javascript function to calculate difference in two dates, return short format, rounding to single unit

Question

I struggled with wording the title, but basically I want a function where I can provide two dates and it would output something like: "2w" if the result was 15 days or "1y" if it was 13 months or "1m" if it was 4 or 5 weeks. Preferably down to the hour... but 1 day minimum.

I found a similar SO question but it's for PHP and isn't complete anyway: How to calculate the difference between two days as a formatted string?

Answer 1

There are a number of javascript date libraries out there that will do all you want and more. Here is an example using XDate

<div id="result"><div/>

var now = new XDate();

var then = new XDate(2013, 04, 01, 0, 0, 0, 0);

document.getElementById("result").textContent = now.diffWeeks(then).toFixed(1) + " Weeks";

Available of jsfiddle

Here is with Moments.js

<div id="result"><div/>

var then = moment("Dec 25, 1995");

document.getElementById("result").textContent = moment(then, "YYYYMMDD").fromNow();

also vailable on jsfiddle