="hljs-literal">undefined</span>) 1085 chunks.<span class="hljs-title function_">push</span>(<span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>(result.<span class="hljs-property">value</span>)); 1086 } <span class="hljs-keyword">while</span> (!result.<span class="hljs-property">done</span>); 1087 1088 <span class="hljs-keyword">return</span> <span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">concat</span>(chunks); 1089} 1090 1091<span class="hljs-keyword">const</span> data = <span class="hljs-keyword">await</span> <span class="hljs-title function_">read</span>(stream); 1092<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>(data).<span class="hljs-title function_">toString</span>());</code> <button class="copy-button">copy</button></pre> 1093<h5><code>new ReadableStreamBYOBReader(stream)</code><span><a class="mark" href="#new-readablestreambyobreaderstream" id="new-readablestreambyobreaderstream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_new_readablestreambyobreader_stream"></a></h5> 1094<div class="api_metadata"> 1095<span>Added in: v16.5.0</span> 1096</div> 1097<ul> 1098<li><code>stream</code> <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a></li> 1099</ul> 1100<p>Creates a new <code>ReadableStreamBYOBReader</code> that is locked to the 1101given <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a>.</p> 1102<h5><code>readableStreamBYOBReader.cancel([reason])</code><span><a class="mark" href="#readablestreambyobreadercancelreason" id="readablestreambyobreadercancelreason">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestreambyobreader_cancel_reason"></a></h5> 1103<div class="api_metadata"> 1104<span>Added in: v16.5.0</span> 1105</div> 1106<ul> 1107<li><code>reason</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1108<li>Returns: A promise fulfilled with <code>undefined</code>.</li> 1109</ul> 1110<p>Cancels the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> and returns a promise that is fulfilled 1111when the underlying stream has been canceled.</p> 1112<h5><code>readableStreamBYOBReader.closed</code><span><a class="mark" href="#readablestreambyobreaderclosed" id="readablestreambyobreaderclosed">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestreambyobreader_closed"></a></h5> 1113<div class="api_metadata"> 1114<span>Added in: v16.5.0</span> 1115</div> 1116<ul> 1117<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise" class="type"><Promise></a> Fulfilled with <code>undefined</code> when the associated 1118<a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> is closed or rejected if the stream errors or the reader's 1119lock is released before the stream finishes closing.</li> 1120</ul> 1121<h5><code>readableStreamBYOBReader.read(view)</code><span><a class="mark" href="#readablestreambyobreaderreadview" id="readablestreambyobreaderreadview">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestreambyobreader_read_view"></a></h5> 1122<div class="api_metadata"> 1123<span>Added in: v16.5.0</span> 1124</div> 1125<ul> 1126<li><code>view</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></li> 1127<li>Returns: A promise fulfilled with an object: 1128<ul> 1129<li><code>value</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a></li> 1130<li><code>done</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a></li> 1131</ul> 1132</li> 1133</ul> 1134<p>Requests the next chunk of data from the underlying <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> 1135and returns a promise that is fulfilled with the data once it is 1136available.</p> 1137<p>Do not pass a pooled <a href="buffer.html#class-buffer" class="type"><Buffer></a> object instance in to this method. 1138Pooled <code>Buffer</code> objects are created using <code>Buffer.allocUnsafe()</code>, 1139or <code>Buffer.from()</code>, or are often returned by various <code>node:fs</code> module 1140callbacks. These types of <code>Buffer</code>s use a shared underlying 1141<a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer" class="type"><ArrayBuffer></a> object that contains all of the data from all of 1142the pooled <code>Buffer</code> instances. When a <code>Buffer</code>, <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type"><TypedArray></a>, 1143or <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type"><DataView></a> is passed in to <code>readableStreamBYOBReader.read()</code>, 1144the view's underlying <code>ArrayBuffer</code> is <em>detached</em>, invalidating 1145all existing views that may exist on that <code>ArrayBuffer</code>. This 1146can have disastrous consequences for your application.</p> 1147<h5><code>readableStreamBYOBReader.releaseLock()</code><span><a class="mark" href="#readablestreambyobreaderreleaselock" id="readablestreambyobreaderreleaselock">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestreambyobreader_releaselock"></a></h5> 1148<div class="api_metadata"> 1149<span>Added in: v16.5.0</span> 1150</div> 1151<p>Releases this reader's lock on the underlying <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a>.</p> 1152<h4>Class: <code>ReadableStreamDefaultController</code><span><a class="mark" href="#class-readablestreamdefaultcontroller" id="class-readablestreamdefaultcontroller">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_readablestreamdefaultcontroller"></a></h4> 1153<div class="api_metadata"> 1154<span>Added in: v16.5.0</span> 1155</div> 1156<p>Every <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> has a controller that is responsible for 1157the internal state and management of the stream's queue. The 1158<code>ReadableStreamDefaultController</code> is the default controller 1159implementation for <code>ReadableStream</code>s that are not byte-oriented.</p> 1160<h5><code>readableStreamDefaultController.close()</code><span><a class="mark" href="#readablestreamdefaultcontrollerclose" id="readablestreamdefaultcontrollerclose">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestreamdefaultcontroller_close"></a></h5> 1161<div class="api_metadata"> 1162<span>Added in: v16.5.0</span> 1163</div> 1164<p>Closes the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> to which this controller is associated.</p> 1165<h5><code>readableStreamDefaultController.desiredSize</code><span><a class="mark" href="#readablestreamdefaultcontrollerdesiredsize" id="readablestreamdefaultcontrollerdesiredsize">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestreamdefaultcontroller_desiredsize"></a></h5> 1166<div class="api_metadata"> 1167<span>Added in: v16.5.0</span> 1168</div> 1169<ul> 1170<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1171</ul> 1172<p>Returns the amount of data remaining to fill the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a>'s 1173queue.</p> 1174<h5><code>readableStreamDefaultController.enqueue([chunk])</code><span><a class="mark" href="#readablestreamdefaultcontrollerenqueuechunk" id="readablestreamdefaultcontrollerenqueuechunk">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestreamdefaultcontroller_enqueue_chunk"></a></h5> 1175<div class="api_metadata"> 1176<span>Added in: v16.5.0</span> 1177</div> 1178<ul> 1179<li><code>chunk</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1180</ul> 1181<p>Appends a new chunk of data to the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a>'s queue.</p> 1182<h5><code>readableStreamDefaultController.error([error])</code><span><a class="mark" href="#readablestreamdefaultcontrollererrorerror" id="readablestreamdefaultcontrollererrorerror">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestreamdefaultcontroller_error_error"></a></h5> 1183<div class="api_metadata"> 1184<span>Added in: v16.5.0</span> 1185</div> 1186<ul> 1187<li><code>error</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1188</ul> 1189<p>Signals an error that causes the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> to error and close.</p> 1190<h4>Class: <code>ReadableByteStreamController</code><span><a class="mark" href="#class-readablebytestreamcontroller" id="class-readablebytestreamcontroller">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_readablebytestreamcontroller"></a></h4> 1191<div class="api_metadata"> 1192<details class="changelog"><summary>History</summary> 1193<table> 1194<tbody><tr><th>Version</th><th>Changes</th></tr> 1195<tr><td>v18.10.0</td> 1196<td><p>Support handling a BYOB pull request from a released reader.</p></td></tr> 1197<tr><td>v16.5.0</td> 1198<td><p><span>Added in: v16.5.0</span></p></td></tr> 1199</tbody></table> 1200</details> 1201</div> 1202<p>Every <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> has a controller that is responsible for 1203the internal state and management of the stream's queue. The 1204<code>ReadableByteStreamController</code> is for byte-oriented <code>ReadableStream</code>s.