{"version":3,"file":"polyfill.es2018.js","sources":["../src/stub/symbol.ts","../src/utils.ts","../src/lib/helpers/miscellaneous.ts","../src/lib/helpers/webidl.ts","../src/lib/simple-queue.ts","../src/lib/readable-stream/generic-reader.ts","../src/lib/abstract-ops/internal-methods.ts","../src/stub/number-isfinite.ts","../src/stub/math-trunc.ts","../src/lib/validators/basic.ts","../src/lib/validators/readable-stream.ts","../src/lib/readable-stream/default-reader.ts","../src/target/es2018/stub/async-iterator-prototype.ts","../src/lib/readable-stream/async-iterator.ts","../src/stub/number-isnan.ts","../src/lib/abstract-ops/ecmascript.ts","../src/lib/abstract-ops/miscellaneous.ts","../src/lib/abstract-ops/queue-with-sizes.ts","../src/lib/readable-stream/byte-stream-controller.ts","../src/lib/readable-stream/byob-reader.ts","../src/lib/abstract-ops/queuing-strategy.ts","../src/lib/validators/queuing-strategy.ts","../src/lib/validators/underlying-sink.ts","../src/lib/validators/writable-stream.ts","../src/lib/abort-signal.ts","../src/lib/writable-stream.ts","../src/stub/native.ts","../src/stub/dom-exception.ts","../src/lib/readable-stream/pipe.ts","../src/lib/readable-stream/default-controller.ts","../src/lib/readable-stream/tee.ts","../src/lib/validators/underlying-source.ts","../src/lib/validators/reader-options.ts","../src/lib/validators/iterator-options.ts","../src/lib/validators/pipe-options.ts","../src/lib/validators/readable-writable-pair.ts","../src/lib/readable-stream.ts","../src/lib/validators/queuing-strategy-init.ts","../src/lib/byte-length-queuing-strategy.ts","../src/lib/count-queuing-strategy.ts","../src/lib/validators/transformer.ts","../src/lib/transform-stream.ts","../src/polyfill.ts"],"sourcesContent":["/// \n\nconst SymbolPolyfill: (description?: string) => symbol =\n typeof Symbol === 'function' && typeof Symbol.iterator === 'symbol' ?\n Symbol :\n description => `Symbol(${description})` as any as symbol;\n\nexport default SymbolPolyfill;\n","/// \n\nexport function noop(): undefined {\n return undefined;\n}\n\nfunction getGlobals() {\n if (typeof self !== 'undefined') {\n return self;\n } else if (typeof window !== 'undefined') {\n return window;\n } else if (typeof global !== 'undefined') {\n return global;\n }\n return undefined;\n}\n\nexport const globals = getGlobals();\n","import { noop } from '../../utils';\nimport { AssertionError } from '../../stub/assert';\n\nexport function typeIsObject(x: any): x is object {\n return (typeof x === 'object' && x !== null) || typeof x === 'function';\n}\n\nexport const rethrowAssertionErrorRejection: (e: any) => void =\n DEBUG ? e => {\n // Used throughout the reference implementation, as `.catch(rethrowAssertionErrorRejection)`, to ensure any errors\n // get shown. There are places in the spec where we do promise transformations and purposefully ignore or don't\n // expect any errors, but assertion errors are always problematic.\n if (e && e instanceof AssertionError) {\n setTimeout(() => {\n throw e;\n }, 0);\n }\n } : noop;\n","import { globals } from '../../utils';\nimport { rethrowAssertionErrorRejection } from './miscellaneous';\nimport assert from '../../stub/assert';\n\nconst originalPromise = Promise;\nconst originalPromiseThen = Promise.prototype.then;\nconst originalPromiseResolve = Promise.resolve.bind(originalPromise);\nconst originalPromiseReject = Promise.reject.bind(originalPromise);\n\nexport function newPromise(executor: (\n resolve: (value: T | PromiseLike) => void,\n reject: (reason?: any) => void\n) => void): Promise {\n return new originalPromise(executor);\n}\n\nexport function promiseResolvedWith(value: T | PromiseLike): Promise {\n return originalPromiseResolve(value);\n}\n\nexport function promiseRejectedWith(reason: any): Promise {\n return originalPromiseReject(reason);\n}\n\nexport function PerformPromiseThen(\n promise: Promise,\n onFulfilled?: (value: T) => TResult1 | PromiseLike,\n onRejected?: (reason: any) => TResult2 | PromiseLike): Promise {\n // There doesn't appear to be any way to correctly emulate the behaviour from JavaScript, so this is just an\n // approximation.\n return originalPromiseThen.call(promise, onFulfilled, onRejected) as Promise;\n}\n\nexport function uponPromise(\n promise: Promise,\n onFulfilled?: (value: T) => void | PromiseLike,\n onRejected?: (reason: any) => void | PromiseLike): void {\n PerformPromiseThen(\n PerformPromiseThen(promise, onFulfilled, onRejected),\n undefined,\n rethrowAssertionErrorRejection\n );\n}\n\nexport function uponFulfillment(promise: Promise, onFulfilled: (value: T) => void | PromiseLike): void {\n uponPromise(promise, onFulfilled);\n}\n\nexport function uponRejection(promise: Promise, onRejected: (reason: any) => void | PromiseLike): void {\n uponPromise(promise, undefined, onRejected);\n}\n\nexport function transformPromiseWith(\n promise: Promise,\n fulfillmentHandler?: (value: T) => TResult1 | PromiseLike,\n rejectionHandler?: (reason: any) => TResult2 | PromiseLike): Promise {\n return PerformPromiseThen(promise, fulfillmentHandler, rejectionHandler);\n}\n\nexport function setPromiseIsHandledToTrue(promise: Promise): void {\n PerformPromiseThen(promise, undefined, rethrowAssertionErrorRejection);\n}\n\nexport const queueMicrotask: (fn: () => void) => void = (() => {\n const globalQueueMicrotask = globals && globals.queueMicrotask;\n if (typeof globalQueueMicrotask === 'function') {\n return globalQueueMicrotask;\n }\n\n const resolvedPromise = promiseResolvedWith(undefined);\n return (fn: () => void) => PerformPromiseThen(resolvedPromise, fn);\n})();\n\nexport function reflectCall(F: (this: T, ...fnArgs: A) => R, V: T, args: A): R {\n if (typeof F !== 'function') {\n throw new TypeError('Argument is not a function');\n }\n return Function.prototype.apply.call(F, V, args);\n}\n\nexport function promiseCall(F: (this: T, ...fnArgs: A) => R | PromiseLike,\n V: T,\n args: A): Promise {\n assert(typeof F === 'function');\n assert(V !== undefined);\n assert(Array.isArray(args));\n try {\n return promiseResolvedWith(reflectCall(F, V, args));\n } catch (value) {\n return promiseRejectedWith(value);\n }\n}\n","import assert from '../stub/assert';\n\n// Original from Chromium\n// https://chromium.googlesource.com/chromium/src/+/0aee4434a4dba42a42abaea9bfbc0cd196a63bc1/third_party/blink/renderer/core/streams/SimpleQueue.js\n\nconst QUEUE_MAX_ARRAY_SIZE = 16384;\n\ninterface Node {\n _elements: T[];\n _next: Node | undefined;\n}\n\n/**\n * Simple queue structure.\n *\n * Avoids scalability issues with using a packed array directly by using\n * multiple arrays in a linked list and keeping the array size bounded.\n */\nexport class SimpleQueue {\n private _front: Node;\n private _back: Node;\n private _cursor = 0;\n private _size = 0;\n\n constructor() {\n // _front and _back are always defined.\n this._front = {\n _elements: [],\n _next: undefined\n };\n this._back = this._front;\n // The cursor is used to avoid calling Array.shift().\n // It contains the index of the front element of the array inside the\n // front-most node. It is always in the range [0, QUEUE_MAX_ARRAY_SIZE).\n this._cursor = 0;\n // When there is only one node, size === elements.length - cursor.\n this._size = 0;\n }\n\n get length(): number {\n return this._size;\n }\n\n // For exception safety, this method is structured in order:\n // 1. Read state\n // 2. Calculate required state mutations\n // 3. Perform state mutations\n push(element: T): void {\n const oldBack = this._back;\n let newBack = oldBack;\n assert(oldBack._next === undefined);\n if (oldBack._elements.length === QUEUE_MAX_ARRAY_SIZE - 1) {\n newBack = {\n _elements: [],\n _next: undefined\n };\n }\n\n // push() is the mutation most likely to throw an exception, so it\n // goes first.\n oldBack._elements.push(element);\n if (newBack !== oldBack) {\n this._back = newBack;\n oldBack._next = newBack;\n }\n ++this._size;\n }\n\n // Like push(), shift() follows the read -> calculate -> mutate pattern for\n // exception safety.\n shift(): T {\n assert(this._size > 0); // must not be called on an empty queue\n\n const oldFront = this._front;\n let newFront = oldFront;\n const oldCursor = this._cursor;\n let newCursor = oldCursor + 1;\n\n const elements = oldFront._elements;\n const element = elements[oldCursor];\n\n if (newCursor === QUEUE_MAX_ARRAY_SIZE) {\n assert(elements.length === QUEUE_MAX_ARRAY_SIZE);\n assert(oldFront._next !== undefined);\n newFront = oldFront._next!;\n newCursor = 0;\n }\n\n // No mutations before this point.\n --this._size;\n this._cursor = newCursor;\n if (oldFront !== newFront) {\n this._front = newFront;\n }\n\n // Permit shifted element to be garbage collected.\n elements[oldCursor] = undefined!;\n\n return element;\n }\n\n // The tricky thing about forEach() is that it can be called\n // re-entrantly. The queue may be mutated inside the callback. It is easy to\n // see that push() within the callback has no negative effects since the end\n // of the queue is checked for on every iteration. If shift() is called\n // repeatedly within the callback then the next iteration may return an\n // element that has been removed. In this case the callback will be called\n // with undefined values until we either \"catch up\" with elements that still\n // exist or reach the back of the queue.\n forEach(callback: (element: T) => void): void {\n let i = this._cursor;\n let node = this._front;\n let elements = node._elements;\n while (i !== elements.length || node._next !== undefined) {\n if (i === elements.length) {\n assert(node._next !== undefined);\n assert(i === QUEUE_MAX_ARRAY_SIZE);\n node = node._next!;\n elements = node._elements;\n i = 0;\n if (elements.length === 0) {\n break;\n }\n }\n callback(elements[i]);\n ++i;\n }\n }\n\n // Return the element that would be returned if shift() was called now,\n // without modifying the queue.\n peek(): T {\n assert(this._size > 0); // must not be called on an empty queue\n\n const front = this._front;\n const cursor = this._cursor;\n return front._elements[cursor];\n }\n}\n","import assert from '../../stub/assert';\nimport { ReadableStream, ReadableStreamCancel, ReadableStreamReader } from '../readable-stream';\nimport { newPromise, setPromiseIsHandledToTrue } from '../helpers/webidl';\n\nexport function ReadableStreamReaderGenericInitialize(reader: ReadableStreamReader, stream: ReadableStream) {\n reader._ownerReadableStream = stream;\n stream._reader = reader;\n\n if (stream._state === 'readable') {\n defaultReaderClosedPromiseInitialize(reader);\n } else if (stream._state === 'closed') {\n defaultReaderClosedPromiseInitializeAsResolved(reader);\n } else {\n assert(stream._state === 'errored');\n\n defaultReaderClosedPromiseInitializeAsRejected(reader, stream._storedError);\n }\n}\n\n// A client of ReadableStreamDefaultReader and ReadableStreamBYOBReader may use these functions directly to bypass state\n// check.\n\nexport function ReadableStreamReaderGenericCancel(reader: ReadableStreamReader, reason: any): Promise {\n const stream = reader._ownerReadableStream;\n assert(stream !== undefined);\n return ReadableStreamCancel(stream, reason);\n}\n\nexport function ReadableStreamReaderGenericRelease(reader: ReadableStreamReader) {\n assert(reader._ownerReadableStream !== undefined);\n assert(reader._ownerReadableStream._reader === reader);\n\n if (reader._ownerReadableStream._state === 'readable') {\n defaultReaderClosedPromiseReject(\n reader,\n new TypeError(`Reader was released and can no longer be used to monitor the stream's closedness`));\n } else {\n defaultReaderClosedPromiseResetToRejected(\n reader,\n new TypeError(`Reader was released and can no longer be used to monitor the stream's closedness`));\n }\n\n reader._ownerReadableStream._reader = undefined;\n reader._ownerReadableStream = undefined!;\n}\n\n// Helper functions for the readers.\n\nexport function readerLockException(name: string): TypeError {\n return new TypeError('Cannot ' + name + ' a stream using a released reader');\n}\n\n// Helper functions for the ReadableStreamDefaultReader.\n\nexport function defaultReaderClosedPromiseInitialize(reader: ReadableStreamReader) {\n reader._closedPromise = newPromise((resolve, reject) => {\n reader._closedPromise_resolve = resolve;\n reader._closedPromise_reject = reject;\n });\n}\n\nexport function defaultReaderClosedPromiseInitializeAsRejected(reader: ReadableStreamReader, reason: any) {\n defaultReaderClosedPromiseInitialize(reader);\n defaultReaderClosedPromiseReject(reader, reason);\n}\n\nexport function defaultReaderClosedPromiseInitializeAsResolved(reader: ReadableStreamReader) {\n defaultReaderClosedPromiseInitialize(reader);\n defaultReaderClosedPromiseResolve(reader);\n}\n\nexport function defaultReaderClosedPromiseReject(reader: ReadableStreamReader, reason: any) {\n if (reader._closedPromise_reject === undefined) {\n return;\n }\n\n setPromiseIsHandledToTrue(reader._closedPromise);\n reader._closedPromise_reject(reason);\n reader._closedPromise_resolve = undefined;\n reader._closedPromise_reject = undefined;\n}\n\nexport function defaultReaderClosedPromiseResetToRejected(reader: ReadableStreamReader, reason: any) {\n assert(reader._closedPromise_resolve === undefined);\n assert(reader._closedPromise_reject === undefined);\n\n defaultReaderClosedPromiseInitializeAsRejected(reader, reason);\n}\n\nexport function defaultReaderClosedPromiseResolve(reader: ReadableStreamReader) {\n if (reader._closedPromise_resolve === undefined) {\n return;\n }\n\n reader._closedPromise_resolve(undefined);\n reader._closedPromise_resolve = undefined;\n reader._closedPromise_reject = undefined;\n}\n","export const AbortSteps = Symbol('[[AbortSteps]]');\nexport const ErrorSteps = Symbol('[[ErrorSteps]]');\nexport const CancelSteps = Symbol('[[CancelSteps]]');\nexport const PullSteps = Symbol('[[PullSteps]]');\n","/// \n\n// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isFinite#Polyfill\nconst NumberIsFinite: typeof Number.isFinite = Number.isFinite || function (x) {\n return typeof x === 'number' && isFinite(x);\n};\n\nexport default NumberIsFinite;\n","/// \n\n// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/trunc#Polyfill\nconst MathTrunc: typeof Math.trunc = Math.trunc || function (v) {\n return v < 0 ? Math.ceil(v) : Math.floor(v);\n};\n\nexport default MathTrunc;\n","import NumberIsFinite from '../../stub/number-isfinite';\nimport MathTrunc from '../../stub/math-trunc';\n\n// https://heycam.github.io/webidl/#idl-dictionaries\nexport function isDictionary(x: any): x is object | null {\n return typeof x === 'object' || typeof x === 'function';\n}\n\nexport function assertDictionary(obj: unknown,\n context: string): asserts obj is object | null | undefined {\n if (obj !== undefined && !isDictionary(obj)) {\n throw new TypeError(`${context} is not an object.