JSFiddle - React, Tailwind, and code Playground

JavaScript

var date = new Date();
alert(date)
function convert(str) {
    var date = new Date(str),
        mnth = ("0" + (date.getMonth() + 1)).slice(-2),
        day = ("0" + date.getDate()).slice(-2);
    return [day, mnth, date.getFullYear()].join("-");
}

var final = convert(date);
alert('date is :' + final)