JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://momentjs.com/downloads/moment.min.js"></script>

JavaScript

var ms = 12345;

var utcdoy = function(ms){
    return (
        parseInt(moment.utc(ms).format("DDD")) - 1 + " " +
        moment.utc(ms).format("HH:mm:ss.SSS")
    );
}

alert(utcdoy(12345));