</p> 1205<h5><code>readableByteStreamController.byobRequest</code><span><a class="mark" href="#readablebytestreamcontrollerbyobrequest" id="readablebytestreamcontrollerbyobrequest">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablebytestreamcontroller_byobrequest"></a></h5> 1206<div class="api_metadata"> 1207<span>Added in: v16.5.0</span> 1208</div> 1209<ul> 1210<li>Type: <a href="webstreams.html#class-readablestreambyobrequest" class="type"><ReadableStreamBYOBRequest></a></li> 1211</ul> 1212<h5><code>readableByteStreamController.close()</code><span><a class="mark" href="#readablebytestreamcontrollerclose" id="readablebytestreamcontrollerclose">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablebytestreamcontroller_close"></a></h5> 1213<div class="api_metadata"> 1214<span>Added in: v16.5.0</span> 1215</div> 1216<p>Closes the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> to which this controller is associated.</p> 1217<h5><code>readableByteStreamController.desiredSize</code><span><a class="mark" href="#readablebytestreamcontrollerdesiredsize" id="readablebytestreamcontrollerdesiredsize">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablebytestreamcontroller_desiredsize"></a></h5> 1218<div class="api_metadata"> 1219<span>Added in: v16.5.0</span> 1220</div> 1221<ul> 1222<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1223</ul> 1224<p>Returns the amount of data remaining to fill the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a>'s 1225queue.</p> 1226<h5><code>readableByteStreamController.enqueue(chunk)</code><span><a class="mark" href="#readablebytestreamcontrollerenqueuechunk" id="readablebytestreamcontrollerenqueuechunk">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablebytestreamcontroller_enqueue_chunk"></a></h5> 1227<div class="api_metadata"> 1228<span>Added in: v16.5.0</span> 1229</div> 1230<ul> 1231<li><code>chunk</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></li> 1232</ul> 1233<p>Appends a new chunk of data to the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a>'s queue.</p> 1234<h5><code>readableByteStreamController.error([error])</code><span><a class="mark" href="#readablebytestreamcontrollererrorerror" id="readablebytestreamcontrollererrorerror">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablebytestreamcontroller_error_error"></a></h5> 1235<div class="api_metadata"> 1236<span>Added in: v16.5.0</span> 1237</div> 1238<ul> 1239<li><code>error</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1240</ul> 1241<p>Signals an error that causes the <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> to error and close.</p> 1242<h4>Class: <code>ReadableStreamBYOBRequest</code><span><a class="mark" href="#class-readablestreambyobrequest" id="class-readablestreambyobrequest">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_readablestreambyobrequest"></a></h4> 1243<div class="api_metadata"> 1244<details class="changelog"><summary>History</summary> 1245<table> 1246<tbody><tr><th>Version</th><th>Changes</th></tr> 1247<tr><td>v18.0.0</td> 1248<td><p>This class is now exposed on the global object.</p></td></tr> 1249<tr><td>v16.5.0</td> 1250<td><p><span>Added in: v16.5.0</span></p></td></tr> 1251</tbody></table> 1252</details> 1253</div> 1254<p>When using <code>ReadableByteStreamController</code> in byte-oriented 1255streams, and when using the <code>ReadableStreamBYOBReader</code>, 1256the <code>readableByteStreamController.byobRequest</code> property 1257provides access to a <code>ReadableStreamBYOBRequest</code> instance 1258that represents the current read request. The object 1259is used to gain access to the <code>ArrayBuffer</code>/<code>TypedArray</code> 1260that has been provided for the read request to fill, 1261and provides methods for signaling that the data has 1262been provided.</p> 1263<h5><code>readableStreamBYOBRequest.respond(bytesWritten)</code><span><a class="mark" href="#readablestreambyobrequestrespondbyteswritten" id="readablestreambyobrequestrespondbyteswritten">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestreambyobrequest_respond_byteswritten"></a></h5> 1264<div class="api_metadata"> 1265<span>Added in: v16.5.0</span> 1266</div> 1267<ul> 1268<li><code>bytesWritten</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1269</ul> 1270<p>Signals that a <code>bytesWritten</code> number of bytes have been written 1271to <code>readableStreamBYOBRequest.view</code>.</p> 1272<h5><code>readableStreamBYOBRequest.respondWithNewView(view)</code><span><a class="mark" href="#readablestreambyobrequestrespondwithnewviewview" id="readablestreambyobrequestrespondwithnewviewview">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestreambyobrequest_respondwithnewview_view"></a></h5> 1273<div class="api_metadata"> 1274<span>Added in: v16.5.0</span> 1275</div> 1276<ul> 1277<li><code>view</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></li> 1278</ul> 1279<p>Signals that the request has been fulfilled with bytes written 1280to a new <code>Buffer</code>, <code>TypedArray</code>, or <code>DataView</code>.</p> 1281<h5><code>readableStreamBYOBRequest.view</code><span><a class="mark" href="#readablestreambyobrequestview" id="readablestreambyobrequestview">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_readablestreambyobrequest_view"></a></h5> 1282<div class="api_metadata"> 1283<span>Added in: v16.5.0</span> 1284</div> 1285<ul> 1286<li>Type: <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></li> 1287</ul> 1288<h4>Class: <code>WritableStream</code><span><a class="mark" href="#class-writablestream" id="class-writablestream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_writablestream"></a></h4> 1289<div class="api_metadata"> 1290<details class="changelog"><summary>History</summary> 1291<table> 1292<tbody><tr><th>Version</th><th>Changes</th></tr> 1293<tr><td>v18.0.0</td> 1294<td><p>This class is now exposed on the global object.</p></td></tr> 1295<tr><td>v16.5.0</td> 1296<td><p><span>Added in: v16.5.0</span></p></td></tr> 1297</tbody></table> 1298</details> 1299</div> 1300<p>The <code>WritableStream</code> is a destination to which stream data is sent.</p> 1301<pre><code class="language-js mjs"><span class="hljs-keyword">import</span> { 1302 <span class="hljs-title class_">WritableStream</span>, 1303} <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream/web'</span>; 1304 1305<span class="hljs-keyword">const</span> stream = <span class="hljs-keyword">new</span> <span class="hljs-title class_">WritableStream</span>({ 1306 <span class="hljs-title function_">write</span>(<span class="hljs-params">chunk</span>) { 1307 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(chunk); 1308 }, 1309}); 1310 1311<span class="hljs-keyword">await</span> stream.<span class="hljs-title function_">getWriter</span>().<span class="hljs-title function_">write</span>(<span class="hljs-string">'Hello World'</span>);</code> <button class="copy-button">copy</button></pre> 1312<h5><code>new WritableStream([underlyingSink[, strategy]])</code><span><a class="mark" href="#new-writablestreamunderlyingsink-strategy" id="new-writablestreamunderlyingsink-strategy">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_new_writablestream_underlyingsink_strategy"></a></h5> 1313<div class="api_metadata"> 1314<span>Added in: v16.5.0</span> 1315</div> 1316<ul> 1317<li><code>underlyingSink</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 1318<ul> 1319<li><code>start</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> A user-defined function that is invoked immediately when 1320the <code>WritableStream</code> is created. 1321<ul> 1322<li><code>controller</code> <a href="webstreams.html#class-writablestreamdefaultcontroller" class="type"><WritableStreamDefaultController></a></li> 1323<li>Returns: <code>undefined</code> or a promise fulfilled with <code>undefined</code>.</li> 1324</ul> 1325</li> 1326<li><code>write</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> A user-defined function that is invoked when a chunk of 1327data has been written to the <code>WritableStream</code>. 1328<ul> 1329<li><code>chunk</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1330<li><code>controller</code> <a href="webstreams.html#class-writablestreamdefaultcontroller" class="type"><WritableStreamDefaultController></a></li> 1331<li>Returns: A promise fulfilled with <code>undefined</code>.</li> 1332</ul> 1333</li> 1334<li><code>close</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> A user-defined function that is called when the 1335<code>WritableStream</code> is closed. 1336<ul> 1337<li>Returns: A promise fulfilled with <code>undefined</code>.</li> 1338</ul> 1339</li> 1340<li><code>abort</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> A user-defined function that is called to abruptly close 1341the <code>WritableStream</code>. 1342<ul> 1343<li><code>reason</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1344<li>Returns: A promise fulfilled with <code>undefined</code>.