javascript format date yyyy-mm-dd

var today = new Date();
var dd = String(today.getDate()).padStart(2, '0');
var mm = String(today.getMonth() + 1).padStart(2, '0'); //January is 0!
var yyyy = today.getFullYear();

today = mm + '/' + dd + '/' + yyyy;
document.write(today);// `date` is a `Date` object
const formatYmd = date => date.toISOString().slice(0, 10);

// Example
formatYmd(new Date());      // 2020-05-06let today = new Date()
today.toISOString().split('T')[0]yourDate.toISOString().split('T')[0] dateString = '2020-04-03 20:30:55';

function formatDate(dateString)
    {
        var allDate = dateString.split(' ');
        var thisDate = allDate[0].split('-');
        var thisTime = allDate[1].split(':');
        var newDate = [thisDate[2],thisDate[1],thisDate[0] ].join("-");

        var suffix = thisTime[0] >= 12 ? "PM":"AM";
        var hour = thisTime[0] > 12 ? thisTime[0] - 12 : thisTime[0];
        var hour =hour < 10 ? "0" + hour : hour;
        var min = thisTime[1] ;
        var sec = thisTime[2] ;
        var newTime = hour + ':' + min + suffix;

        return newDate + ' ' + newTime;
    }