sort.js

Array.prototype.swap = function(idx1, idx2) {
    if(idx1 >= this.length || idx2 >= this.length) {
        throw new Error("index out of bounds");
    }


    let first = Math.max(idx1, idx2);
    let last = Math.min(idx1, idx2);

    let value = this.splice(first, 1, this[last])[0];

    this.splice(last, 1, value);
};


function bubbleSort(arr) {
    /* very inefficient -- O(n^2) */
    let sorted;
    let times = 0;

    do {
        sorted = true;
        for(var i=0;i<arr.length-1;i++) {

            if(arr[i] > arr[i+1]) {
                arr.swap(i, i+1);
                sorted = false;
            }
        }
        times++;
    } while(!sorted);
    console.log(`bubble sort took ${times} passes`);
    return arr;
}

function selectionSort(arr) {
    let len = arr.length;

    for(var i=0;i<len;i++) {
        let min = i;

        for(var j=i+1;j<len;j++) {
            if(arr[j] < arr[min]) {
                min = j;
            }
        }
        arr.swap(min, i);
    }

    return arr;
}


function insertionSort(arr) {
    let len = arr.length;
    let value, hole;

    for(var i=0;i<len;i++) {
        value = arr[i];

        for(var j=i-1; j> -1 && arr[j] > value;j--) {
            arr[j+1] = arr[j];
        }

        arr[j+1] = value;
    }

    return arr;
}


function quickSort(arr) {
    if (arr.length == 0) return [];

    var left = [], right = [], pivot = arr[arr.length-1];

    for (var i = 0; i < arr.length-1; i++) {
        if(arr[i] < pivot)
            left.push(arr[i]);
        else
            right.push(arr[i]);
    }

    return quickSort(left).concat(pivot, quickSort(right));
}

let list = [1]; //[100,5,35,99,0,9,8,7,1,15,2,6,10,11,-3,5];

console.log(list);

list = quickSort(list);
console.log(list);


function merge(left, right){
    var result  = [],
        il      = 0,
        ir      = 0;

    while (il < left.length || ir < right.length){
        if (left[il] < right[ir]){
            result.push(left[il]);
            il++;
        } else {
            result.push(right[ir]);
            ir++;
        }
    }

    return result;
}

console.log(merge([0,5,2], [2,3,1]));