Javascript Code To Do Quick Sort

const arr = [3,2,1,4,6,5,7,9,8,10]

const pivot = (arr, start = 0, end = arr.length - 1) => {
    const swap = (arr, idx1, idx2) => [arr[idx1], arr[idx2]] = [arr[idx2], arr[idx1]]

    let pivot = arr[start]
    let swapIdx = start

    for (let i = start+1; i <= end; i++) {
        if (pivot > arr[i]) {
            swapIdx++
            swap(arr, swapIdx, i)
        }
    }

    swap(arr, start, swapIdx)
    return swapIdx
}

const quickSort = (arr, left = 0, right = arr.length - 1) => {
    if (left < right) {
        let pivotIndex = pivot(arr, left, right)
        quickSort(arr, left, pivotIndex-1)
        quickSort(arr, pivotIndex+1, right)
    }

    return arr
}

console.log(quickSort(arr)) // [1,2,3,4,5,6,7,8,9,10]