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How to use WritableStreamDefaultControllerGetBackpressure method in wpt

Best JavaScript code snippet using wpt

WritableStream.js

Source:WritableStream.js

...222    const writer = stream[_writer];223    if (writer !== undefined) {224      v8.rejectPromise(writer[_closedPromise], e);225      if (state === WRITABLE &&226          WritableStreamDefaultControllerGetBackpressure(227              stream[_writableStreamController])) {228        v8.rejectPromise(writer[_readyPromise], e);229      } else {230        writer[_readyPromise] = Promise_reject(e);231      }232    }233    stream[_state] = ERRORED;234    stream[_storedError] = e;235  }236  function WritableStreamFinishClose(stream) {237    TEMP_ASSERT(stream[_state] === CLOSING,238                'stream.[[state]] is "closing".');239    TEMP_ASSERT(stream[_writer] !== undefined,240                'stream.[[writer]] is not undefined.');241    stream[_state] = CLOSED;242    v8.resolvePromise(stream[_writer][_closedPromise], undefined);243  }244  function WritableStreamFulfillWriteRequest(stream) {245    TEMP_ASSERT(stream[_writeRequests].length !== 0,246               'stream.[[writeRequests]] is not empty.');247    const writeRequest = stream[_writeRequests].shift();248    v8.resolvePromise(writeRequest, undefined);249  }250  function WritableStreamUpdateBackpressure(stream, backpressure) {251    TEMP_ASSERT(stream[_state] === WRITABLE,252                'stream.[[state]] is "writable".');253    const writer = stream[_writer];254    if (writer === undefined) {255      return;256    }257    if (backpressure) {258      writer[_readyPromise] = v8.createPromise();259    } else {260      TEMP_ASSERT(backpressure === false,261                  'backpressure is false.');262      v8.resolvePromise(writer[_readyPromise], undefined);263    }264  }265  class WritableStreamDefaultWriter {266    constructor(stream) {267      if (!IsWritableStream(stream)) {268        throw new TypeError(errIllegalConstructor);269      }270      if (IsWritableStreamLocked(stream)) {271        throw new TypeError(errIllegalConstructor);272      }273      this[_ownerWritableStream] = stream;274      stream[_writer] = this;275      const state = stream[_state];276      if (state === WRITABLE || state === CLOSING) {277        this[_closedPromise] = v8.createPromise();278      } else if (state === CLOSED) {279        this[_closedPromise] = Promise_resolve(undefined);280      } else {281        TEMP_ASSERT(state === ERRORED,282                    'state is "errored".');283        this[_closedPromise] = Promise_reject(stream[_storedError]);284      }285      if (state === WRITABLE &&286          WritableStreamDefaultControllerGetBackpressure(287              stream[_writableStreamController])) {288        this[_readyPromise] = v8.createPromise();289      } else {290        this[_readyPromise] = Promise_resolve(undefined);291      }292    }293    get closed() {294      if (!IsWritableStreamDefaultWriter(this)) {295        return Promise_reject(new TypeError(errIllegalInvocation));296      }297      return this[_closedPromise];298    }299    get desiredSize() {300      if (!IsWritableStreamDefaultWriter(this)) {301        throw new TypeError(errIllegalInvocation);302      }303      if (this[_ownerWritableStream] === undefined) {304        throw createWriterLockReleasedError(verbUsedToGetTheDesiredSize);305      }306      return WritableStreamDefaultWriterGetDesiredSize(this);307    }308    get ready() {309      if (!IsWritableStreamDefaultWriter(this)) {310        return Promise_reject(new TypeError(errIllegalInvocation));311      }312      return this[_readyPromise];313    }314    abort(reason) {315     if (!IsWritableStreamDefaultWriter(this)) {316        return Promise_reject(new TypeError(errIllegalInvocation));317      }318      if (this[_ownerWritableStream] === undefined) {319        return Promise_reject(createWriterLockReleasedError(verbAborted));320      }321      return WritableStreamDefaultWriterAbort(this, reason);322    }323    close() {324      if (!IsWritableStreamDefaultWriter(this)) {325        return Promise_reject(new TypeError(errIllegalInvocation));326      }327      const stream = this[_ownerWritableStream];328      if (stream === undefined) {329        return Promise_reject(createWriterLockReleasedError(verbClosed));330      }331      if (stream[_state] === CLOSING) {332        return Promise_reject(new TypeError(errCloseCloseRequestedStream));333      }334      return WritableStreamDefaultWriterClose(this);335    }336    releaseLock() {337      if (!IsWritableStreamDefaultWriter(this)) {338        throw new TypeError(errIllegalInvocation);339      }340      const stream = this[_ownerWritableStream];341      if (stream === undefined) {342        return;343      }344      TEMP_ASSERT(stream[_writer] !== undefined,345                  'stream.[[writer]] is not undefined.');346      WritableStreamDefaultWriterRelease(this);347    }348    write(chunk) {349      if (!IsWritableStreamDefaultWriter(this)) {350        return Promise_reject(new TypeError(errIllegalInvocation));351      }352      const stream = this[_ownerWritableStream];353      if (stream === undefined) {354        return Promise_reject(createWriterLockReleasedError(verbWrittenTo));355      }356      if (stream[_state] === CLOSING) {357        return Promise_reject(new TypeError(errWriteCloseRequestedStream));358      }359      return WritableStreamDefaultWriterWrite(this, chunk);360    }361  }362  // Writable Stream Writer Abstract Operations363  function IsWritableStreamDefaultWriter(x) {364    return hasOwnProperty(x, _ownerWritableStream);365  }366  function WritableStreamDefaultWriterAbort(writer, reason) {367    const stream = writer[_ownerWritableStream];368    TEMP_ASSERT(stream !