Node.js模块无法通信

Question

I am in the process of teaching myself node.js by building a personal project. I am trying to follow best practices by splitting my code up into separate modules. However, I've run into a problem where one of my modules is communicating back to the caller module. I've used callback functions and events, but the caller module never gets anything back from the called module, unless the called module returns a value immediately. Please look at the below code and let me know what I'm missing:

blogs.controller.js (caller module)

var ImageParser = require('../../components/parsers/ImageParser.js');
.....
var imageParser = new ImageParser();
imageParser.on('imagesParsed', function(){
console.log('test)});

ImageParser.js (called module)

var EventEmitter = require('events').EventEmitter;
var util = require('util');

var ImageParser = function(){
    this.emit('imagesParsed');
};

util.inherits(ImageParser, EventEmitter);

module.exports = ImageParser;

Within the ImageParser function, I can listen for the event, but outside of it, I can't. Any help would be greatly appreciated.

Thanks

Answer 1

I actually found my answer in an answer to another question, answered by @linus-g-thiel Also, thanks to @Pointy

Turns out I need to emit the event from a method, not the constructor, and the listener needs to be BEFORE the method call. It's working now.