</li> 1345</ul> 1346</li> 1347<li><code>type</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a> The <code>type</code> option is reserved for future use and <em>must</em> be 1348undefined.</li> 1349</ul> 1350</li> 1351<li><code>strategy</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 1352<ul> 1353<li><code>highWaterMark</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> The maximum internal queue size before backpressure 1354is applied.</li> 1355<li><code>size</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> A user-defined function used to identify the size of each 1356chunk of data. 1357<ul> 1358<li><code>chunk</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1359<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1360</ul> 1361</li> 1362</ul> 1363</li> 1364</ul> 1365<h5><code>writableStream.abort([reason])</code><span><a class="mark" href="#writablestreamabortreason" id="writablestreamabortreason">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_writablestream_abort_reason"></a></h5> 1366<div class="api_metadata"> 1367<span>Added in: v16.5.0</span> 1368</div> 1369<ul> 1370<li><code>reason</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1371<li>Returns: A promise fulfilled with <code>undefined</code>.</li> 1372</ul> 1373<p>Abruptly terminates the <code>WritableStream</code>. All queued writes will be 1374canceled with their associated promises rejected.</p> 1375<h5><code>writableStream.close()</code><span><a class="mark" href="#writablestreamclose" id="writablestreamclose">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_writablestream_close"></a></h5> 1376<div class="api_metadata"> 1377<span>Added in: v16.5.0</span> 1378</div> 1379<ul> 1380<li>Returns: A promise fulfilled with <code>undefined</code>.</li> 1381</ul> 1382<p>Closes the <code>WritableStream</code> when no additional writes are expected.</p> 1383<h5><code>writableStream.getWriter()</code><span><a class="mark" href="#writablestreamgetwriter" id="writablestreamgetwriter">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_writablestream_getwriter"></a></h5> 1384<div class="api_metadata"> 1385<span>Added in: v16.5.0</span> 1386</div> 1387<ul> 1388<li>Returns: <a href="webstreams.html#class-writablestreamdefaultwriter" class="type"><WritableStreamDefaultWriter></a></li> 1389</ul> 1390<p>Creates and creates a new writer instance that can be used to write 1391data into the <code>WritableStream</code>.</p> 1392<h5><code>writableStream.locked</code><span><a class="mark" href="#writablestreamlocked" id="writablestreamlocked">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_writablestream_locked"></a></h5> 1393<div class="api_metadata"> 1394<span>Added in: v16.5.0</span> 1395</div> 1396<ul> 1397<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a></li> 1398</ul> 1399<p>The <code>writableStream.locked</code> property is <code>false</code> by default, and is 1400switched to <code>true</code> while there is an active writer attached to this 1401<code>WritableStream</code>.</p> 1402<h5>Transferring with postMessage()<span><a class="mark" href="#transferring-with-postmessage_1" id="transferring-with-postmessage_1">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_transferring_with_postmessage_1"></a></h5> 1403<p>A <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a> instance can be transferred using a <a href="worker_threads.html#class-messageport" class="type"><MessagePort></a>.</p> 1404<pre><code class="language-js"><span class="hljs-keyword">const</span> stream = <span class="hljs-keyword">new</span> <span class="hljs-title class_">WritableStream</span>(<span class="hljs-title function_">getWritableSinkSomehow</span>()); 1405 1406<span class="hljs-keyword">const</span> { port1, port2 } = <span class="hljs-keyword">new</span> <span class="hljs-title class_">MessageChannel</span>(); 1407 1408port1.<span class="hljs-property">onmessage</span> = <span class="hljs-function">(<span class="hljs-params">{ data }</span>) =></span> { 1409 data.<span class="hljs-title function_">getWriter</span>().<span class="hljs-title function_">write</span>(<span class="hljs-string">'hello'</span>); 1410}; 1411 1412port2.<span class="hljs-title function_">postMessage</span>(stream, [stream]);</code> <button class="copy-button">copy</button></pre> 1413<h4>Class: <code>WritableStreamDefaultWriter</code><span><a class="mark" href="#class-writablestreamdefaultwriter" id="class-writablestreamdefaultwriter">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_writablestreamdefaultwriter"></a></h4> 1414<div class="api_metadata"> 1415<details class="changelog"><summary>History</summary> 1416<table> 1417<tbody><tr><th>Version</th><th>Changes</th></tr> 1418<tr><td>v18.0.0</td> 1419<td><p>This class is now exposed on the global object.</p></td></tr> 1420<tr><td>v16.5.0</td> 1421<td><p><span>Added in: v16.5.0</span></p></td></tr> 1422</tbody></table> 1423</details> 1424</div> 1425<h5><code>new WritableStreamDefaultWriter(stream)</code><span><a class="mark" href="#new-writablestreamdefaultwriterstream" id="new-writablestreamdefaultwriterstream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_new_writablestreamdefaultwriter_stream"></a></h5> 1426<div class="api_metadata"> 1427<span>Added in: v16.5.0</span> 1428</div> 1429<ul> 1430<li><code>stream</code> <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a></li> 1431</ul> 1432<p>Creates a new <code>WritableStreamDefaultWriter</code> that is locked to the given 1433<code>WritableStream</code>.</p> 1434<h5><code>writableStreamDefaultWriter.abort([reason])</code><span><a class="mark" href="#writablestreamdefaultwriterabortreason" id="writablestreamdefaultwriterabortreason">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_writablestreamdefaultwriter_abort_reason"></a></h5> 1435<div class="api_metadata"> 1436<span>Added in: v16.5.0</span> 1437</div> 1438<ul> 1439<li><code>reason</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1440<li>Returns: A promise fulfilled with <code>undefined</code>.</li> 1441</ul> 1442<p>Abruptly terminates the <code>WritableStream</code>. All queued writes will be 1443canceled with their associated promises rejected.</p> 1444<h5><code>writableStreamDefaultWriter.close()</code><span><a class="mark" href="#writablestreamdefaultwriterclose" id="writablestreamdefaultwriterclose">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_writablestreamdefaultwriter_close"></a></h5> 1445<div class="api_metadata"> 1446<span>Added in: v16.5.0</span> 1447</div> 1448<ul> 1449<li>Returns: A promise fulfilled with <code>undefined</code>.</li> 1450</ul> 1451<p>Closes the <code>WritableStream</code> when no additional writes are expected.</p> 1452<h5><code>writableStreamDefaultWriter.closed</code><span><a class="mark" href="#writablestreamdefaultwriterclosed" id="writablestreamdefaultwriterclosed">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_writablestreamdefaultwriter_closed"></a></h5> 1453<div class="api_metadata"> 1454<span>Added in: v16.5.0</span> 1455</div> 1456<ul> 1457<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise" class="type"><Promise></a> Fulfilled with <code>undefined</code> when the associated 1458<a href="webstreams.html#class-writablestream" class="type"><WritableStream></a> is closed or rejected if the stream errors or the writer's 1459lock is released before the stream finishes closing.</li> 1460</ul> 1461<h5><code>writableStreamDefaultWriter.desiredSize</code><span><a class="mark" href="#writablestreamdefaultwriterdesiredsize" id="writablestreamdefaultwriterdesiredsize">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_writablestreamdefaultwriter_desiredsize"></a></h5> 1462<div class="api_metadata"> 1463<span>Added in: v16.5.0</span> 1464</div> 1465<ul> 1466<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1467</ul> 1468<p>The amount of data required to fill the <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a>'s queue.</p> 1469<h5><code>writableStreamDefaultWriter.ready</code><span><a class="mark" href="#writablestreamdefaultwriterready" id="writablestreamdefaultwriterready">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_writablestreamdefaultwriter_ready"></a></h5> 1470<div class="api_metadata"> 1471<span>Added in: v16.5.0</span> 1472</div> 1473<ul> 1474<li>type: A promise that is fulfilled with <code>undefined</code> when the 1475writer is ready to be used.</li> 1476</ul> 1477<h5><code>writableStreamDefaultWriter.releaseLock()</code><span><a class="mark" href="#writablestreamdefaultwriterreleaselock" id="writablestreamdefaultwriterreleaselock">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_writablestreamdefaultwriter_releaselock"></a></h5> 1478<div class="api_metadata"> 1479<span>Added in: v16.5.0</span> 1480</div> 1481<p>Releases this writer's lock on the underlying <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a>.