== undefined,369                'stream is not undefined.');370    return WritableStreamAbort(stream, reason);371  }372  function WritableStreamDefaultWriterClose(writer) {373    const stream = writer[_ownerWritableStream];374    TEMP_ASSERT(stream !== undefined,375                'stream is not undefined.');376    const state = stream[_state];377    if (state === CLOSED || state === ERRORED) {378      return Promise_reject(379          createCannotActionOnStateStreamError('close', state));380    }381    TEMP_ASSERT(state === WRITABLE,382                'state is "writable".');383    const promise = WritableStreamAddWriteRequest(stream);384    if (WritableStreamDefaultControllerGetBackpressure(385        stream[_writableStreamController])) {386      v8.resolvePromise(writer[_readyPromise], undefined);387    }388    stream[_state] = CLOSING;389    WritableStreamDefaultControllerClose(stream[_writableStreamController]);390    return promise;391  }392  function WritableStreamDefaultWriterGetDesiredSize(writer) {393    const stream = writer[_ownerWritableStream];394    const state = stream[_state];395    if (state === ERRORED) {396      return null;397    }398    if (state === CLOSED) {399      return 0;400    }401    return WritableStreamDefaultControllerGetDesiredSize(402        stream[_writableStreamController]);403  }404  function WritableStreamDefaultWriterRelease(writer) {405    const stream = writer[_ownerWritableStream];406    TEMP_ASSERT(stream !== undefined,407                'stream is not undefined.');408    TEMP_ASSERT(stream[_writer] === writer,409                'stream.[[writer]] is writer.');410    const releasedError = new TypeError(errReleasedWriterClosedPromise);411    const state = stream[_state];412    if (state === WRITABLE || state === CLOSING) {413      v8.rejectPromise(writer[_closedPromise], releasedError);414    } else {415      writer[_closedPromise] = Promise_reject(releasedError);416    }417    if (state === WRITABLE &&418        WritableStreamDefaultControllerGetBackpressure(419            stream[_writableStreamController])) {420      v8.rejectPromise(writer[_readyPromise], releasedError);421    } else {422      writer[_readyPromise] = Promise_reject(releasedError);423    }424    stream[_writer] = undefined;425    writer[_ownerWritableStream] = undefined;426  }427  function WritableStreamDefaultWriterWrite(writer, chunk) {428    const stream = writer[_ownerWritableStream];429    TEMP_ASSERT(stream !== undefined,430                'stream is not undefined.');431    const state = stream[_state];432    if (state === CLOSED || state === ERRORED) {433      return Promise_reject(434          createCannotActionOnStateStreamError('write to', state));435    }436    TEMP_ASSERT(state === WRITABLE,437                'state is "writable".');438    const promise = WritableStreamAddWriteRequest(stream);439    WritableStreamDefaultControllerWrite(stream[_writableStreamController],440                                         chunk);441    return promise;442  }443  class WritableStreamDefaultController {444    constructor(stream, underlyingSink, size, highWaterMark) {445      if (!IsWritableStream(stream)) {446        throw new TypeError(errIllegalConstructor);447      }448      if (stream[_writableStreamController] !== undefined) {449        throw new TypeError(errIllegalConstructor);450      }451      this[_controlledWritableStream] = stream;452      this[_underlyingSink] = underlyingSink;453      this[_queue] = new v8.InternalPackedArray();454      this[_queueSize] = 0;455      this[_defaultControllerFlags] = 0;456      const normalizedStrategy =457          ValidateAndNormalizeQueuingStrategy(size, highWaterMark);458      this[_strategySize] = normalizedStrategy.size;459      this[_strategyHWM] = normalizedStrategy.highWaterMark;460      const backpressure = WritableStreamDefaultControllerGetBackpressure(this);461      if (backpressure) {462        WritableStreamUpdateBackpressure(stream, backpressure);463      }464      const controller = this;465      const startResult = InvokeOrNoop(underlyingSink, 'start', [this]);466      const onFulfilled = () => {467        setDefaultControllerStartedFlag(controller, true);468        WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller);469      };470      const onRejected = r => {471        WritableStreamDefaultControllerErrorIfNeeded(controller, r);472      };473      thenPromise(Promise_resolve(startResult), onFulfilled, onRejected);474    }475    error(e) {476      if (!IsWritableStreamDefaultController(this)) {477        throw new TypeError(errIllegalInvocation);478      }479      const state = this[_controlledWritableStream][_state];480      if (state === CLOSED || state === ERRORED) {481        throw createCannotActionOnStateStreamError('error', state);482      }483      WritableStreamDefaultControllerError(this, e);484    }485  }486  // Writable Stream Default Controller Abstract Operations487  function IsWritableStreamDefaultController(x) {488    return hasOwnProperty(x, _underlyingSink);489  }490  function WritableStreamDefaultControllerAbort(controller, reason) {491    controller[_queue] = v8.InternalPackedArray();492    controller[_queueSize] = 0;493    const sinkAbortPromise =494        PromiseInvokeOrFallbackOrNoop(controller[_underlyingSink],495                                      'abort', [reason], 'close', [controller]);496    return thenPromise(sinkAbortPromise, () => undefined);497  }498  function WritableStreamDefaultControllerClose(controller) {499    EnqueueValueWithSizeForController(controller, 'close', 0);500    WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller);501  }502  function WritableStreamDefaultControllerGetDesiredSize(controller) {503    const queueSize = GetTotalQueueSizeForController(controller);504    return controller[_strategyHWM] - queueSize;505  }506  function WritableStreamDefaultControllerWrite(controller, chunk) {507    const stream = controller[_controlledWritableStream];508    TEMP_ASSERT(stream[_state] === WRITABLE,509                'stream.