node.js v0.12.x changes in EventEmitter ruins inheritance

Question

There is some changes in node.js 0.12.x related to events module. This changes makes my code that extends EventEmitter class non-workable. Here is code that works fine in node.js v0.10.35: teh_emitter.js:

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

util.inherits(TehEmitter, EventEmitter);


function TehEmitter(){

 EventEmitter.call(this);
}


TehEmitter.prototype.on('start', function (fCallback) {

 fCallback();
});

module.exports = TehEmitter;

test_teh_emitter.js:

var TehEmitter =  require('./teh_emitter');

describe('EventEmitter tests', function(){

 describe('#emit() function', function(){

  it('should fire start event', function(fCallback){

   var oEmitter = new TehEmitter(fCallback);

   oEmitter.emit('start', fCallback);

  });
 })
});

But on node.js v0.12.7 it says: 0 passing (2s) 1 failing

1) EventEmitter tests #emit() function should fire start event:
Error: timeout of 2000ms exceeded. Ensure the done() callback is being called in this test.

I know that in 0.12.x one should assign: var EventEmitter = require('events'); (though require('events').EventEmitter; should still work for backwards compatability). But it doesn't helps.

How am I gonna fix this problem?

score 0 · Accepted Answer · answered Sep 04 '15 at 22:28

This was changed in 2c6b424 because of a bug involving event handlers bleeding into all other instances of the same object/"class" (see 7157).

Probably your best bet for compatibility is to just add the event handler in the constructor:

function TehEmitter(){
  EventEmitter.call(this);
  this.on('start', onStart);
}

function onStart(fCallback) {
  fCallback();
}

node.js v0.12.x changes in EventEmitter ruins inheritance

1 Answers1