# Bubble sort

JavaScript, Algorithm, Array · Dec 29, 2020

Sorts an array of numbers, using the bubble sort algorithm.

- Declare a variable,
`swapped`

, that indicates if any values were swapped during the current iteration. - Use the spread operator (
`...`

) to clone the original array,`arr`

. - Use a
`for`

loop to iterate over the elements of the cloned array, terminating before the last element. - Use a nested
`for`

loop to iterate over the segment of the array between`0`

and`i`

, swapping any adjacent out of order elements and setting`swapped`

to`true`

. - If
`swapped`

is`false`

after an iteration, no more changes are needed, so the cloned array is returned.

```
const bubbleSort = arr => {
let swapped = false;
const a = [...arr];
for (let i = 1; i < a.length; i++) {
swapped = false;
for (let j = 0; j < a.length - i; j++) {
if (a[j + 1] < a[j]) {
[a[j], a[j + 1]] = [a[j + 1], a[j]];
swapped = true;
}
}
if (!swapped) return a;
}
return a;
};
```

`bubbleSort([2, 1, 4, 3]); // [1, 2, 3, 4]`