mirror of https://github.com/nodejs/node.git
53 lines
1.1 KiB
JavaScript
53 lines
1.1 KiB
JavaScript
const os = require('os')
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// availableParallelism available only since node v19, for older versions use
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// cpus() cpus() can return an empty list if /proc is not mounted, use 1 in
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// this case
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/* istanbul ignore next - version-specific workaround */
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const defLimit = 'availableParallelism' in os
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? os.availableParallelism()
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: Math.max(1, os.cpus().length)
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const callLimit = (queue, limit = defLimit) => new Promise((res, rej) => {
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let active = 0
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let current = 0
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const results = []
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let rejected = false
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const reject = er => {
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if (rejected)
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return
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rejected = true
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rej(er)
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}
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let resolved = false
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const resolve = () => {
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if (resolved || active > 0)
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return
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resolved = true
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res(results)
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}
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const run = () => {
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const c = current++
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if (c >= queue.length) {
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return resolve()
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}
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active ++
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results[c] = queue[c]().then(result => {
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active --
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results[c] = result
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run()
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return result
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}, reject)
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}
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for (let i = 0; i < limit; i++) {
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run()
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}
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})
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module.exports = callLimit
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