// insertion-sort

'use strict';

module.exports = function (array, compare) {

// Not an array, empty or array of 1 is already sorted

if (!Array.isArray(array) || array.length < 2) {

return array;

}

// Swap elements of the array

var swap = function (array, first, second) {

var temp = array[first];

array[first] = array[second];

array[second] = temp;

return array;

};

// Create a compare function if one is not passed in

if (typeof compare !== 'function') {

compare = function (a, b) {

return a > b ? 1 : -1;

};

}

var i, j;

/*

* Assume first element is sorted

* Add first unsorted element to sorted array

* Compare new element in sorted array with previous elements

* to determine correct destination index in sorted array

*/

for (i = 1; i < array.length; i++) {

j = i;

// Make sure we don't walk off the array and compare until sorted

while ((j - 1) >= 0 && compare(array[j], array[j - 1]) < 0) {

swap(array, j, j-1);

j--;

}

}

return array;

};