javascript date format dd-mmm-yyyy

let today = new Date()
today.toISOString().split('T')[0]

yourDate.toISOString().split('T')[0]

var date_format = new Date();
    document.write(innerHTML = date_format.getMonth()+'-'+ date_format.getDate()+'-'+date_format.getFullYear());

function formatDate(date) {
  var monthNames = [
    "January", "February", "March",
    "April", "May", "June", "July",
    "August", "September", "October",
    "November", "December"
  ];

  var day = date.getDate();
  var monthIndex = date.getMonth();
  var year = date.getFullYear();

  return day + ' ' + monthNames[monthIndex] + ' ' + year;
}

console.log(formatDate(new Date()));  // show current date-time in console