This is my implementation of quicksort.

quickSort.js

function quickSort(arr){
    const size = arr.length;

    if(size === 0) return [];
    else {
        let pivot = arr[0];
        let left = [];
        let right = [];

        for(let i = 1; i<size;i++){
            let item = arr[i];

            if(item < pivot){
                left.push(item);
            } else {
                right.push(item);
            }
        }

        return [...quickSort(left), pivot, ...quickSort(right)];
    }
}

quickSort([1,2,5,9,7,15,23]);
//(7) [1, 2, 5, 7, 9, 15, 23]