`);\n }\n}\n\nexport type AnyFunction = (...args: any[]) => any;\n\n// https://heycam.github.io/webidl/#idl-callback-functions\nexport function assertFunction(x: unknown, context: string): asserts x is AnyFunction {\n if (typeof x !== 'function') {\n throw new TypeError(`${context} is not a function.`);\n }\n}\n\n// https://heycam.github.io/webidl/#idl-object\nexport function isObject(x: any): x is object {\n return (typeof x === 'object' && x !== null) || typeof x === 'function';\n}\n\nexport function assertObject(x: unknown,\n context: string): asserts x is object {\n if (!isObject(x)) {\n throw new TypeError(`${context} is not an object.`);\n }\n}\n\nexport function assertRequiredArgument(x: T | undefined,\n position: number,\n context: string): asserts x is T {\n if (x === undefined) {\n throw new TypeError(`Parameter ${position} is required in '${context}'.`);\n }\n}\n\nexport function assertRequiredField(x: T | undefined,\n field: string,\n context: string): asserts x is T {\n if (x === undefined) {\n throw new TypeError(`${field} is required in '${context}'.`);\n }\n}\n\n// https://heycam.github.io/webidl/#idl-unrestricted-double\nexport function convertUnrestrictedDouble(value: unknown): number {\n return Number(value);\n}\n\nfunction censorNegativeZero(x: number): number {\n return x === 0 ? 0 : x;\n}\n\nfunction integerPart(x: number): number {\n return censorNegativeZero(MathTrunc(x));\n}\n\n// https://heycam.github.io/webidl/#idl-unsigned-long-long\nexport function convertUnsignedLongLongWithEnforceRange(value: unknown, context: string): number {\n const lowerBound = 0;\n const upperBound = Number.MAX_SAFE_INTEGER;\n\n let x = Number(value);\n x = censorNegativeZero(x);\n\n if (!NumberIsFinite(x)) {\n throw new TypeError(`${context} is not a finite number`);\n }\n\n x = integerPart(x);\n\n if (x < lowerBound || x > upperBound) {\n throw new TypeError(`${context} is outside the accepted range of ${lowerBound} to ${upperBound}, inclusive`);\n }\n\n if (!NumberIsFinite(x) || x === 0) {\n return 0;\n }\n\n // TODO Use BigInt if supported?\n // let xBigInt = BigInt(integerPart(x));\n // xBigInt = BigInt.asUintN(64, xBigInt);\n // return Number(xBigInt);\n\n return x;\n}\n","import { IsReadableStream, ReadableStream } from '../readable-stream';\n\nexport function assertReadableStream(x: unknown, context: string): asserts x is ReadableStream {\n if (!IsReadableStream(x)) {\n throw new TypeError(`${context} is not a ReadableStream.`);\n }\n}\n","import assert from '../../stub/assert';\nimport { SimpleQueue } from '../simple-queue';\nimport {\n ReadableStreamReaderGenericCancel,\n ReadableStreamReaderGenericInitialize,\n ReadableStreamReaderGenericRelease,\n readerLockException\n} from './generic-reader';\nimport { IsReadableStreamLocked, ReadableStream } from '../readable-stream';\nimport { typeIsObject } from '../helpers/miscellaneous';\nimport { PullSteps } from '../abstract-ops/internal-methods';\nimport { newPromise, promiseRejectedWith } from '../helpers/webidl';\nimport { assertRequiredArgument } from '../validators/basic';\nimport { assertReadableStream } from '../validators/readable-stream';\n\n/**\n * A result returned by {@link ReadableStreamDefaultReader.read}.\n *\n * @public\n */\nexport type ReadableStreamDefaultReadResult = {\n done: false;\n value: T;\n} | {\n done: true;\n value?: undefined;\n}\n\n// Abstract operations for the ReadableStream.\n\nexport function AcquireReadableStreamDefaultReader(stream: ReadableStream): ReadableStreamDefaultReader {\n return new ReadableStreamDefaultReader(stream);\n}\n\n// ReadableStream API exposed for controllers.\n\nexport function ReadableStreamAddReadRequest(stream: ReadableStream,\n readRequest: ReadRequest): void {\n assert(IsReadableStreamDefaultReader(stream._reader));\n assert(stream._state === 'readable');\n\n (stream._reader! as ReadableStreamDefaultReader)._readRequests.push(readRequest);\n}\n\nexport function ReadableStreamFulfillReadRequest(stream: ReadableStream, chunk: R | undefined, done: boolean) {\n const reader = stream._reader as ReadableStreamDefaultReader;\n\n assert(reader._readRequests.length > 0);\n\n const readRequest = reader._readRequests.shift()!;\n if (done) {\n readRequest._closeSteps();\n } else {\n readRequest._chunkSteps(chunk!);\n }\n}\n\nexport function ReadableStreamGetNumReadRequests(stream: ReadableStream): number {\n return (stream._reader as ReadableStreamDefaultReader)._readRequests.length;\n}\n\nexport function ReadableStreamHasDefaultReader(stream: ReadableStream): boolean {\n const reader = stream._reader;\n\n if (reader === undefined) {\n return false;\n }\n\n if (!IsReadableStreamDefaultReader(reader)) {\n return false;\n }\n\n return true;\n}\n\n// Readers\n\nexport interface ReadRequest {\n _chunkSteps(chunk: R): void;\n\n _closeSteps(): void;\n\n _errorSteps(e: any): void;\n}\n\n/**\n * A default reader vended by a {@link ReadableStream}.\n *\n * @public\n */\nexport class ReadableStreamDefaultReader {\n /** @internal */\n _ownerReadableStream!: ReadableStream;\n /** @internal */\n _closedPromise!: Promise;\n /** @internal */\n _closedPromise_resolve?: (value?: undefined) => void;\n /** @internal */\n _closedPromise_reject?: (reason: any) => void;\n /** @internal */\n _readRequests: SimpleQueue>;\n\n constructor(stream: ReadableStream) {\n assertRequiredArgument(stream, 1, 'ReadableStreamDefaultReader');\n assertReadableStream(stream, 'First parameter');\n\n if (IsReadableStreamLocked(stream)) {\n throw new TypeError('This stream has already been locked for exclusive reading by another reader');\n }\n\n ReadableStreamReaderGenericInitialize(this, stream);\n\n this._readRequests = new SimpleQueue();\n }\n\n /**\n * Returns a promise that will be fulfilled when the stream becomes closed,\n * or rejected if the stream ever errors or the reader's lock is released before the stream finishes closing.\n */\n get closed(): Promise {\n if (!IsReadableStreamDefaultReader(this)) {\n return promiseRejectedWith(defaultReaderBrandCheckException('closed'));\n }\n\n return this._closedPromise;\n }\n\n /**\n * If the reader is active, behaves the same as {@link ReadableStream.cancel | stream.cancel(reason)}.\n */\n cancel(reason: any = undefined): Promise {\n if (!IsReadableStreamDefaultReader(this)) {\n return promiseRejectedWith(defaultReaderBrandCheckException('cancel'));\n }\n\n if (this._ownerReadableStream === undefined) {\n return promiseRejectedWith(readerLockException('cancel'));\n }\n\n return ReadableStreamReaderGenericCancel(this, reason);\n }\n\n /**\n * Returns a promise that allows access to the next chunk from the stream's internal queue, if available.\n *\n * If reading a chunk causes the queue to become empty, more data will be pulled from the underlying source.\n */\n read(): Promise> {\n if (!IsReadableStreamDefaultReader(this)) {\n return promiseRejectedWith(defaultReaderBrandCheckException('read'));\n }\n\n if (this._ownerReadableStream === undefined) {\n return promiseRejectedWith(readerLockException('read from'));\n }\n\n let resolvePromise!: (result: ReadableStreamDefaultReadResult) => void;\n let rejectPromise!: (reason: any) => void;\n const promise = newPromise>((resolve, reject) => {\n resolvePromise = resolve;\n rejectPromise = reject;\n });\n const readRequest: ReadRequest = {\n _chunkSteps: chunk => resolvePromise({ value: chunk, done: false }),\n _closeSteps: () => resolvePromise({ value: undefined, done: true }),\n _errorSteps: e => rejectPromise(e)\n };\n ReadableStreamDefaultReaderRead(this, readRequest);\n return promise;\n }\n\n /**\n * Releases the reader's lock on the corresponding stream. After the lock is released, the reader is no longer active.\n * If the associated stream is errored when the lock is released, the reader will appear errored in the same way\n * from now on; otherwise, the reader will appear closed.\n *\n * A reader's lock cannot be released while it still has a pending read request, i.e., if a promise returned by\n * the reader's {@link ReadableStreamDefaultReader.read | read()} method has not yet been settled. Attempting to\n * do so will throw a `TypeError` and leave the reader locked to the stream.\n */\n releaseLock(): void {\n if (!IsReadableStreamDefaultReader(this)) {\n throw defaultReaderBrandCheckException('releaseLock');\n }\n\n if (this._ownerReadableStream === undefined) {\n return;\n }\n\n if (this._readRequests.length > 0) {\n throw new TypeError('Tried to release a reader lock when that reader has pending read() calls un-settled');\n }\n\n ReadableStreamReaderGenericRelease(this);\n }\n}\n\nObject.defineProperties(ReadableStreamDefaultReader.prototype, {\n cancel: { enumerable: true },\n read: { enumerable: true },\n releaseLock: { enumerable: true },\n closed: { enumerable: true }\n});\nif (typeof Symbol.toStringTag === 'symbol') {\n Object.defineProperty(ReadableStreamDefaultReader.prototype, Symbol.toStringTag, {\n value: 'ReadableStreamDefaultReader',\n configurable: true\n });\n}\n\n// Abstract operations for the readers.\n\nexport function IsReadableStreamDefaultReader(x: any): x is ReadableStreamDefaultReader {\n if (!typeIsObject(x)) {\n return false;\n }\n\n if (!Object.prototype.hasOwnProperty.call(x, '_readRequests')) {\n return false;\n }\n\n return x instanceof ReadableStreamDefaultReader;\n}\n\nexport function ReadableStreamDefaultReaderRead(reader: ReadableStreamDefaultReader,\n readRequest: ReadRequest): void {\n const stream = reader._ownerReadableStream;\n\n assert(stream !== undefined);\n\n stream._disturbed = true;\n\n if (stream._state === 'closed') {\n readRequest._closeSteps();\n } else if (stream._state === 'errored') {\n readRequest._errorSteps(stream._storedError);\n } else {\n assert(stream._state === 'readable');\n stream._readableStreamController[PullSteps](readRequest as ReadRequest);\n }\n}\n\n// Helper functions for the ReadableStreamDefaultReader.\n\nfunction defaultReaderBrandCheckException(name: string): TypeError {\n return new TypeError(\n `ReadableStreamDefaultReader.prototype.${name} can only be used on a ReadableStreamDefaultReader`);\n}\n","/// \n\n/* eslint-disable @typescript-eslint/no-empty-function */\nexport const AsyncIteratorPrototype: AsyncIterable | undefined =\n Object.getPrototypeOf(Object.getPrototypeOf(async function* (): AsyncIterableIterator {}).prototype);\n","/// \n\nimport { ReadableStream } from '../readable-stream';\nimport {\n AcquireReadableStreamDefaultReader,\n ReadableStreamDefaultReader,\n ReadableStreamDefaultReaderRead,\n ReadableStreamDefaultReadResult,\n ReadRequest\n} from './default-reader';\nimport {\n ReadableStreamReaderGenericCancel,\n ReadableStreamReaderGenericRelease,\n readerLockException\n} from './generic-reader';\nimport assert from '../../stub/assert';\nimport { AsyncIteratorPrototype } from '@@target/stub/async-iterator-prototype';\nimport { typeIsObject } from '../helpers/miscellaneous';\nimport {\n newPromise,\n promiseRejectedWith,\n promiseResolvedWith,\n queueMicrotask,\n transformPromiseWith\n} from '../helpers/webidl';\n\n/**\n * An async iterator returned by {@link ReadableStream.values}.\n *\n * @public\n */\nexport interface ReadableStreamAsyncIterator extends AsyncIterator {\n next(): Promise>;\n\n return(value?: any): Promise>;\n}\n\nexport class ReadableStreamAsyncIteratorImpl {\n private readonly _reader: ReadableStreamDefaultReader;\n private readonly _preventCancel: boolean;\n private _ongoingPromise: Promise> | undefined = undefined;\n private _isFinished = false;\n\n constructor(reader: ReadableStreamDefaultReader, preventCancel: boolean) {\n this._reader = reader;\n this._preventCancel = preventCancel;\n }\n\n next(): Promise> {\n const nextSteps = () => this._nextSteps();\n this._ongoingPromise = this._ongoingPromise ?\n transformPromiseWith(this._ongoingPromise, nextSteps, nextSteps) :\n nextSteps();\n return this._ongoingPromise;\n }\n\n return(value: any): Promise> {\n const returnSteps = () => this._returnSteps(value);\n return this._ongoingPromise ?\n transformPromiseWith(this._ongoingPromise, returnSteps, returnSteps) :\n returnSteps();\n }\n\n private _nextSteps(): Promise> {\n if (this._isFinished) {\n return Promise.resolve({ value: undefined, done: true });\n }\n\n const reader = this._reader;\n if (reader._ownerReadableStream === undefined) {\n return promiseRejectedWith(readerLockException('iterate'));\n }\n\n let resolvePromise!: (result: ReadableStreamDefaultReadResult) => void;\n let rejectPromise!: (reason: any) => void;\n const promise = newPromise>((resolve, reject) => {\n resolvePromise = resolve;\n rejectPromise = reject;\n });\n const readRequest: ReadRequest = {\n _chunkSteps: chunk => {\n this._ongoingPromise = undefined;\n // This needs to be delayed by one microtask, otherwise we stop pulling too early which breaks a test.\n // FIXME Is this a bug in the specification, or in the test?\n queueMicrotask(() => resolvePromise({ value: chunk, done: false }));\n },\n _closeSteps: () => {\n this._ongoingPromise = undefined;\n this._isFinished = true;\n ReadableStreamReaderGenericRelease(reader);\n resolvePromise({ value: undefined, done: true });\n },\n _errorSteps: reason => {\n this._ongoingPromise = undefined;\n this._isFinished = true;\n ReadableStreamReaderGenericRelease(reader);\n rejectPromise(reason);\n }\n };\n ReadableStreamDefaultReaderRead(reader, readRequest);\n return promise;\n }\n\n private _returnSteps(value: any): Promise> {\n if (this._isFinished) {\n return Promise.resolve({ value, done: true });\n }\n this._isFinished = true;\n\n const reader = this._reader;\n if (reader._ownerReadableStream === undefined) {\n return promiseRejectedWith(readerLockException('finish iterating'));\n }\n\n assert(reader._readRequests.length === 0);\n\n if (!this._preventCancel) {\n const result = ReadableStreamReaderGenericCancel(reader, value);\n ReadableStreamReaderGenericRelease(reader);\n return transformPromiseWith(result, () => ({ value, done: true }));\n }\n\n ReadableStreamReaderGenericRelease(reader);\n return promiseResolvedWith({ value, done: true });\n }\n}\n\ndeclare class ReadableStreamAsyncIteratorInstance implements ReadableStreamAsyncIterator {\n /** @interal */\n _asyncIteratorImpl: ReadableStreamAsyncIteratorImpl;\n\n next(): Promise>;\n\n return(value?: any): Promise>;\n}\n\nconst ReadableStreamAsyncIteratorPrototype: ReadableStreamAsyncIteratorInstance = {\n next(this: ReadableStreamAsyncIteratorInstance): Promise> {\n if (!IsReadableStreamAsyncIterator(this)) {\n return promiseRejectedWith(streamAsyncIteratorBrandCheckException('next'));\n }\n return this._asyncIteratorImpl.next();\n },\n\n return(this: ReadableStreamAsyncIteratorInstance, value: any): Promise> {\n if (!IsReadableStreamAsyncIterator(this)) {\n return promiseRejectedWith(streamAsyncIteratorBrandCheckException('return'));\n }\n return this._asyncIteratorImpl.return(value);\n }\n} as any;\nif (AsyncIteratorPrototype !