# Does sort(), Ever sort anything

When sorting an array, if you are like me the first thing that comes to mind is `sort()`.

An hour before writing this, I was having a great Sunday and decided to do some of the easy katas in [codewars](http://codewars.com). One of the questions I found required me to add one line of code to sort an integer array, easy right?

![](https://media.giphy.com/media/3o7btNa0RUYa5E7iiQ/giphy.gif align="center")

The `sort()` method sorts the elements of an array in place and returns the sorted array. By default, the `sort()` method sorts the elements in ascending order according to the **<mark>Unicode values</mark>** of the elements.

```javascript
// input: [1, 2, 3, 10, 5]
function sortArr(input) {
 return input.sort()
}

// output: [1, 10, 2, 3, 5]
// 😡 expect output: [1, 2, 3, 5, 10]
```

So this got me 😡 but then if we are to go back and re-read how the sort method works, it by default sorts the elements in ascending order according to the Unicode values of the elements with <mark>Unicode values</mark> being highlighted.

So what is happening here:

The `sort()` method converts the numbers to strings and sorts them lexicographically (dictionary order) based on their string representations.

The Unicode code points for the characters "10" and "2" are:

* "1": U+0031
    
* "0": U+0030
    
* "2": U+0032
    

In the string "10", the character "1" has a lower Unicode code point than the character "2", which means that in lexicographic order, "10" comes before "2". This is why the `sort()` method sorts the array `[1,2,3,10,5]` as `[1,10,2,3,5]`.

But we are not doomed,

![](https://media.giphy.com/media/8JQOSC9rq8StxyzKz6/giphy.gif align="center")

that's how `sort()` works by default, but you can provide a function to the `sort()` *(I guess that would make it the sorting function)* to specify a custom sort order. so to sort elements in ascending order by their numerical values add this function.

```javascript
// input: [1, 2, 3, 10, 5]
function sortArr(input) {
 return input.sort((a,b) => a - b)
}

//😃 output: [1, 2, 3, 5, 10]
```

In this example, the sorting function `(a, b) => a - b` subtracts `b` from `a`, so if `a` is less than `b`, the result is negative and `a` is sorted before `b`. If `a` is greater than `b`, the result is positive and `b` is sorted before `a`. If `a` and `b` are equal, the result is 0 and their order in the sorted array is unchanged.

You are sorted now, take that, elements :)