Nodejs Utililty Methods Date Format

Date.prototype.formatMMDDYYYY = function () {
   return this.getMonth() + 1 + '/' + this.getDate() + '/' + this.getFullYear();
};

Date.prototype.formatStr=function(){
    function convert2fixed(str){
        var _num=Number(str);
        if(!isNaN(str)){
            if(_num<10){
                return '0'+_num;
            }else
            return _num;
...

function formatTime(date) {
  if(date instanceof Date === false) {
    return console.log('err');
  var hour = pad(date.getHours());
  var minute = pad(date.getMinutes());
  return [hour, minute].join(':');

Date.prototype.formatTime = function (pattern) {
    pattern = pattern.replace(/hh/g, this.getHours().toString().padLeft(2, 0));
    pattern = pattern.replace(/mm/g, this.getMinutes().toString().padLeft(2, 0));
    return pattern;
};

Date.prototype.formateDate = function() {
  var mm = this.getMonth() + 1;
  var dd = this.getDate();
  return [this.getFullYear(), !mm[1] && '0', mm, !dd[1] && '0', dd].join('');
};

Date.prototype.format = function f(format) {
    const o = {
        'M+': this.getMonth() + 1,
        'd+': this.getDate(),
        'h+': this.getHours(),
        'm+': this.getMinutes(),
        's+': this.getSeconds(),
        'q+': Math.floor((this.getMonth() + 3) / 3),
        S: this.getMilliseconds(),
...

Date.prototype.formattedDate = function(){
  var dd   = (this.getDate() < 10 ? "0" : "") + this.getDate();
  var mm   = (this.getMonth() + 1 < 10 ? "0" : "") + (this.getMonth() + 1);
  var yyyy = this.getFullYear();
  return yyyy + '/' + mm + '/' + dd;

Date.prototype.formattedDate = function (delemeter) {
  var dm = delemeter;
  if (!dm) dm = '';
  var yyyy = this.getFullYear().toString();
  var mm = (this.getMonth() + 1).toString();
  var dd = this.getDate().toString();
  if (mm < 10) mm = "0" + mm;
  if (dd < 10) dd = "0" + dd;
  return "" + yyyy + dm + mm + dm + dd;
...

Date.prototype.formattedTime = function(){
  var hours   = (this.getHours() < 10 ? "0" : "")   + this.getHours();
  var minutes = (this.getMinutes() < 10 ? "0" : "") + this.getMinutes();
  var seconds = (this.getSeconds() < 10 ? "0" : "") + this.getSeconds();
  return hours + ':' + minutes + ':' + seconds

Date.prototype.fromISO= function(s){
  var day, tz, rx=  /^(\d{4}\-\d\d\-\d\d([tT][\d:\.]*)?)([zZ]|([+\-])(\d\d):(\d\d))?$/, p= rx.exec(s) || [];
  if(p[1]){
    day= p[1].split(/\D/).map(function(itm){
      return parseInt(itm, 10) || 0;
    });
    day[1]-= 1;
    day= new Date(Date.UTC.apply(Date, day));
    if(!day.getDate()) return NaN;
...