== undefined) {\n Object.setPrototypeOf(ReadableStreamAsyncIteratorPrototype, AsyncIteratorPrototype);\n}\n\n// Abstract operations for the ReadableStream.\n\nexport function AcquireReadableStreamAsyncIterator(stream: ReadableStream,\n preventCancel: boolean): ReadableStreamAsyncIterator {\n const reader = AcquireReadableStreamDefaultReader(stream);\n const impl = new ReadableStreamAsyncIteratorImpl(reader, preventCancel);\n const iterator: ReadableStreamAsyncIteratorInstance = Object.create(ReadableStreamAsyncIteratorPrototype);\n iterator._asyncIteratorImpl = impl;\n return iterator;\n}\n\nfunction IsReadableStreamAsyncIterator(x: any): x is ReadableStreamAsyncIterator {\n if (!typeIsObject(x)) {\n return false;\n }\n\n if (!Object.prototype.hasOwnProperty.call(x, '_asyncIteratorImpl')) {\n return false;\n }\n\n try {\n // noinspection SuspiciousTypeOfGuard\n return (x as ReadableStreamAsyncIteratorInstance)._asyncIteratorImpl instanceof\n ReadableStreamAsyncIteratorImpl;\n } catch {\n return false;\n }\n}\n\n// Helper functions for the ReadableStream.\n\nfunction streamAsyncIteratorBrandCheckException(name: string): TypeError {\n return new TypeError(`ReadableStreamAsyncIterator.${name} can only be used on a ReadableSteamAsyncIterator`);\n}\n","/// \n\n// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isNaN#Polyfill\nconst NumberIsNaN: typeof Number.isNaN = Number.isNaN || function (x) {\n // eslint-disable-next-line no-self-compare\n return x !== x;\n};\n\nexport default NumberIsNaN;\n","export function CreateArrayFromList(elements: T): T {\n // We use arrays to represent lists, so this is basically a no-op.\n // Do a slice though just in case we happen to depend on the unique-ness.\n return elements.slice() as T;\n}\n\nexport function CopyDataBlockBytes(dest: ArrayBuffer,\n destOffset: number,\n src: ArrayBuffer,\n srcOffset: number,\n n: number) {\n new Uint8Array(dest).set(new Uint8Array(src, srcOffset, n), destOffset);\n}\n\n// Not implemented correctly\nexport function TransferArrayBuffer(O: T): T {\n return O;\n}\n\n// Not implemented correctly\n// eslint-disable-next-line @typescript-eslint/no-unused-vars\nexport function CanTransferArrayBuffer(O: ArrayBufferLike): boolean {\n return true;\n}\n\n// Not implemented correctly\n// eslint-disable-next-line @typescript-eslint/no-unused-vars\nexport function IsDetachedBuffer(O: ArrayBufferLike): boolean {\n return false;\n}\n\nexport function ArrayBufferSlice(buffer: ArrayBufferLike, begin: number, end: number): ArrayBufferLike {\n // ArrayBuffer.prototype.slice is not available on IE10\n // https://www.caniuse.com/mdn-javascript_builtins_arraybuffer_slice\n if (buffer.slice) {\n return buffer.slice(begin, end);\n }\n const length = end - begin;\n const slice = new ArrayBuffer(length);\n CopyDataBlockBytes(slice, 0, buffer, begin, length);\n return slice;\n}\n","import NumberIsNaN from '../../stub/number-isnan';\nimport { ArrayBufferSlice } from './ecmascript';\n\nexport function IsNonNegativeNumber(v: number): boolean {\n if (typeof v !== 'number') {\n return false;\n }\n\n if (NumberIsNaN(v)) {\n return false;\n }\n\n if (v < 0) {\n return false;\n }\n\n return true;\n}\n\nexport function CloneAsUint8Array(O: ArrayBufferView): Uint8Array {\n const buffer = ArrayBufferSlice(O.buffer, O.byteOffset, O.byteOffset + O.byteLength);\n return new Uint8Array(buffer);\n}\n","import assert from '../../stub/assert';\nimport { SimpleQueue } from '../simple-queue';\nimport { IsNonNegativeNumber } from './miscellaneous';\n\nexport interface QueueContainer {\n _queue: SimpleQueue;\n _queueTotalSize: number;\n}\n\nexport interface QueuePair {\n value: T;\n size: number;\n}\n\nexport function DequeueValue(container: QueueContainer>): T {\n assert('_queue' in container && '_queueTotalSize' in container);\n assert(container._queue.length > 0);\n\n const pair = container._queue.shift()!;\n container._queueTotalSize -= pair.size;\n if (container._queueTotalSize < 0) {\n container._queueTotalSize = 0;\n }\n\n return pair.value;\n}\n\nexport function EnqueueValueWithSize(container: QueueContainer>, value: T, size: number) {\n assert('_queue' in container && '_queueTotalSize' in container);\n\n if (!IsNonNegativeNumber(size) || size === Infinity) {\n throw new RangeError('Size must be a finite, non-NaN, non-negative number.');\n }\n\n container._queue.push({ value, size });\n container._queueTotalSize += size;\n}\n\nexport function PeekQueueValue(container: QueueContainer>): T {\n assert('_queue' in container && '_queueTotalSize' in container);\n assert(container._queue.length > 0);\n\n const pair = container._queue.peek();\n return pair.value;\n}\n\nexport function ResetQueue(container: QueueContainer) {\n assert('_queue' in container && '_queueTotalSize' in container);\n\n container._queue = new SimpleQueue();\n container._queueTotalSize = 0;\n}\n","import assert from '../../stub/assert';\nimport { SimpleQueue } from '../simple-queue';\nimport { ResetQueue } from '../abstract-ops/queue-with-sizes';\nimport {\n ReadableStreamAddReadRequest,\n ReadableStreamFulfillReadRequest,\n ReadableStreamGetNumReadRequests,\n ReadableStreamHasDefaultReader,\n ReadRequest\n} from './default-reader';\nimport {\n ReadableStreamAddReadIntoRequest,\n ReadableStreamFulfillReadIntoRequest,\n ReadableStreamGetNumReadIntoRequests,\n ReadableStreamHasBYOBReader,\n ReadIntoRequest\n} from './byob-reader';\nimport NumberIsInteger from '../../stub/number-isinteger';\nimport {\n IsReadableStreamLocked,\n ReadableByteStream,\n ReadableStreamClose,\n ReadableStreamError\n} from '../readable-stream';\nimport { ValidatedUnderlyingByteSource } from './underlying-source';\nimport { typeIsObject } from '../helpers/miscellaneous';\nimport {\n ArrayBufferSlice,\n CanTransferArrayBuffer,\n CopyDataBlockBytes,\n IsDetachedBuffer,\n TransferArrayBuffer\n} from '../abstract-ops/ecmascript';\nimport { CancelSteps, PullSteps } from '../abstract-ops/internal-methods';\nimport { promiseResolvedWith, uponPromise } from '../helpers/webidl';\nimport { assertRequiredArgument, convertUnsignedLongLongWithEnforceRange } from '../validators/basic';\n\n/**\n * A pull-into request in a {@link ReadableByteStreamController}.\n *\n * @public\n */\nexport class ReadableStreamBYOBRequest {\n /** @internal */\n _associatedReadableByteStreamController!: ReadableByteStreamController;\n /** @internal */\n _view!: ArrayBufferView | null;\n\n private constructor() {\n throw new TypeError('Illegal constructor');\n }\n\n /**\n * Returns the view for writing in to, or `null` if the BYOB request has already been responded to.\n */\n get view(): ArrayBufferView | null {\n if (!IsReadableStreamBYOBRequest(this)) {\n throw byobRequestBrandCheckException('view');\n }\n\n return this._view;\n }\n\n /**\n * Indicates to the associated readable byte stream that `bytesWritten` bytes were written into\n * {@link ReadableStreamBYOBRequest.view | view}, causing the result be surfaced to the consumer.\n *\n * After this method is called, {@link ReadableStreamBYOBRequest.view | view} will be transferred and no longer\n * modifiable.\n */\n respond(bytesWritten: number): void;\n respond(bytesWritten: number | undefined): void {\n if (!IsReadableStreamBYOBRequest(this)) {\n throw byobRequestBrandCheckException('respond');\n }\n assertRequiredArgument(bytesWritten, 1, 'respond');\n bytesWritten = convertUnsignedLongLongWithEnforceRange(bytesWritten, 'First parameter');\n\n if (this._associatedReadableByteStreamController === undefined) {\n throw new TypeError('This BYOB request has been invalidated');\n }\n\n if (IsDetachedBuffer(this._view!.buffer)) {\n throw new TypeError(`The BYOB request's buffer has been detached and so cannot be used as a response`);\n }\n\n assert(this._view!.byteLength > 0);\n assert(this._view!.buffer.byteLength > 0);\n\n ReadableByteStreamControllerRespond(this._associatedReadableByteStreamController, bytesWritten);\n }\n\n /**\n * Indicates to the associated readable byte stream that instead of writing into\n * {@link ReadableStreamBYOBRequest.view | view}, the underlying byte source is providing a new `ArrayBufferView`,\n * which will be given to the consumer of the readable byte stream.\n *\n * After this method is called, `view` will be transferred and no longer modifiable.\n */\n respondWithNewView(view: ArrayBufferView): void;\n respondWithNewView(view: ArrayBufferView | undefined): void {\n if (!IsReadableStreamBYOBRequest(this)) {\n throw byobRequestBrandCheckException('respondWithNewView');\n }\n assertRequiredArgument(view, 1, 'respondWithNewView');\n\n if (!ArrayBuffer.isView(view)) {\n throw new TypeError('You can only respond with array buffer views');\n }\n\n if (this._associatedReadableByteStreamController === undefined) {\n throw new TypeError('This BYOB request has been invalidated');\n }\n\n if (IsDetachedBuffer(view.buffer)) {\n throw new TypeError('The given view\\'s buffer has been detached and so cannot be used as a response');\n }\n\n ReadableByteStreamControllerRespondWithNewView(this._associatedReadableByteStreamController, view);\n }\n}\n\nObject.defineProperties(ReadableStreamBYOBRequest.prototype, {\n respond: { enumerable: true },\n respondWithNewView: { enumerable: true },\n view: { enumerable: true }\n});\nif (typeof Symbol.toStringTag === 'symbol') {\n Object.defineProperty(ReadableStreamBYOBRequest.prototype, Symbol.toStringTag, {\n value: 'ReadableStreamBYOBRequest',\n configurable: true\n });\n}\n\ninterface ArrayBufferViewConstructor {\n new(buffer: ArrayBufferLike, byteOffset: number, length?: number): T;\n\n readonly prototype: T;\n readonly BYTES_PER_ELEMENT: number;\n}\n\ninterface ByteQueueElement {\n buffer: ArrayBufferLike;\n byteOffset: number;\n byteLength: number;\n}\n\ntype PullIntoDescriptor =\n DefaultPullIntoDescriptor\n | BYOBPullIntoDescriptor;\n\ninterface DefaultPullIntoDescriptor {\n buffer: ArrayBufferLike;\n bufferByteLength: number;\n byteOffset: number;\n byteLength: number;\n bytesFilled: number;\n elementSize: number;\n viewConstructor: ArrayBufferViewConstructor;\n readerType: 'default';\n}\n\ninterface BYOBPullIntoDescriptor {\n buffer: ArrayBufferLike;\n bufferByteLength: number;\n byteOffset: number;\n byteLength: number;\n bytesFilled: number;\n elementSize: number;\n viewConstructor: ArrayBufferViewConstructor;\n readerType: 'byob';\n}\n\n/**\n * Allows control of a {@link ReadableStream | readable byte stream}'s state and internal queue.\n *\n * @public\n */\nexport class ReadableByteStreamController {\n /** @internal */\n _controlledReadableByteStream!: ReadableByteStream;\n /** @internal */\n _queue!: SimpleQueue;\n /** @internal */\n _queueTotalSize!: number;\n /** @internal */\n _started!: boolean;\n /** @internal */\n _closeRequested!: boolean;\n /** @internal */\n _pullAgain!: boolean;\n /** @internal */\n _pulling !: boolean;\n /** @internal */\n _strategyHWM!: number;\n /** @internal */\n _pullAlgorithm!: () => Promise;\n /** @internal */\n _cancelAlgorithm!: (reason: any) => Promise;\n /** @internal */\n _autoAllocateChunkSize: number | undefined;\n /** @internal */\n _byobRequest: ReadableStreamBYOBRequest | null;\n /** @internal */\n _pendingPullIntos!: SimpleQueue;\n\n private constructor() {\n throw new TypeError('Illegal constructor');\n }\n\n /**\n * Returns the current BYOB pull request, or `null` if there isn't one.\n */\n get byobRequest(): ReadableStreamBYOBRequest | null {\n if (!IsReadableByteStreamController(this)) {\n throw byteStreamControllerBrandCheckException('byobRequest');\n }\n\n return ReadableByteStreamControllerGetBYOBRequest(this);\n }\n\n /**\n * Returns the desired size to fill the controlled stream's internal queue. It can be negative, if the queue is\n * over-full. An underlying byte source ought to use this information to determine when and how to apply backpressure.\n */\n get desiredSize(): number | null {\n if (!IsReadableByteStreamController(this)) {\n throw byteStreamControllerBrandCheckException('desiredSize');\n }\n\n return ReadableByteStreamControllerGetDesiredSize(this);\n }\n\n /**\n * Closes the controlled readable stream. Consumers will still be able to read any previously-enqueued chunks from\n * the stream, but once those are read, the stream will become closed.\n */\n close(): void {\n if (!IsReadableByteStreamController(this)) {\n throw byteStreamControllerBrandCheckException('close');\n }\n\n if (this._closeRequested) {\n throw new TypeError('The stream has already been closed; do not close it again!');\n }\n\n const state = this._controlledReadableByteStream._state;\n if (state !== 'readable') {\n throw new TypeError(`The stream (in ${state} state) is not in the readable state and cannot be closed`);\n }\n\n ReadableByteStreamControllerClose(this);\n }\n\n /**\n * Enqueues the given chunk chunk in the controlled readable stream.\n * The chunk has to be an `ArrayBufferView` instance, or else a `TypeError` will be thrown.\n */\n enqueue(chunk: ArrayBufferView): void;\n enqueue(chunk: ArrayBufferView | undefined): void {\n if (!IsReadableByteStreamController(this)) {\n throw byteStreamControllerBrandCheckException('enqueue');\n }\n\n assertRequiredArgument(chunk, 1, 'enqueue');\n if (!ArrayBuffer.isView(chunk)) {\n throw new TypeError('chunk must be an array buffer view');\n }\n if (chunk.byteLength === 0) {\n throw new TypeError('chunk must have non-zero byteLength');\n }\n if (chunk.buffer.byteLength === 0) {\n throw new TypeError(`chunk's buffer must have non-zero byteLength`);\n }\n\n if (this._closeRequested) {\n throw new TypeError('stream is closed or draining');\n }\n\n const state = this._controlledReadableByteStream._state;\n if (state !== 'readable') {\n throw new TypeError(`The stream (in ${state} state) is not in the readable state and cannot be enqueued to`);\n }\n\n ReadableByteStreamControllerEnqueue(this, chunk);\n }\n\n /**\n * Errors the controlled readable stream, making all future interactions with it fail with the given error `e`.\n */\n error(e: any = undefined): void {\n if (!IsReadableByteStreamController(this)) {\n throw byteStreamControllerBrandCheckException('error');\n }\n\n ReadableByteStreamControllerError(this, e);\n }\n\n /** @internal */\n [CancelSteps](reason: any): Promise {\n ReadableByteStreamControllerClearPendingPullIntos(this);\n\n ResetQueue(this);\n\n const result = this._cancelAlgorithm(reason);\n ReadableByteStreamControllerClearAlgorithms(this);\n return result;\n }\n\n /** @internal */\n [PullSteps](readRequest: ReadRequest): void {\n const stream = this._controlledReadableByteStream;\n assert(ReadableStreamHasDefaultReader(stream));\n\n if (this._queueTotalSize > 0) {\n assert(ReadableStreamGetNumReadRequests(stream) === 0);\n\n const entry = this._queue.shift()!;\n this._queueTotalSize -= entry.byteLength;\n\n ReadableByteStreamControllerHandleQueueDrain(this);\n\n const view = new Uint8Array(entry.buffer, entry.byteOffset, entry.byteLength);\n\n readRequest._chunkSteps(view);\n return;\n }\n\n const autoAllocateChunkSize = this._autoAllocateChunkSize;\n if (autoAllocateChunkSize !