Get Yesterday's Date in Elixir

May 7, 2020

I’m working on my second production Elixir system and ran into something that’s a bit of a no-brainer in Ruby. I needed yesterday’s date. I’m working on an integration that needs to send a date range as start date and end date for an API request. That date is always yesterday and today. Basically, give me everything from yesterday until now.

Crazy simple in Ruby. Without Rails: Date.today.prev_day and with Rails: Date.yesterday.

I tried typing that in Elixir. Doesn’t work.

Elixir’s date library is really good, but doesn’t have something for yesterday. And this is rare, but the docs don’t really tell you how to do that.

The solution is to create a date and pipe into the add function with -1 as the parameter.

We can just use utc_today() to get today’s date and use that for our pipe.

Date.utc_today()
|> Date.add(-1)

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