</p> 1482<h5><code>writableStreamDefaultWriter.write([chunk])</code><span><a class="mark" href="#writablestreamdefaultwriterwritechunk" id="writablestreamdefaultwriterwritechunk">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_writablestreamdefaultwriter_write_chunk"></a></h5> 1483<div class="api_metadata"> 1484<span>Added in: v16.5.0</span> 1485</div> 1486<ul> 1487<li><code>chunk</code>: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1488<li>Returns: A promise fulfilled with <code>undefined</code>.</li> 1489</ul> 1490<p>Appends a new chunk of data to the <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a>'s queue.</p> 1491<h4>Class: <code>WritableStreamDefaultController</code><span><a class="mark" href="#class-writablestreamdefaultcontroller" id="class-writablestreamdefaultcontroller">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_writablestreamdefaultcontroller"></a></h4> 1492<div class="api_metadata"> 1493<details class="changelog"><summary>History</summary> 1494<table> 1495<tbody><tr><th>Version</th><th>Changes</th></tr> 1496<tr><td>v18.0.0</td> 1497<td><p>This class is now exposed on the global object.</p></td></tr> 1498<tr><td>v16.5.0</td> 1499<td><p><span>Added in: v16.5.0</span></p></td></tr> 1500</tbody></table> 1501</details> 1502</div> 1503<p>The <code>WritableStreamDefaultController</code> manage's the <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a>'s 1504internal state.</p> 1505<h5><code>writableStreamDefaultController.error([error])</code><span><a class="mark" href="#writablestreamdefaultcontrollererrorerror" id="writablestreamdefaultcontrollererrorerror">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_writablestreamdefaultcontroller_error_error"></a></h5> 1506<div class="api_metadata"> 1507<span>Added in: v16.5.0</span> 1508</div> 1509<ul> 1510<li><code>error</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1511</ul> 1512<p>Called by user-code to signal that an error has occurred while processing 1513the <code>WritableStream</code> data. When called, the <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a> will be aborted, 1514with currently pending writes canceled.</p> 1515<h5><code>writableStreamDefaultController.signal</code><span><a class="mark" href="#writablestreamdefaultcontrollersignal" id="writablestreamdefaultcontrollersignal">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_writablestreamdefaultcontroller_signal"></a></h5> 1516<ul> 1517<li>Type: <a href="globals.html#class-abortsignal" class="type"><AbortSignal></a> An <code>AbortSignal</code> that can be used to cancel pending 1518write or close operations when a <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a> is aborted.</li> 1519</ul> 1520<h4>Class: <code>TransformStream</code><span><a class="mark" href="#class-transformstream" id="class-transformstream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_transformstream"></a></h4> 1521<div class="api_metadata"> 1522<details class="changelog"><summary>History</summary> 1523<table> 1524<tbody><tr><th>Version</th><th>Changes</th></tr> 1525<tr><td>v18.0.0</td> 1526<td><p>This class is now exposed on the global object.</p></td></tr> 1527<tr><td>v16.5.0</td> 1528<td><p><span>Added in: v16.5.0</span></p></td></tr> 1529</tbody></table> 1530</details> 1531</div> 1532<p>A <code>TransformStream</code> consists of a <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> and a <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a> that 1533are connected such that the data written to the <code>WritableStream</code> is received, 1534and potentially transformed, before being pushed into the <code>ReadableStream</code>'s 1535queue.</p> 1536<pre><code class="language-js mjs"><span class="hljs-keyword">import</span> { 1537 <span class="hljs-title class_">TransformStream</span>, 1538} <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream/web'</span>; 1539 1540<span class="hljs-keyword">const</span> transform = <span class="hljs-keyword">new</span> <span class="hljs-title class_">TransformStream</span>({ 1541 <span class="hljs-title function_">transform</span>(<span class="hljs-params">chunk, controller</span>) { 1542 controller.<span class="hljs-title function_">enqueue</span>(chunk.<span class="hljs-title function_">toUpperCase</span>()); 1543 }, 1544}); 1545 1546<span class="hljs-keyword">await</span> <span class="hljs-title class_">Promise</span>.<span class="hljs-title function_">all</span>([ 1547 transform.<span class="hljs-property">writable</span>.<span class="hljs-title function_">getWriter</span>().<span class="hljs-title function_">write</span>(<span class="hljs-string">'A'</span>), 1548 transform.<span class="hljs-property">readable</span>.<span class="hljs-title function_">getReader</span>().<span class="hljs-title function_">read</span>(), 1549]);</code> <button class="copy-button">copy</button></pre> 1550<h5><code>new TransformStream([transformer[, writableStrategy[, readableStrategy]]])</code><span><a class="mark" href="#new-transformstreamtransformer-writablestrategy-readablestrategy" id="new-transformstreamtransformer-writablestrategy-readablestrategy">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_new_transformstream_transformer_writablestrategy_readablestrategy"></a></h5> 1551<div class="api_metadata"> 1552<span>Added in: v16.5.0</span> 1553</div> 1554<ul> 1555<li><code>transformer</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 1556<ul> 1557<li><code>start</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> A user-defined function that is invoked immediately when 1558the <code>TransformStream</code> is created. 1559<ul> 1560<li><code>controller</code> <a href="webstreams.html#class-transformstreamdefaultcontroller" class="type"><TransformStreamDefaultController></a></li> 1561<li>Returns: <code>undefined</code> or a promise fulfilled with <code>undefined</code></li> 1562</ul> 1563</li> 1564<li><code>transform</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> A user-defined function that receives, and 1565potentially modifies, a chunk of data written to <code>transformStream.writable</code>, 1566before forwarding that on to <code>transformStream.readable</code>. 1567<ul> 1568<li><code>chunk</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1569<li><code>controller</code> <a href="webstreams.html#class-transformstreamdefaultcontroller" class="type"><TransformStreamDefaultController></a></li> 1570<li>Returns: A promise fulfilled with <code>undefined</code>.</li> 1571</ul> 1572</li> 1573<li><code>flush</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> A user-defined function that is called immediately before 1574the writable side of the <code>TransformStream</code> is closed, signaling the end of 1575the transformation process. 1576<ul> 1577<li><code>controller</code> <a href="webstreams.html#class-transformstreamdefaultcontroller" class="type"><TransformStreamDefaultController></a></li> 1578<li>Returns: A promise fulfilled with <code>undefined</code>.</li> 1579</ul> 1580</li> 1581<li><code>readableType</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a> the <code>readableType</code> option is reserved for future use 1582and <em>must</em> be <code>undefined</code>.</li> 1583<li><code>writableType</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a> the <code>writableType</code> option is reserved for future use 1584and <em>must</em> be <code>undefined</code>.</li> 1585</ul> 1586</li> 1587<li><code>writableStrategy</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 1588<ul> 1589<li><code>highWaterMark</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> The maximum internal queue size before backpressure 1590is applied.</li> 1591<li><code>size</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> A user-defined function used to identify the size of each 1592chunk of data. 1593<ul> 1594<li><code>chunk</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1595<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1596</ul> 1597</li> 1598</ul> 1599</li> 1600<li><code>readableStrategy</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 1601<ul> 1602<li><code>highWaterMark</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> The maximum internal queue size before backpressure 1603is applied.