javascript - 子类化 events.EventEmitter 不工作

Question

如何继承 EventEmitter？我正在尝试以下测试:

 var util = require('util')
   ,events = require('events');

function Downloader() {

    events.EventEmitter.call(this);
}
util.inherits(Downloader, events.EventEmitter);
console.log(new Downloader() instanceof events.EventEmitter); // true
Downloader.prototype.download = function(episode) {
    var self = this;

    var statusMessage = 'Downloading: ' + episode;
    self.emit('status', statusMessage);    

    setTimeout(function() {
        var finishedMessage = 'Downloaded ' + episode;
        self.emit('finished', finishedMessage);
    }, 5000);    
}

exports.Downloader = new Downloader();

Node 提示“对象”没有方法“开”。但是，当检查下载程序 instanceOf EventEmitter 时返回 true。

谁能解释一下？谢谢!

Answer 1

天哪。首先它应该是'module.exports'。其次，它的“instanceof”不是“instanceOf”。

我的错。这是一个工作示例

var util = require('util')
   ,events = require('events');

function Downloader() {

    events.EventEmitter.call(this);
}
util.inherits(Downloader, events.EventEmitter);

Downloader.prototype.download = function(episode) {
    var self = this;

    var statusMessage = 'Downloading: ' + episode;
    self.emit('status', statusMessage);    

    setTimeout(function() {
        var finishedMessage = 'Downloaded ' + episode;
        self.emit('finished', finishedMessage);
    }, 5000);    
}

module.exports = new Downloader();