Fix pages nav empty state

app/components/lookbook/ui/app/layout/layout.html.erb

@@ -11,21 +11,8 @@
 
   <% if pages.any? || previews.any? %>    
     <%=
-      lb_pane_group("app-body",
-        tag: :div,
-        opts: {
-          orientation: :vertical,
-          sizes: ["280px", "auto"],
-          min_sizes: [200, 200]
-        }) do |body|
-        body.with_pane do
-          lb_pane_group("app-sidebar",
-          opts: {
-            orientation: :horizontal,
-            sizes: nav_panels.take(2).map {"#{100 / nav_panels.size}%"},
-            min_sizes: nav_panels.take(2).map {100}
-          }) do |sidebar|
-
+      lb_pane_group("app-body", tag: :div, opts: body_split) do |body|
+        body.with_pane do lb_pane_group("app-sidebar", opts: sidebar_split) do |sidebar|
             config.ui_nav_panels.each do |name|
               if name.to_sym == :previews
                 sidebar.with_pane("previews-nav") do |pane|

app/components/lookbook/ui/app/layout/layout.rb

@@ -33,8 +33,33 @@ def previews
         Lookbook::Previews
       end
 
+      def body_split
+        {
+          orientation: :vertical,
+          sizes: ["280px", "auto"],
+          min_sizes: [200, 200]
+        }
+      end
+
+      def sidebar_split
+        {
+          orientation: :horizontal,
+          sizes: nav_panels.map { "#{100 / nav_panels.size}%" },
+          min_sizes: nav_panels.map { 100 }
+        }
+      end
+
       def nav_panels
-        config.ui_nav_panels.take(2)
+        config.ui_nav_panels.take(2).filter do |name|
+          case name.to_sym
+          when :previews
+            previews_nav?
+          when :pages
+            pages_nav?
+          else
+            false
+          end
+        end
       end
     end
   end

app/components/lookbook/ui/elements/nav/nav.js

@@ -77,7 +77,11 @@ export default AlpineComponent("nav", (id) => {
     },
 
     get children() {
-      return Array.from(this.$refs.nav.children).map((node) => getData(node));
+      if (this.$refs.nav) {
+        return Array.from(this.$refs.nav.children).map((node) => getData(node));
+      } else {
+        return [];
+      }
     },
   };
 });

app/views/layouts/lookbook/application.html.erb

@@ -6,7 +6,7 @@
           layout.with_header
 
           layout.with_previews_nav(@previews.tree)
-          layout.with_pages_nav(@pages.tree) if @pages.any?
+          layout.with_pages_nav(@pages.tree) if @pages.directory_exists?
 
           layout.with_main do
             tag.main { yield }

lib/lookbook/pages/pages.rb

@@ -83,6 +83,10 @@ def parser
         @parser ||= PagesParser.new(page_paths)
       end
 
+      def directory_exists?
+        page_paths.find { File.exist?(_1) }
+      end
+
       private
 
       def clear_cache