Date countdown without javascript

Question

I have a content type that when created is "due" 10 days later. I'm looking to create a field that has a numerical value of the days left before it is due and if it is past due, show a negative integer value. This field will be used for Views sorting, so I can't use javascript counters like the countdown module.

Can anyone help on how to do this?

Answer 1

I would start with a standard date field and then create a new field formatter that displays the date in the way you describe.

Before you dig in I would look around for someone that has already done this, it seems like a pretty common use case for working with a date.