Moment.js Sandbox

HTML

<script src="//cdnjs.cloudflare.com/ajax/libs/moment.js/2.2.1/moment.min.js"></script>

JavaScript

let endTime = "23:07";
let startTime = "22:07";
var diff = moment.utc(moment.duration(endTime) - moment.duration(startTime)).format('HH:mm')
console.log(diff);