dtable-utils/lib/number.js

dtable common utils

'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

/**
 * Check whether is number
 * @param {number} number
 * @returns boolean
 */
var isNumber = function isNumber(number) {
  return (number || number === 0) && Object.prototype.toString.call(number) === '[object Number]';
};

/**
 * Check whether the numbers is equal
 * Two numbers are considered equal if the absolute value of their difference is less than 0.00001
 * @param {number} leftNumber
 * @param {number} rightNumber
 * @returns bool
 */
var isNumberEqual = function isNumberEqual(leftNumber, rightNumber) {
  return leftNumber === rightNumber || Math.abs(leftNumber - rightNumber) < 0.00001;
};

/**
 * Math.round(number) with digits
 * @param {number} number
 * @param {number} decimalDigits, default as 0
 * @returns number
 */
var round = function round(number) {
  var decimalDigits = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 0;
  if (decimalDigits === 0) {
    return Math.round(number);
  }
  var offsets = Math.pow(10, decimalDigits);
  var fixedNum = number * offsets;
  if (decimalDigits > 0) {
    // unexpected precision problem
    // e.g. round(8330.845, 2): 8330.845 * 100 = 833084.4999999999
    fixedNum = Number.parseFloat(fixedNum.toFixed(1));
  }
  return Math.round(fixedNum) / offsets;
};

exports.isNumber = isNumber;
exports.isNumberEqual = isNumberEqual;
exports.round = round;