Ajax call output and timeout - arrays

Question

Ive build an ajax counter which outputs max 6 digits - e.g. "120398" and repeats the call
function updateNumbers(){
$.ajax({
url: totalnumbers.ajaxurl,
data: {
action: 'numberstotal'
},
success: function (response) {
var numbers = response.toString(10).replace(/\D/g, '0').split('').map(Number);
//console.log(numbers);
var newHTML = [];
for (var i = 0; i < 6; i++) {
newHTML.push('<span>' + numbers[i] + '</span>');
}
$('.counter').html(newHTML.join(""));
}
});
setTimeout(updateMinutes, 5000);
}
updateNumbers();
this works so far.
Question 1:
Now when there are only 4 digits (1234) I still need an output of total like this
<span>0</span>
<span>0</span>
<span>1</span>
<span>2</span>
<span>3</span>
<span>4</span>
what I get is
<span>1</span>
<span>2</span>
<span>3</span>
<span>4</span>
<span>undefined</span>
<span>undefined</span>
Question 2:
When theres a total of 200000 I want to quit the setTimeout-Function. But I dont know how to get the response out of the ajax call to check before setting the timeout.
Help would be great. It seems like I am almost there :(

Answer 1

After a little thinking I made it happen:
function updateNumbers(){
$.ajax({
url: totalnumbers.ajaxurl,
data: {
action: 'numberstotal'
},
success: function (response) {
if (response < 20000) {
var stringlength = response.length;
var numbers = response.toString(10).replace(/\D/g, '0').split('').map(Number);
var newNumbers = numbers;
for (var i = stringlength; i < 7; i++) {
newNumbers.unshift(0);
}
var totalNumbers = $.map(newNumbers, function(num) {
return('<span>' + num + '</span>');
});
$('.counter').html(totalNumbers.join(""));
setTimeout(updateNumbers, 5000);
}
else {
var numbers = response.toString(10).replace(/\D/g, '0').split('').map(Number);
var totalNumbers = $.map(numbers, function(num) {
return('<span>' + num + '</span>');
});
$('.counter').html(totalNumbers.join(""));
}
}
});
}
updateNumbers();