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31 lines
934 B
31 lines
934 B
'use strict'; |
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const pLimit = require('p-limit'); |
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class EndError extends Error { |
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constructor(value) { |
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super(); |
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this.value = value; |
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} |
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} |
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// the input can also be a promise, so we `Promise.all()` them both |
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const finder = el => Promise.all(el).then(val => val[1] === true && Promise.reject(new EndError(val[0]))); |
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module.exports = (iterable, tester, opts) => { |
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opts = Object.assign({ |
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concurrency: Infinity, |
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preserveOrder: true |
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}, opts); |
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const limit = pLimit(opts.concurrency); |
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// start all the promises concurrently with optional limit |
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const items = Array.from(iterable).map(el => [el, limit(() => Promise.resolve(el).then(tester))]); |
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// check the promises either serially or concurrently |
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const checkLimit = pLimit(opts.preserveOrder ? 1 : Infinity); |
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return Promise.all(items.map(el => checkLimit(() => finder(el)))) |
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.then(() => {}) |
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.catch(err => err instanceof EndError ? err.value : Promise.reject(err)); |
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};
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