mout/array/sort.js

Modular Utilities

"use strict";
exports.__esModule = true;
/**
 * Merge sort (http://en.wikipedia.org/wiki/Merge_sort)
 */
function mergeSort(arr, compareFn) {
    if (arr == null) {
        return [];
    }
    else if (arr.length < 2) {
        return arr;
    }
    if (compareFn == null) {
        compareFn = defaultCompare;
    }
    var mid = ~~(arr.length / 2);
    var left = mergeSort(arr.slice(0, mid), compareFn);
    var right = mergeSort(arr.slice(mid, arr.length), compareFn);
    return merge(left, right, compareFn);
}
function defaultCompare(a, b) {
    return a < b ? -1 : a > b ? 1 : 0;
}
function merge(left, right, compareFn) {
    var result = [];
    while (left.length && right.length) {
        if (compareFn(left[0], right[0]) <= 0) {
            // if 0 it should preserve same order (stable)
            result.push(left.shift());
        }
        else {
            result.push(right.shift());
        }
    }
    if (left.length) {
        result.push.apply(result, left);
    }
    if (right.length) {
        result.push.apply(result, right);
    }
    return result;
}
exports["default"] = mergeSort;