Safe navigate when iterating over the documents ivar in various export views

Author: jkeck

app/views/catalog/_citation.html.erb

@@ -5,7 +5,7 @@
   </button>
 </div>
 <div class="modal-body">
-  <% @documents.each do |document| %>
+  <% @documents&.each do |document| %>
     <h1 class="modal-title"><%= document_heading(document) %></h1>
 
     <% if document.respond_to?(:export_as_mla_citation_txt) %>

app/views/catalog/_email_form.html.erb

@@ -24,7 +24,7 @@
       </div>
     </div>
 
-    <% @documents.each do |doc| %>
+    <% @documents&.each do |doc| %>
       <%=hidden_field_tag "id[]", doc.id %>
     <% end %>
     <%- if params[:sort] -%>

app/views/catalog/_sms_form.html.erb

@@ -22,7 +22,7 @@
       </div>
 
     </div>
-    <% @documents.each do |doc| %>
+    <% @documents&.each do |doc| %>
        <%=hidden_field_tag "id[]", doc.id %>
     <% end %>
 </div>