458 lines
12 KiB
JavaScript
458 lines
12 KiB
JavaScript
'use strict'
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const AbortController = globalThis.AbortController || require('abort-controller').AbortController
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const {
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codes: { ERR_INVALID_ARG_VALUE, ERR_INVALID_ARG_TYPE, ERR_MISSING_ARGS, ERR_OUT_OF_RANGE },
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AbortError
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} = require('../../ours/errors')
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const { validateAbortSignal, validateInteger, validateObject } = require('../validators')
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const kWeakHandler = require('../../ours/primordials').Symbol('kWeak')
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const { finished } = require('./end-of-stream')
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const staticCompose = require('./compose')
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const { addAbortSignalNoValidate } = require('./add-abort-signal')
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const { isWritable, isNodeStream } = require('./utils')
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const {
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ArrayPrototypePush,
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MathFloor,
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Number,
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NumberIsNaN,
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Promise,
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PromiseReject,
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PromisePrototypeThen,
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Symbol
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} = require('../../ours/primordials')
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const kEmpty = Symbol('kEmpty')
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const kEof = Symbol('kEof')
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function compose(stream, options) {
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if (options != null) {
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validateObject(options, 'options')
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}
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if ((options === null || options === undefined ? undefined : options.signal) != null) {
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validateAbortSignal(options.signal, 'options.signal')
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}
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if (isNodeStream(stream) && !isWritable(stream)) {
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throw new ERR_INVALID_ARG_VALUE('stream', stream, 'must be writable')
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}
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const composedStream = staticCompose(this, stream)
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if (options !== null && options !== undefined && options.signal) {
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// Not validating as we already validated before
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addAbortSignalNoValidate(options.signal, composedStream)
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}
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return composedStream
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}
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function map(fn, options) {
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if (typeof fn !== 'function') {
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throw new ERR_INVALID_ARG_TYPE('fn', ['Function', 'AsyncFunction'], fn)
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}
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if (options != null) {
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validateObject(options, 'options')
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}
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if ((options === null || options === undefined ? undefined : options.signal) != null) {
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validateAbortSignal(options.signal, 'options.signal')
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}
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let concurrency = 1
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if ((options === null || options === undefined ? undefined : options.concurrency) != null) {
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concurrency = MathFloor(options.concurrency)
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}
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validateInteger(concurrency, 'concurrency', 1)
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return async function* map() {
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var _options$signal, _options$signal2
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const ac = new AbortController()
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const stream = this
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const queue = []
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const signal = ac.signal
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const signalOpt = {
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signal
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}
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const abort = () => ac.abort()
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if (
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options !== null &&
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options !== undefined &&
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(_options$signal = options.signal) !== null &&
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_options$signal !== undefined &&
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_options$signal.aborted
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) {
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abort()
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}
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options === null || options === undefined
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? undefined
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: (_options$signal2 = options.signal) === null || _options$signal2 === undefined
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? undefined
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: _options$signal2.addEventListener('abort', abort)
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let next
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let resume
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let done = false
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function onDone() {
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done = true
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}
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async function pump() {
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try {
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for await (let val of stream) {
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var _val
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if (done) {
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return
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}
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if (signal.aborted) {
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throw new AbortError()
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}
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try {
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val = fn(val, signalOpt)
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} catch (err) {
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val = PromiseReject(err)
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}
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if (val === kEmpty) {
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continue
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}
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if (typeof ((_val = val) === null || _val === undefined ? undefined : _val.catch) === 'function') {
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val.catch(onDone)
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}
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queue.push(val)
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if (next) {
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next()
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next = null
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}
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if (!done && queue.length && queue.length >= concurrency) {
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await new Promise((resolve) => {
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resume = resolve
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})
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}
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}
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queue.push(kEof)
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} catch (err) {
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const val = PromiseReject(err)
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PromisePrototypeThen(val, undefined, onDone)
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queue.push(val)
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} finally {
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var _options$signal3
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done = true
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if (next) {
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next()
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next = null
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}
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options === null || options === undefined
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? undefined
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: (_options$signal3 = options.signal) === null || _options$signal3 === undefined
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? undefined
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: _options$signal3.removeEventListener('abort', abort)
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}
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}
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pump()
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try {
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while (true) {
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while (queue.length > 0) {
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const val = await queue[0]
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if (val === kEof) {
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return
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}
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if (signal.aborted) {
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throw new AbortError()
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}
