getFormatedDate()

//@returns String
function getFormatedDate(formating, date) {
  const format = formating || 'DD MMM YYYY';
  const days = ["Sun", "Mon", "Tue", "We", "Thu", "Fri", "Sat"];
  const monthNames = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];

  function parse(str) {
    var time = new Date(date);
    return isNaN(time.getTime()) ? null : time;
  }

  var now;

  if (date instanceof Date) {
    now = date
  } else if (typeof (date) == 'string') {
    const time = parse(date);
    if (!time) {
      now = new Date();
    } else {
      now = time 
    }
  } else {
    now = new Date();
  }

  var year = now.getFullYear();
  var month = now.getMonth() + 1;
  var currDate = now.getDate();
  var monthName = monthNames[now.getMonth()];
  var dayOfWeek = days[now.getDay()];

  var map = {
    YYYY: year,
    YY: year.toString().substr(2, 2),
    MMM: monthName,
    MM: ("0" + month).slice(-2),
    M: month,
    DD: ("0" + currDate).slice(-2),
    D: currDate,
    dddd: dayOfWeek
  };

  return format.replace(/Y+|M+|D+|d+/g, function (str) {
    return map[str];
  });

};

getFormatedDate(); //"01 Feb 2019"
getFormatedDate('YYYY-MM-DD'); //"2019-02-01"
getFormatedDate('YYYY/MM/DD', new Date()); //"2019/02/01"
getFormatedDate('DD MMM YYYY', new Date('2000-02-01')); //"01 Feb 2000"
getFormatedDate('dddd DD MMM YY'); //"Fri 01 Feb 19"
getFormatedDate('dddd DD MMM YYYY'); //"Fri 01 Feb 2019"
getFormatedDate(null, '2010/02/01'); //"01 Feb 2010"
getFormatedDate(null, '2010-02-01'); //"01 Feb 2010"
getFormatedDate('dddd DD MMM YYYY', '02-01-2010'); //"Mon 01 Feb 2010"