</li> 1604<li><code>size</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> A user-defined function used to identify the size of each 1605chunk of data. 1606<ul> 1607<li><code>chunk</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1608<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1609</ul> 1610</li> 1611</ul> 1612</li> 1613</ul> 1614<h5><code>transformStream.readable</code><span><a class="mark" href="#transformstreamreadable" id="transformstreamreadable">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_transformstream_readable"></a></h5> 1615<div class="api_metadata"> 1616<span>Added in: v16.5.0</span> 1617</div> 1618<ul> 1619<li>Type: <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a></li> 1620</ul> 1621<h5><code>transformStream.writable</code><span><a class="mark" href="#transformstreamwritable" id="transformstreamwritable">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_transformstream_writable"></a></h5> 1622<div class="api_metadata"> 1623<span>Added in: v16.5.0</span> 1624</div> 1625<ul> 1626<li>Type: <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a></li> 1627</ul> 1628<h5>Transferring with postMessage()<span><a class="mark" href="#transferring-with-postmessage_2" id="transferring-with-postmessage_2">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_transferring_with_postmessage_2"></a></h5> 1629<p>A <a href="webstreams.html#class-transformstream" class="type"><TransformStream></a> instance can be transferred using a <a href="worker_threads.html#class-messageport" class="type"><MessagePort></a>.</p> 1630<pre><code class="language-js"><span class="hljs-keyword">const</span> stream = <span class="hljs-keyword">new</span> <span class="hljs-title class_">TransformStream</span>(); 1631 1632<span class="hljs-keyword">const</span> { port1, port2 } = <span class="hljs-keyword">new</span> <span class="hljs-title class_">MessageChannel</span>(); 1633 1634port1.<span class="hljs-property">onmessage</span> = <span class="hljs-function">(<span class="hljs-params">{ data }</span>) =></span> { 1635 <span class="hljs-keyword">const</span> { writable, readable } = data; 1636 <span class="hljs-comment">// ...</span> 1637}; 1638 1639port2.<span class="hljs-title function_">postMessage</span>(stream, [stream]);</code> <button class="copy-button">copy</button></pre> 1640<h4>Class: <code>TransformStreamDefaultController</code><span><a class="mark" href="#class-transformstreamdefaultcontroller" id="class-transformstreamdefaultcontroller">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_transformstreamdefaultcontroller"></a></h4> 1641<div class="api_metadata"> 1642<details class="changelog"><summary>History</summary> 1643<table> 1644<tbody><tr><th>Version</th><th>Changes</th></tr> 1645<tr><td>v18.0.0</td> 1646<td><p>This class is now exposed on the global object.</p></td></tr> 1647<tr><td>v16.5.0</td> 1648<td><p><span>Added in: v16.5.0</span></p></td></tr> 1649</tbody></table> 1650</details> 1651</div> 1652<p>The <code>TransformStreamDefaultController</code> manages the internal state 1653of the <code>TransformStream</code>.</p> 1654<h5><code>transformStreamDefaultController.desiredSize</code><span><a class="mark" href="#transformstreamdefaultcontrollerdesiredsize" id="transformstreamdefaultcontrollerdesiredsize">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_transformstreamdefaultcontroller_desiredsize"></a></h5> 1655<div class="api_metadata"> 1656<span>Added in: v16.5.0</span> 1657</div> 1658<ul> 1659<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1660</ul> 1661<p>The amount of data required to fill the readable side's queue.</p> 1662<h5><code>transformStreamDefaultController.enqueue([chunk])</code><span><a class="mark" href="#transformstreamdefaultcontrollerenqueuechunk" id="transformstreamdefaultcontrollerenqueuechunk">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_transformstreamdefaultcontroller_enqueue_chunk"></a></h5> 1663<div class="api_metadata"> 1664<span>Added in: v16.5.0</span> 1665</div> 1666<ul> 1667<li><code>chunk</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1668</ul> 1669<p>Appends a chunk of data to the readable side's queue.</p> 1670<h5><code>transformStreamDefaultController.error([reason])</code><span><a class="mark" href="#transformstreamdefaultcontrollererrorreason" id="transformstreamdefaultcontrollererrorreason">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_transformstreamdefaultcontroller_error_reason"></a></h5> 1671<div class="api_metadata"> 1672<span>Added in: v16.5.0</span> 1673</div> 1674<ul> 1675<li><code>reason</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1676</ul> 1677<p>Signals to both the readable and writable side that an error has occurred 1678while processing the transform data, causing both sides to be abruptly 1679closed.</p> 1680<h5><code>transformStreamDefaultController.terminate()</code><span><a class="mark" href="#transformstreamdefaultcontrollerterminate" id="transformstreamdefaultcontrollerterminate">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_transformstreamdefaultcontroller_terminate"></a></h5> 1681<div class="api_metadata"> 1682<span>Added in: v16.5.0</span> 1683</div> 1684<p>Closes the readable side of the transport and causes the writable side 1685to be abruptly closed with an error.</p> 1686<h4>Class: <code>ByteLengthQueuingStrategy</code><span><a class="mark" href="#class-bytelengthqueuingstrategy" id="class-bytelengthqueuingstrategy">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_bytelengthqueuingstrategy"></a></h4> 1687<div class="api_metadata"> 1688<details class="changelog"><summary>History</summary> 1689<table> 1690<tbody><tr><th>Version</th><th>Changes</th></tr> 1691<tr><td>v18.0.0</td> 1692<td><p>This class is now exposed on the global object.</p></td></tr> 1693<tr><td>v16.5.0</td> 1694<td><p><span>Added in: v16.5.0</span></p></td></tr> 1695</tbody></table> 1696</details> 1697</div> 1698<h5><code>new ByteLengthQueuingStrategy(options)</code><span><a class="mark" href="#new-bytelengthqueuingstrategyoptions" id="new-bytelengthqueuingstrategyoptions">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_new_bytelengthqueuingstrategy_options"></a></h5> 1699<div class="api_metadata"> 1700<span>Added in: v16.5.0</span> 1701</div> 1702<ul> 1703<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 1704<ul> 1705<li><code>highWaterMark</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1706</ul> 1707</li> 1708</ul> 1709<h5><code>byteLengthQueuingStrategy.highWaterMark</code><span><a class="mark" href="#bytelengthqueuingstrategyhighwatermark" id="bytelengthqueuingstrategyhighwatermark">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_bytelengthqueuingstrategy_highwatermark"></a></h5> 1710<div class="api_metadata"> 1711<span>Added in: v16.5.0</span> 1712</div> 1713<ul> 1714<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1715</ul> 1716<h5><code>byteLengthQueuingStrategy.size</code><span><a class="mark" href="#bytelengthqueuingstrategysize" id="bytelengthqueuingstrategysize">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_bytelengthqueuingstrategy_size"></a></h5> 1717<div class="api_metadata"> 1718<span>Added in: v16.5.0</span> 1719</div> 1720<ul> 1721<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> 1722<ul> 1723<li><code>chunk</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1724<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1725</ul> 1726</li> 1727</ul> 1728<h4>Class: <code>CountQueuingStrategy</code><span><a class="mark" href="#class-countqueuingstrategy" id="class-countqueuingstrategy">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_countqueuingstrategy"></a></h4> 1729<div class="api_metadata"> 1730<details class="changelog"><summary>History</summary> 1731<table> 1732<tbody><tr><th>Version</th><th>Changes</th></tr> 1733<tr><td>v18.0.0</td> 1734<td><p>This class is now exposed on the global object.</p></td></tr> 1735<tr><td>v16.5.0</td> 1736<td><p><span>Added in: v16.5.0</span></p></td></tr> 1737</tbody></table> 1738</details> 1739</div> 1740<h5><code>new CountQueuingStrategy(options)</code><span><a class="mark" href="#new-countqueuingstrategyoptions" id="new-countqueuingstrategyoptions">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_new_countqueuingstrategy_options"></a></h5> 1741<div class="api_metadata"> 1742<span>Added in: v16.5.0</span> 1743</div> 1744<ul> 1745<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 1746<ul> 1747<li><code>highWaterMark</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1748</ul> 1749</li> 1750</ul> 1751<h5><code>countQueuingStrategy.highWaterMark</code><span><a class="mark" href="#countqueuingstrategyhighwatermark" id="countqueuingstrategyhighwatermark">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_countqueuingstrategy_highwatermark"></a></h5> 1752<div class="api_metadata"> 1753<span>Added in: v16.5.0</span> 1754</div> 1755<ul> 1756<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1757</ul> 1758<h5><code>countQueuingStrategy.size</code><span><a class="mark" href="#countqueuingstrategysize" id="countqueuingstrategysize">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_countqueuingstrategy_size"></a></h5> 1759<div class="api_metadata"> 1760<span>Added in: v16.5.0</span> 1761</div> 1762<ul> 1763<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> 1764<ul> 1765<li><code>chunk</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a></li> 1766<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> 1767</ul> 1768</li> 1769</ul> 1770<h4>Class: <code>TextEncoderStream</code><span><a class="mark" href="#class-textencoderstream" id="class-textencoderstream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_textencoderstream"></a></h4> 1771<div class="api_metadata"> 1772<details class="changelog"><summary>History</summary> 1773<table> 1774<tbody><tr><th>Version</th><th>Changes</th></tr> 1775<tr><td>v18.0.0</td> 1776<td><p>This class is now exposed on the global object.