Not able to hook up listener on eventEmitter

Question

I'm trying to setup email notification using node's events module. I'm not able to make it work, as in its not doing when email event is emitted. Not sure whats wrong. Could you please help me debug this code. Thanks in advance!

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
        });
    });
};
...
...
...

I see the log statement notify being printed from notify() function but not email notifier which is hooked to email event

score 1 · Accepted Answer · answered Jul 07 '15 at 22:41

Indeed, the function below is never invoked, so you are not attaching any listener to the event emitter.

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

Change it as follows:

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

this.on('email', notifier);

Not able to hook up listener on eventEmitter

1 Answers1