JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://davis-design.de/marktadresse/layout/js/moment.js"></script>

JavaScript

startdate = "2017-11-29T23:59:59.999Z";
var new_date = moment(startdate).format('DD/MM/YYYY');

alert(new_date);

startdate = "2017-11-29";
new_date = moment(startdate).format('DD/MM/YYYY');

alert(new_date);