SOURCE

function quickSort(nums) {
    if (nums.length < 2) {
        return nums;
    }
    let  middle = Math.floor((nums.length - 1) / 2);
    let middleValue = nums.splice(middle, 1)[0];
    let left = [], right = [];
    for (let i of nums) {
        if (i < middleValue) {
            left.push(i);
        } else {
            right.push(i);
        }
    }
    return quickSort(left).concat(middleValue, quickSort(right));
}
let a = [2,5,7,4,1,45,65,55]
console.log(quickSort(a))