Question

I have the following in a controller to enable will_paginate sorting:

def sort_column
  ['name', 'scheduled', 'status'].include?(params[:sort]) ? params[:sort] : "scheduled"
end
def sort_direction
  %w[asc desc].include?(params[:direction]) ? params[:direction] : "desc"
end

These are supplemented by <%= sortable "status", "Status" %> at the top of a table column – clicking this will sort the table.

How can I make some columns default to ASC and some default to DESC?

Rationale

A text-based column works very well under ASC sorting. However, where I have columns with percentages or numbers, sometimes I want to show the best/highest first instead of requiring that the user click twice to get the column sorted the way they want.

Answer 1

Figured it out!

This was the original application_helper.rb code from Railscasts #228 and #240.

def sortable(column, title = nil)
  title ||= column.titleize
  css_class = column == sort_column ? "current #{sort_direction}" : nil
  if direction == "desc"
    direction = column == sort_column && sort_direction == "desc" ? "asc" : "desc"
  else
    direction = column == sort_column && sort_direction == "asc" ? "desc" : "asc"
  end
  link_to title, params.merge(:sort => column, :direction => direction, :page => nil), {:class => css_class}
end

I changed it to (changes on lines 1 and 4):

def sortable(column, title = nil, direction = nil)
  title ||= column.titleize
  css_class = column == sort_column ? "current #{sort_direction}" : nil
  direction ||= column == sort_column && sort_direction == "asc" ? "desc" : "asc"
  link_to title, params.merge(:sort => column, :direction => direction, :page => nil), {:class => css_class}
end

This enables me to now specify a default direction in a column heading:

<div class="col> 
  <%= sortable "priority_number", "Priority", "desc" %> 
</div>