Using ruby to make a class active via helper method - error in variables

Question

I have been having problems with my coffeescript, so instead I would like to use ruby to make my classes active in the view when clicked. I created a helper method called nav "active", and I have a variable called 'link' in the view that increments up for each step. The idea is to have params[:id] == link , and make the class active when that is the case . However, being newer to rails and ruby I am not sure how to implement this. Any help would be appreciated.

My error

 undefined local variable or method `link' for #<#<Class:0x007fb21e087820>:0x007fb21e53fd18>

My Method in application helper

    def nav_active(options = {})

      return "active" if params[:id] == link

    end

My view

     <% icon= ["icon-link", "icon-bar-chart", "icon-edit", "icon-beaker","icon-link", "icon-bar-chart", "icon-edit", "icon-beaker"] %>
    <% link = 0 %>

    <% @step_list.each_with_index do |step, i| %>

    <% case step.media_type %>
    <% when 'video' %>
     <% link += 1 %>
             <li class="<%= nav_active %>">
               <span class="glow"></span>
               <a href="<%= link %>">
                  <i class='icon-info-sign icon-2x'></i>
                  <span>Video</span>
               </a>
             </li>


<% when 'excel' %>
<% link += 1 %>
        <li class="<%= nav_active %>">
          <span class="glow"></span>
          <a href="<%= link %>">
              <i class="<%= icon[i] %> icon-2x"></i>
              <span>Step <%= i %> </span>
          </a>
        </li>

<% else %>
<% link += 1 %>
        <li class="dark-nav <%= nav_active %> ">
          <span class="glow"></span>
         <a href="<%= link %>">
              <i class="<%= icon[i] %> icon-2x"></i>
              <span>Step <%= i %></span>
          </a>
        </li>

<% end %>   

Answer 1

The helper method nav_active doesn't have access to the local variables in your view. You have to pass that in as an argument.

# Helper
def nav_active(link)
  return "active" if params[:id] == link
end

This helper now accepts an argument named link . Now link will be defined in the helper method.

<% link += 1 %>
<li class="dark-nav <%= nav_active link %> ">

In the view you also must also pass in the current value of link, so the helper method can operate on it.