javascript - 无法连接 eventEmitter 上的监听器

Question

我正在尝试使用 Node 的events模块设置电子邮件通知。我无法使其工作，因为在发出 email 事件时它不起作用。不知道出了什么问题。你能帮我调试这段代码吗？提前致谢!

email.js

var express = require('express');
var nodemailer = require('nodemailer');
var events = require('events');
var util = require('util');
var _ = require('lodash');


var Notify = function() {
    events.EventEmitter.call(this);
    var transporter = nodemailer.createTransport();
    this.eventNames = {
        newBug: 'new bug',
        updatedBug: 'updated bug',
        commentedOnBug: 'commented on bug',
        updatedAndCommentedOnBug: 'updated and commented on bug',
    };
    this.notifier = function(eventName, data) {
        this.on('email', function() {
            console.log('email notifier......');
        })
    };
    this.notify = function(eventName, data) {
        console.log('notify...');
        this.emit('email', data);
    };

    this.send = function(eventName, data) {
        var email = {
            from: 'new_bugtrack@example.com',
            to: '',
            subject: '',
            text: ''
        };
        email.to = data.assignTo.email || '';

        switch (eventName) {
            case this.eventNames.newBug:
                email.subject = 'Created new bug ' + data.id
                email.text = data.title
                break;
            case this.eventNames.updatedBug:
                email.subject = _.last(data.changeHistory).updatedBy.name + ' updated bug-' + data.id
                email.text = data._.last(data.changeHistory).change
                break;
            case this.eventNames.commentedOnBug:
                email.subject = _.last(data.changeHistory).updatedBy.name + ' commented on bug-' + data.id
                email.text = data._.last(data.changeHistory).comment
                break;
            case this.eventNames.updatedAndCommentedOnBug:
                email.subject = _.last(data.changeHistory).updatedBy.name + 'updated and commented on bug-' + data.id
                email.text = _.last(data.changeHistory).change + '-----' + _.last(data.changeHistory).comment
                break;
            default:
                break;
        }

        if (process.env.NODE_ENV === "development" || process.env.NODE_ENV === "test") {    
            email.to = 'example@example.com';
        }

        console.log('email emit activated');
        transporter.sendMail(email);
    };

};

util.inherits(Notify, events.EventEmitter);



//  dont't send emails in dev/test env
if (process.env.NODE_ENV === "development" || process.env.NODE_ENV === "test") {    
    Notify.send = function(eventName, data) {
        console.log('emailed data', JSON.stringify(data, null, 2));
    };
}


module.exports.Notify = Notify;

bug.controller.js

var marklogic = require('marklogic');
var conn = require('../../config/db-config.js').connection;
var db = marklogic.createDatabaseClient(conn);
var Notify = require('../../email/email').Notify;

var email = new Notify();
console.log('notify',  email);
// just a simple function for demo
exports.count = function(req, res) {

    db.documents.query(
        q.where(
            q.collection('bugs')
        )
        .slice(1, 1)
        .withOptions({
            debug: true,
            categories: 'metadata'
        })
    ).result(function(response) {
     email.notify(email.eventNames.newBug,  {a: 2})
        res.status(200).json({
            count: response[0].total
        });
    });
};
...
...
...

我看到日志语句notify是从notify()函数打印出来的，但没有看到email notifier它被挂接到email 事件

Answer 1

事实上，下面的函数永远不会被调用，因此您没有将任何监听器附加到事件发射器。

this.notifier = function(eventName, data) {
    this.on('email', function() {
        console.log('email notifier......');
    })
}; 

按如下方式更改:

var notifier = function(data) {
    console.log('email notifier......');
};

this.on('email', notifier);