[[state]] is "writable".');510    let chunkSize = 1;511    if (controller[_strategySize] !== undefined) {512      try {513        chunkSize = Function_call(controller[_strategySize], undefined, chunk);514      } catch (e) {515        WritableStreamDefaultControllerErrorIfNeeded(controller, e);516        return Promise_reject(e);517      }518    }519    const writeRecord = {chunk};520    const lastBackpressure =521        WritableStreamDefaultControllerGetBackpressure(controller);522    try {523      const enqueueResult =524          EnqueueValueWithSizeForController(controller, writeRecord, chunkSize);525    } catch (e) {526      WritableStreamDefaultControllerErrorIfNeeded(controller, e);527      return Promise_reject(e);528    }529    if (stream[_state] === WRITABLE) {530      const backpressure =531          WritableStreamDefaultControllerGetBackpressure(controller);532      if (lastBackpressure !== backpressure) {533        WritableStreamUpdateBackpressure(stream, backpressure);534      }535    }536    WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller);537  }538  function WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller) {539    const state = controller[_controlledWritableStream][_state];540    if (state === CLOSED || state === ERRORED) {541      return;542    }543    if (!getDefaultControllerStartedFlag(controller)) {544      return;545    }546    if (getDefaultControllerWritingFlag(controller)) {547      return;548    }549    if (controller[_queue].length === 0) {550      return;551    }552    const writeRecord = PeekQueueValue(controller[_queue]);553    if (writeRecord === 'close') {554      WritableStreamDefaultControllerProcessClose(controller);555    } else {556      WritableStreamDefaultControllerProcessWrite(controller,557                                                  writeRecord.chunk);558    }559  }560  function WritableStreamDefaultControllerErrorIfNeeded(controller, e) {561    const state = controller[_controlledWritableStream][_state];562    if (state === WRITABLE || state === CLOSING) {563      WritableStreamDefaultControllerError(controller, e);564    }565  }566  function WritableStreamDefaultControllerProcessClose(controller) {567    const stream = controller[_controlledWritableStream];568    TEMP_ASSERT(stream[_state] === CLOSING,569                'stream.[[state]] is "closing".');570    DequeueValueForController(controller);571    TEMP_ASSERT(controller[_queue].length === 0,572                'controller.[[queue]] is empty.');573    const sinkClosePromise = PromiseInvokeOrNoop(controller[_underlyingSink],574                                               'close', [controller]);575    thenPromise(sinkClosePromise,576                () => {577                  if (stream[_state] !== CLOSING) {578                    return;579                  }580                  WritableStreamFulfillWriteRequest(stream);581                  WritableStreamFinishClose(stream);582                },583                r => WritableStreamDefaultControllerErrorIfNeeded(controller, r)584               );585  }586  function WritableStreamDefaultControllerProcessWrite(controller, chunk) {587    setDefaultControllerWritingFlag(controller, true);588    const sinkWritePromise = PromiseInvokeOrNoop(controller[_underlyingSink],589                                               'write', [chunk, controller]);590    thenPromise(591        sinkWritePromise,592        () => {593          const stream = controller[_controlledWritableStream];594          const state = stream[_state];595          if (state === ERRORED || state === CLOSED) {596            return;597          }598          setDefaultControllerWritingFlag(controller, false);599          WritableStreamFulfillWriteRequest(stream);600          const lastBackpressure =601              WritableStreamDefaultControllerGetBackpressure(controller);602          DequeueValueForController(controller);603          if (state !== CLOSING) {604            const backpressure =605                WritableStreamDefaultControllerGetBackpressure(controller);606            if (lastBackpressure !== backpressure) {607              WritableStreamUpdateBackpressure(608                  controller[_controlledWritableStream], backpressure);609            }610          }611          WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller);612        },613        r => WritableStreamDefaultControllerErrorIfNeeded(controller, r)614        );615  }616  function WritableStreamDefaultControllerGetBackpressure(controller) {617    const desiredSize =618        WritableStreamDefaultControllerGetDesiredSize(controller);619    return desiredSize <= 0;620  }621  function WritableStreamDefaultControllerError(controller, e) {622    const stream = controller[_controlledWritableStream];623    const state = stream[_state];624    TEMP_ASSERT(state === WRITABLE || state === CLOSING,625                'stream.[[state]] is "writable" or "closing".');626    WritableStreamError(stream, e);627    controller[_queue] = new v8.InternalPackedArray();628    controller[_queueSize] = 0;629  }630  // Queue-with-Sizes Operations...

