Node: extend EventEmitter to non-prototype object

Question

I see this all the time:

Parrot.prototype.__proto__ = EventEmitter.prototype;

With this, each time you construct a new parrot, it can squawk.

However, supposing I construct an object with functions and don't intend to create multiple instances:

var parrot = {
  squawk: function(whatYouSaid){
    this.emit("SQUAWK!!!!", whatYouSaid);
  }
}

How would I make this extend EventEmitter? I tried this, and it didn't work:

_.extend(parrot, (new EventEmitter()));

I there a reason why you are not using native `util.inherits`? — Razvan, Jul 06 '15 at 18:29
Duplicate [http://stackoverflow.com/questions/8898399/node-js-inheriting-from-eventemitter](http://stackoverflow.com/questions/8898399/node-js-inheriting-from-eventemitter) — Razvan, Jul 06 '15 at 18:55
Razvan, you didn't even read the question. It's not a duplicate. Sigh. — dthree, Jul 06 '15 at 19:32

score 3 · Accepted Answer · answered Jul 06 '15 at 18:23

3

You should extend/assign EventEmitter.prototype to your object:

_.assign(parrot, EventEmitter.prototype);

answered Jul 06 '15 at 18:23

robertklep

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score -1 · Answer 2 · answered Jul 06 '15 at 18:54

-1

util.inherits is the native api for doing inheritance in NodeJS.

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

function Parrot(){
  EventEmitter.call(this);
  ...
}

util.inherits(Parrot, EventEmitter);

var parrot = new Parrot();

parrot.on('SQUAWK!!!!', whatYouSaid);

parrot.emit('SQUAWK!!!!', 'I said this!');

I made a demo of different ways of doing inheritance: https://github.com/razvanz/nodejs-inheritance-demo.

answered Jul 06 '15 at 18:54

Razvan

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But this isn't what the OP was asking. – robertklep Jul 06 '15 at 18:57
Thank you for putting in the time to answer this, but it seems like you didn't fully read my question. – dthree Jul 06 '15 at 19:33

Node: extend EventEmitter to non-prototype object

2 Answers2