.once only working if there is an .on call for the same event type

[andyburke]

Seeing an issue where .once( 'data' ... ) on a stream will only be hit if there is an .on( 'data'... ) call somewhere on the same eventemitter object.

I've spent an hour or so in the code trying to figure out the issue, but I am stumped. Could you give me any guidance on why a .once() would not be hit unless there's a .on() for the same event type?

Specifically I am seeing this using the node-postgres module with longjohn included. In their connection module, I tracked it down to this:

  // without this, .once below seems inconsistent
  this.stream.on( 'data', function() {
    var nop = 1;
  });

  this.stream.once('data', function(buffer) {
    var responseCode = buffer.toString('utf8');
    if(responseCode != 'S') {
      return self.emit('error', new Error('The server does not support SSL connections'));
    }
    var tls = require('tls');
    self.stream = tls.connect({
      socket: self.stream,
      servername: host,
      rejectUnauthorized: self.ssl.rejectUnauthorized,
      ca: self.ssl.ca,
      pfx: self.ssl.pfx,
      key: self.ssl.key,
      passphrase: self.ssl.passphrase,
      cert: self.ssl.cert,
      NPNProtocols: self.ssl.NPNProtocols
    });
    self.attachListeners(self.stream);
    self.emit('sslconnect');

    self.stream.on('error', function(error){
      self.emit('error', error);
    });
  });

If I don't add the .on( 'data'...) the .once( 'data'... will never be hit while longjohn is loaded.

[nodo-digital]

Fixed by #67