快速排序

arr = [5, 4, 3, 2, 1]

const quickSort = (arr) => {
	if (arr.length < 2) return arr
	const pivot = arr[0]
	const left = []
	const right = []
	for (let i = 1; i < arr.length; i++) {
		if (arr[i] < pivot) {
			left.push(arr[i])
		} else {
			right.push(arr[i])
		}
	}
	return [...quickSort(left), pivot, ...quickSort(right)]
}

console.log(quickSort(arr))