How do i write a cleaner date picker input for SimpleForm

The answers here seem a bit out of date if you are using simple_form 2.0.

I’ve been fighting with this for a while and was able to concoct this; it uses inheritance (notice that it is a subclass of StringInput, not Base), supports i18n and adds the datepicker css class in a more clean way, IMHO.

# app/inputs/date_picker_input.rb

class DatePickerInput < SimpleForm::Inputs::StringInput 
  def input                    
    value = input_html_options[:value]
    value ||= object.send(attribute_name) if object.respond_to? attribute_name
    input_html_options[:value] ||= I18n.localize(value) if value.present?
    input_html_classes << "datepicker"

    super # leave StringInput do the real rendering
  end
end

The usage is like above:

<%= f.input :deadline, :as => :date_picker %>

And the javascript remains the same:

$("input.date_picker").datepicker();