Nodejs Utililty Methods Number Calculate

Number.prototype.separators = function separators(){
  var string = this.toString();
  var x      = string.split('.');
  var x1     = x[0];
  var x2     = x.length > 1 ? '.' + x[1] : '';
  var regex  = /(\d+)(\d{3})/;
  while (regex.test(x1)) {
      x1 = x1.replace(regex, '$1' + ',' + '$2');
  return x1 + x2;
};

'use strict';
const assert = require('assert');
const nan = Symbol('NaN');
const define = Object.defineProperty;
Number.prototype[nan] = Object.create(null);
Number.prototype.set = function (key, value) {
  if (null == this || !isNaN(this)) { return this; }
  const space = this[nan];
  const accessor = {
...

Number.prototype.setInCircle = function setInCircle(lower, upper){
  var zahl = this;
  if (lower === upper){
    return lower;
  if (lower > upper){
    var l = lower;
    lower = upper;
    upper = l;
...

Number.prototype.setInRange = function setInRange(lower, upper){
  if (typeof lower === "undefined" || lower === null){
    lower = this;
  if (typeof upper === "undefined" || upper === null){
    upper = this;
  lower = parseFloat(lower) || 0;
  upper = parseFloat(upper) || 0;
...

'use strict'
Number.prototype.sigFig = function(precision){
    if( !precision ) precision = 2;
    var d = Math.pow(10, precision);
    return ( parseInt( this.valueOf() * d) / d ).toFixed(precision);
};

DEFAULT_DIGIT = 5;
Number.prototype.simEq = function(number, digits) {
  digits = digits == undefined ? DEFAULT_DIGIT : digits;
  var n1 = this.toFixed(digits);
  var n2 = number.toFixed(digits);
  if (n1 == -0)
    n1 = 0;
  if (n2 == -0)
    n2 = 0;
...

Number.prototype.sin = function() {
    return Math.sin(this);

Number.prototype.smallerThan = function(num) {
    return this < num;

Number.prototype.snap = function(resolution) {
  return Math.floor(this / resolution) * resolution;
};

Number.prototype.sqrt = function() {
  return Math.sqrt(this);
};