== undefined) {\n let buffer: ArrayBuffer;\n try {\n buffer = new ArrayBuffer(autoAllocateChunkSize);\n } catch (bufferE) {\n readRequest._errorSteps(bufferE);\n return;\n }\n\n const pullIntoDescriptor: DefaultPullIntoDescriptor = {\n buffer,\n bufferByteLength: autoAllocateChunkSize,\n byteOffset: 0,\n byteLength: autoAllocateChunkSize,\n bytesFilled: 0,\n elementSize: 1,\n viewConstructor: Uint8Array,\n readerType: 'default'\n };\n\n this._pendingPullIntos.push(pullIntoDescriptor);\n }\n\n ReadableStreamAddReadRequest(stream, readRequest);\n ReadableByteStreamControllerCallPullIfNeeded(this);\n }\n}\n\nObject.defineProperties(ReadableByteStreamController.prototype, {\n close: { enumerable: true },\n enqueue: { enumerable: true },\n error: { enumerable: true },\n byobRequest: { enumerable: true },\n desiredSize: { enumerable: true }\n});\nif (typeof Symbol.toStringTag === 'symbol') {\n Object.defineProperty(ReadableByteStreamController.prototype, Symbol.toStringTag, {\n value: 'ReadableByteStreamController',\n configurable: true\n });\n}\n\n// Abstract operations for the ReadableByteStreamController.\n\nexport function IsReadableByteStreamController(x: any): x is ReadableByteStreamController {\n if (!typeIsObject(x)) {\n return false;\n }\n\n if (!Object.prototype.hasOwnProperty.call(x, '_controlledReadableByteStream')) {\n return false;\n }\n\n return x instanceof ReadableByteStreamController;\n}\n\nfunction IsReadableStreamBYOBRequest(x: any): x is ReadableStreamBYOBRequest {\n if (!typeIsObject(x)) {\n return false;\n }\n\n if (!Object.prototype.hasOwnProperty.call(x, '_associatedReadableByteStreamController')) {\n return false;\n }\n\n return x instanceof ReadableStreamBYOBRequest;\n}\n\nfunction ReadableByteStreamControllerCallPullIfNeeded(controller: ReadableByteStreamController): void {\n const shouldPull = ReadableByteStreamControllerShouldCallPull(controller);\n if (!shouldPull) {\n return;\n }\n\n if (controller._pulling) {\n controller._pullAgain = true;\n return;\n }\n\n assert(!controller._pullAgain);\n\n controller._pulling = true;\n\n // TODO: Test controller argument\n const pullPromise = controller._pullAlgorithm();\n uponPromise(\n pullPromise,\n () => {\n controller._pulling = false;\n\n if (controller._pullAgain) {\n controller._pullAgain = false;\n ReadableByteStreamControllerCallPullIfNeeded(controller);\n }\n },\n e => {\n ReadableByteStreamControllerError(controller, e);\n }\n );\n}\n\nfunction ReadableByteStreamControllerClearPendingPullIntos(controller: ReadableByteStreamController) {\n ReadableByteStreamControllerInvalidateBYOBRequest(controller);\n controller._pendingPullIntos = new SimpleQueue();\n}\n\nfunction ReadableByteStreamControllerCommitPullIntoDescriptor(\n stream: ReadableByteStream,\n pullIntoDescriptor: PullIntoDescriptor\n) {\n assert(stream._state !== 'errored');\n\n let done = false;\n if (stream._state === 'closed') {\n assert(pullIntoDescriptor.bytesFilled === 0);\n done = true;\n }\n\n const filledView = ReadableByteStreamControllerConvertPullIntoDescriptor(pullIntoDescriptor);\n if (pullIntoDescriptor.readerType === 'default') {\n ReadableStreamFulfillReadRequest(stream, filledView as unknown as Uint8Array, done);\n } else {\n assert(pullIntoDescriptor.readerType === 'byob');\n ReadableStreamFulfillReadIntoRequest(stream, filledView, done);\n }\n}\n\nfunction ReadableByteStreamControllerConvertPullIntoDescriptor(\n pullIntoDescriptor: PullIntoDescriptor\n): T {\n const bytesFilled = pullIntoDescriptor.bytesFilled;\n const elementSize = pullIntoDescriptor.elementSize;\n\n assert(bytesFilled <= pullIntoDescriptor.byteLength);\n assert(bytesFilled % elementSize === 0);\n\n return new pullIntoDescriptor.viewConstructor(\n pullIntoDescriptor.buffer, pullIntoDescriptor.byteOffset, bytesFilled / elementSize) as T;\n}\n\nfunction ReadableByteStreamControllerEnqueueChunkToQueue(controller: ReadableByteStreamController,\n buffer: ArrayBufferLike,\n byteOffset: number,\n byteLength: number) {\n controller._queue.push({ buffer, byteOffset, byteLength });\n controller._queueTotalSize += byteLength;\n}\n\nfunction ReadableByteStreamControllerFillPullIntoDescriptorFromQueue(controller: ReadableByteStreamController,\n pullIntoDescriptor: PullIntoDescriptor) {\n const elementSize = pullIntoDescriptor.elementSize;\n\n const currentAlignedBytes = pullIntoDescriptor.bytesFilled - pullIntoDescriptor.bytesFilled % elementSize;\n\n const maxBytesToCopy = Math.min(controller._queueTotalSize,\n pullIntoDescriptor.byteLength - pullIntoDescriptor.bytesFilled);\n const maxBytesFilled = pullIntoDescriptor.bytesFilled + maxBytesToCopy;\n const maxAlignedBytes = maxBytesFilled - maxBytesFilled % elementSize;\n\n let totalBytesToCopyRemaining = maxBytesToCopy;\n let ready = false;\n if (maxAlignedBytes > currentAlignedBytes) {\n totalBytesToCopyRemaining = maxAlignedBytes - pullIntoDescriptor.bytesFilled;\n ready = true;\n }\n\n const queue = controller._queue;\n\n while (totalBytesToCopyRemaining > 0) {\n const headOfQueue = queue.peek();\n\n const bytesToCopy = Math.min(totalBytesToCopyRemaining, headOfQueue.byteLength);\n\n const destStart = pullIntoDescriptor.byteOffset + pullIntoDescriptor.bytesFilled;\n CopyDataBlockBytes(pullIntoDescriptor.buffer, destStart, headOfQueue.buffer, headOfQueue.byteOffset, bytesToCopy);\n\n if (headOfQueue.byteLength === bytesToCopy) {\n queue.shift();\n } else {\n headOfQueue.byteOffset += bytesToCopy;\n headOfQueue.byteLength -= bytesToCopy;\n }\n controller._queueTotalSize -= bytesToCopy;\n\n ReadableByteStreamControllerFillHeadPullIntoDescriptor(controller, bytesToCopy, pullIntoDescriptor);\n\n totalBytesToCopyRemaining -= bytesToCopy;\n }\n\n if (!ready) {\n assert(controller._queueTotalSize === 0);\n assert(pullIntoDescriptor.bytesFilled > 0);\n assert(pullIntoDescriptor.bytesFilled < pullIntoDescriptor.elementSize);\n }\n\n return ready;\n}\n\nfunction ReadableByteStreamControllerFillHeadPullIntoDescriptor(controller: ReadableByteStreamController,\n size: number,\n pullIntoDescriptor: PullIntoDescriptor) {\n assert(controller._pendingPullIntos.length === 0 || controller._pendingPullIntos.peek() === pullIntoDescriptor);\n assert(controller._byobRequest === null);\n pullIntoDescriptor.bytesFilled += size;\n}\n\nfunction ReadableByteStreamControllerHandleQueueDrain(controller: ReadableByteStreamController) {\n assert(controller._controlledReadableByteStream._state === 'readable');\n\n if (controller._queueTotalSize === 0 && controller._closeRequested) {\n ReadableByteStreamControllerClearAlgorithms(controller);\n ReadableStreamClose(controller._controlledReadableByteStream);\n } else {\n ReadableByteStreamControllerCallPullIfNeeded(controller);\n }\n}\n\nfunction ReadableByteStreamControllerInvalidateBYOBRequest(controller: ReadableByteStreamController) {\n if (controller._byobRequest === null) {\n return;\n }\n\n controller._byobRequest._associatedReadableByteStreamController = undefined!;\n controller._byobRequest._view = null!;\n controller._byobRequest = null;\n}\n\nfunction ReadableByteStreamControllerProcessPullIntoDescriptorsUsingQueue(controller: ReadableByteStreamController) {\n assert(!controller._closeRequested);\n\n while (controller._pendingPullIntos.length > 0) {\n if (controller._queueTotalSize === 0) {\n return;\n }\n\n const pullIntoDescriptor = controller._pendingPullIntos.peek();\n\n if (ReadableByteStreamControllerFillPullIntoDescriptorFromQueue(controller, pullIntoDescriptor)) {\n ReadableByteStreamControllerShiftPendingPullInto(controller);\n\n ReadableByteStreamControllerCommitPullIntoDescriptor(\n controller._controlledReadableByteStream,\n pullIntoDescriptor\n );\n }\n }\n}\n\nexport function ReadableByteStreamControllerPullInto(\n controller: ReadableByteStreamController,\n view: T,\n readIntoRequest: ReadIntoRequest\n): void {\n const stream = controller._controlledReadableByteStream;\n\n let elementSize = 1;\n if (view.constructor !== DataView) {\n elementSize = (view.constructor as ArrayBufferViewConstructor).BYTES_PER_ELEMENT;\n }\n\n const ctor = view.constructor as ArrayBufferViewConstructor;\n\n // try {\n const buffer = TransferArrayBuffer(view.buffer);\n // } catch (e) {\n // readIntoRequest._errorSteps(e);\n // return;\n // }\n\n const pullIntoDescriptor: BYOBPullIntoDescriptor = {\n buffer,\n bufferByteLength: buffer.byteLength,\n byteOffset: view.byteOffset,\n byteLength: view.byteLength,\n bytesFilled: 0,\n elementSize,\n viewConstructor: ctor,\n readerType: 'byob'\n };\n\n if (controller._pendingPullIntos.length > 0) {\n controller._pendingPullIntos.push(pullIntoDescriptor);\n\n // No ReadableByteStreamControllerCallPullIfNeeded() call since:\n // - No change happens on desiredSize\n // - The source has already been notified of that there's at least 1 pending read(view)\n\n ReadableStreamAddReadIntoRequest(stream, readIntoRequest);\n return;\n }\n\n if (stream._state === 'closed') {\n const emptyView = new ctor(pullIntoDescriptor.buffer, pullIntoDescriptor.byteOffset, 0);\n readIntoRequest._closeSteps(emptyView);\n return;\n }\n\n if (controller._queueTotalSize > 0) {\n if (ReadableByteStreamControllerFillPullIntoDescriptorFromQueue(controller, pullIntoDescriptor)) {\n const filledView = ReadableByteStreamControllerConvertPullIntoDescriptor(pullIntoDescriptor);\n\n ReadableByteStreamControllerHandleQueueDrain(controller);\n\n readIntoRequest._chunkSteps(filledView);\n return;\n }\n\n if (controller._closeRequested) {\n const e = new TypeError('Insufficient bytes to fill elements in the given buffer');\n ReadableByteStreamControllerError(controller, e);\n\n readIntoRequest._errorSteps(e);\n return;\n }\n }\n\n controller._pendingPullIntos.push(pullIntoDescriptor);\n\n ReadableStreamAddReadIntoRequest(stream, readIntoRequest);\n ReadableByteStreamControllerCallPullIfNeeded(controller);\n}\n\nfunction ReadableByteStreamControllerRespondInClosedState(controller: ReadableByteStreamController,\n firstDescriptor: PullIntoDescriptor) {\n assert(firstDescriptor.bytesFilled === 0);\n\n const stream = controller._controlledReadableByteStream;\n if (ReadableStreamHasBYOBReader(stream)) {\n while (ReadableStreamGetNumReadIntoRequests(stream) > 0) {\n const pullIntoDescriptor = ReadableByteStreamControllerShiftPendingPullInto(controller);\n ReadableByteStreamControllerCommitPullIntoDescriptor(stream, pullIntoDescriptor);\n }\n }\n}\n\nfunction ReadableByteStreamControllerRespondInReadableState(controller: ReadableByteStreamController,\n bytesWritten: number,\n pullIntoDescriptor: PullIntoDescriptor) {\n assert(pullIntoDescriptor.bytesFilled + bytesWritten <= pullIntoDescriptor.byteLength);\n\n ReadableByteStreamControllerFillHeadPullIntoDescriptor(controller, bytesWritten, pullIntoDescriptor);\n\n if (pullIntoDescriptor.bytesFilled < pullIntoDescriptor.elementSize) {\n return;\n }\n\n ReadableByteStreamControllerShiftPendingPullInto(controller);\n\n const remainderSize = pullIntoDescriptor.bytesFilled % pullIntoDescriptor.elementSize;\n if (remainderSize > 0) {\n const end = pullIntoDescriptor.byteOffset + pullIntoDescriptor.bytesFilled;\n const remainder = ArrayBufferSlice(pullIntoDescriptor.buffer, end - remainderSize, end);\n ReadableByteStreamControllerEnqueueChunkToQueue(controller, remainder, 0, remainder.byteLength);\n }\n\n pullIntoDescriptor.bytesFilled -= remainderSize;\n ReadableByteStreamControllerCommitPullIntoDescriptor(controller._controlledReadableByteStream, pullIntoDescriptor);\n\n ReadableByteStreamControllerProcessPullIntoDescriptorsUsingQueue(controller);\n}\n\nfunction ReadableByteStreamControllerRespondInternal(controller: ReadableByteStreamController, bytesWritten: number) {\n const firstDescriptor = controller._pendingPullIntos.peek();\n assert(CanTransferArrayBuffer(firstDescriptor.buffer));\n\n ReadableByteStreamControllerInvalidateBYOBRequest(controller);\n\n const state = controller._controlledReadableByteStream._state;\n if (state === 'closed') {\n assert(bytesWritten === 0);\n ReadableByteStreamControllerRespondInClosedState(controller, firstDescriptor);\n } else {\n assert(state === 'readable');\n assert(bytesWritten > 0);\n ReadableByteStreamControllerRespondInReadableState(controller, bytesWritten, firstDescriptor);\n }\n\n ReadableByteStreamControllerCallPullIfNeeded(controller);\n}\n\nfunction ReadableByteStreamControllerShiftPendingPullInto(\n controller: ReadableByteStreamController\n): PullIntoDescriptor {\n assert(controller._byobRequest === null);\n const descriptor = controller._pendingPullIntos.shift()!;\n return descriptor;\n}\n\nfunction ReadableByteStreamControllerShouldCallPull(controller: ReadableByteStreamController): boolean {\n const stream = controller._controlledReadableByteStream;\n\n if (stream._state !== 'readable') {\n return false;\n }\n\n if (controller._closeRequested) {\n return false;\n }\n\n if (!controller._started) {\n return false;\n }\n\n if (ReadableStreamHasDefaultReader(stream) && ReadableStreamGetNumReadRequests(stream) > 0) {\n return true;\n }\n\n if (ReadableStreamHasBYOBReader(stream) && ReadableStreamGetNumReadIntoRequests(stream) > 0) {\n return true;\n }\n\n const desiredSize = ReadableByteStreamControllerGetDesiredSize(controller);\n assert(desiredSize !== null);\n if (desiredSize! > 0) {\n return true;\n }\n\n return false;\n}\n\nfunction ReadableByteStreamControllerClearAlgorithms(controller: ReadableByteStreamController) {\n controller._pullAlgorithm = undefined!;\n controller._cancelAlgorithm = undefined!;\n}\n\n// A client of ReadableByteStreamController may use these functions directly to bypass state check.\n\nexport function ReadableByteStreamControllerClose(controller: ReadableByteStreamController) {\n const stream = controller._controlledReadableByteStream;\n\n if (controller._closeRequested || stream._state !== 'readable') {\n return;\n }\n\n if (controller._queueTotalSize > 0) {\n controller._closeRequested = true;\n\n return;\n }\n\n if (controller._pendingPullIntos.length > 0) {\n const firstPendingPullInto = controller._pendingPullIntos.peek();\n if (firstPendingPullInto.bytesFilled > 0) {\n const e = new TypeError('Insufficient bytes to fill elements in the given buffer');\n ReadableByteStreamControllerError(controller, e);\n\n throw e;\n }\n }\n\n ReadableByteStreamControllerClearAlgorithms(controller);\n ReadableStreamClose(stream);\n}\n\nexport function ReadableByteStreamControllerEnqueue(controller: ReadableByteStreamController, chunk: ArrayBufferView) {\n const stream = controller._controlledReadableByteStream;\n\n if (controller._closeRequested || stream._state !