Algorithm of JavaScript "sort()" Function

user_332019 0
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Recently when I was working with JavaScript "sort()" function, I found in one of the tutorials that this function does not sort the numbers properly. Instead to sort numbers, a function must be added that compares numbers, like the following code:-

<script type="text/javascript">
function sortNumber(a,b)
{
    return a - b;
}

var n = ["10", "5", "40", "25", "100", "1"];
document.write(n.sort(sortNumber));
</script>

The output then comes as:-

1,5,10,25,40,100

Now what I didn't understand is that why is this occurring & can anybody please tell in details as to what type of algorithm is being used in this "sort()" function? This is because for any other language, I didn't find this problem where the function didn't sort the numbers correctly.

Any help is greatly appreciated.

sorting algorithm javascript
8 Answers

The “default” comparison function calls toString on both values and does a lexicographical comparison on the string representations. V8 engine uses Timsort algorithms which runs in O(nlogn). Source

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