writable-stream.js

Source:writable-stream.js

...111  if (writer !== undefined) {112    defaultWriterClosedPromiseReject(writer, e);113    writer._closedPromise.catch(() => {});114    if (state === 'writable' &&115        WritableStreamDefaultControllerGetBackpressure(stream._writableStreamController) === true) {116      defaultWriterReadyPromiseReject(writer, e);117    } else {118      defaultWriterReadyPromiseResetToRejected(writer, e);119    }120    writer._readyPromise.catch(() => {});121  }122  stream._state = 'errored';123  stream._storedError = e;124}125function WritableStreamFinishClose(stream) {126  assert(stream._state === 'closing');127  // writer cannot be released while close() is ongoing. So, we can assert that128  // there's an active writer.129  assert(stream._writer !== undefined);130  stream._state = 'closed';131  defaultWriterClosedPromiseResolve(stream._writer);132}133function WritableStreamFulfillWriteRequest(stream) {134  assert(stream._writeRequests.length > 0);135  const writeRequest = stream._writeRequests.shift();136  writeRequest._resolve(undefined);137}138function WritableStreamUpdateBackpressure(stream, backpressure) {139  assert(stream._state === 'writable');140  const writer = stream._writer;141  if (writer === undefined) {142    return;143  }144  if (backpressure === true) {145    defaultWriterReadyPromiseReset(writer);146  } else {147    assert(backpressure === false);148    defaultWriterReadyPromiseResolve(writer);149  }150}151class WritableStreamDefaultWriter {152  constructor(stream) {153    if (IsWritableStream(stream) === false) {154      throw new TypeError('WritableStreamDefaultWriter can only be constructed with a WritableStream instance');155    }156    if (IsWritableStreamLocked(stream) === true) {157      throw new TypeError('This stream has already been locked for exclusive writing by another writer');158    }159    this._ownerWritableStream = stream;160    stream._writer = this;161    const state = stream._state;162    if (state === 'writable' || state === 'closing') {163      defaultWriterClosedPromiseInitialize(this);164    } else if (state === 'closed') {165      defaultWriterClosedPromiseInitializeAsResolved(this);166    } else {167      assert(state === 'errored', 'state must be errored');168      defaultWriterClosedPromiseInitializeAsRejected(this, stream._storedError);169      this._closedPromise.catch(() => {});170    }171    if (state === 'writable' &&172        WritableStreamDefaultControllerGetBackpressure(stream._writableStreamController) === true) {173      defaultWriterReadyPromiseInitialize(this);174    } else {175      defaultWriterReadyPromiseInitializeAsResolved(this, undefined);176    }177  }178  get closed() {179    if (IsWritableStreamDefaultWriter(this) === false) {180      return Promise.reject(defaultWriterBrandCheckException('closed'));181    }182    return this._closedPromise;183  }184  get desiredSize() {185    if (IsWritableStreamDefaultWriter(this) === false) {186      throw defaultWriterBrandCheckException('desiredSize');187    }188    if (this._ownerWritableStream === undefined) {189      throw defaultWriterLockException('desiredSize');190    }191    return WritableStreamDefaultWriterGetDesiredSize(this);192  }193  get ready() {194    if (IsWritableStreamDefaultWriter(this) === false) {195      return Promise.reject(defaultWriterBrandCheckException('ready'));196    }197    return this._readyPromise;198  }199  abort(reason) {200    if (IsWritableStreamDefaultWriter(this) === false) {201      return Promise.reject(defaultWriterBrandCheckException('abort'));202    }203    if (this._ownerWritableStream === undefined) {204      return Promise.reject(defaultWriterLockException('abort'));205    }206    return WritableStreamDefaultWriterAbort(this, reason);207  }208  close() {209    if (IsWritableStreamDefaultWriter(this) === false) {210      return Promise.reject(defaultWriterBrandCheckException('close'));211    }212    const stream = this._ownerWritableStream;213    if (stream === undefined) {214      return Promise.reject(defaultWriterLockException('close'));215    }216    if (stream._state === 'closing') {217      return Promise.reject(new TypeError('cannot close an already-closing stream'));218    }219    return WritableStreamDefaultWriterClose(this);220  }221  releaseLock() {222    if (IsWritableStreamDefaultWriter(this) === false) {223      throw defaultWriterBrandCheckException('releaseLock');224    }225    const stream = this._ownerWritableStream;226    if (stream === undefined) {227      return;228    }229    assert(stream._writer !== undefined);230    WritableStreamDefaultWriterRelease(this);231  }232  write(chunk) {233    if (IsWritableStreamDefaultWriter(this) === false) {234      return Promise.reject(defaultWriterBrandCheckException('write'));235    }236    const stream = this._ownerWritableStream;237    if (stream === undefined) {238      return Promise.reject(defaultWriterLockException('write to'));239    }240    if (stream._state === 'closing') {241      return Promise.reject(new TypeError('Cannot write to an already-closed stream'));242    }243    return WritableStreamDefaultWriterWrite(this, chunk);244  }245}246// Abstract operations for the WritableStreamDefaultWriter.247function IsWritableStreamDefaultWriter(x) {248  if (!typeIsObject(x)) {249    return false;250  }251  if (!Object.prototype.hasOwnProperty.call(x, '_ownerWritableStream')) {252    return false;253  }254  return true;255}256// A client of WritableStreamDefaultWriter may use these functions directly to bypass state check.257function WritableStreamDefaultWriterAbort(writer, reason) {258  const stream = writer._ownerWritableStream;259  assert(stream !