== 'readable') {\n return;\n }\n\n const buffer = chunk.buffer;\n const byteOffset = chunk.byteOffset;\n const byteLength = chunk.byteLength;\n if (IsDetachedBuffer(buffer)) {\n throw new TypeError('chunk\\'s buffer is detached and so cannot be enqueued');\n }\n const transferredBuffer = TransferArrayBuffer(buffer);\n\n if (controller._pendingPullIntos.length > 0) {\n const firstPendingPullInto = controller._pendingPullIntos.peek();\n if (IsDetachedBuffer(firstPendingPullInto.buffer)) {\n throw new TypeError(\n 'The BYOB request\\'s buffer has been detached and so cannot be filled with an enqueued chunk'\n );\n }\n firstPendingPullInto.buffer = TransferArrayBuffer(firstPendingPullInto.buffer);\n }\n\n ReadableByteStreamControllerInvalidateBYOBRequest(controller);\n\n if (ReadableStreamHasDefaultReader(stream)) {\n if (ReadableStreamGetNumReadRequests(stream) === 0) {\n assert(controller._pendingPullIntos.length === 0);\n ReadableByteStreamControllerEnqueueChunkToQueue(controller, transferredBuffer, byteOffset, byteLength);\n } else {\n assert(controller._queue.length === 0);\n if (controller._pendingPullIntos.length > 0) {\n assert(controller._pendingPullIntos.peek().readerType === 'default');\n ReadableByteStreamControllerShiftPendingPullInto(controller);\n }\n const transferredView = new Uint8Array(transferredBuffer, byteOffset, byteLength);\n ReadableStreamFulfillReadRequest(stream, transferredView, false);\n }\n } else if (ReadableStreamHasBYOBReader(stream)) {\n // TODO: Ideally in this branch detaching should happen only if the buffer is not consumed fully.\n ReadableByteStreamControllerEnqueueChunkToQueue(controller, transferredBuffer, byteOffset, byteLength);\n ReadableByteStreamControllerProcessPullIntoDescriptorsUsingQueue(controller);\n } else {\n assert(!IsReadableStreamLocked(stream));\n ReadableByteStreamControllerEnqueueChunkToQueue(controller, transferredBuffer, byteOffset, byteLength);\n }\n\n ReadableByteStreamControllerCallPullIfNeeded(controller);\n}\n\nexport function ReadableByteStreamControllerError(controller: ReadableByteStreamController, e: any) {\n const stream = controller._controlledReadableByteStream;\n\n if (stream._state !== 'readable') {\n return;\n }\n\n ReadableByteStreamControllerClearPendingPullIntos(controller);\n\n ResetQueue(controller);\n ReadableByteStreamControllerClearAlgorithms(controller);\n ReadableStreamError(stream, e);\n}\n\nexport function ReadableByteStreamControllerGetBYOBRequest(\n controller: ReadableByteStreamController\n): ReadableStreamBYOBRequest | null {\n if (controller._byobRequest === null && controller._pendingPullIntos.length > 0) {\n const firstDescriptor = controller._pendingPullIntos.peek();\n const view = new Uint8Array(firstDescriptor.buffer,\n firstDescriptor.byteOffset + firstDescriptor.bytesFilled,\n firstDescriptor.byteLength - firstDescriptor.bytesFilled);\n\n const byobRequest: ReadableStreamBYOBRequest = Object.create(ReadableStreamBYOBRequest.prototype);\n SetUpReadableStreamBYOBRequest(byobRequest, controller, view);\n controller._byobRequest = byobRequest;\n }\n return controller._byobRequest;\n}\n\nfunction ReadableByteStreamControllerGetDesiredSize(controller: ReadableByteStreamController): number | null {\n const state = controller._controlledReadableByteStream._state;\n\n if (state === 'errored') {\n return null;\n }\n if (state === 'closed') {\n return 0;\n }\n\n return controller._strategyHWM - controller._queueTotalSize;\n}\n\nexport function ReadableByteStreamControllerRespond(controller: ReadableByteStreamController, bytesWritten: number) {\n assert(controller._pendingPullIntos.length > 0);\n\n const firstDescriptor = controller._pendingPullIntos.peek();\n const state = controller._controlledReadableByteStream._state;\n\n if (state === 'closed') {\n if (bytesWritten !== 0) {\n throw new TypeError('bytesWritten must be 0 when calling respond() on a closed stream');\n }\n } else {\n assert(state === 'readable');\n if (bytesWritten === 0) {\n throw new TypeError('bytesWritten must be greater than 0 when calling respond() on a readable stream');\n }\n if (firstDescriptor.bytesFilled + bytesWritten > firstDescriptor.byteLength) {\n throw new RangeError('bytesWritten out of range');\n }\n }\n\n firstDescriptor.buffer = TransferArrayBuffer(firstDescriptor.buffer);\n\n ReadableByteStreamControllerRespondInternal(controller, bytesWritten);\n}\n\nexport function ReadableByteStreamControllerRespondWithNewView(controller: ReadableByteStreamController,\n view: ArrayBufferView) {\n assert(controller._pendingPullIntos.length > 0);\n assert(!IsDetachedBuffer(view.buffer));\n\n const firstDescriptor = controller._pendingPullIntos.peek();\n const state = controller._controlledReadableByteStream._state;\n\n if (state === 'closed') {\n if (view.byteLength !== 0) {\n throw new TypeError('The view\\'s length must be 0 when calling respondWithNewView() on a closed stream');\n }\n } else {\n assert(state === 'readable');\n if (view.byteLength === 0) {\n throw new TypeError(\n 'The view\\'s length must be greater than 0 when calling respondWithNewView() on a readable stream'\n );\n }\n }\n\n if (firstDescriptor.byteOffset + firstDescriptor.bytesFilled !== view.byteOffset) {\n throw new RangeError('The region specified by view does not match byobRequest');\n }\n if (firstDescriptor.bufferByteLength !== view.buffer.byteLength) {\n throw new RangeError('The buffer of view has different capacity than byobRequest');\n }\n if (firstDescriptor.bytesFilled + view.byteLength > firstDescriptor.byteLength) {\n throw new RangeError('The region specified by view is larger than byobRequest');\n }\n\n const viewByteLength = view.byteLength;\n firstDescriptor.buffer = TransferArrayBuffer(view.buffer);\n ReadableByteStreamControllerRespondInternal(controller, viewByteLength);\n}\n\nexport function SetUpReadableByteStreamController(stream: ReadableByteStream,\n controller: ReadableByteStreamController,\n startAlgorithm: () => void | PromiseLike,\n pullAlgorithm: () => Promise,\n cancelAlgorithm: (reason: any) => Promise,\n highWaterMark: number,\n autoAllocateChunkSize: number | undefined) {\n assert(stream._readableStreamController === undefined);\n if (autoAllocateChunkSize !== undefined) {\n assert(NumberIsInteger(autoAllocateChunkSize));\n assert(autoAllocateChunkSize > 0);\n }\n\n controller._controlledReadableByteStream = stream;\n\n controller._pullAgain = false;\n controller._pulling = false;\n\n controller._byobRequest = null;\n\n // Need to set the slots so that the assert doesn't fire. In the spec the slots already exist implicitly.\n controller._queue = controller._queueTotalSize = undefined!;\n ResetQueue(controller);\n\n controller._closeRequested = false;\n controller._started = false;\n\n controller._strategyHWM = highWaterMark;\n\n controller._pullAlgorithm = pullAlgorithm;\n controller._cancelAlgorithm = cancelAlgorithm;\n\n controller._autoAllocateChunkSize = autoAllocateChunkSize;\n\n controller._pendingPullIntos = new SimpleQueue();\n\n stream._readableStreamController = controller;\n\n const startResult = startAlgorithm();\n uponPromise(\n promiseResolvedWith(startResult),\n () => {\n controller._started = true;\n\n assert(!controller._pulling);\n assert(!controller._pullAgain);\n\n ReadableByteStreamControllerCallPullIfNeeded(controller);\n },\n r => {\n ReadableByteStreamControllerError(controller, r);\n }\n );\n}\n\nexport function SetUpReadableByteStreamControllerFromUnderlyingSource(\n stream: ReadableByteStream,\n underlyingByteSource: ValidatedUnderlyingByteSource,\n highWaterMark: number\n) {\n const controller: ReadableByteStreamController = Object.create(ReadableByteStreamController.prototype);\n\n let startAlgorithm: () => void | PromiseLike = () => undefined;\n let pullAlgorithm: () => Promise = () => promiseResolvedWith(undefined);\n let cancelAlgorithm: (reason: any) => Promise = () => promiseResolvedWith(undefined);\n\n if (underlyingByteSource.start !== undefined) {\n startAlgorithm = () => underlyingByteSource.start!(controller);\n }\n if (underlyingByteSource.pull !== undefined) {\n pullAlgorithm = () => underlyingByteSource.pull!(controller);\n }\n if (underlyingByteSource.cancel !== undefined) {\n cancelAlgorithm = reason => underlyingByteSource.cancel!(reason);\n }\n\n const autoAllocateChunkSize = underlyingByteSource.autoAllocateChunkSize;\n if (autoAllocateChunkSize === 0) {\n throw new TypeError('autoAllocateChunkSize must be greater than 0');\n }\n\n SetUpReadableByteStreamController(\n stream, controller, startAlgorithm, pullAlgorithm, cancelAlgorithm, highWaterMark, autoAllocateChunkSize\n );\n}\n\nfunction SetUpReadableStreamBYOBRequest(request: ReadableStreamBYOBRequest,\n controller: ReadableByteStreamController,\n view: ArrayBufferView) {\n assert(IsReadableByteStreamController(controller));\n assert(typeof view === 'object');\n assert(ArrayBuffer.isView(view));\n assert(!IsDetachedBuffer(view.buffer));\n request._associatedReadableByteStreamController = controller;\n request._view = view;\n}\n\n// Helper functions for the ReadableStreamBYOBRequest.\n\nfunction byobRequestBrandCheckException(name: string): TypeError {\n return new TypeError(\n `ReadableStreamBYOBRequest.prototype.${name} can only be used on a ReadableStreamBYOBRequest`);\n}\n\n// Helper functions for the ReadableByteStreamController.\n\nfunction byteStreamControllerBrandCheckException(name: string): TypeError {\n return new TypeError(\n `ReadableByteStreamController.prototype.${name} can only be used on a ReadableByteStreamController`);\n}\n","import assert from '../../stub/assert';\nimport { SimpleQueue } from '../simple-queue';\nimport {\n ReadableStreamReaderGenericCancel,\n ReadableStreamReaderGenericInitialize,\n ReadableStreamReaderGenericRelease,\n readerLockException\n} from './generic-reader';\nimport { IsReadableStreamLocked, ReadableByteStream, ReadableStream } from '../readable-stream';\nimport {\n IsReadableByteStreamController,\n ReadableByteStreamController,\n ReadableByteStreamControllerPullInto\n} from './byte-stream-controller';\nimport { typeIsObject } from '../helpers/miscellaneous';\nimport { newPromise, promiseRejectedWith } from '../helpers/webidl';\nimport { assertRequiredArgument } from '../validators/basic';\nimport { assertReadableStream } from '../validators/readable-stream';\nimport { IsDetachedBuffer } from '../abstract-ops/ecmascript';\n\n/**\n * A result returned by {@link ReadableStreamBYOBReader.read}.\n *\n * @public\n */\nexport type ReadableStreamBYOBReadResult = {\n done: false;\n value: T;\n} | {\n done: true;\n value: T | undefined;\n};\n\n// Abstract operations for the ReadableStream.\n\nexport function AcquireReadableStreamBYOBReader(stream: ReadableByteStream): ReadableStreamBYOBReader {\n return new ReadableStreamBYOBReader(stream);\n}\n\n// ReadableStream API exposed for controllers.\n\nexport function ReadableStreamAddReadIntoRequest(stream: ReadableByteStream,\n readIntoRequest: ReadIntoRequest): void {\n assert(IsReadableStreamBYOBReader(stream._reader));\n assert(stream._state === 'readable' || stream._state === 'closed');\n\n (stream._reader! as ReadableStreamBYOBReader)._readIntoRequests.push(readIntoRequest);\n}\n\nexport function ReadableStreamFulfillReadIntoRequest(stream: ReadableByteStream,\n chunk: ArrayBufferView,\n done: boolean) {\n const reader = stream._reader as ReadableStreamBYOBReader;\n\n assert(reader._readIntoRequests.length > 0);\n\n const readIntoRequest = reader._readIntoRequests.shift()!;\n if (done) {\n readIntoRequest._closeSteps(chunk);\n } else {\n readIntoRequest._chunkSteps(chunk);\n }\n}\n\nexport function ReadableStreamGetNumReadIntoRequests(stream: ReadableByteStream): number {\n return (stream._reader as ReadableStreamBYOBReader)._readIntoRequests.length;\n}\n\nexport function ReadableStreamHasBYOBReader(stream: ReadableByteStream): boolean {\n const reader = stream._reader;\n\n if (reader === undefined) {\n return false;\n }\n\n if (!IsReadableStreamBYOBReader(reader)) {\n return false;\n }\n\n return true;\n}\n\n// Readers\n\nexport interface ReadIntoRequest {\n _chunkSteps(chunk: T): void;\n\n _closeSteps(chunk: T | undefined): void;\n\n _errorSteps(e: any): void;\n}\n\n/**\n * A BYOB reader vended by a {@link ReadableStream}.\n *\n * @public\n */\nexport class ReadableStreamBYOBReader {\n /** @internal */\n _ownerReadableStream!: ReadableByteStream;\n /** @internal */\n _closedPromise!: Promise;\n /** @internal */\n _closedPromise_resolve?: (value?: undefined) => void;\n /** @internal */\n _closedPromise_reject?: (reason: any) => void;\n /** @internal */\n _readIntoRequests: SimpleQueue>;\n\n constructor(stream: ReadableByteStream) {\n assertRequiredArgument(stream, 1, 'ReadableStreamBYOBReader');\n assertReadableStream(stream, 'First parameter');\n\n if (IsReadableStreamLocked(stream)) {\n throw new TypeError('This stream has already been locked for exclusive reading by another reader');\n }\n\n if (!IsReadableByteStreamController(stream._readableStreamController)) {\n throw new TypeError('Cannot construct a ReadableStreamBYOBReader for a stream not constructed with a byte ' +\n 'source');\n }\n\n ReadableStreamReaderGenericInitialize(this, stream);\n\n this._readIntoRequests = new SimpleQueue();\n }\n\n /**\n * Returns a promise that will be fulfilled when the stream becomes closed, or rejected if the stream ever errors or\n * the reader's lock is released before the stream finishes closing.\n */\n get closed(): Promise {\n if (!IsReadableStreamBYOBReader(this)) {\n return promiseRejectedWith(byobReaderBrandCheckException('closed'));\n }\n\n return this._closedPromise;\n }\n\n /**\n * If the reader is active, behaves the same as {@link ReadableStream.cancel | stream.cancel(reason)}.\n */\n cancel(reason: any = undefined): Promise {\n if (!IsReadableStreamBYOBReader(this)) {\n return promiseRejectedWith(byobReaderBrandCheckException('cancel'));\n }\n\n if (this._ownerReadableStream === undefined) {\n return promiseRejectedWith(readerLockException('cancel'));\n }\n\n return ReadableStreamReaderGenericCancel(this, reason);\n }\n\n /**\n * Attempts to reads bytes into view, and returns a promise resolved with the result.\n *\n * If reading a chunk causes the queue to become empty, more data will be pulled from the underlying source.