SOURCE

function quickSort(arr) {
    if (arr.length < 2) return arr;
    var pivot = arr[0];
    var left = [];
    var right = [];
    for (let i = 1; i < arr.length; i++) {
        arr[i] < pivot ? left.push(arr[i]) : right.push(arr[i]);
    }
    return quickSort(left).concat([pivot], quickSort(right));
}
function quickSort2(arr) {
    if (arr.length < 2) { return arr; }
    const pivot = arr.shift();
    const left = [];
    const right = [];
    arr.forEach((element) => {
        element < pivot ? left.push(element) : right.push(element);
    });

    return quickSort2(left).concat([pivot], quickSort2(right));
}
var list = [13, 98, 5, 47, 136, 2];
document.write(quickSort2(list));