How to run script and pass arguments if client is connected over socket?

Question

How to run script and pass arguments if client is connected over socket?

Is it possible to run some script and if client connected pass arguments to it, something like this:

 var io = require('socket.io').listen(http);
 io.sockets.on('connection', function (client) {
     console.log('Client connected');
     var notifikacija = function (array) {
         client.emit('populate', array);
     }
 });

 ///////////////////////////////////////////////////////////////////////

 setInterval(function(){
     var array = newArray();
     array[0]='test';
     notifikacija(array);
 }, 2000);

Now it shows error: notifikacija is not defined. It is quite a strugle...

javascript
node.js
sockets

Answer 1

The notifikacija function is local to the scope of the io.sockets.on handler. You want it to be global so that you can access it in setInterval:

var notifikacija = function(){}; // just an empty function, in case it gets called before it has something to do
var io = require('socket.io').listen(http);
io.sockets.on('connection', function(client) {
     console.log('Client connected');
     notifikacija = function(array){ // once the client is available assign the function
         client.emit('populate', array);
     }  
});

setInterval(function(){
    var array = newArray();
    array[0]='test';
    notifikacija(array);
}, 2000);

Here's a blog post with some more information on scope in Javascript.