\n */\n read(view: T): Promise> {\n if (!IsReadableStreamBYOBReader(this)) {\n return promiseRejectedWith(byobReaderBrandCheckException('read'));\n }\n\n if (!ArrayBuffer.isView(view)) {\n return promiseRejectedWith(new TypeError('view must be an array buffer view'));\n }\n if (view.byteLength === 0) {\n return promiseRejectedWith(new TypeError('view must have non-zero byteLength'));\n }\n if (view.buffer.byteLength === 0) {\n return promiseRejectedWith(new TypeError(`view's buffer must have non-zero byteLength`));\n }\n if (IsDetachedBuffer(view.buffer)) {\n return promiseRejectedWith(new TypeError('view\\'s buffer has been detached'));\n }\n\n if (this._ownerReadableStream === undefined) {\n return promiseRejectedWith(readerLockException('read from'));\n }\n\n let resolvePromise!: (result: ReadableStreamBYOBReadResult) => void;\n let rejectPromise!: (reason: any) => void;\n const promise = newPromise>((resolve, reject) => {\n resolvePromise = resolve;\n rejectPromise = reject;\n });\n const readIntoRequest: ReadIntoRequest = {\n _chunkSteps: chunk => resolvePromise({ value: chunk, done: false }),\n _closeSteps: chunk => resolvePromise({ value: chunk, done: true }),\n _errorSteps: e => rejectPromise(e)\n };\n ReadableStreamBYOBReaderRead(this, view, readIntoRequest);\n return promise;\n }\n\n /**\n * Releases the reader's lock on the corresponding stream. After the lock is released, the reader is no longer active.\n * If the associated stream is errored when the lock is released, the reader will appear errored in the same way\n * from now on; otherwise, the reader will appear closed.\n *\n * A reader's lock cannot be released while it still has a pending read request, i.e., if a promise returned by\n * the reader's {@link ReadableStreamBYOBReader.read | read()} method has not yet been settled. Attempting to\n * do so will throw a `TypeError` and leave the reader locked to the stream.\n */\n releaseLock(): void {\n if (!IsReadableStreamBYOBReader(this)) {\n throw byobReaderBrandCheckException('releaseLock');\n }\n\n if (this._ownerReadableStream === undefined) {\n return;\n }\n\n if (this._readIntoRequests.length > 0) {\n throw new TypeError('Tried to release a reader lock when that reader has pending read() calls un-settled');\n }\n\n ReadableStreamReaderGenericRelease(this);\n }\n}\n\nObject.defineProperties(ReadableStreamBYOBReader.prototype, {\n cancel: { enumerable: true },\n read: { enumerable: true },\n releaseLock: { enumerable: true },\n closed: { enumerable: true }\n});\nif (typeof Symbol.toStringTag === 'symbol') {\n Object.defineProperty(ReadableStreamBYOBReader.prototype, Symbol.toStringTag, {\n value: 'ReadableStreamBYOBReader',\n configurable: true\n });\n}\n\n// Abstract operations for the readers.\n\nexport function IsReadableStreamBYOBReader(x: any): x is ReadableStreamBYOBReader {\n if (!typeIsObject(x)) {\n return false;\n }\n\n if (!Object.prototype.hasOwnProperty.call(x, '_readIntoRequests')) {\n return false;\n }\n\n return x instanceof ReadableStreamBYOBReader;\n}\n\nexport function ReadableStreamBYOBReaderRead(\n reader: ReadableStreamBYOBReader,\n view: T,\n readIntoRequest: ReadIntoRequest\n): void {\n const stream = reader._ownerReadableStream;\n\n assert(stream !== undefined);\n\n stream._disturbed = true;\n\n if (stream._state === 'errored') {\n readIntoRequest._errorSteps(stream._storedError);\n } else {\n ReadableByteStreamControllerPullInto(\n stream._readableStreamController as ReadableByteStreamController,\n view,\n readIntoRequest\n );\n }\n}\n\n// Helper functions for the ReadableStreamBYOBReader.\n\nfunction byobReaderBrandCheckException(name: string): TypeError {\n return new TypeError(\n `ReadableStreamBYOBReader.prototype.${name} can only be used on a ReadableStreamBYOBReader`);\n}\n","import { QueuingStrategy, QueuingStrategySizeCallback } from '../queuing-strategy';\nimport NumberIsNaN from '../../stub/number-isnan';\n\nexport function ExtractHighWaterMark(strategy: QueuingStrategy, defaultHWM: number): number {\n const { highWaterMark } = strategy;\n\n if (highWaterMark === undefined) {\n return defaultHWM;\n }\n\n if (NumberIsNaN(highWaterMark) || highWaterMark < 0) {\n throw new RangeError('Invalid highWaterMark');\n }\n\n return highWaterMark;\n}\n\nexport function ExtractSizeAlgorithm(strategy: QueuingStrategy): QueuingStrategySizeCallback {\n const { size } = strategy;\n\n if (!size) {\n return () => 1;\n }\n\n return size;\n}\n","import { QueuingStrategy, QueuingStrategySizeCallback } from '../queuing-strategy';\nimport { assertDictionary, assertFunction, convertUnrestrictedDouble } from './basic';\n\nexport function convertQueuingStrategy(init: QueuingStrategy | null | undefined,\n context: string): QueuingStrategy {\n assertDictionary(init, context);\n const highWaterMark = init?.highWaterMark;\n const size = init?.size;\n return {\n highWaterMark: highWaterMark === undefined ? undefined : convertUnrestrictedDouble(highWaterMark),\n size: size === undefined ? undefined : convertQueuingStrategySize(size, `${context} has member 'size' that`)\n };\n}\n\nfunction convertQueuingStrategySize(fn: QueuingStrategySizeCallback,\n context: string): QueuingStrategySizeCallback {\n assertFunction(fn, context);\n return chunk => convertUnrestrictedDouble(fn(chunk));\n}\n","import { assertDictionary, assertFunction } from './basic';\nimport { promiseCall, reflectCall } from '../helpers/webidl';\nimport {\n UnderlyingSink,\n UnderlyingSinkAbortCallback,\n UnderlyingSinkCloseCallback,\n UnderlyingSinkStartCallback,\n UnderlyingSinkWriteCallback,\n ValidatedUnderlyingSink\n} from '../writable-stream/underlying-sink';\nimport { WritableStreamDefaultController } from '../writable-stream';\n\nexport function convertUnderlyingSink(original: UnderlyingSink | null,\n context: string): ValidatedUnderlyingSink {\n assertDictionary(original, context);\n const abort = original?.abort;\n const close = original?.close;\n const start = original?.start;\n const type = original?.type;\n const write = original?.write;\n return {\n abort: abort === undefined ?\n undefined :\n convertUnderlyingSinkAbortCallback(abort, original!, `${context} has member 'abort' that`),\n close: close === undefined ?\n undefined :\n convertUnderlyingSinkCloseCallback(close, original!, `${context} has member 'close' that`),\n start: start === undefined ?\n undefined :\n convertUnderlyingSinkStartCallback(start, original!, `${context} has member 'start' that`),\n write: write === undefined ?\n undefined :\n convertUnderlyingSinkWriteCallback(write, original!, `${context} has member 'write' that`),\n type\n };\n}\n\nfunction convertUnderlyingSinkAbortCallback(\n fn: UnderlyingSinkAbortCallback,\n original: UnderlyingSink,\n context: string\n): (reason: any) => Promise {\n assertFunction(fn, context);\n return (reason: any) => promiseCall(fn, original, [reason]);\n}\n\nfunction convertUnderlyingSinkCloseCallback(\n fn: UnderlyingSinkCloseCallback,\n original: UnderlyingSink,\n context: string\n): () => Promise {\n assertFunction(fn, context);\n return () => promiseCall(fn, original, []);\n}\n\nfunction convertUnderlyingSinkStartCallback(\n fn: UnderlyingSinkStartCallback,\n original: UnderlyingSink,\n context: string\n): UnderlyingSinkStartCallback {\n assertFunction(fn, context);\n return (controller: WritableStreamDefaultController) => reflectCall(fn, original, [controller]);\n}\n\nfunction convertUnderlyingSinkWriteCallback(\n fn: UnderlyingSinkWriteCallback,\n original: UnderlyingSink,\n context: string\n): (chunk: W, controller: WritableStreamDefaultController) => Promise {\n assertFunction(fn, context);\n return (chunk: W, controller: WritableStreamDefaultController) => promiseCall(fn, original, [chunk, controller]);\n}\n","import { IsWritableStream, WritableStream } from '../writable-stream';\n\nexport function assertWritableStream(x: unknown, context: string): asserts x is WritableStream {\n if (!IsWritableStream(x)) {\n throw new TypeError(`${context} is not a WritableStream.`);\n }\n}\n","/**\n * A signal object that allows you to communicate with a request and abort it if required\n * via its associated `AbortController` object.\n *\n * @remarks\n * This interface is compatible with the `AbortSignal` interface defined in TypeScript's DOM types.\n * It is redefined here, so it can be polyfilled without a DOM, for example with\n * {@link https://www.npmjs.com/package/abortcontroller-polyfill | abortcontroller-polyfill} in a Node environment.\n *\n * @public\n */\nexport interface AbortSignal {\n /**\n * Whether the request is aborted.\n */\n readonly aborted: boolean;\n\n /**\n * Add an event listener to be triggered when this signal becomes aborted.\n */\n addEventListener(type: 'abort', listener: () => void): void;\n\n /**\n * Remove an event listener that was previously added with {@link AbortSignal.addEventListener}.\n */\n removeEventListener(type: 'abort', listener: () => void): void;\n}\n\nexport function isAbortSignal(value: unknown): value is AbortSignal {\n if (typeof value !== 'object' || value === null) {\n return false;\n }\n try {\n return typeof (value as AbortSignal).aborted === 'boolean';\n } catch {\n // AbortSignal.prototype.aborted throws if its brand check fails\n return false;\n }\n}\n\n/**\n * A controller object that allows you to abort an `AbortSignal` when desired.\n *\n * @remarks\n * This interface is compatible with the `AbortController` interface defined in TypeScript's DOM types.\n * It is redefined here, so it can be polyfilled without a DOM, for example with\n * {@link https://www.npmjs.com/package/abortcontroller-polyfill | abortcontroller-polyfill} in a Node environment.\n *\n * @internal\n */\nexport interface AbortController {\n readonly signal: AbortSignal;\n\n abort(): void;\n}\n\ninterface AbortControllerConstructor {\n new(): AbortController;\n}\n\nconst supportsAbortController = typeof (AbortController as any) === 'function';\n\n/**\n * Construct a new AbortController, if supported by the platform.\n *\n * @internal\n */\nexport function createAbortController(): AbortController | undefined {\n if (supportsAbortController) {\n return new (AbortController as AbortControllerConstructor)();\n }\n return undefined;\n}\n","import assert from '../stub/assert';\nimport {\n newPromise,\n promiseRejectedWith,\n promiseResolvedWith,\n setPromiseIsHandledToTrue,\n uponPromise\n} from './helpers/webidl';\nimport {\n DequeueValue,\n EnqueueValueWithSize,\n PeekQueueValue,\n QueuePair,\n ResetQueue\n} from './abstract-ops/queue-with-sizes';\nimport { QueuingStrategy, QueuingStrategySizeCallback } from './queuing-strategy';\nimport { SimpleQueue } from './simple-queue';\nimport { typeIsObject } from './helpers/miscellaneous';\nimport { AbortSteps, ErrorSteps } from './abstract-ops/internal-methods';\nimport { IsNonNegativeNumber } from './abstract-ops/miscellaneous';\nimport { ExtractHighWaterMark, ExtractSizeAlgorithm } from './abstract-ops/queuing-strategy';\nimport { convertQueuingStrategy } from './validators/queuing-strategy';\nimport {\n UnderlyingSink,\n UnderlyingSinkAbortCallback,\n UnderlyingSinkCloseCallback,\n UnderlyingSinkStartCallback,\n UnderlyingSinkWriteCallback,\n ValidatedUnderlyingSink\n} from './writable-stream/underlying-sink';\nimport { assertObject, assertRequiredArgument } from './validators/basic';\nimport { convertUnderlyingSink } from './validators/underlying-sink';\nimport { assertWritableStream } from './validators/writable-stream';\nimport { AbortController, AbortSignal, createAbortController } from './abort-signal';\n\ntype WritableStreamState = 'writable' | 'closed' | 'erroring' | 'errored';\n\ninterface WriteOrCloseRequest {\n _resolve: (value?: undefined) => void;\n _reject: (reason: any) => void;\n}\n\ntype WriteRequest = WriteOrCloseRequest;\ntype CloseRequest = WriteOrCloseRequest;\n\ninterface PendingAbortRequest {\n _promise: Promise;\n _resolve: (value?: undefined) => void;\n _reject: (reason: any) => void;\n _reason: any;\n _wasAlreadyErroring: boolean;\n}\n\n/**\n * A writable stream represents a destination for data, into which you can write.\n *\n * @public\n */\nclass WritableStream {\n /** @internal */\n _state!: WritableStreamState;\n /** @internal */\n _storedError: any;\n /** @internal */\n _writer: WritableStreamDefaultWriter | undefined;\n /** @internal */\n _writableStreamController!: WritableStreamDefaultController;\n /** @internal */\n _writeRequests!: SimpleQueue;\n /** @internal */\n _inFlightWriteRequest: WriteRequest | undefined;\n /** @internal */\n _closeRequest: CloseRequest | undefined;\n /** @internal */\n _inFlightCloseRequest: CloseRequest | undefined;\n /** @internal */\n _pendingAbortRequest: PendingAbortRequest | undefined;\n /** @internal */\n _backpressure!: boolean;\n\n constructor(underlyingSink?: UnderlyingSink, strategy?: QueuingStrategy);\n constructor(rawUnderlyingSink: UnderlyingSink | null | undefined = {},\n rawStrategy: QueuingStrategy | null | undefined = {}) {\n if (rawUnderlyingSink === undefined) {\n rawUnderlyingSink = null;\n } else {\n assertObject(rawUnderlyingSink, 'First parameter');\n }\n\n const strategy = convertQueuingStrategy(rawStrategy, 'Second parameter');\n const underlyingSink = convertUnderlyingSink(rawUnderlyingSink, 'First parameter');\n\n InitializeWritableStream(this);\n\n const type = underlyingSink.type;\n if (type !== undefined) {\n throw new RangeError('Invalid type is specified');\n }\n\n const sizeAlgorithm = ExtractSizeAlgorithm(strategy);\n const highWaterMark = ExtractHighWaterMark(strategy, 1);\n\n SetUpWritableStreamDefaultControllerFromUnderlyingSink(this, underlyingSink, highWaterMark, sizeAlgorithm);\n }\n\n /**\n * Returns whether or not the writable stream is locked to a writer.\n */\n get locked(): boolean {\n if (!IsWritableStream(this)) {\n throw streamBrandCheckException('locked');\n }\n\n return IsWritableStreamLocked(this);\n }\n\n /**\n * Aborts the stream, signaling that the producer can no longer successfully write to the stream and it is to be\n * immediately moved to an errored state, with any queued-up writes discarded. This will also execute any abort\n * mechanism of the underlying sink.\n *\n * The returned promise will fulfill if the stream shuts down successfully, or reject if the underlying sink signaled\n * that there was an error doing so. Additionally, it will reject with a `TypeError` (without attempting to cancel\n * the stream) if the stream is currently locked.\n */\n abort(reason: any = undefined): Promise {\n if (!IsWritableStream(this)) {\n return promiseRejectedWith(streamBrandCheckException('abort'));\n }\n\n if (IsWritableStreamLocked(this)) {\n return promiseRejectedWith(new TypeError('Cannot abort a stream that already has a writer'));\n }\n\n return WritableStreamAbort(this, reason);\n }\n\n /**\n * Closes the stream. The underlying sink will finish processing any previously-written chunks, before invoking its\n * close behavior. During this time any further attempts to write will fail (without erroring the stream).\n *\n * The method returns a promise that will fulfill if all remaining chunks are successfully written and the stream\n * successfully closes, or rejects if an error is encountered during this process. Additionally, it will reject with\n * a `TypeError` (without attempting to cancel the stream) if the stream is currently locked.