JSFiddle - React, Tailwind, and code Playground

JavaScript

var date1 = new Date("1/1/2014"),
    date2 = new Date("1/1/2013");

function subtractDate(date1, date2) {
    subtracted = new Date(+date1 - +date2);
    return subtracted;
}

console.log(subtractDate(date1, date2));