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if (val !== kEmpty) {
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yield val
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}
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queue.shift()
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if (resume) {
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resume()
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resume = null
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}
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}
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await new Promise((resolve) => {
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next = resolve
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})
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}
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} finally {
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ac.abort()
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done = true
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if (resume) {
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resume()
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resume = null
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}
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}
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}.call(this)
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}
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function asIndexedPairs(options = undefined) {
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if (options != null) {
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validateObject(options, 'options')
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}
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if ((options === null || options === undefined ? undefined : options.signal) != null) {
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validateAbortSignal(options.signal, 'options.signal')
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}
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return async function* asIndexedPairs() {
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let index = 0
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for await (const val of this) {
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var _options$signal4
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if (
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options !== null &&
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options !== undefined &&
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(_options$signal4 = options.signal) !== null &&
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_options$signal4 !== undefined &&
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_options$signal4.aborted
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) {
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throw new AbortError({
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cause: options.signal.reason
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})
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}
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yield [index++, val]
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}
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}.call(this)
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}
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async function some(fn, options = undefined) {
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for await (const unused of filter.call(this, fn, options)) {
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return true
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}
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return false
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}
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async function every(fn, options = undefined) {
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if (typeof fn !== 'function') {
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throw new ERR_INVALID_ARG_TYPE('fn', ['Function', 'AsyncFunction'], fn)
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}
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// https://en.wikipedia.org/wiki/De_Morgan%27s_laws
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return !(await some.call(
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this,
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async (...args) => {
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return !(await fn(...args))
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},
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options
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))
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}
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async function find(fn, options) {
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for await (const result of filter.call(this, fn, options)) {
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return result
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}
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return undefined
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}
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async function forEach(fn, options) {
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if (typeof fn !== 'function') {
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throw new ERR_INVALID_ARG_TYPE('fn', ['Function', 'AsyncFunction'], fn)
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}
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async function forEachFn(value, options) {
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await fn(value, options)
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return kEmpty
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}
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// eslint-disable-next-line no-unused-vars
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for await (const unused of map.call(this, forEachFn, options));
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}
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function filter(fn, options) {
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if (typeof fn !== 'function') {
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throw new ERR_INVALID_ARG_TYPE('fn', ['Function', 'AsyncFunction'], fn)
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}
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async function filterFn(value, options) {
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if (await fn(value, options)) {
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return value
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}
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return kEmpty
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}
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return map.call(this, filterFn, options)
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}
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// Specific to provide better error to reduce since the argument is only
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// missing if the stream has no items in it - but the code is still appropriate
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class ReduceAwareErrMissingArgs extends ERR_MISSING_ARGS {
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constructor() {
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super('reduce')
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this.message = 'Reduce of an empty stream requires an initial value'
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}
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}
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async function reduce(reducer, initialValue, options) {
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var _options$signal5
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if (typeof reducer !== 'function') {
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throw new ERR_INVALID_ARG_TYPE('reducer', ['Function', 'AsyncFunction'], reducer)
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}
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if (options != null) {
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validateObject(options, 'options')
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}
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if ((options === null || options === undefined ? undefined : options.signal) != null) {
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validateAbortSignal(options.signal, 'options.signal')
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}
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let hasInitialValue = arguments.length > 1
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if (
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options !== null &&
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options !== undefined &&
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(_options$signal5 = options.signal) !== null &&
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_options$signal5 !== undefined &&
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_options$signal5.aborted
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) {
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const err = new AbortError(undefined, {
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cause: options.signal.reason
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})
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this.once('error', () => {}) // The error is already propagated
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await finished(this.destroy(err))
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throw err
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}
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const ac = new AbortController()
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const signal = ac.signal
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if (options !== null && options !== undefined && options.signal) {
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const opts = {
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once: true,
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[kWeakHandler]: this
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}
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options.signal.addEventListener('abort', () => ac.abort(), opts)
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}
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let gotAnyItemFromStream = false
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try {
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for await (const value of this) {
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var _options$signal6
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gotAnyItemFromStream = true
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if (
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options !== null &&
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options !== undefined &&
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(_options$signal6 = options.signal) !== null &&
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_options$signal6 !== undefined &&
