'use strict'; const pTry = require('p-try'); const pLimit = concurrency => { if (concurrency < 1) { throw new TypeError('Expected `concurrency` to be a number from 1 and up'); } const queue = []; let activeCount = 0; const next = () => { activeCount--; if (queue.length > 0) { queue.shift()(); } }; const run = (fn, resolve, ...args) => { activeCount++; const result = pTry(fn, ...args); resolve(result); result.then(next, next); }; const enqueue = (fn, resolve, ...args) => { if (activeCount < concurrency) { run(fn, resolve, ...args); } else { queue.push(run.bind(null, fn, resolve, ...args)); } }; const generator = (fn, ...args) => new Promise(resolve => enqueue(fn, resolve, ...args)); Object.defineProperties(generator, { activeCount: { get: () => activeCount }, pendingCount: { get: () => queue.length } }); return generator; }; module.exports = pLimit; module.exports.default = pLimit;