node.js server not always clearing data from previous run - node.js

Question

I'm brand new to node.js (or javascript in general) and not sure what's going on here. Sometimes when I run my node.js server, right when it starts up it begins printing data from the last time it ran. Is there something that could be keeping everything from resetting on a new run? I have arduino XBee nodes connecting to this server. Here's my node.js code:
var SerialPort = require("serialport");
var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);
var ON_DEATH = require('death');
// Set up serial port
var portName = process.argv[2],
portConfig = {
baudRate: 9600,
parser: SerialPort.parsers.readline("\n")
};
var sp = new SerialPort(portName, portConfig); // got rid of deprecation issue with sp4
// Respond with file when a GET request is made to the homepage: app.METHOD(PATH, HANDLER) '/'=homepage
app.get('/', function(req, res){
res.sendfile('index.html');
});
// Listen on the connection event for incoming sockets, and log it to the console.
io.on('connection', function(socket){
console.log('a user connected');
socket.on('disconnect', function(){
});
socket.on('chat message', function(msg){
io.emit('chat message', msg);
sp.write(msg + "\n");
});
});
// Make the http server listen on port 3000
http.listen(3000, function(){
console.log('listening on *:3000');
});
/////////////////////////////////////////////////////////////////////////////////////////////////
sp.on("open", function (err) {
if (err)
return console.log('Error opening port: ', err.message);
console.log('open');
// INFO VARIABLES
//var nodeCount = 0;
var pendingNodes = [];
var connectedNodes = [];
var buffer0;
var nodeInfo;
// Cleanup when termination signals are sent to process
ON_DEATH(function(signal, err) {
var death_msg = "Q";
sp.write(death_msg);
sp.close();
// zero out all variables
pendingNodes = [];
connectedNodes = [];
buffer0 = [];
nodeInfo = [];
console.log("\n\nSending reset signal to nodes.\n\n")
sp.flush(function(err,results){});
process.exit();
})
// listen for data, grab time, delimit
sp.on('data', function(data) {
var time = new Date();
buffer0 = data.split('\n'); // array of data till newline
// Split again into either "#ID" into [#ID] (if new broadcast), or "#ID Data" into [#ID, Data] (preconnected node)
nodeInfo = buffer0[0].split(' ');
//console.log(" nodeInfo: " + nodeInfo);
// DEBUGGING PRINT -- DELETE LATER
//console.log(" pendingNodes: " + pendingNodes + " connectedNodes: " + connectedNodes);
////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Receiving ID or [ID, Data] -- Testing all possible cases
// if first char
if (nodeInfo[0][0] == "#") { // could check up here for && no temp data too
// Brand new node (ID not in pendingNodes or connectedNodes)
if ((pendingNodes.indexOf(nodeInfo[0]) == -1) && (connectedNodes.indexOf(nodeInfo[0]) == -1)) {
console.log("Brand new node: " + nodeInfo[0])
pendingNodes.push(nodeInfo[0]);
}
// Pending node (ID in pendingNodes, but not in connectedNodes)
else if ((pendingNodes.indexOf(nodeInfo[0]) != -1) && ((connectedNodes.indexOf(nodeInfo[0]) == -1))) {
console.log(" Pending node: " + nodeInfo[0])
// send back ID to confirm handshake
sp.write(nodeInfo[0]);
// Remove from pendingNodes
var index = pendingNodes.indexOf(nodeInfo[0]);
if (index > -1) {
pendingNodes.splice(index, 1);
}
// Add to connectedNodes
//var
connectedNodes.push(nodeInfo[0]);
}
// Connected node (ID in connectedNodes, but not in pendingNodes)
else if ((pendingNodes.indexOf(nodeInfo[0]) == -1) && (connectedNodes.indexOf(nodeInfo[0]) != -1)) {
console.log(" Connected node: " + nodeInfo[0] + " " + nodeInfo[1]);
// Disconnect nodes with undefined temperatures to force restart
if (typeof nodeInfo[1] == 'undefined') {
console.log("Undefined data for node: " + nodeInfo[0] + ". Dropping connection to this node.");
var index = connectedNodes.indexOf(nodeInfo[0]);
if (index > -1) {
connectedNodes.splice(index, 1);
}
}
//var t = time.getTime();
// FIRST: fix bug -- sometimes temp showing as undefined
// Then:
// Update data properly
// Average data
// add 3rd element to nodes for time stamp, check that all timestamps are recent periodically
// Detect drop-offs and remove nodes
}
// Error (ID in both pendingNodes and connectedNodes [should not happen])
else {
console.log("Error: node exists in both pending and connected.")
}
}
else if (nodeInfo[0][0] != "#") {
// FOR DEBUGGING PURPOSES, DELETE LATER
console.log("Error 2: incoming data does not start with '#'.")
}
/* // placeholders for functionality to add
var CalcAverage = function() {
console.log("CalcAverage: * every 1 second(s) *");
}
setInterval(function(){ CalcAverage() },2000);
var CheckNodes = function() {
console.log("CheckNodes: * every 6 second(s) *");
}
setInterval(function(){ CheckNodes() },6000);
*/
}); // end data
}); // end open
And here's an example of old node data showing up somehow:

Answer 1

Some possibilities:
Old (or new data that you didn't know it sent) data from clients has been buffered somehow on the serial port, or socket.io auto-reconnects on the client browsers and starts sending data even though you didn't interact with the client browser web page.