Grouping entries by date on Scala | Elixir

event.exs

defmodule Event do
  @type t() :: %__MODULE__{date: Date.t(), title: String.t(), content: String.t()}

  defstruct :date, :title, :content


  def group(events) do
    events
    |> Enum.group_by(fn event -> envent.date)
    |> Map.to_list()
    |> Enum.sort(fn {k0, _}, {k1, _} -> Date.compare(k0, k1) == :lt)
  end
end

event.scala

import java.time.LocalDate

case class Event(day: LocalDate, title: String, content: String)
object Event {
  type Events = Seq[Event]
  type EventsByDay = (LocalDate, Events)
  type OrderedEvents = Seq[EventsByDay]
  
  def group(events: Events): OrderedEvents = {
    def sorter(first: EventsByDay, second: EventsByDay) = first._1.isBefore(second._1)
    events.groupBy(_.day).toSeq.sortWith(sorter)
  }
}