Quicksort (Javascript)

quicksort.js

'use strict';

function ArrayUtil() { }

ArrayUtil.prototype.show = function(arr, rowLength = 5) {
    var lengthCount = rowLength;
    arr.forEach(function(element) {
        process.stdout.write(element + "\t");
        lengthCount--;
        if (lengthCount == 0) {
            process.stdout.write("\n");
            lengthCount = rowLength;
        }
    }, this);
    console.log('length : ' + arr.length);
}

ArrayUtil.prototype.generateMockData = function(size, maxium_value, overlapped = false) {
    var data = [];
    for (var i = 0; i < size; ) {
        var number = Math.round(Math.random() * maxium_value);
        if (overlapped) {
            data.push(number);
            i++;
        } else if (!ArrayUtil.prototype.isNumberExist(data, number)) {
            data.push(number);
            i++;
        }
    }
    return data;
}

ArrayUtil.prototype.isNumberExist = function(arr, number) {
    return arr.indexOf(number) > -1 ? true : false;
}

function quicksort(arr) { 
    if (arr.length <= 1) {
        return arr;
    }
    var lte = [];
    var gte = [];
    var pivotArr = [];
    var pivot = arr[parseInt(arr.length / 2)];
        
    for (var i = arr.length - 1; i >= 0; i--) {
        if (arr[i] > pivot) {
            gte.push(arr[i]);
        } else if (arr[i] < pivot){
            lte.push(arr[i]);
        } else {
            // Push overlapped value.
            pivotArr.push(arr[i]);
        }
    }
    return Array.prototype.concat(quicksort(lte), pivotArr, quicksort(gte));
}

/*
    Script option

    -size [integer] : Mock data size ex) -size 100
    -maxium [integer] : Maxium mock data value. ex) -maxium 100
    -overlap : Overlapped mock data value.
    -no-display : Not showing mock data.
*/

var mockDataSize = process.argv.indexOf('-size') > 0 ? process.argv[process.argv.indexOf('-size') + 1] : 100;
var mockMaxiumValue = process.argv.indexOf('-maxium') > 0 ? process.argv[process.argv.indexOf('-maxium') + 1] : 100;
var isOverlapped = process.argv.indexOf('-overlap') > 0 ? true : false;
var isMockShow = process.argv.indexOf('-no-display') > 0 ? false : true;

var data = ArrayUtil.prototype.generateMockData(mockDataSize, mockMaxiumValue, isOverlapped);
if (isMockShow) {
    console.log("<Before sort>");
    ArrayUtil.prototype.show(data);
}
var startTime = new Date().getTime();
// Sort test
data = quicksort(data);
var elapsedTime = (new Date().getTime() - startTime) / 1000;

console.log();
if (isMockShow) {
    console.log("<After sort>");
    ArrayUtil.prototype.show(data);
    console.log();
}
console.log('Elapsed Time : ' + elapsedTime);