Refactor for https://robots.thoughtbot.com/using-yieldself-for-composable-activerecord-relations

query_object.rb

def call
  scope = base_relation.joins(:care_periods)

  if params.care_provider_id.present?
    scope = scope
      .where(care_periods: { care_provider_id: params.care_provider_id })
  end

  if params.hospital_id.present?
    scope = scope
      .where(care_periods: { hospital_id: params.hospital_id })
  end

  if params.discharge_period.present?
    scope = scope.joins(:hospital_visit)
      .where(hospital_visits: { end_on: params.discharge_period }
  end

  scope
end