Moment JS playground.

by Mi Ku

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.18.1/moment.min.js"></script>
<p id="output"></p>

JavaScript

var dt = moment();
console.log(dt.subtract(1, 'months').format('YYYY-MM-01'));
console.log(dt.endOf('month').format('YYYY-MM-DD'));