</p></td></tr> 1777<tr><td>v16.6.0</td> 1778<td><p><span>Added in: v16.6.0</span></p></td></tr> 1779</tbody></table> 1780</details> 1781</div> 1782<h5><code>new TextEncoderStream()</code><span><a class="mark" href="#new-textencoderstream" id="new-textencoderstream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_new_textencoderstream"></a></h5> 1783<div class="api_metadata"> 1784<span>Added in: v16.6.0</span> 1785</div> 1786<p>Creates a new <code>TextEncoderStream</code> instance.</p> 1787<h5><code>textEncoderStream.encoding</code><span><a class="mark" href="#textencoderstreamencoding" id="textencoderstreamencoding">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_textencoderstream_encoding"></a></h5> 1788<div class="api_metadata"> 1789<span>Added in: v16.6.0</span> 1790</div> 1791<ul> 1792<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 1793</ul> 1794<p>The encoding supported by the <code>TextEncoderStream</code> instance.</p> 1795<h5><code>textEncoderStream.readable</code><span><a class="mark" href="#textencoderstreamreadable" id="textencoderstreamreadable">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_textencoderstream_readable"></a></h5> 1796<div class="api_metadata"> 1797<span>Added in: v16.6.0</span> 1798</div> 1799<ul> 1800<li>Type: <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a></li> 1801</ul> 1802<h5><code>textEncoderStream.writable</code><span><a class="mark" href="#textencoderstreamwritable" id="textencoderstreamwritable">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_textencoderstream_writable"></a></h5> 1803<div class="api_metadata"> 1804<span>Added in: v16.6.0</span> 1805</div> 1806<ul> 1807<li>Type: <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a></li> 1808</ul> 1809<h4>Class: <code>TextDecoderStream</code><span><a class="mark" href="#class-textdecoderstream" id="class-textdecoderstream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_textdecoderstream"></a></h4> 1810<div class="api_metadata"> 1811<details class="changelog"><summary>History</summary> 1812<table> 1813<tbody><tr><th>Version</th><th>Changes</th></tr> 1814<tr><td>v18.0.0</td> 1815<td><p>This class is now exposed on the global object.</p></td></tr> 1816<tr><td>v16.6.0</td> 1817<td><p><span>Added in: v16.6.0</span></p></td></tr> 1818</tbody></table> 1819</details> 1820</div> 1821<h5><code>new TextDecoderStream([encoding[, options]])</code><span><a class="mark" href="#new-textdecoderstreamencoding-options" id="new-textdecoderstreamencoding-options">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_new_textdecoderstream_encoding_options"></a></h5> 1822<div class="api_metadata"> 1823<span>Added in: v16.6.0</span> 1824</div> 1825<ul> 1826<li><code>encoding</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Identifies the <code>encoding</code> that this <code>TextDecoder</code> instance 1827supports. <strong>Default:</strong> <code>'utf-8'</code>.</li> 1828<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 1829<ul> 1830<li><code>fatal</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> <code>true</code> if decoding failures are fatal.</li> 1831<li><code>ignoreBOM</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> When <code>true</code>, the <code>TextDecoderStream</code> will include the 1832byte order mark in the decoded result. When <code>false</code>, the byte order mark 1833will be removed from the output. This option is only used when <code>encoding</code> is 1834<code>'utf-8'</code>, <code>'utf-16be'</code>, or <code>'utf-16le'</code>. <strong>Default:</strong> <code>false</code>.</li> 1835</ul> 1836</li> 1837</ul> 1838<p>Creates a new <code>TextDecoderStream</code> instance.</p> 1839<h5><code>textDecoderStream.encoding</code><span><a class="mark" href="#textdecoderstreamencoding" id="textdecoderstreamencoding">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_textdecoderstream_encoding"></a></h5> 1840<div class="api_metadata"> 1841<span>Added in: v16.6.0</span> 1842</div> 1843<ul> 1844<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> 1845</ul> 1846<p>The encoding supported by the <code>TextDecoderStream</code> instance.</p> 1847<h5><code>textDecoderStream.fatal</code><span><a class="mark" href="#textdecoderstreamfatal" id="textdecoderstreamfatal">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_textdecoderstream_fatal"></a></h5> 1848<div class="api_metadata"> 1849<span>Added in: v16.6.0</span> 1850</div> 1851<ul> 1852<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a></li> 1853</ul> 1854<p>The value will be <code>true</code> if decoding errors result in a <code>TypeError</code> being 1855thrown.</p> 1856<h5><code>textDecoderStream.ignoreBOM</code><span><a class="mark" href="#textdecoderstreamignorebom" id="textdecoderstreamignorebom">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_textdecoderstream_ignorebom"></a></h5> 1857<div class="api_metadata"> 1858<span>Added in: v16.6.0</span> 1859</div> 1860<ul> 1861<li>Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a></li> 1862</ul> 1863<p>The value will be <code>true</code> if the decoding result will include the byte order 1864mark.</p> 1865<h5><code>textDecoderStream.readable</code><span><a class="mark" href="#textdecoderstreamreadable" id="textdecoderstreamreadable">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_textdecoderstream_readable"></a></h5> 1866<div class="api_metadata"> 1867<span>Added in: v16.6.0</span> 1868</div> 1869<ul> 1870<li>Type: <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a></li> 1871</ul> 1872<h5><code>textDecoderStream.writable</code><span><a class="mark" href="#textdecoderstreamwritable" id="textdecoderstreamwritable">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_textdecoderstream_writable"></a></h5> 1873<div class="api_metadata"> 1874<span>Added in: v16.6.0</span> 1875</div> 1876<ul> 1877<li>Type: <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a></li> 1878</ul> 1879<h4>Class: <code>CompressionStream</code><span><a class="mark" href="#class-compressionstream" id="class-compressionstream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_compressionstream"></a></h4> 1880<div class="api_metadata"> 1881<details class="changelog"><summary>History</summary> 1882<table> 1883<tbody><tr><th>Version</th><th>Changes</th></tr> 1884<tr><td>v18.0.0</td> 1885<td><p>This class is now exposed on the global object.</p></td></tr> 1886<tr><td>v17.0.0</td> 1887<td><p><span>Added in: v17.0.0</span></p></td></tr> 1888</tbody></table> 1889</details> 1890</div> 1891<h5><code>new CompressionStream(format)</code><span><a class="mark" href="#new-compressionstreamformat" id="new-compressionstreamformat">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_new_compressionstream_format"></a></h5> 1892<div class="api_metadata"> 1893<span>Added in: v17.0.0</span> 1894</div> 1895<ul> 1896<li><code>format</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> One of either <code>'deflate'</code> or <code>'gzip'</code>.</li> 1897</ul> 1898<h5><code>compressionStream.readable</code><span><a class="mark" href="#compressionstreamreadable" id="compressionstreamreadable">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_compressionstream_readable"></a></h5> 1899<div class="api_metadata"> 1900<span>Added in: v17.0.0</span> 1901</div> 1902<ul> 1903<li>Type: <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a></li> 1904</ul> 1905<h5><code>compressionStream.writable</code><span><a class="mark" href="#compressionstreamwritable" id="compressionstreamwritable">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_compressionstream_writable"></a></h5> 1906<div class="api_metadata"> 1907<span>Added in: v17.0.0</span> 1908</div> 1909<ul> 1910<li>Type: <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a></li> 1911</ul> 1912<h4>Class: <code>DecompressionStream</code><span><a class="mark" href="#class-decompressionstream" id="class-decompressionstream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_class_decompressionstream"></a></h4> 1913<div class="api_metadata"> 1914<details class="changelog"><summary>History</summary> 1915<table> 1916<tbody><tr><th>Version</th><th>Changes</th></tr> 1917<tr><td>v18.0.0</td> 1918<td><p>This class is now exposed on the global object.