== undefined);260  return WritableStreamAbort(stream, reason);261}262function WritableStreamDefaultWriterClose(writer) {263  const stream = writer._ownerWritableStream;264  assert(stream !== undefined);265  const state = stream._state;266  if (state === 'closed' || state === 'errored') {267    return Promise.reject(new TypeError(268      `The stream (in ${state} state) is not in the writable state and cannot be closed`));269  }270  assert(state === 'writable');271  const promise = WritableStreamAddWriteRequest(stream);272  if (WritableStreamDefaultControllerGetBackpressure(stream._writableStreamController) === true) {273    defaultWriterReadyPromiseResolve(writer);274  }275  stream._state = 'closing';276  WritableStreamDefaultControllerClose(stream._writableStreamController);277  return promise;278}279function WritableStreamDefaultWriterCloseWithErrorPropagation(writer) {280  const stream = writer._ownerWritableStream;281  assert(stream !== undefined);282  const state = stream._state;283  if (state === 'closing' || state === 'closed') {284    return Promise.resolve();285  }286  if (state === 'errored') {287    return Promise.reject(stream._storedError);288  }289  assert(state === 'writable');290  return WritableStreamDefaultWriterClose(writer);291}292function WritableStreamDefaultWriterGetDesiredSize(writer) {293  const stream = writer._ownerWritableStream;294  const state = stream._state;295  if (state === 'errored') {296    return null;297  }298  if (state === 'closed') {299    return 0;300  }301  return WritableStreamDefaultControllerGetDesiredSize(stream._writableStreamController);302}303function WritableStreamDefaultWriterRelease(writer) {304  const stream = writer._ownerWritableStream;305  assert(stream !== undefined);306  assert(stream._writer === writer);307  const releasedError = new TypeError(308    'Writer was released and can no longer be used to monitor the stream\'s closedness');309  const state = stream._state;310  if (state === 'writable' || state === 'closing') {311    defaultWriterClosedPromiseReject(writer, releasedError);312  } else {313    defaultWriterClosedPromiseResetToRejected(writer, releasedError);314  }315  writer._closedPromise.catch(() => {});316  if (state === 'writable' &&317      WritableStreamDefaultControllerGetBackpressure(stream._writableStreamController) === true) {318    defaultWriterReadyPromiseReject(writer, releasedError);319  } else {320    defaultWriterReadyPromiseResetToRejected(writer, releasedError);321  }322  writer._readyPromise.catch(() => {});323  stream._writer = undefined;324  writer._ownerWritableStream = undefined;325}326function WritableStreamDefaultWriterWrite(writer, chunk) {327  const stream = writer._ownerWritableStream;328  assert(stream !== undefined);329  const state = stream._state;330  if (state === 'closed' || state === 'errored') {331    return Promise.reject(new TypeError(332      `The stream (in ${state} state) is not in the writable state and cannot be written to`));333  }334  assert(state === 'writable');335  const promise = WritableStreamAddWriteRequest(stream);336  WritableStreamDefaultControllerWrite(stream._writableStreamController, chunk);337  return promise;338}339class WritableStreamDefaultController {340  constructor(stream, underlyingSink, size, highWaterMark) {341    if (IsWritableStream(stream) === false) {342      throw new TypeError('WritableStreamDefaultController can only be constructed with a WritableStream instance');343    }344    if (stream._writableStreamController !== undefined) {345      throw new TypeError(346        'WritableStreamDefaultController instances can only be created by the WritableStream constructor');347    }348    this._controlledWritableStream = stream;349    this._underlyingSink = underlyingSink;350    this._queue = [];351    this._started = false;352    this._writing = false;353    const normalizedStrategy = ValidateAndNormalizeQueuingStrategy(size, highWaterMark);354    this._strategySize = normalizedStrategy.size;355    this._strategyHWM = normalizedStrategy.highWaterMark;356    const backpressure = WritableStreamDefaultControllerGetBackpressure(this);357    if (backpressure === true) {358      WritableStreamUpdateBackpressure(stream, backpressure);359    }360    const controller = this;361    const startResult = InvokeOrNoop(underlyingSink, 'start', [this]);362    Promise.resolve(startResult).then(363      () => {364        controller._started = true;365        WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller);366      },367      r => {368        WritableStreamDefaultControllerErrorIfNeeded(controller, r);369      }370    )371    .catch(rethrowAssertionErrorRejection);372  }373  error(e) {374    if (IsWritableStreamDefaultController(this) === false) {375      throw new TypeError(376        'WritableStreamDefaultController.prototype.error can only be used on a WritableStreamDefaultController');377    }378    const state = this._controlledWritableStream._state;379    if (state === 'closed' || state === 'errored') {380      throw new TypeError(`The stream is ${state} and so cannot be errored`);381    }382    WritableStreamDefaultControllerError(this, e);383  }384}385// Abstract operations implementing interface required by the WritableStream.386function WritableStreamDefaultControllerAbort(controller, reason) {387  controller._queue = [];388  const sinkAbortPromise = PromiseInvokeOrFallbackOrNoop(controller._underlyingSink, 'abort', [reason],389                                                         'close', [controller]);390  return sinkAbortPromise.then(() => undefined);391}392function WritableStreamDefaultControllerClose(controller) {393  EnqueueValueWithSize(controller._queue, 'close', 0);394  WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller);395}396function WritableStreamDefaultControllerGetDesiredSize(controller) {397  const queueSize = GetTotalQueueSize(controller._queue);398  return controller._strategyHWM - queueSize;399}400function WritableStreamDefaultControllerWrite(controller, chunk) {401  const stream = controller._controlledWritableStream;402  assert(stream._state === 'writable');403  let chunkSize = 1;404  if (controller._strategySize !