JSFiddle - React, Tailwind, and code Playground

JavaScript

var formDate = "05/01/13";
var myDate = new Date(formDate);
var startDate = new Date();

startDate.setMonth(myDate.getMonth() + 1);
startDate.setFullYear(myDate.getFullYear());
var FormattedDate = startDate.getFullYear() + "-" + ((startDate.getMonth() <= 10) ? "0" : "") + startDate.getMonth() + "-01"; // the day is always 01

alert(FormattedDate);