Here is your issue :
for (var i = 0; i < output.length; i++) {
var item = output[i].substring(0,1);
list.push(item);
}
[Edit]
Try below code :
var concateVal = "";
for (var i = 0; i < output.length; i++) {
var item = output[i].substring(0, 1);
if (concateVal == "")
concateVal = item;
else
concateVal = concateVal + "." + item;
}
var Code = currentdate.getFullYear() + "/" + concateVal + "/" + (currentdate.getMonth() + 1) + "/" + currentdate.getDate() + "/" + (pad + '@(m + 1)');
Good luck.