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array-sort.js
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array-sort.js
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// TODO: use something more complex like timsort?
var floor = Math.floor;
var mergeSort = function (array, comparefn) {
var length = array.length;
var middle = floor(length / 2);
return length < 8 ? insertionSort(array, comparefn) : merge(
mergeSort(array.slice(0, middle), comparefn),
mergeSort(array.slice(middle), comparefn),
comparefn
);
};
var insertionSort = function (array, comparefn) {
var length = array.length;
var i = 1;
var element, j;
while (i < length) {
j = i;
element = array[i];
while (j && comparefn(array[j - 1], element) > 0) {
array[j] = array[--j];
}
if (j !== i++) array[j] = element;
} return array;
};
var merge = function (left, right, comparefn) {
var llength = left.length;
var rlength = right.length;
var lindex = 0;
var rindex = 0;
var result = [];
while (lindex < llength || rindex < rlength) {
if (lindex < llength && rindex < rlength) {
result.push(comparefn(left[lindex], right[rindex]) <= 0 ? left[lindex++] : right[rindex++]);
} else {
result.push(lindex < llength ? left[lindex++] : right[rindex++]);
}
} return result;
};
module.exports = mergeSort;