node.js - 将 "require(' events').eventEmitter"更改为 "require ('events' )"？

Question

我的老师告诉我使用:

const EventEmitter = require('events').eventEmitter;

但是，当前的nodejs文档说要使用:

const EventEmitter = require('events');

我的老师错了吗，node.js 是否改变了或者为什么会这样？

Answer 1

Nodejs过去要求你使用:

var EventEmitter = require('events').eventEmitter

但是，2013 年 5 月，this change已在 GitHub 上提交:

events: have events module exports EventEmitter This change is 100% backwards compatible.

This change will make using EventEmitter slightly simpler / nicer and adheres to the best practice set forth by substack.

var EventEmitter = require("events")

var emitter = new EventEmitter()

The only difference is that we now have to set EventEmitter as a property of EventEmitter for backwards compatibility like we do with Stream

We have also set the usingDomains property on the EventEmitter constructor itself because that aligns with it's current usage of require("events").usingDomains = true

There are other internals that would benefit from this change as well like StringDecoder

现在允许更简单的语法:

var EventEmitter = require('events');

同时仍然保持与旧语法的向后兼容性。