an.hour.ago is a small utility which enables wonderfully expressive date and time manipulation in JavaScript.

Before we proceed, let me be clear that if supporting Internet Explorer is a requirement, you'd best turn back now. If, on the other hand, you're writing server-side JavaScript (or CoffeeScript) and desire an elegant means of expressing relative dates and times, read on!

Let's start with a simple example...


This produces a Date instance representing 72 hours before the present. Neat. What about the future?


Easy! Note the use of minute rather than minutes. The two are synonymous; singular and plural properties exist for each of the supported units.

Decimals? You betcha:


In fact, they read very nicely since they don't require an awkward double dot.

What about dates relative to other points in time?

var tomorrow  =
var halloween = new Date("31 October 2011")
var christmas = new Date("25 December 2011")




from and after are synonymous; use whichever reads better.

This is pleasing, you may be thinking, but I'd never say “one week from tomorrow” – it sounds a bit stiff.

Well, if you must...

var a  = NaturalDate.a
var an =




Oh, and I should mention, you can add NaturalDate instances using the and method:



Can you help me with date comparison? To determine whether an event occurred more than a week ago I have to ask whether its numeric representation is less than that of "a week ago". It makes my head hurt.

Perhaps you find this more natural?


A practical example:

var user_registered = db.get(id).registration_date

if (user_registered.less_than(15..minutes).ago) $("#tips").show()

before/after can follow less_than/more_than:

if (costume_returned.more_than(2..days).after(halloween)) apply_late_fee()

There's also an either_side_of method which does what it says on the tin:

var unfortunate = birthday.less_than(3..days).either_side_of(christmas)

That just about covers it.

Running the test suite

npm install
npm test

One last thing...

To be clear, an.hour.ago fiddles with Date.prototype and Number.prototype. Two properties are added to Date.prototype:

  • less_than
  • more_than

The following properties are added to Number.prototype:

  • day
  • days
  • hour
  • hours
  • millisecond
  • milliseconds
  • minute
  • minutes
  • second
  • seconds
  • week
  • weeks

Each of these properties has a "getter" which returns a NaturalDate object. The rest of the methods (before, after/from, and and) are to be found on NaturalDate.prototype.

NaturalDate is the only property added to the global object.