scinote-web/app/views/shared/navigation/_breadcrumbs.html.erb

<% if @breadcrumbs_items&.length %>
  <% shortened = @breadcrumbs_items.length > 4 %>

  <% if shortened %>
    <% first_breadcrumb_item = @breadcrumbs_items.shift
      last_breadcrumb_items = @breadcrumbs_items.pop(2) %>
    <%= link_to(first_breadcrumb_item[:label], first_breadcrumb_item[:url],
                  class: "breadcrumbs-link",
                  title: first_breadcrumb_item[:label]) %>
    <span class="delimiter">
      <%= image_tag "icon_small/navigate_next.svg",
                    alt: "navigate next",
                    class: "navigate_next" %>
    </span>
    <span class="breadcrumbs-collapsed-container">
        <span class="show-breadcrumbs" data-toggle="dropdown" title="<%= t('projects.index.breadcrumbs_collapsed') %>">
          •••
          <span class="caret pull-right"></span>
        </span>
        <ul class="dropdown-menu breadcrumbs-dropdown" role="menu">
          <% @breadcrumbs_items.each do |item| %>
            <li>
              <%= link_to(item[:label], item[:url]) %>
            </li>
          <% end %>
        </ul>
    </span>
    <span class="delimiter">
      <%= image_tag "icon_small/navigate_next.svg",
                    alt: "navigate next",
                    class: "navigate_next" %>
    </span>
    <% item = last_breadcrumb_items.first %>
    <%= link_to(item[:label], item[:url],
                class: "breadcrumbs-link",
                title: item[:label]) %>
    <span class="delimiter">
      <%= image_tag "icon_small/navigate_next.svg",
                    alt: "navigate next",
                    class: "navigate_next" %>
    </span>
    <% last_item = last_breadcrumb_items.last %>
    <span class="breadcrumbs-link" title="<%= last_item[:label] %>">
      <%= last_item[:label] %>
    </span>
  <% else %>
    <% template_paths = [/^\/protocols\/\d+$/, /^\/label_templates\/\d+$/] %>
    <% if template_paths.any? { |pattern| request.path.match?(pattern) }%>
     <% last_breadcrumb_items = @breadcrumbs_items.pop(2) %>
    <% else %>
      <% last_item = @breadcrumbs_items.pop %>
    <% end %>

    <% @breadcrumbs_items.each do |item| %>
      <%= link_to(item[:label], item[:url],
                  class: "breadcrumbs-link",
                  title: item[:label]) %>
      <span class="delimiter">
        <img src="<%= asset_path "icon_small/navigate_next.svg"%>"
             alt="navigate next"
             class="navigate_next">
      </span>
    <% end %>

    <% if last_breadcrumb_items %>
      <span class="breadcrumbs-link" style="color: var(--sn-grey);" title="<%= last_breadcrumb_items.first[:label] %>">
        <%= last_breadcrumb_items.first[:label] %>
      </span>
      <span class="delimiter">
        <img src="<%= asset_path "icon_small/navigate_next.svg"%>"
             alt="navigate next"
             class="navigate_next">
      </span>
      <span class="breadcrumbs-link" style="color: var(--sn-grey);" title="<%= last_breadcrumb_items.last[:label] %>">
        <%= last_breadcrumb_items.last[:label] %>
      </span>
    <% end %>
    <% if last_item %>
      <span class="breadcrumbs-link" title="<%= last_item[:label] %>">
        <%= last_item[:label] %>
      </span>
    <% end %>
  <% end %>
<% end %>