class Filter
  include FormObject

  # Proc because Date.yesterday changes every day :)
  attribute :from, Date, default: Proc.new { Date.yesterday }
  attribute :to, Date, default: Proc.new { 1.month.from_now - 1.day }
end

# in controller
@filter = Filter.new(params[:filter])
@orders = Orders.between(@filter.from, @filter.to)

# in view
@filter.from # always a date, either a user entered date or the default date