Javascript ES6和ES2016在cluster.on上使用babel时的不同行为

我试图使用集群来利用拥有多核CPU的好处。代码为：

var cluster = require('cluster');

if (cluster.isMaster) {
    for(var i = 0; i < 2; ++i) {
        cluster.fork();
    }
    cluster.on('exit', function (worker) {
        console.log('Worker ' + worker.process.pid + ' exitted.');
    });
} else {
    console.log('Worker ' + cluster.worker.process.pid);
    process.exit(0);
}

但是，当我尝试与babel一起使用

import

时，我遇到了以下问题：

import *  as cluster from 'cluster'

if (cluster.isMaster) {
    for(let i = 0; i < 2; ++i) {
        cluster.fork();
    }
    cluster.on('exit', (worker) => console.log('Worker ' + worker.process.pid + ' exitted.'));
} else {
    console.log('Worker ' + cluster.worker.process.pid);
    process.exit(0);
}

---

知道发生了什么吗？

好的，我找到了原因，参考：

重点是将

import*作为集群从'cluster'

更改为

import cluster from'cluster'

使用“集群”中的

import*作为集群

，所有可导出的内容都将导出到名为

cluster

的对象中，该对象具有以下结构：

{ domain: null,
  _events: {},
  _eventsCount: 0,
  _maxListeners: undefined,
  Worker: 
   { [Function: Worker]
     super_: 
      { [Function: EventEmitter]
        EventEmitter: [Circular],
        usingDomains: false,
        defaultMaxListeners: 10,
        init: [Function],
        listenerCount: [Function] } },
  isWorker: false,
  isMaster: true,
  workers: {},
  settings: {},
  schedulingPolicy: 2,
  SCHED_NONE: 1,
  SCHED_RR: 2,
  setupMaster: [Function],
  fork: [Function],
  disconnect: [Function],
  default: 
   EventEmitter {
     domain: null,
     _events: {},
     _eventsCount: 0,
     _maxListeners: undefined,
     Worker: { [Function: Worker] super_: [Object] },
     isWorker: false,
     isMaster: true,
     workers: {},
     settings: {},
     schedulingPolicy: 2,
     SCHED_NONE: 1,
     SCHED_RR: 2,
     setupMaster: [Function],
     fork: [Function],
     disconnect: [Function] } }

另一方面，当

从“集群”导入集群时，
集群
对象是默认的导出：

EventEmitter {
  domain: null,
  _events: {},
  _eventsCount: 0,
  _maxListeners: undefined,
  Worker: 
   { [Function: Worker]
     super_: 
      { [Function: EventEmitter]
        EventEmitter: [Circular],
        usingDomains: false,
        defaultMaxListeners: 10,
        init: [Function],
        listenerCount: [Function] } },
  isWorker: false,
  isMaster: true,
  workers: {},
  settings: {},
  schedulingPolicy: 2,
  SCHED_NONE: 1,
  SCHED_RR: 2,
  setupMaster: [Function],
  fork: [Function],
  disconnect: [Function] }

将您的代码保存在test.js中，然后查看神奇的
表单“我”一个接一个地导入，通过对集群中需要的内容进行解构，它成功了：

import { fork, on, isMaster } from 'cluster';

然后

虽然这段代码可以回答这个问题，但提供关于它如何和/或为什么解决问题的附加上下文将提高答案的长期价值。
{ domain: null,
  _events: {},
  _eventsCount: 0,
  _maxListeners: undefined,
  Worker: 
   { [Function: Worker]
     super_: 
      { [Function: EventEmitter]
        EventEmitter: [Circular],
        usingDomains: false,
        defaultMaxListeners: 10,
        init: [Function],
        listenerCount: [Function] } },
  isWorker: false,
  isMaster: true,
  workers: {},
  settings: {},
  schedulingPolicy: 2,
  SCHED_NONE: 1,
  SCHED_RR: 2,
  setupMaster: [Function],
  fork: [Function],
  disconnect: [Function],
  default: 
   EventEmitter {
     domain: null,
     _events: {},
     _eventsCount: 0,
     _maxListeners: undefined,
     Worker: { [Function: Worker] super_: [Object] },
     isWorker: false,
     isMaster: true,
     workers: {},
     settings: {},
     schedulingPolicy: 2,
     SCHED_NONE: 1,
     SCHED_RR: 2,
     setupMaster: [Function],
     fork: [Function],
     disconnect: [Function] } }

EventEmitter {
  domain: null,
  _events: {},
  _eventsCount: 0,
  _maxListeners: undefined,
  Worker: 
   { [Function: Worker]
     super_: 
      { [Function: EventEmitter]
        EventEmitter: [Circular],
        usingDomains: false,
        defaultMaxListeners: 10,
        init: [Function],
        listenerCount: [Function] } },
  isWorker: false,
  isMaster: true,
  workers: {},
  settings: {},
  schedulingPolicy: 2,
  SCHED_NONE: 1,
  SCHED_RR: 2,
  setupMaster: [Function],
  fork: [Function],
  disconnect: [Function] }

require('babel-core/register')({
  presets: ['node6']
});

const app = require('./test.js');
app();

import { fork, on, isMaster } from 'cluster';

   if (isMaster) {
      console.log(`Forking ${numWorkers} workers`);
      const workers = [...Array(numWorkers)].map(_ => fork());

      on('online', worker => console.log(`Worker ${worker.process.pid} is online`));
}