向各位前端工程师请教一道笔试题，有关JS并发处理异步任务的
const assert = require('assert');
/**
* --- 问题描述 ---
*
* 给出一组异步任务方法，和允许同时执行的个数，实现一个方法，用于并发执行异步任务
*
* --- 说明 ---
*
* - 当有任务执行完毕后，自动补充任务，始终保持正在执行的任务有 `concurrency` 个
* - 返回 { resolved: [], rejected: [] }
*
**/
async function parallel(tasks, concurrency) {
}
/*******测试部分*******/
module.exports = async function doTest() {
try {
const child_process = require('child_process');
const fs = require('fs');
const path = require('path');
const util = require('util');
const readFile = util.promisify(fs.readFile);
const exec = util.promisify(child_process.exec);
const tasks = [
() => readFile(__filename, 'utf-8'),
() => Promise.resolve('foo'),
() => exec('npm -v'),
() => readFile(path.join(__dirname, '../package.json'), 'utf-8'),
() => process.cpuUsage(),
() => exec('node -v'),
() => Promise.reject(new Error('bar')),
() => exec('ls -al'),
() => new Promise(resolve => process.nextTick(resolve)),
() => exec('whoami')
];
const { resolved, rejected } = await parallel(tasks, 3);
assert.equal(resolved.length, 9);
assert.equal(rejected.length, 1);
return '通过';
} catch (err) {
return '不通过';
}
};
#笔经#
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