SocketIO emit with callback fails while upgrading 0.9.16 to 1.35

[tonyjose009]

Hi,

In 0.9.16, I use socket.emit with callback so that the chat server return some data and I can handle the result as per the acknowledgement. But after the upgrade to 1.35 I've found a error in console like this

Uncaught TypeError: Cannot read property 'apply' of undefined.

I've done something like this,

From web

            socket.emit('userToUser', { 'usename': 'John',
                'message': 'hi'
            }, function(callback){
                //callback handled    
            });

Chat Server

    socket.on('userToUser', function(content, callback){
        //do something
        if(callback) return callback({'result':'success', 'messageid':content.messageid,        'chatid':content.chatid});
    });

[tonyjose009]

When I removed the callback from client side, there is no error. So I believe there will be some changes to be done in the callback, please help

[nkzawa]

I'm not sure about v0.9, but on v1.x, you can't accept a function as an argument on ack callback.

[tonyjose009]

So how is it possible to manage server acknowledgement(success/failure) in client side ?

[nkzawa]

You can get an acknowledgement from the server anyway. Isn't it enough for you?

socket.emit('userToUser', { 'usename': 'John',
  'message': 'hi'
}, function(data){
   console.log(data);
    // prints {'result': 'success', 'messageid': messageid, 'chatid': chatid}    
});

[tonyjose009]

See I'm getting the callback and the chat is working.
But my concern is about the error.

Uncaught TypeError: Cannot read property 'apply' of undefined.

which points to socketio.js

/**

• Called upon a server acknowlegement.
  *
• @param {Object} packet
• @api private
  */

Socket.prototype.onack = function(packet){
debug('calling ack %s with %j', packet.id, packet.data);
var fn = this.acks[packet.id];
fn.apply(this, packet.data);
delete this.acks[packet.id];
};

[nkzawa]

How can we reproduce the error?

[tonyjose009]

Issue fixed guys,
Thanks for your comments.

See this http://stackoverflow.com/questions/29935861/socketio-emit-with-callback-fails-while-upgrading-0-9-16-to-1-3-5/30045575#30045575