Sorts in Javascript

sorts.js

// Helper function to clone array
function cloneArray(arr) {
    return arr.slice();
}

// Helper function to generate random number array
function randomArray(min, max, len) {
    
    // Set default values
    min = min || 0;
    max = max || 10;
    len = len || 10;
    
    // Create blank array
    var arr = new Array(len);
    
    // Set array values
    for (var i=0; i<len; i++) {
        arr[i] = min + Math.round(Math.random() * max);
    }
    return arr;
}

// Generate long random array

var data = randomArray(0, 10, 20000);

// Bubble Sort

var bubbleSortArr = cloneArray(data);

function bubbleSort(arr) {

    // Declare variable to remember whether 
    // any swaps have been made
    var swap;
    do {
        // Assume no swaps have been made in the beginning
        swap = false;
        
        // Loop through the items in the array
        for (var i=0; i<arr.length-1; i++) {
            
            // Check if the current item is greater than the next
            if (arr[i] > arr[i+1]) {
                
                // Swap the items if true
                var temp = arr[i];
                arr[i] = arr[i+1];
                arr[i+1] = temp;
                
                // Remember that a swap has been made
                swap = true;
            }
        }
        
        // If items swapped, check again
    } while (swap);
}

console.time('BubbleSort');
bubbleSort(bubbleSortArr);
console.timeEnd('BubbleSort');

// Selection Sort

var selectionSortArr = cloneArray(data);

function selectionSort(arr){
    
    
    var len = arr.length,   // Length of array
        min;                // Variable to remember the index of the smallest item

    // Loop through all the items
    for (var i=0; i <len; i++){
        
        //set minimum to this position
        min = i;

        // Check the rest of the array to see if anything is smaller
        for (var j=i+1; j <len; j++){
            if (arr[j] < arr[min]){
                min = j;
            }
        }

        // If the minimum isn't in the position, swap it
        if (i != min){
            var temp = arr[i];
            arr[min] = arr[i];
            arr[i] = temp;
        }
    }
}

console.time('SelectionSort');
bubbleSort(selectionSortArr);
console.timeEnd('SelectionSort');



// Insertion Sort

var insertionSortArr = cloneArray(data);

function insertionSort(arr) {

    var len = arr.length,   // Number of items in the array
        value,              // The value currently being compared
        i,                  // Index into unsorted section
        j;                  // Index into sorted section

    for (i=0; i < len; i++) {

        // Store the current value because it may shift later
        value = arr[i];

        // Whenever the value in the sorted section is greater than the value
        // in the unsorted section, shift all items in the sorted section over
        // by one. This creates space in which to insert the value.
        for (j=i-1; j > -1 && arr[j] > value; j--) {
            arr[j+1] = arr[j];
        }

        arr[j+1] = value;
    }
}


console.time('InsertionSort');
insertionSort(insertionSortArr);
console.timeEnd('InsertionSort');




// Shell Sort

function shellSort (arr) {
    
    var len = arr.length;
    
    for (var h = len; h = parseInt(h / 2);) {
        for (var i = h; i < a.length; i++) {
            var k = a[i];
            for (var j = i; j >= h && k < a[j - h]; j -= h)
                a[j] = a[j - h];
            a[j] = k;
        }
    }
    return a;
}