insertionsort.js

/*In insertion sort, we divide the initial unsorted array into two parts;		 +
 * sorted part and unsorted part. Initially the sorted part just has one		
 * element (Array of only 1 element is a sorted array). We then pick up		
 * element one by one from unsorted part; insert into the sorted part at		
 * the correct position and expand sorted part one element at a time.		
*/

function insertionSort(unsortedList) {
  var len = unsortedList.length;
  for (var i = 1; i < len; i++) {
    var tmp = unsortedList[i]; //Copy of the current element.
    /*Check through the sorted part and compare with the number in tmp. If large, shift the number*/
    for (var j = i - 1; j >= 0 && (unsortedList[j] > tmp); j--) {
      //Shift the number
      unsortedList[j + 1] = unsortedList[j];
    }
    //Insert the copied number at the correct position
    //in sorted part.
    unsortedList[j + 1] = tmp;
  }
}

var arr = [5, 3, 1, 2, 4, 8, 3, 8];
insertionSort(arr);
console.log(arr);