wcfsetup/install/files/js/WoltLabSuite/Core/NumberUtil.js

   1 /**
   2  * Provides helper functions for Number handling.
   3  *
   4  * @author      Tim Duesterhus
   5  * @copyright   2001-2018 WoltLab GmbH
   6  * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
   7  * @module      WoltLabSuite/Core/NumberUtil
   8  */
   9 define([], function() {
  10         "use strict";
  11
  12         /**
  13          * @exports     WoltLabSuite/Core/NumberUtil
  14          */
  15         var NumberUtil = {
  16                 /**
  17                  * Decimal adjustment of a number.
  18                  *
  19                  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/round
  20                  * @param       {Number}        value   The number.
  21                  * @param       {Integer}       exp     The exponent (the 10 logarithm of the adjustment base).
  22                  * @returns     {Number}        The adjusted value.
  23                  */
  24                 round: function (value, exp) {
  25                         // If the exp is undefined or zero...
  26                         if (typeof exp === 'undefined' || +exp === 0) {
  27                                 return Math.round(value);
  28                         }
  29                         value = +value;
  30                         exp = +exp;
  31
  32                         // If the value is not a number or the exp is not an integer...
  33                         if (isNaN(value) || !(typeof exp === 'number' && exp % 1 === 0)) {
  34                                 return NaN;
  35                         }
  36
  37                         // Shift
  38                         value = value.toString().split('e');
  39                         value = Math.round(+(value[0] + 'e' + (value[1] ? (+value[1] - exp) : -exp)));
  40
  41                         // Shift back
  42                         value = value.toString().split('e');
  43                         return +(value[0] + 'e' + (value[1] ? (+value[1] + exp) : exp));
  44                 }
  45         };
  46
  47         return NumberUtil;
  48 });