\n */\n close() {\n if (!IsWritableStream(this)) {\n return promiseRejectedWith(streamBrandCheckException('close'));\n }\n\n if (IsWritableStreamLocked(this)) {\n return promiseRejectedWith(new TypeError('Cannot close a stream that already has a writer'));\n }\n\n if (WritableStreamCloseQueuedOrInFlight(this)) {\n return promiseRejectedWith(new TypeError('Cannot close an already-closing stream'));\n }\n\n return WritableStreamClose(this);\n }\n\n /**\n * Creates a {@link WritableStreamDefaultWriter | writer} and locks the stream to the new writer. While the stream\n * is locked, no other writer can be acquired until this one is released.\n *\n * This functionality is especially useful for creating abstractions that desire the ability to write to a stream\n * without interruption or interleaving. By getting a writer for the stream, you can ensure nobody else can write at\n * the same time, which would cause the resulting written data to be unpredictable and probably useless.\n */\n getWriter(): WritableStreamDefaultWriter {\n if (!IsWritableStream(this)) {\n throw streamBrandCheckException('getWriter');\n }\n\n return AcquireWritableStreamDefaultWriter(this);\n }\n}\n\nObject.defineProperties(WritableStream.prototype, {\n abort: { enumerable: true },\n close: { enumerable: true },\n getWriter: { enumerable: true },\n locked: { enumerable: true }\n});\nif (typeof Symbol.toStringTag === 'symbol') {\n Object.defineProperty(WritableStream.prototype, Symbol.toStringTag, {\n value: 'WritableStream',\n configurable: true\n });\n}\n\nexport {\n AcquireWritableStreamDefaultWriter,\n CreateWritableStream,\n IsWritableStream,\n IsWritableStreamLocked,\n WritableStream,\n WritableStreamAbort,\n WritableStreamDefaultControllerErrorIfNeeded,\n WritableStreamDefaultWriterCloseWithErrorPropagation,\n WritableStreamDefaultWriterRelease,\n WritableStreamDefaultWriterWrite,\n WritableStreamCloseQueuedOrInFlight,\n UnderlyingSink,\n UnderlyingSinkStartCallback,\n UnderlyingSinkWriteCallback,\n UnderlyingSinkCloseCallback,\n UnderlyingSinkAbortCallback\n};\n\n// Abstract operations for the WritableStream.\n\nfunction AcquireWritableStreamDefaultWriter(stream: WritableStream): WritableStreamDefaultWriter {\n return new WritableStreamDefaultWriter(stream);\n}\n\n// Throws if and only if startAlgorithm throws.\nfunction CreateWritableStream(startAlgorithm: () => void | PromiseLike,\n writeAlgorithm: (chunk: W) => Promise,\n closeAlgorithm: () => Promise,\n abortAlgorithm: (reason: any) => Promise,\n highWaterMark = 1,\n sizeAlgorithm: QueuingStrategySizeCallback = () => 1) {\n assert(IsNonNegativeNumber(highWaterMark));\n\n const stream: WritableStream = Object.create(WritableStream.prototype);\n InitializeWritableStream(stream);\n\n const controller: WritableStreamDefaultController = Object.create(WritableStreamDefaultController.prototype);\n\n SetUpWritableStreamDefaultController(stream, controller, startAlgorithm, writeAlgorithm, closeAlgorithm,\n abortAlgorithm, highWaterMark, sizeAlgorithm);\n return stream;\n}\n\nfunction InitializeWritableStream(stream: WritableStream) {\n stream._state = 'writable';\n\n // The error that will be reported by new method calls once the state becomes errored. Only set when [[state]] is\n // 'erroring' or 'errored'. May be set to an undefined value.\n stream._storedError = undefined;\n\n stream._writer = undefined;\n\n // Initialize to undefined first because the constructor of the controller checks this\n // variable to validate the caller.\n stream._writableStreamController = undefined!;\n\n // This queue is placed here instead of the writer class in order to allow for passing a writer to the next data\n // producer without waiting for the queued writes to finish.\n stream._writeRequests = new SimpleQueue();\n\n // Write requests are removed from _writeRequests when write() is called on the underlying sink. This prevents\n // them from being erroneously rejected on error. If a write() call is in-flight, the request is stored here.\n stream._inFlightWriteRequest = undefined;\n\n // The promise that was returned from writer.close(). Stored here because it may be fulfilled after the writer\n // has been detached.\n stream._closeRequest = undefined;\n\n // Close request is removed from _closeRequest when close() is called on the underlying sink. This prevents it\n // from being erroneously rejected on error. If a close() call is in-flight, the request is stored here.\n stream._inFlightCloseRequest = undefined;\n\n // The promise that was returned from writer.abort(). This may also be fulfilled after the writer has detached.\n stream._pendingAbortRequest = undefined;\n\n // The backpressure signal set by the controller.\n stream._backpressure = false;\n}\n\nfunction IsWritableStream(x: unknown): x is WritableStream {\n if (!typeIsObject(x)) {\n return false;\n }\n\n if (!Object.prototype.hasOwnProperty.call(x, '_writableStreamController')) {\n return false;\n }\n\n return x instanceof WritableStream;\n}\n\nfunction IsWritableStreamLocked(stream: WritableStream): boolean {\n assert(IsWritableStream(stream));\n\n if (stream._writer === undefined) {\n return false;\n }\n\n return true;\n}\n\nfunction WritableStreamAbort(stream: WritableStream, reason: any): Promise {\n if (stream._state === 'closed' || stream._state === 'errored') {\n return promiseResolvedWith(undefined);\n }\n stream._writableStreamController._abortReason = reason;\n stream._writableStreamController._abortController?.abort();\n\n // TypeScript narrows the type of `stream._state` down to 'writable' | 'erroring',\n // but it doesn't know that signaling abort runs author code that might have changed the state.\n // Widen the type again by casting to WritableStreamState.\n const state = stream._state as WritableStreamState;\n\n if (state === 'closed' || state === 'errored') {\n return promiseResolvedWith(undefined);\n }\n if (stream._pendingAbortRequest !== undefined) {\n return stream._pendingAbortRequest._promise;\n }\n\n assert(state === 'writable' || state === 'erroring');\n\n let wasAlreadyErroring = false;\n if (state === 'erroring') {\n wasAlreadyErroring = true;\n // reason will not be used, so don't keep a reference to it.\n reason = undefined;\n }\n\n const promise = newPromise((resolve, reject) => {\n stream._pendingAbortRequest = {\n _promise: undefined!,\n _resolve: resolve,\n _reject: reject,\n _reason: reason,\n _wasAlreadyErroring: wasAlreadyErroring\n };\n });\n stream._pendingAbortRequest!._promise = promise;\n\n if (!wasAlreadyErroring) {\n WritableStreamStartErroring(stream, reason);\n }\n\n return promise;\n}\n\nfunction WritableStreamClose(stream: WritableStream): Promise {\n const state = stream._state;\n if (state === 'closed' || state === 'errored') {\n return promiseRejectedWith(new TypeError(\n `The stream (in ${state} state) is not in the writable state and cannot be closed`));\n }\n\n assert(state === 'writable' || state === 'erroring');\n assert(!WritableStreamCloseQueuedOrInFlight(stream));\n\n const promise = newPromise((resolve, reject) => {\n const closeRequest: CloseRequest = {\n _resolve: resolve,\n _reject: reject\n };\n\n stream._closeRequest = closeRequest;\n });\n\n const writer = stream._writer;\n if (writer !== undefined && stream._backpressure && state === 'writable') {\n defaultWriterReadyPromiseResolve(writer);\n }\n\n WritableStreamDefaultControllerClose(stream._writableStreamController);\n\n return promise;\n}\n\n// WritableStream API exposed for controllers.\n\nfunction WritableStreamAddWriteRequest(stream: WritableStream): Promise {\n assert(IsWritableStreamLocked(stream));\n assert(stream._state === 'writable');\n\n const promise = newPromise((resolve, reject) => {\n const writeRequest: WriteRequest = {\n _resolve: resolve,\n _reject: reject\n };\n\n stream._writeRequests.push(writeRequest);\n });\n\n return promise;\n}\n\nfunction WritableStreamDealWithRejection(stream: WritableStream, error: any) {\n const state = stream._state;\n\n if (state === 'writable') {\n WritableStreamStartErroring(stream, error);\n return;\n }\n\n assert(state === 'erroring');\n WritableStreamFinishErroring(stream);\n}\n\nfunction WritableStreamStartErroring(stream: WritableStream, reason: any) {\n assert(stream._storedError === undefined);\n assert(stream._state === 'writable');\n\n const controller = stream._writableStreamController;\n assert(controller !== undefined);\n\n stream._state = 'erroring';\n stream._storedError = reason;\n const writer = stream._writer;\n if (writer !== undefined) {\n WritableStreamDefaultWriterEnsureReadyPromiseRejected(writer, reason);\n }\n\n if (!WritableStreamHasOperationMarkedInFlight(stream) && controller._started) {\n WritableStreamFinishErroring(stream);\n }\n}\n\nfunction WritableStreamFinishErroring(stream: WritableStream) {\n assert(stream._state === 'erroring');\n assert(!WritableStreamHasOperationMarkedInFlight(stream));\n stream._state = 'errored';\n stream._writableStreamController[ErrorSteps]();\n\n const storedError = stream._storedError;\n stream._writeRequests.forEach(writeRequest => {\n writeRequest._reject(storedError);\n });\n stream._writeRequests = new SimpleQueue();\n\n if (stream._pendingAbortRequest === undefined) {\n WritableStreamRejectCloseAndClosedPromiseIfNeeded(stream);\n return;\n }\n\n const abortRequest = stream._pendingAbortRequest;\n stream._pendingAbortRequest = undefined;\n\n if (abortRequest._wasAlreadyErroring) {\n abortRequest._reject(storedError);\n WritableStreamRejectCloseAndClosedPromiseIfNeeded(stream);\n return;\n }\n\n const promise = stream._writableStreamController[AbortSteps](abortRequest._reason);\n uponPromise(\n promise,\n () => {\n abortRequest._resolve();\n WritableStreamRejectCloseAndClosedPromiseIfNeeded(stream);\n },\n (reason: any) => {\n abortRequest._reject(reason);\n WritableStreamRejectCloseAndClosedPromiseIfNeeded(stream);\n });\n}\n\nfunction WritableStreamFinishInFlightWrite(stream: WritableStream) {\n assert(stream._inFlightWriteRequest !== undefined);\n stream._inFlightWriteRequest!._resolve(undefined);\n stream._inFlightWriteRequest = undefined;\n}\n\nfunction WritableStreamFinishInFlightWriteWithError(stream: WritableStream, error: any) {\n assert(stream._inFlightWriteRequest !== undefined);\n stream._inFlightWriteRequest!._reject(error);\n stream._inFlightWriteRequest = undefined;\n\n assert(stream._state === 'writable' || stream._state === 'erroring');\n\n WritableStreamDealWithRejection(stream, error);\n}\n\nfunction WritableStreamFinishInFlightClose(stream: WritableStream) {\n assert(stream._inFlightCloseRequest !== undefined);\n stream._inFlightCloseRequest!._resolve(undefined);\n stream._inFlightCloseRequest = undefined;\n\n const state = stream._state;\n\n assert(state === 'writable' || state === 'erroring');\n\n if (state === 'erroring') {\n // The error was too late to do anything, so it is ignored.\n stream._storedError = undefined;\n if (stream._pendingAbortRequest !== undefined) {\n stream._pendingAbortRequest._resolve();\n stream._pendingAbortRequest = undefined;\n }\n }\n\n stream._state = 'closed';\n\n const writer = stream._writer;\n if (writer !== undefined) {\n defaultWriterClosedPromiseResolve(writer);\n }\n\n assert(stream._pendingAbortRequest === undefined);\n assert(stream._storedError === undefined);\n}\n\nfunction WritableStreamFinishInFlightCloseWithError(stream: WritableStream, error: any) {\n assert(stream._inFlightCloseRequest !== undefined);\n stream._inFlightCloseRequest!._reject(error);\n stream._inFlightCloseRequest = undefined;\n\n assert(stream._state === 'writable' || stream._state === 'erroring');\n\n // Never execute sink abort() after sink close().\n if (stream._pendingAbortRequest !== undefined) {\n stream._pendingAbortRequest._reject(error);\n stream._pendingAbortRequest = undefined;\n }\n WritableStreamDealWithRejection(stream, error);\n}\n\n// TODO(ricea): Fix alphabetical order.\nfunction WritableStreamCloseQueuedOrInFlight(stream: WritableStream): boolean {\n if (stream._closeRequest === undefined && stream._inFlightCloseRequest === undefined) {\n return false;\n }\n\n return true;\n}\n\nfunction WritableStreamHasOperationMarkedInFlight(stream: WritableStream): boolean {\n if (stream._inFlightWriteRequest === undefined && stream._inFlightCloseRequest === undefined) {\n return false;\n }\n\n return true;\n}\n\nfunction WritableStreamMarkCloseRequestInFlight(stream: WritableStream) {\n assert(stream._inFlightCloseRequest === undefined);\n assert(stream._closeRequest !== undefined);\n stream._inFlightCloseRequest = stream._closeRequest;\n stream._closeRequest = undefined;\n}\n\nfunction WritableStreamMarkFirstWriteRequestInFlight(stream: WritableStream) {\n assert(stream._inFlightWriteRequest === undefined);\n assert(stream._writeRequests.length !== 0);\n stream._inFlightWriteRequest = stream._writeRequests.shift();\n}\n\nfunction WritableStreamRejectCloseAndClosedPromiseIfNeeded(stream: WritableStream) {\n assert(stream._state === 'errored');\n if (stream._closeRequest !== undefined) {\n assert(stream._inFlightCloseRequest === undefined);\n\n stream._closeRequest._reject(stream._storedError);\n stream._closeRequest = undefined;\n }\n const writer = stream._writer;\n if (writer !== undefined) {\n defaultWriterClosedPromiseReject(writer, stream._storedError);\n }\n}\n\nfunction WritableStreamUpdateBackpressure(stream: WritableStream, backpressure: boolean) {\n assert(stream._state === 'writable');\n assert(!WritableStreamCloseQueuedOrInFlight(stream));\n\n const writer = stream._writer;\n if (writer !== undefined && backpressure !== stream._backpressure) {\n if (backpressure) {\n defaultWriterReadyPromiseReset(writer);\n } else {\n assert(!backpressure);\n\n defaultWriterReadyPromiseResolve(writer);\n }\n }\n\n stream._backpressure = backpressure;\n}\n\n/**\n * A default writer vended by a {@link WritableStream}.