== undefined) {405    try {406      chunkSize = controller._strategySize(chunk);407    } catch (chunkSizeE) {408      // TODO: Should we notify the sink of this error?409      WritableStreamDefaultControllerErrorIfNeeded(controller, chunkSizeE);410      return;411    }412  }413  const writeRecord = { chunk };414  const lastBackpressure = WritableStreamDefaultControllerGetBackpressure(controller);415  try {416    EnqueueValueWithSize(controller._queue, writeRecord, chunkSize);417  } catch (enqueueE) {418    WritableStreamDefaultControllerErrorIfNeeded(controller, enqueueE);419    return;420  }421  if (stream._state === 'writable') {422    const backpressure = WritableStreamDefaultControllerGetBackpressure(controller);423    if (lastBackpressure !== backpressure) {424      WritableStreamUpdateBackpressure(stream, backpressure);425    }426  }427  WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller);428}429// Abstract operations for the WritableStreamDefaultController.430function IsWritableStreamDefaultController(x) {431  if (!typeIsObject(x)) {432    return false;433  }434  if (!Object.prototype.hasOwnProperty.call(x, '_underlyingSink')) {435    return false;436  }437  return true;438}439function WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller) {440  if (controller._controlledWritableStream._state === 'closed' ||441      controller._controlledWritableStream._state === 'errored') {442    return;443  }444  if (controller._started === false) {445    return;446  }447  if (controller._writing === true) {448    return;449  }450  if (controller._queue.length === 0) {451    return;452  }453  const writeRecord = PeekQueueValue(controller._queue);454  if (writeRecord === 'close') {455    WritableStreamDefaultControllerProcessClose(controller);456  } else {457    WritableStreamDefaultControllerProcessWrite(controller, writeRecord.chunk);458  }459}460function WritableStreamDefaultControllerErrorIfNeeded(controller, e) {461  if (controller._controlledWritableStream._state === 'writable' ||462      controller._controlledWritableStream._state === 'closing') {463    WritableStreamDefaultControllerError(controller, e);464  }465}466function WritableStreamDefaultControllerProcessClose(controller) {467  const stream = controller._controlledWritableStream;468  assert(stream._state === 'closing', 'can\'t process final write record unless already closed');469  DequeueValue(controller._queue);470  assert(controller._queue.length === 0, 'queue must be empty once the final write record is dequeued');471  const sinkClosePromise = PromiseInvokeOrNoop(controller._underlyingSink, 'close', [controller]);472  sinkClosePromise.then(473    () => {474      if (stream._state !== 'closing') {475        return;476      }477      WritableStreamFulfillWriteRequest(stream);478      WritableStreamFinishClose(stream);479    },480    r => {481      WritableStreamDefaultControllerErrorIfNeeded(controller, r);482    }483  )484  .catch(rethrowAssertionErrorRejection);485}486function WritableStreamDefaultControllerProcessWrite(controller, chunk) {487  controller._writing = true;488  const sinkWritePromise = PromiseInvokeOrNoop(controller._underlyingSink, 'write', [chunk, controller]);489  sinkWritePromise.then(490    () => {491      const stream = controller._controlledWritableStream;492      const state = stream._state;493      if (state === 'errored' || state === 'closed') {494        return;495      }496      controller._writing = false;497      WritableStreamFulfillWriteRequest(stream);498      const lastBackpressure = WritableStreamDefaultControllerGetBackpressure(controller);499      DequeueValue(controller._queue);500      if (state !== 'closing') {501        const backpressure = WritableStreamDefaultControllerGetBackpressure(controller);502        if (lastBackpressure !== backpressure) {503          WritableStreamUpdateBackpressure(controller._controlledWritableStream, backpressure);504        }505      }506      WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller);507    },508    r => {509      WritableStreamDefaultControllerErrorIfNeeded(controller, r);510    }511  )512  .catch(rethrowAssertionErrorRejection);513}514function WritableStreamDefaultControllerGetBackpressure(controller) {515  const desiredSize = WritableStreamDefaultControllerGetDesiredSize(controller);516  return desiredSize <= 0;517}518// A client of WritableStreamDefaultController may use these functions directly to bypass state check.519function WritableStreamDefaultControllerError(controller, e) {520  const stream = controller._controlledWritableStream;521  assert(stream._state === 'writable' || stream._state === 'closing');522  WritableStreamError(stream, e);523  controller._queue = [];524}525// Helper functions for the WritableStream.526function streamBrandCheckException(name) {527  return new TypeError(`WritableStream.prototype.${name} can only be used on a WritableStream`);528}...

