_categories.html.erb

<% branch_path_name = "#{params[:action]}_posts_path" %>

<div class="col-sm-12">
  <ul class="categories-list">
    <%= render all_categories_button_partial_path, 
               branch_path_name: branch_path_name %>
    <% @categories.each do |category| %>
      <li class="category-item">
        <%= link_to category.name, 
                    send(branch_path_name, category: category.name), 
                    :class => ("selected-item" if params[:category] == category.name) %>
      </li>
    <% end %>
  </ul>
</div><!-- col-sm-12 -->