\n *\n * @public\n */\nexport class WritableStreamDefaultWriter {\n /** @internal */\n _ownerWritableStream: WritableStream;\n /** @internal */\n _closedPromise!: Promise;\n /** @internal */\n _closedPromise_resolve?: (value?: undefined) => void;\n /** @internal */\n _closedPromise_reject?: (reason: any) => void;\n /** @internal */\n _closedPromiseState!: 'pending' | 'resolved' | 'rejected';\n /** @internal */\n _readyPromise!: Promise;\n /** @internal */\n _readyPromise_resolve?: (value?: undefined) => void;\n /** @internal */\n _readyPromise_reject?: (reason: any) => void;\n /** @internal */\n _readyPromiseState!: 'pending' | 'fulfilled' | 'rejected';\n\n constructor(stream: WritableStream) {\n assertRequiredArgument(stream, 1, 'WritableStreamDefaultWriter');\n assertWritableStream(stream, 'First parameter');\n\n if (IsWritableStreamLocked(stream)) {\n throw new TypeError('This stream has already been locked for exclusive writing by another writer');\n }\n\n this._ownerWritableStream = stream;\n stream._writer = this;\n\n const state = stream._state;\n\n if (state === 'writable') {\n if (!WritableStreamCloseQueuedOrInFlight(stream) && stream._backpressure) {\n defaultWriterReadyPromiseInitialize(this);\n } else {\n defaultWriterReadyPromiseInitializeAsResolved(this);\n }\n\n defaultWriterClosedPromiseInitialize(this);\n } else if (state === 'erroring') {\n defaultWriterReadyPromiseInitializeAsRejected(this, stream._storedError);\n defaultWriterClosedPromiseInitialize(this);\n } else if (state === 'closed') {\n defaultWriterReadyPromiseInitializeAsResolved(this);\n defaultWriterClosedPromiseInitializeAsResolved(this);\n } else {\n assert(state === 'errored');\n\n const storedError = stream._storedError;\n defaultWriterReadyPromiseInitializeAsRejected(this, storedError);\n defaultWriterClosedPromiseInitializeAsRejected(this, storedError);\n }\n }\n\n /**\n * Returns a promise that will be fulfilled when the stream becomes closed, or rejected if the stream ever errors or\n * the writer’s lock is released before the stream finishes closing.\n */\n get closed(): Promise {\n if (!IsWritableStreamDefaultWriter(this)) {\n return promiseRejectedWith(defaultWriterBrandCheckException('closed'));\n }\n\n return this._closedPromise;\n }\n\n /**\n * Returns the desired size to fill the stream’s internal queue. It can be negative, if the queue is over-full.\n * A producer can use this information to determine the right amount of data to write.\n *\n * It will be `null` if the stream cannot be successfully written to (due to either being errored, or having an abort\n * queued up). It will return zero if the stream is closed. And the getter will throw an exception if invoked when\n * the writer’s lock is released.\n */\n get desiredSize(): number | null {\n if (!IsWritableStreamDefaultWriter(this)) {\n throw defaultWriterBrandCheckException('desiredSize');\n }\n\n if (this._ownerWritableStream === undefined) {\n throw defaultWriterLockException('desiredSize');\n }\n\n return WritableStreamDefaultWriterGetDesiredSize(this);\n }\n\n /**\n * Returns a promise that will be fulfilled when the desired size to fill the stream’s internal queue transitions\n * from non-positive to positive, signaling that it is no longer applying backpressure. Once the desired size dips\n * back to zero or below, the getter will return a new promise that stays pending until the next transition.\n *\n * If the stream becomes errored or aborted, or the writer’s lock is released, the returned promise will become\n * rejected.\n */\n get ready(): Promise {\n if (!IsWritableStreamDefaultWriter(this)) {\n return promiseRejectedWith(defaultWriterBrandCheckException('ready'));\n }\n\n return this._readyPromise;\n }\n\n /**\n * If the reader is active, behaves the same as {@link WritableStream.abort | stream.abort(reason)}.\n */\n abort(reason: any = undefined): Promise {\n if (!IsWritableStreamDefaultWriter(this)) {\n return promiseRejectedWith(defaultWriterBrandCheckException('abort'));\n }\n\n if (this._ownerWritableStream === undefined) {\n return promiseRejectedWith(defaultWriterLockException('abort'));\n }\n\n return WritableStreamDefaultWriterAbort(this, reason);\n }\n\n /**\n * If the reader is active, behaves the same as {@link WritableStream.close | stream.close()}.\n */\n close(): Promise {\n if (!IsWritableStreamDefaultWriter(this)) {\n return promiseRejectedWith(defaultWriterBrandCheckException('close'));\n }\n\n const stream = this._ownerWritableStream;\n\n if (stream === undefined) {\n return promiseRejectedWith(defaultWriterLockException('close'));\n }\n\n if (WritableStreamCloseQueuedOrInFlight(stream)) {\n return promiseRejectedWith(new TypeError('Cannot close an already-closing stream'));\n }\n\n return WritableStreamDefaultWriterClose(this);\n }\n\n /**\n * Releases the writer’s lock on the corresponding stream. After the lock is released, the writer is no longer active.\n * If the associated stream is errored when the lock is released, the writer will appear errored in the same way from\n * now on; otherwise, the writer will appear closed.\n *\n * Note that the lock can still be released even if some ongoing writes have not yet finished (i.e. even if the\n * promises returned from previous calls to {@link WritableStreamDefaultWriter.write | write()} have not yet settled).\n * It’s not necessary to hold the lock on the writer for the duration of the write; the lock instead simply prevents\n * other producers from writing in an interleaved manner.\n */\n releaseLock(): void {\n if (!IsWritableStreamDefaultWriter(this)) {\n throw defaultWriterBrandCheckException('releaseLock');\n }\n\n const stream = this._ownerWritableStream;\n\n if (stream === undefined) {\n return;\n }\n\n assert(stream._writer !== undefined);\n\n WritableStreamDefaultWriterRelease(this);\n }\n\n /**\n * Writes the given chunk to the writable stream, by waiting until any previous writes have finished successfully,\n * and then sending the chunk to the underlying sink's {@link UnderlyingSink.write | write()} method. It will return\n * a promise that fulfills with undefined upon a successful write, or rejects if the write fails or stream becomes\n * errored before the writing process is initiated.\n *\n * Note that what \"success\" means is up to the underlying sink; it might indicate simply that the chunk has been\n * accepted, and not necessarily that it is safely saved to its ultimate destination.\n */\n write(chunk: W): Promise;\n write(chunk: W = undefined!): Promise {\n if (!IsWritableStreamDefaultWriter(this)) {\n return promiseRejectedWith(defaultWriterBrandCheckException('write'));\n }\n\n if (this._ownerWritableStream === undefined) {\n return promiseRejectedWith(defaultWriterLockException('write to'));\n }\n\n return WritableStreamDefaultWriterWrite(this, chunk);\n }\n}\n\nObject.defineProperties(WritableStreamDefaultWriter.prototype, {\n abort: { enumerable: true },\n close: { enumerable: true },\n releaseLock: { enumerable: true },\n write: { enumerable: true },\n closed: { enumerable: true },\n desiredSize: { enumerable: true },\n ready: { enumerable: true }\n});\nif (typeof Symbol.toStringTag === 'symbol') {\n Object.defineProperty(WritableStreamDefaultWriter.prototype, Symbol.toStringTag, {\n value: 'WritableStreamDefaultWriter',\n configurable: true\n });\n}\n\n// Abstract operations for the WritableStreamDefaultWriter.\n\nfunction IsWritableStreamDefaultWriter(x: any): x is WritableStreamDefaultWriter {\n if (!typeIsObject(x)) {\n return false;\n }\n\n if (!Object.prototype.hasOwnProperty.call(x, '_ownerWritableStream')) {\n return false;\n }\n\n return x instanceof WritableStreamDefaultWriter;\n}\n\n// A client of WritableStreamDefaultWriter may use these functions directly to bypass state check.\n\nfunction WritableStreamDefaultWriterAbort(writer: WritableStreamDefaultWriter, reason: any) {\n const stream = writer._ownerWritableStream;\n\n assert(stream !== undefined);\n\n return WritableStreamAbort(stream, reason);\n}\n\nfunction WritableStreamDefaultWriterClose(writer: WritableStreamDefaultWriter): Promise {\n const stream = writer._ownerWritableStream;\n\n assert(stream !== undefined);\n\n return WritableStreamClose(stream);\n}\n\nfunction WritableStreamDefaultWriterCloseWithErrorPropagation(writer: WritableStreamDefaultWriter): Promise {\n const stream = writer._ownerWritableStream;\n\n assert(stream !== undefined);\n\n const state = stream._state;\n if (WritableStreamCloseQueuedOrInFlight(stream) || state === 'closed') {\n return promiseResolvedWith(undefined);\n }\n\n if (state === 'errored') {\n return promiseRejectedWith(stream._storedError);\n }\n\n assert(state === 'writable' || state === 'erroring');\n\n return WritableStreamDefaultWriterClose(writer);\n}\n\nfunction WritableStreamDefaultWriterEnsureClosedPromiseRejected(writer: WritableStreamDefaultWriter, error: any) {\n if (writer._closedPromiseState === 'pending') {\n defaultWriterClosedPromiseReject(writer, error);\n } else {\n defaultWriterClosedPromiseResetToRejected(writer, error);\n }\n}\n\nfunction WritableStreamDefaultWriterEnsureReadyPromiseRejected(writer: WritableStreamDefaultWriter, error: any) {\n if (writer._readyPromiseState === 'pending') {\n defaultWriterReadyPromiseReject(writer, error);\n } else {\n defaultWriterReadyPromiseResetToRejected(writer, error);\n }\n}\n\nfunction WritableStreamDefaultWriterGetDesiredSize(writer: WritableStreamDefaultWriter): number | null {\n const stream = writer._ownerWritableStream;\n const state = stream._state;\n\n if (state === 'errored' || state === 'erroring') {\n return null;\n }\n\n if (state === 'closed') {\n return 0;\n }\n\n return WritableStreamDefaultControllerGetDesiredSize(stream._writableStreamController);\n}\n\nfunction WritableStreamDefaultWriterRelease(writer: WritableStreamDefaultWriter) {\n const stream = writer._ownerWritableStream;\n assert(stream !== undefined);\n assert(stream._writer === writer);\n\n const releasedError = new TypeError(\n `Writer was released and can no longer be used to monitor the stream's closedness`);\n\n WritableStreamDefaultWriterEnsureReadyPromiseRejected(writer, releasedError);\n\n // The state transitions to \"errored\" before the sink abort() method runs, but the writer.closed promise is not\n // rejected until afterwards. This means that simply testing state will not work.\n WritableStreamDefaultWriterEnsureClosedPromiseRejected(writer, releasedError);\n\n stream._writer = undefined;\n writer._ownerWritableStream = undefined!;\n}\n\nfunction WritableStreamDefaultWriterWrite(writer: WritableStreamDefaultWriter, chunk: W): Promise {\n const stream = writer._ownerWritableStream;\n\n assert(stream !== undefined);\n\n const controller = stream._writableStreamController;\n\n const chunkSize = WritableStreamDefaultControllerGetChunkSize(controller, chunk);\n\n if (stream !== writer._ownerWritableStream) {\n return promiseRejectedWith(defaultWriterLockException('write to'));\n }\n\n const state = stream._state;\n if (state === 'errored') {\n return promiseRejectedWith(stream._storedError);\n }\n if (WritableStreamCloseQueuedOrInFlight(stream) || state === 'closed') {\n return promiseRejectedWith(new TypeError('The stream is closing or closed and cannot be written to'));\n }\n if (state === 'erroring') {\n return promiseRejectedWith(stream._storedError);\n }\n\n assert(state === 'writable');\n\n const promise = WritableStreamAddWriteRequest(stream);\n\n WritableStreamDefaultControllerWrite(controller, chunk, chunkSize);\n\n return promise;\n}\n\nconst closeSentinel: unique symbol = {} as any;\n\ntype QueueRecord = W | typeof closeSentinel;\n\n/**\n * Allows control of a {@link WritableStream | writable stream}'s state and internal queue.\n *\n * @public\n */\nexport class WritableStreamDefaultController {\n /** @internal */\n _controlledWritableStream!: WritableStream;\n /** @internal */\n _queue!: SimpleQueue>>;\n /** @internal */\n _queueTotalSize!: number;\n /** @internal */\n _abortReason: any;\n /** @internal */\n _abortController: AbortController | undefined;\n /** @internal */\n _started!: boolean;\n /** @internal */\n _strategySizeAlgorithm!: QueuingStrategySizeCallback;\n /** @internal */\n _strategyHWM!: number;\n /** @internal */\n _writeAlgorithm!: (chunk: W) => Promise;\n /** @internal */\n _closeAlgorithm!: () => Promise;\n /** @internal */\n _abortAlgorithm!: (reason: any) => Promise;\n\n private constructor() {\n throw new TypeError('Illegal constructor');\n }\n\n /**\n * The reason which was passed to `WritableStream.abort(reason)` when the stream was aborted.\n *\n * @deprecated\n * This property has been removed from the specification, see https://github.com/whatwg/streams/pull/1177.\n * Use {@link WritableStreamDefaultController.signal}'s `reason` instead.\n */\n get abortReason(): any {\n if (!IsWritableStreamDefaultController(this)) {\n throw defaultControllerBrandCheckException('abortReason');\n }\n return this._abortReason;\n }\n\n /**\n * An `AbortSignal` that can be used to abort the pending write or close operation when the stream is aborted.\n */\n get signal(): AbortSignal {\n if (!IsWritableStreamDefaultController(this)) {\n throw defaultControllerBrandCheckException('signal');\n }\n if (this._abortController === undefined) {\n // Older browsers or older Node versions may not support `AbortController` or `AbortSignal`.\n // We don't want to bundle and ship an `AbortController` polyfill together with our polyfill,\n // so instead we only implement support for `signal` if we find a global `AbortController` constructor.\n throw new TypeError('WritableStreamDefaultController.prototype.signal is not supported');\n }\n return this._abortController.signal;\n }\n\n /**\n * Closes the controlled writable stream, making all future interactions with it fail with the given error `e`.\n *\n * This method is rarely used, since usually it suffices to return a rejected promise from one of the underlying\n * sink's methods. However, it can be useful for suddenly shutting down a stream in response to an event outside the\n * normal lifecycle of interactions with the underlying sink.\n */\n error(e: any = undefined): void {\n if (!IsWritableStreamDefaultController(this)) {\n throw defaultControllerBrandCheckException('error');\n }\n const state = this._controlledWritableStream._state;\n if (state !== 'writable') {\n // The stream is closed, errored or will be soon. The sink can't do anything useful if it gets an error here, so\n // just treat it as a no-op.\n return;\n }\n\n WritableStreamDefaultControllerError(this, e);\n }\n\n /** @internal */\n [AbortSteps](reason: any): Promise {\n const result = this._abortAlgorithm(reason);\n WritableStreamDefaultControllerClearAlgorithms(this);\n return result;\n }\n\n /** @internal */\n [ErrorSteps]() {\n ResetQueue(this);\n }\n}\n\nObject.defineProperties(WritableStreamDefaultController.prototype, {\n abortReason: { enumerable: true },\n signal: { enumerable: true },\n error: { enumerable: true }\n});\nif (typeof Symbol.toStringTag === 'symbol') {\n Object.defineProperty(WritableStreamDefaultController.prototype, Symbol.toStringTag, {\n value: 'WritableStreamDefaultController',\n configurable: true\n });\n}\n\n// Abstract operations implementing interface required by the WritableStream.\n\nfunction IsWritableStreamDefaultController(x: any): x is WritableStreamDefaultController {\n if (!typeIsObject(x)) {\n return false;\n }\n\n if (!Object.prototype.hasOwnProperty.call(x, '_controlledWritableStream')) {\n return false;\n }\n\n return x instanceof WritableStreamDefaultController;\n}\n\nfunction SetUpWritableStreamDefaultController