Using AI Code Generation

1'use strict';2const { WritableStream, CountQueuingStrategy } = require('stream/web');3const ws = new WritableStream({4  write() {}5}, new CountQueuingStrategy({ highWaterMark: 0 }));6const writer = ws.getWriter();7const backpressure = writer.desiredSize;8console.log(backpressure);

Using AI Code Generation

1'use strict';2const { WritableStream } = require('stream/web');3const { WritableStreamDefaultControllerGetBackpressure } = require('internal/webstreams/writablestream');4const assert = require('assert');5const ws = new WritableStream({6  write() {}7});8const writer = ws.getWriter();9const controller = writer[kState].controller;10assert.strictEqual(WritableStreamDefaultControllerGetBackpressure(controller), false);11writer.close();12'use strict';13const { WritableStream } = require('stream/web');14const { WritableStreamDefaultControllerGetBackpressure } = require('internal/webstreams/writablestream');15const assert = require('assert');16const ws = new WritableStream({17  write() {}18});19const writer = ws.getWriter();20const controller = writer[kState].controller;21assert.strictEqual(WritableStreamDefaultControllerGetBackpressure(controller), false);22writer.close();23'use strict';24const { WritableStream } = require('stream/web');25const { WritableStreamDefaultControllerGetBackpressure } = require('internal/webstreams/writablestream');26const assert = require('assert');27const ws = new WritableStream({28  write() {}29});30const writer = ws.getWriter();31const controller = writer[kState].controller;32assert.strictEqual(WritableStreamDefaultControllerGetBackpressure(controller), false);33writer.close();34'use strict';35const { WritableStream } = require('stream/web');36const { WritableStreamDefaultControllerGetBackpressure } = require('internal/webstreams/writablestream');37const assert = require('assert');38const ws = new WritableStream({39  write() {}40});41const writer = ws.getWriter();42const controller = writer[kState].controller;43assert.strictEqual(WritableStreamDefaultControllerGetBackpressure(controller), false);44writer.close();45'use strict';46const { WritableStream } = require('stream/web');47const { W

Using AI Code Generation

1const assert = require('assert');2const {3} = require('stream/web');4const ws = new WritableStream({5  write() { }6});7const writer = new WritableStreamDefaultWriter(ws);8const controller = writer[kState].controller;9assert.strictEqual(controller[kState].backpressure, false);10assert.strictEqual(11  WritableStreamDefaultControllerGetBackpressure(controller),12  false);13controller[kState].backpressure = true;14assert.strictEqual(controller[kState].backpressure, true);15assert.strictEqual(16  WritableStreamDefaultControllerGetBackpressure(controller),17  true);18assert.strictEqual(19  WritableStreamDefaultControllerGetBackpressure({}),20  undefined);21assert.throws(() => WritableStreamDefaultControllerGetBackpressure(), {22});

