HTMLCalendar date presenter example

my_custom_date_presenter.rb

class MyCustomDatePresenter < HTMLCalendar::DatePresenter
  # Available methods: `date` and `template`
  
  # The only required method
  def html_classes
    if monday?
      ['a-case-of-the-mundays']
    else
      []
    end
  end
  
  private
  
  def monday?
    date.wday == 1
  end
end

some_view.html.erb

<section>
  <%= html_calendar Date.current, presenter: MyCustomDatePresenter %>
</section>