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_options$signal6.aborted
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) {
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throw new AbortError()
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}
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if (!hasInitialValue) {
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initialValue = value
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hasInitialValue = true
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} else {
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initialValue = await reducer(initialValue, value, {
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signal
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})
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}
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}
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if (!gotAnyItemFromStream && !hasInitialValue) {
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throw new ReduceAwareErrMissingArgs()
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}
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} finally {
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ac.abort()
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}
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return initialValue
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}
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async function toArray(options) {
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if (options != null) {
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validateObject(options, 'options')
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}
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if ((options === null || options === undefined ? undefined : options.signal) != null) {
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validateAbortSignal(options.signal, 'options.signal')
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}
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const result = []
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for await (const val of this) {
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var _options$signal7
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if (
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options !== null &&
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options !== undefined &&
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(_options$signal7 = options.signal) !== null &&
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_options$signal7 !== undefined &&
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_options$signal7.aborted
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) {
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throw new AbortError(undefined, {
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cause: options.signal.reason
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})
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}
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ArrayPrototypePush(result, val)
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}
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return result
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}
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function flatMap(fn, options) {
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const values = map.call(this, fn, options)
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return async function* flatMap() {
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for await (const val of values) {
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yield* val
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}
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}.call(this)
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}
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function toIntegerOrInfinity(number) {
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// We coerce here to align with the spec
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// https://github.com/tc39/proposal-iterator-helpers/issues/169
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number = Number(number)
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if (NumberIsNaN(number)) {
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return 0
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}
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if (number < 0) {
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throw new ERR_OUT_OF_RANGE('number', '>= 0', number)
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}
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return number
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}
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function drop(number, options = undefined) {
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if (options != null) {
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validateObject(options, 'options')
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}
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if ((options === null || options === undefined ? undefined : options.signal) != null) {
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validateAbortSignal(options.signal, 'options.signal')
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}
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number = toIntegerOrInfinity(number)
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return async function* drop() {
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var _options$signal8
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if (
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options !== null &&
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options !== undefined &&
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(_options$signal8 = options.signal) !== null &&
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_options$signal8 !== undefined &&
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_options$signal8.aborted
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) {
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throw new AbortError()
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}
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for await (const val of this) {
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var _options$signal9
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if (
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options !== null &&
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options !== undefined &&
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(_options$signal9 = options.signal) !== null &&
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_options$signal9 !== undefined &&
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_options$signal9.aborted
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) {
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throw new AbortError()
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}
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if (number-- <= 0) {
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yield val
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}
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}
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}.call(this)
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}
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function take(number, options = undefined) {
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if (options != null) {
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validateObject(options, 'options')
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}
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if ((options === null || options === undefined ? undefined : options.signal) != null) {
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validateAbortSignal(options.signal, 'options.signal')
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}
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number = toIntegerOrInfinity(number)
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return async function* take() {
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var _options$signal10
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if (
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options !== null &&
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options !== undefined &&
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(_options$signal10 = options.signal) !== null &&
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_options$signal10 !== undefined &&
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_options$signal10.aborted
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) {
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throw new AbortError()
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}
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for await (const val of this) {
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var _options$signal11
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if (
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options !== null &&
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options !== undefined &&
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(_options$signal11 = options.signal) !== null &&
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_options$signal11 !== undefined &&
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_options$signal11.aborted
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) {
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throw new AbortError()
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}
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if (number-- > 0) {
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yield val
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} else {
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return
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}
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}
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}.call(this)
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}
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module.exports.streamReturningOperators = {
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asIndexedPairs,
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drop,
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filter,
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flatMap,
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map,
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take,
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compose
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}
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module.exports.promiseReturningOperators = {
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every,
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forEach,
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reduce,
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toArray,
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some,
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find
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}
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