</p></td></tr> 1919<tr><td>v17.0.0</td> 1920<td><p><span>Added in: v17.0.0</span></p></td></tr> 1921</tbody></table> 1922</details> 1923</div> 1924<h5><code>new DecompressionStream(format)</code><span><a class="mark" href="#new-decompressionstreamformat" id="new-decompressionstreamformat">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_new_decompressionstream_format"></a></h5> 1925<div class="api_metadata"> 1926<span>Added in: v17.0.0</span> 1927</div> 1928<ul> 1929<li><code>format</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> One of either <code>'deflate'</code> or <code>'gzip'</code>.</li> 1930</ul> 1931<h5><code>decompressionStream.readable</code><span><a class="mark" href="#decompressionstreamreadable" id="decompressionstreamreadable">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_decompressionstream_readable"></a></h5> 1932<div class="api_metadata"> 1933<span>Added in: v17.0.0</span> 1934</div> 1935<ul> 1936<li>Type: <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a></li> 1937</ul> 1938<h5><code>decompressionStream.writable</code><span><a class="mark" href="#decompressionstreamwritable" id="decompressionstreamwritable">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_decompressionstream_writable"></a></h5> 1939<div class="api_metadata"> 1940<span>Added in: v17.0.0</span> 1941</div> 1942<ul> 1943<li>Type: <a href="webstreams.html#class-writablestream" class="type"><WritableStream></a></li> 1944</ul> 1945<h4>Utility Consumers<span><a class="mark" href="#utility-consumers" id="utility-consumers">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_utility_consumers"></a></h4> 1946<div class="api_metadata"> 1947<span>Added in: v16.7.0</span> 1948</div> 1949<p>The utility consumer functions provide common options for consuming 1950streams.</p> 1951<p>They are accessed using:</p> 1952 1953<pre class="with-14-chars"><input class="js-flavor-selector" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> { 1954 arrayBuffer, 1955 blob, 1956 buffer, 1957 json, 1958 text, 1959} <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream/consumers'</span>;</code><code class="language-js cjs"><span class="hljs-keyword">const</span> { 1960 arrayBuffer, 1961 blob, 1962 buffer, 1963 json, 1964 text, 1965} = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream/consumers'</span>);</code><button class="copy-button">copy</button></pre> 1966<h5><code>streamConsumers.arrayBuffer(stream)</code><span><a class="mark" href="#streamconsumersarraybufferstream" id="streamconsumersarraybufferstream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_streamconsumers_arraybuffer_stream"></a></h5> 1967<div class="api_metadata"> 1968<span>Added in: v16.7.0</span> 1969</div> 1970<ul> 1971<li><code>stream</code> <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> | <a href="stream.html#class-streamreadable" class="type"><stream.Readable></a> | <a href="https://tc39.github.io/ecma262/#sec-asynciterator-interface" class="type"><AsyncIterator></a></li> 1972<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise" class="type"><Promise></a> Fulfills with an <code>ArrayBuffer</code> containing the full 1973contents of the stream.</li> 1974</ul> 1975 1976<pre class="with-57-chars"><input class="js-flavor-selector" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> { arrayBuffer } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream/consumers'</span>; 1977<span class="hljs-keyword">import</span> { <span class="hljs-title class_">Readable</span> } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream'</span>; 1978<span class="hljs-keyword">import</span> { <span class="hljs-title class_">TextEncoder</span> } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:util'</span>; 1979 1980<span class="hljs-keyword">const</span> encoder = <span class="hljs-keyword">new</span> <span class="hljs-title class_">TextEncoder</span>(); 1981<span class="hljs-keyword">const</span> dataArray = encoder.<span class="hljs-title function_">encode</span>(<span class="hljs-string">'hello world from consumers!'</span>); 1982 1983<span class="hljs-keyword">const</span> readable = <span class="hljs-title class_">Readable</span>.<span class="hljs-title function_">from</span>(dataArray); 1984<span class="hljs-keyword">const</span> data = <span class="hljs-keyword">await</span> <span class="hljs-title function_">arrayBuffer</span>(readable); 1985<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`from readable: <span class="hljs-subst">${data.byteLength}</span>`</span>);</code><code class="language-js cjs"><span class="hljs-keyword">const</span> { arrayBuffer } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream/consumers'</span>); 1986<span class="hljs-keyword">const</span> { <span class="hljs-title class_">Readable</span> } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream'</span>); 1987<span class="hljs-keyword">const</span> { <span class="hljs-title class_">TextEncoder</span> } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:util'</span>); 1988 1989<span class="hljs-keyword">const</span> encoder = <span class="hljs-keyword">new</span> <span class="hljs-title class_">TextEncoder</span>(); 1990<span class="hljs-keyword">const</span> dataArray = encoder.<span class="hljs-title function_">encode</span>(<span class="hljs-string">'hello world from consumers!'</span>); 1991<span class="hljs-keyword">const</span> readable = <span class="hljs-title class_">Readable</span>.<span class="hljs-title function_">from</span>(dataArray); 1992<span class="hljs-title function_">arrayBuffer</span>(readable).<span class="hljs-title function_">then</span>(<span class="hljs-function">(<span class="hljs-params">data</span>) =></span> { 1993 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`from readable: <span class="hljs-subst">${data.byteLength}</span>`</span>); 1994});</code><button class="copy-button">copy</button></pre> 1995<h5><code>streamConsumers.blob(stream)</code><span><a class="mark" href="#streamconsumersblobstream" id="streamconsumersblobstream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_streamconsumers_blob_stream"></a></h5> 1996<div class="api_metadata"> 1997<span>Added in: v16.7.0</span> 1998</div> 1999<ul> 2000<li><code>stream</code> <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> | <a href="stream.html#class-streamreadable" class="type"><stream.Readable></a> | <a href="https://tc39.github.io/ecma262/#sec-asynciterator-interface" class="type"><AsyncIterator></a></li> 2001<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise" class="type"><Promise></a> Fulfills with a <a href="buffer.html#class-blob" class="type"><Blob></a> containing the full contents 2002of the stream.</li> 2003</ul> 2004 2005<pre class="with-50-chars"><input class="js-flavor-selector" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> { blob } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream/consumers'</span>; 2006 2007<span class="hljs-keyword">const</span> dataBlob = <span class="hljs-keyword">new</span> <span class="hljs-title class_">Blob</span>([<span class="hljs-string">'hello world from consumers!'</span>]); 2008 2009<span class="hljs-keyword">const</span> readable = dataBlob.<span class="hljs-title function_">stream</span>(); 2010<span class="hljs-keyword">const</span> data = <span class="hljs-keyword">await</span> <span class="hljs-title function_">blob</span>(readable); 2011<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`from readable: <span class="hljs-subst">${data.size}</span>`</span>);</code><code class="language-js cjs"><span class="hljs-keyword">const</span> { blob } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream/consumers'</span>); 2012 2013<span class="hljs-keyword">const</span> dataBlob = <span class="hljs-keyword">new</span> <span class="hljs-title class_">Blob</span>([<span class="hljs-string">'hello world from consumers!'</span>]); 2014 2015<span class="hljs-keyword">const</span> readable = dataBlob.<span class="hljs-title function_">stream</span>(); 2016<span class="hljs-title function_">blob</span>(readable).<span class="hljs-title function_">then</span>(<span class="hljs-function">(<span class="hljs-params">data</span>) =></span> { 2017 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`from readable: <span class="hljs-subst">${data.size}</span>`</span>); 2018});</code><button class="copy-button">copy</button></pre> 2019<h5><code>streamConsumers.buffer(stream)</code><span><a class="mark" href="#streamconsumersbufferstream" id="streamconsumersbufferstream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_streamconsumers_buffer_stream"></a></h5> 2020<div class="api_metadata"> 2021<span>Added in: v16.7.0</span> 2022</div> 2023<ul> 2024<li><code>stream</code> <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> | <a href="stream.html#class-streamreadable" class="type"><stream.Readable></a> | <a href="https://tc39.github.io/ecma262/#sec-asynciterator-interface" class="type"><AsyncIterator></a></li> 2025<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise" class="type"><Promise></a> Fulfills with a <a href="buffer.html#class-buffer" class="type"><Buffer></a> containing the full 2026contents of the stream.