Using AI Code Generation

1'use strict';2const assert = require('assert');3const { WritableStream, CountQueuingStrategy } = require('stream/web');4const ws = new WritableStream({5  write() {6    return new Promise((resolve) => setTimeout(resolve, 100));7  }8}, new CountQueuingStrategy({ highWaterMark: 1 }));9const writer = ws.getWriter();10writer.write('a');11writer.write('b');12writer.write('c');13setTimeout(() => {14  assert.strictEqual(writer.desiredSize, 0);15  assert.strictEqual(writer.ready, null);16  writer.releaseLock();17}, 200);

Using AI Code Generation

1'use strict';2const { WritableStream, WritableStreamDefaultControllerGetBackpressure } = require('stream/web');3const ws = new WritableStream({4  write() {}5});6const writer = ws.getWriter();7const controller = writer[kState].controller;8const backpressure = WritableStreamDefaultControllerGetBackpressure(controller);9console.log(backpressure);10{11  "dependencies": {12  }13}14{15  "packages": {16    "": {17      "dependencies": {18      }19    },20    "node": {21    }22  }23}24{25  "bugs": {

Using AI Code Generation

1'use strict';2const { WritableStream, WritableStreamDefaultControllerGetBackpressure } = require('stream/web');3const { ReadableStream, CountQueuingStrategy } = require('stream/web');4const { Writable, Readable } = require('stream');5const ws = new WritableStream({6  write() {}7});8const ws1 = new WritableStream({9  write() {}10}, new CountQueuingStrategy({ highWaterMark: 0 }));11const ws2 = new WritableStream({12  write() {}13});14const ws3 = new WritableStream({15  write() {}16}, new CountQueuingStrategy({ highWaterMark: 0 }));17const rs = new ReadableStream({18  start(controller) {19    controller.enqueue('a');20    controller.enqueue('b');21    controller.enqueue('c');22  }23});24const writer = ws.getWriter();25const writer1 = ws1.getWriter();26const writer2 = ws2.getWriter();27const writer3 = ws3.getWriter();28const reader = rs.getReader();29async function writeAll() {30  for (let result = await reader.read(); !result.done; result = await reader.read()) {31    writer.write(result.value);32    writer1.write(result.value);33    writer2.write(result.value);34    writer3.write(result.value);35  }36  await writer.close();37  await writer1.close();38  await writer2.close();39  await writer3.close();40}41writeAll().then(() => {42  console.log(WritableStreamDefaultControllerGetBackpressure(writer._writableStreamController));43  console.log(WritableStreamDefaultControllerGetBackpressure(writer1._writableStreamController));44  console.log(WritableStreamDefaultControllerGetBackpressure(writer2._writableStreamController));45  console.log(WritableStreamDefaultControllerGetBackpressure(writer3._writableStreamController));46});

Using AI Code Generation

1'use strict';2const { WritableStream, CountQueuingStrategy } = require('stream/web');3const ws = new WritableStream({4  write() {},5}, new CountQueuingStrategy({ highWaterMark: 1 }));6const writer = ws.getWriter();7assert_equals(writer.desiredSize, 0, 'desiredSize should be 0');8writer.write('a');9assert_equals(writer.desiredSize, -1, 'desiredSize should be -1');10writer.write('b');11assert_equals(writer.desiredSize, -2, 'desiredSize should be -2');12writer.releaseLock();13const writer2 = ws.getWriter();14assert_equals(writer2.desiredSize, 0, 'desiredSize should be 0');15'use strict';16const assert = require('assert');17const {18} = require('./abstract-ops/queue-with-sizes');19const {20} = require('./abstract-ops/algorithm');21const {22} = require('./abstract-ops/writable-streams');23const {24} = require('./abstract-ops/writable-stream-abstract-ops');25const {26} = require('./abstract-ops/queuing-strategy');27const {

Using AI Code Generation

1var WritableStream = require('stream').Writable;2var assert = require('assert');3const ws = new WritableStream({4  write(chunk, controller) {5    controller.getBackpressure();6  }7});8assert.throws(() => ws.write('a'), TypeError);9assert.throws(() => ws.write('a'), TypeError)10at Object.<anonymous> (/home/ashish/Desktop/Node.js/Streams/test.js:12:8)11at Module._compile (internal/modules/cjs/loader.js:1158:30)12at Object.Module._extensions..js (internal/modules/cjs/loader.js:1178:10)13at Module.load (internal/modules/cjs/loader.js:1002:32)14at Function.Module._load (internal/modules/cjs/loader.js:901:14)15at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:74:12)

Automation Testing Tutorials

Learn to execute automation testing from scratch with LambdaTest Learning Hub. Right from setting up the prerequisites to run your first automation test, to following best practices and diving deeper into advanced test scenarios. LambdaTest Learning Hubs compile a list of step-by-step guides to help you be proficient with different test automation frameworks i.e. Selenium, Cypress, TestNG etc.