create a preprocess function to handle grouping site structure into chapters by folder instead of doing this logic in templates

Author: ajpiano

Rules

@@ -72,7 +72,41 @@ end
 
 Nanoc3::Filter.register 'CodeBlocks',        :code_blocks
 
+preprocess do
+  @chapterOrder = [
+    "getting-started",
+    "javascript-101",
+    "jquery-basics",
+    "using-jquery-core",
+    "events",
+    "effects",
+    "ajax",
+    "plugins",
+    "performance",
+    "code-organization",
+    "custom-events",
+    "how-to"
+  ]
+
+  @chapters = {}
+  @items.each do |item|
+    item[:chapter] = item[:filename].split('/')[1] 
+    item[:chapter_title] = item[:chapter].gsub(/-/, " ").upcase
+  end
+
+  @groupedItems = @items.group_by {|item| item[:chapter]}
 
+  @chapterOrder.each do |folder|
+    myitems = @groupedItems[ folder ]
+    @chapters [ folder] = {}
+    @chapters[ folder ][ :items ] = @groupedItems[folder].sort_by {|i| i[:section] || 0 }
+    @chapters[ folder ][ :title ] = folder.gsub(/-/, " ").upcase
+    @chapters[ folder ][ :folder ] = folder
+  end
+  
+  @site.config[:chapterOrder] = @chapterOrder
+  @site.config[:chapters] = @chapters
+end
 
 compile '/assets/*' do
   # don’t filter or layout

layouts/chapter_contents.html

@@ -1,9 +1,9 @@
-<% myFolder = @item[:filename].split('/')[1] %>
-<% folderItems = @items.group_by {|item| item[:filename].split('/')[1] } %>
 <ul>
-  <% folderItems[ myFolder ].sort_by {|i| i[:section] || 0 }. each do |i| %>
-    <% if i[:title] && !(i[:filename] =~ /\/dex\.md$/) %>
-    <li <% if item[:filename] == i[:filename] %>class="active"<% end %>><a href="<%= i.path %>"><%= i[:title] %></a></li>
+  <% if @site.config[:chapters][item[:chapter]] %>
+    <% @site.config[:chapters][item[:chapter]][:items].each do|i| %>
+      <% if i[:title] && !(i[:filename] =~ /\/dex\.md$/) %>
+      <li <% if @item[:filename] == i[:filename] %>class="active"<% end %>><a href="<%= i.path %>"><%= i[:title] %></a></li>
+      <% end %>
     <% end %>
   <% end %>
 </ul>

layouts/sidebar.html

@@ -5,24 +5,8 @@ <h2>Categories</h2>
         <hr>
 
         <ul class="nav">
-          <% chapters = [ 
-            "getting-started",
-            "javascript-101",
-            "jquery-basics",
-            "using-jquery-core",
-            "events",
-            "effects",
-            "ajax",
-            "plugins",
-            "performance",
-            "code-organization",
-            "custom-events",
-            "how-to"
-          ] %>
-        <% currentChapter = @item[:filename].split('/')[1] %>
-        <% folders = @items.group_by {|item| item[:filename].split('/')[1] } %>
-        <% chapters.each do |chapter| %>
-          <li <% if chapter == currentChapter %>class="active"<% end %>><a href="/<%= chapter %>"><%= chapter.gsub(/-/, " ").upcase %></a></li>
+        <% @site.config[:chapters].each do |folder, chapter| %>
+        <li <% if folder == @item[:chapter] %>class="active"<% end %>><a href="/<%= folder %>"><%= chapter[:title] %></a></li>
         <% end %>
         </ul>