</li> 2027</ul> 2028 2029<pre class="with-52-chars"><input class="js-flavor-selector" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> { buffer } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream/consumers'</span>; 2030<span class="hljs-keyword">import</span> { <span class="hljs-title class_">Readable</span> } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream'</span>; 2031<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>; 2032 2033<span class="hljs-keyword">const</span> dataBuffer = <span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>(<span class="hljs-string">'hello world from consumers!'</span>); 2034 2035<span class="hljs-keyword">const</span> readable = <span class="hljs-title class_">Readable</span>.<span class="hljs-title function_">from</span>(dataBuffer); 2036<span class="hljs-keyword">const</span> data = <span class="hljs-keyword">await</span> <span class="hljs-title function_">buffer</span>(readable); 2037<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`from readable: <span class="hljs-subst">${data.length}</span>`</span>);</code><code class="language-js cjs"><span class="hljs-keyword">const</span> { buffer } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream/consumers'</span>); 2038<span class="hljs-keyword">const</span> { <span class="hljs-title class_">Readable</span> } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream'</span>); 2039<span class="hljs-keyword">const</span> { <span class="hljs-title class_">Buffer</span> } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:buffer'</span>); 2040 2041<span class="hljs-keyword">const</span> dataBuffer = <span class="hljs-title class_">Buffer</span>.<span class="hljs-title function_">from</span>(<span class="hljs-string">'hello world from consumers!'</span>); 2042 2043<span class="hljs-keyword">const</span> readable = <span class="hljs-title class_">Readable</span>.<span class="hljs-title function_">from</span>(dataBuffer); 2044<span class="hljs-title function_">buffer</span>(readable).<span class="hljs-title function_">then</span>(<span class="hljs-function">(<span class="hljs-params">data</span>) =></span> { 2045 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`from readable: <span class="hljs-subst">${data.length}</span>`</span>); 2046});</code><button class="copy-button">copy</button></pre> 2047<h5><code>streamConsumers.json(stream)</code><span><a class="mark" href="#streamconsumersjsonstream" id="streamconsumersjsonstream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_streamconsumers_json_stream"></a></h5> 2048<div class="api_metadata"> 2049<span>Added in: v16.7.0</span> 2050</div> 2051<ul> 2052<li><code>stream</code> <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> | <a href="stream.html#class-streamreadable" class="type"><stream.Readable></a> | <a href="https://tc39.github.io/ecma262/#sec-asynciterator-interface" class="type"><AsyncIterator></a></li> 2053<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise" class="type"><Promise></a> Fulfills with the contents of the stream parsed as a 2054UTF-8 encoded string that is then passed through <code>JSON.parse()</code>.</li> 2055</ul> 2056 2057<pre class="with-50-chars"><input class="js-flavor-selector" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> { json } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream/consumers'</span>; 2058<span class="hljs-keyword">import</span> { <span class="hljs-title class_">Readable</span> } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream'</span>; 2059 2060<span class="hljs-keyword">const</span> items = <span class="hljs-title class_">Array</span>.<span class="hljs-title function_">from</span>( 2061 { 2062 <span class="hljs-attr">length</span>: <span class="hljs-number">100</span>, 2063 }, 2064 <span class="hljs-function">() =></span> ({ 2065 <span class="hljs-attr">message</span>: <span class="hljs-string">'hello world from consumers!'</span>, 2066 }), 2067); 2068 2069<span class="hljs-keyword">const</span> readable = <span class="hljs-title class_">Readable</span>.<span class="hljs-title function_">from</span>(<span class="hljs-title class_">JSON</span>.<span class="hljs-title function_">stringify</span>(items)); 2070<span class="hljs-keyword">const</span> data = <span class="hljs-keyword">await</span> <span class="hljs-title function_">json</span>(readable); 2071<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`from readable: <span class="hljs-subst">${data.length}</span>`</span>);</code><code class="language-js cjs"><span class="hljs-keyword">const</span> { json } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream/consumers'</span>); 2072<span class="hljs-keyword">const</span> { <span class="hljs-title class_">Readable</span> } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream'</span>); 2073 2074<span class="hljs-keyword">const</span> items = <span class="hljs-title class_">Array</span>.<span class="hljs-title function_">from</span>( 2075 { 2076 <span class="hljs-attr">length</span>: <span class="hljs-number">100</span>, 2077 }, 2078 <span class="hljs-function">() =></span> ({ 2079 <span class="hljs-attr">message</span>: <span class="hljs-string">'hello world from consumers!'</span>, 2080 }), 2081); 2082 2083<span class="hljs-keyword">const</span> readable = <span class="hljs-title class_">Readable</span>.<span class="hljs-title function_">from</span>(<span class="hljs-title class_">JSON</span>.<span class="hljs-title function_">stringify</span>(items)); 2084<span class="hljs-title function_">json</span>(readable).<span class="hljs-title function_">then</span>(<span class="hljs-function">(<span class="hljs-params">data</span>) =></span> { 2085 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`from readable: <span class="hljs-subst">${data.length}</span>`</span>); 2086});</code><button class="copy-button">copy</button></pre> 2087<h5><code>streamConsumers.text(stream)</code><span><a class="mark" href="#streamconsumerstextstream" id="streamconsumerstextstream">#</a></span><a aria-hidden="true" class="legacy" id="webstreams_streamconsumers_text_stream"></a></h5> 2088<div class="api_metadata"> 2089<span>Added in: v16.7.0</span> 2090</div> 2091<ul> 2092<li><code>stream</code> <a href="webstreams.html#class-readablestream" class="type"><ReadableStream></a> | <a href="stream.html#class-streamreadable" class="type"><stream.Readable></a> | <a href="https://tc39.github.io/ecma262/#sec-asynciterator-interface" class="type"><AsyncIterator></a></li> 2093<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise" class="type"><Promise></a> Fulfills with the contents of the stream parsed as a 2094UTF-8 encoded string.</li> 2095</ul> 2096 2097<pre class="with-50-chars"><input class="js-flavor-selector" type="checkbox" checked aria-label="Show modern ES modules syntax"><code class="language-js mjs"><span class="hljs-keyword">import</span> { text } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream/consumers'</span>; 2098<span class="hljs-keyword">import</span> { <span class="hljs-title class_">Readable</span> } <span class="hljs-keyword">from</span> <span class="hljs-string">'node:stream'</span>; 2099 2100<span class="hljs-keyword">const</span> readable = <span class="hljs-title class_">Readable</span>.<span class="hljs-title function_">from</span>(<span class="hljs-string">'Hello world from consumers!'</span>); 2101<span class="hljs-keyword">const</span> data = <span class="hljs-keyword">await</span> <span class="hljs-title function_">text</span>(readable); 2102<span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`from readable: <span class="hljs-subst">${data.length}</span>`</span>);</code><code class="language-js cjs"><span class="hljs-keyword">const</span> { text } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream/consumers'</span>); 2103<span class="hljs-keyword">const</span> { <span class="hljs-title class_">Readable</span> } = <span class="hljs-built_in">require</span>(<span class="hljs-string">'node:stream'</span>); 2104 2105<span class="hljs-keyword">const</span> readable = <span class="hljs-title class_">Readable</span>.<span class="hljs-title function_">from</span>(<span class="hljs-string">'Hello world from consumers!'</span>); 2106<span class="hljs-title function_">text</span>(readable).<span class="hljs-title function_">then</span>(<span class="hljs-function">(<span class="hljs-params">data</span>) =></span> { 2107 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`from readable: <span class="hljs-subst">${data.length}</span>`</span>); 2108});</code><button class="copy-button">copy</button></pre></section> 2109 <!-- API END --> 2110 </div> 2111 </div> 2112 </div> 2113</body> 2114</html> 2115