Adding prompt to select_tag

Rails's select method is pretty advanced. You can pass in all sorts of funky options to format your selector nicely, including :include_blank => true and the related :prompt => 'Pick one or else!'

select_tag, however, seems to have fallen behind in the usefulness-stakes and implements neither of the above... even though it does an extremely similar thing.

So here's a quick-hack function you can drop into ApplicationHelper to implement that functionality for you.

  # override select_tag to allow the ":include_blank => true" and ":prompt => 'whatever'" options
  include ActionView::Helpers::FormTagHelper
  alias_method :orig_select_tag, :select_tag
  def select_tag(name, select_options, options = {}, html_options = {})
    # remove the options that select_tag doesn't currently recognise
    include_blank = options.has_key?(:include_blank) && options.delete(:include_blank)
    prompt = options.has_key?(:prompt) && options.delete(:prompt)
    # if we didn't pass either - continue on as before
    return orig_select_tag(name, select_options, options.merge(html_options)) unless include_blank || prompt

    # otherwise, add them in ourselves
    prompt_option  = "<option value=\"\">" # to make sure it shows up as nil
    prompt_option += (prompt ? prompt.to_s : "") + "</option>"
    new_select_options = prompt_option + select_options
    orig_select_tag(name, new_select_options, options.merge(html_options))
  end