Easter

The Easter module adds functions to get the date of Easter for a given year. It’s more complicated than you might think!. This module uses the algorithm described here.

Installation

If available in Hex, the package can be installed by adding easter to your list of dependencies in mix.exs:

def deps do
  [
    {:easter, "~> 1.0.0"}
  ]
end

Usage

To get the date of Easter for a given year, use Easter.get_date:

iex> Easter.get_date(2023)
{:ok, ~D[2023-04-09]}

If the year is outside of the Calendar.ISO valid range (-9999 to 9999), an error will be returned:

iex> Easter.get_date(10_000)
{:error, :invalid_date}

There is also Easter.get_date! if you want it to raise an exception instead.