convert mm-dd-yyyy to yyyy-mm-dd in javascript code example

Example 1: javascript convert date to yyyy-mm-dd

// `date` is a `Date` object
const formatYmd = date => date.toISOString().slice(0, 10);

// Example
formatYmd(new Date());      // 2020-05-06

Example 2: javascript format date to dd-mm-yyyy

function pad2(n) {
  return (n < 10 ? '0' : '') + n;
}

var date = new Date();
var month = pad2(date.getMonth()+1);//months (0-11)
var day = pad2(date.getDate());//day (1-31)
var year= date.getFullYear();

var formattedDate =  day+"-"+month+"-"+year;
alert(formattedDate); //28-02-2021

Example 3: javascript convert date from mm/dd/yyyy to yyyymmdd

var yourdate = date.split("/").reverse().join("-");