i var undefined inside a for loop

Question

//Server Functions
var socketArray = [];
var socketRcon = [];
for (var i = 0; i < serversConfig.serversArray.length; i++) {
    socketArray[i] = new Socket;
    socketArray[i].setEncoding("utf8");
    socketArray[i].setNoDelay();
    socketArray[i].setTimeout(1000);
    socketArray[i].connect(serversConfig.serversArray[i].port, serversConfig.serversArray[i].ip);
    socketRcon[i] = serversConfig.serversArray[i].rcon;
    socketArray[i].on("connect", function() {
        this.write(socketRcon[i] + "\n", "utf8");
        console.log("CONNECTED TO THE SERVER...");
    });
    socketArray[i].on("data", function(data) {
        console.log(data);
    });
    socketArray[i].on("error", function(err) {
        console.log("ERROR:" + err);
    });

    socketArray[i].on("close", function(err) {
        console.log("CLOSED:" + err);
    });
};

This is the code I have now to connect to multiple servers from a config file, and I need that each time the socket connects, I need to send a password to it. But 'socketRcon[i]' is undefined, why is that happening and how do i fix it?

Niet the Dark Absol · Accepted Answer · 2014-04-17 14:52:14Z

2

Because by the time that code is run, i is equal to serversConfig.serversArray.length, meaning socketRcon[i] is undefined.

Anchor your value:

for( var i=0; i<l; i++) (function(i) {
    // do stuff here
})(i);

answered Apr 17, 2014 at 14:52

Niet the Dark Absol

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2 Comments

Lucas T. Over a year ago

I tried with: pastebin.com/LBkBRY5g , but apparently the loop didn't execute.

user61470 Over a year ago

See jslinterrors.com/dont-make-functions-within-a-loop for the reason for having an immediately invoked function expression (IIFE) in the loop and another option that is, in my opinion, more readable.

mscdex · Accepted Answer · 2014-04-17 15:26:14Z

1

You could also just do:

serversConfig.serversArray.forEach(function(srvconfig) {
  var sock = new Socket();
  sock.setEncoding("utf8");
  sock.setNoDelay();
  sock.setTimeout(1000);

  socketArray.push(sock);
  socketRcon.push(srvconfig.rcon);

  sock.on("connect", function() {
    this.write(srvconfig.rcon + "\n", "utf8");
    console.log("CONNECTED TO THE SERVER...");
  });
  sock.on("data", function(data) {
    console.log(data);
  });
  sock.on("error", function(err) {
    console.log("ERROR:" + err);
  });
  sock.on("close", function(err) {
    console.log("CLOSED:" + err);
  });

  sock.connect(srvconfig.port, srvconfig.ip);
});

edited Apr 17, 2014 at 15:26

answered Apr 17, 2014 at 15:11

mscdex

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