rails 3 undefined method `+' for nil:NilClass

Question

i am making a sorting table in rails and getting an error. This is my index.html.erb

<table>  
  <tr>  
    <th><%= sortable "name" %></th>
    <th><%= sortable "city" %></th>
    <th><%= sortable "country" %></th>
    <th><%= sortable "street_address" %></th>
    <th><%= sortable "sector" %></th>
    <th><%= sortable "telephone" %></th>
    <th><%= sortable "fax" %></th>
  </tr>  

  <% for company in @companies %>  
  <tr>  
    <td><%= company.name %></td>
    <td><%= company.city %></td>
    <td><%= company.country %></td>
    <td><%= company.street_address %></td>
    <td><%= company.sector %></td>
    <td><%= company.telephone %></td>
    <td><%= company.fax %></td>
  </tr>
  <% end %>
</table>

This is my companies_controller

def index
  @companies = Company.order(params[:sort] + ' ' + params[:direction])
end

This is my application_helper

def sortable(column, title = nil)  
    title ||= column.titleize  
    direction = (column == params[:sort] && params[:direction] == "asc") ? "desc" : "asc"  
    link_to title, :sort => column, :direction => direction  
end

And the error is:

NoMethodError in CompaniesController#index

undefined method `+' for nil:NilClass
app/controllers/companies_controller.rb:21:in `index'

What is the problem and how can i fix it?

Answer 1

Your params[:sort] returns nil.

You can fix it for example by checking your params:

@companies = Company.scoped
if params[:sort].present? && params[:direction].present?
  @companies = @companies.order(params[:sort] + ' ' + params[:direction])
end

Answer 2

Your params[:sort] is nil, so you'd better do:

def index
  @companies = params[:sort].blank? || params[:direction].blank? ? Company.scoped : Company.order(params[:sort] + ' ' + params[:direction])
end