Nodejs Utililty Methods Date ISO Format

Date.prototype.getISO8601 = function () {
  var month = (this.getMonth() + 1 < 10) ? "0" + this.getMonth() + 1 : this.getMonth() + 1;
  var day = (this.getDate() < 10) ? "0" + this.getDate() : this.getDate();
  var hours = (this.getHours() < 10) ? "0" + this.getHours() : this.getHours();
  var minutes = (this.getMinutes() < 10) ? "0" + this.getMinutes() : this.getMinutes();
  var seconds = (this.getSeconds() < 10) ? "0" + this.getSeconds() : this.getSeconds();
  var offset = this.getTimezoneOffset() / 60;
  return this.getFullYear() + "-" + month + "-" + day + "T" + hours + ":" + minutes + ":" + seconds + "-0" + offset + "00";
};
...

Date.prototype.getISODate = function()
  var mth = this.getMonth() + 1;
  mth = (mth < 10 ? '0' : '') + mth;
  var date = this.getDate();
  date = (date < 10 ? '0' : '') + date;
  return this.getFullYear() + mth + date;
};

Date.prototype.getISODate = function () {
  let month = this.getMonth() + 1;
  if (month < 10) month = '0' + month;
  let day = this.getDate();
  if (day < 10) day = '0' + day;
  return this.getFullYear() + '-' + month + '-' + day;
};

Date.prototype.getISODay = function(){
    return (this.getDay() + 6) % 7;

Date.prototype.getISOWeek = function () {
  var target = new Date(this.valueOf());
  var dayNr = (this.getDay() + 6) % 7;
  target.setDate(target.getDate() - dayNr + 3);
  var firstThursday = target.valueOf();
  target.setMonth(0, 1);
  if (target.getDay() != 4) {
    target.setMonth(0, 1 + ((4 - target.getDay()) + 7) % 7);
  return 1 + Math.ceil((firstThursday - target) / 604800000);

Date.prototype.getISOYear = function () {
  var target  = new Date(this.valueOf());
  target.setDate(target.getDate() - ((this.getDay() + 6) % 7) + 3);
  return target.getFullYear();

Date.prototype.iso8601 = function () {
    return this.getUTCFullYear() + '-' +
        (this.getUTCMonth() + 1).zfill(2) + '-' +
        this.getUTCDate().zfill(2) + 'T' +
        this.getUTCHours().zfill(2) + ':' +
        this.getUTCMinutes().zfill(2) + ':' +
        this.getUTCSeconds().zfill(2) + '.' +
        this.getUTCMilliseconds().zfill(3);
};
...

Date.prototype.isoDate = function() {
  return this.getFullYear() + "-" + (parseInt(this.getMonth())+1) + "-" + this.getDate();

Date.prototype.isoDate = function(){
  var d = this;
  return d.year();
function toJSArray(arr) {
  var len = [arr count],
      res = [];
  while(len--){
    res.push(arr[len]);
...

function f(n) {
    return n < 10 ? '0' + n : n;
Date.prototype.rfc3339 = function() {
    return this.getUTCFullYear()   + '-' +
         f(this.getUTCMonth() + 1) + '-' +
         f(this.getUTCDate())      + 'T' +
         f(this.getUTCHours())     + ':' +
         f(this.getUTCMinutes())   + ':' +
...