Adding an overlapping dates function to Timex.Interval

[threeaccents]

Timex.Interval Has a handy overlaps? function that helps us know if two intervals overlap each other. I wanted to propose a new function overlapping_dates which creates a new interval with the actual dates that overlap.

Something along the lines of

def overlapping_dates(a, b) do
    if Timex.Interval.overlaps?(a, b) do
      Timex.Interval.new(
        from: latest_date(a.from, b.from),
        until: earliest_date(a.until, b.until)
      )
    else
      []
    end
end

defp earliest_date(a, b) do
  if Timex.before?(a, b) do
    a
  else
    b
  end
end

defp latest_date(a, b) do
  if Timex.before?(a, b) do
    b
  else
    a
  end
end

Though it is trivial to create this function with the helpers Timex already provides I thought it would be handy if it was already part of the library.