Only localize js when there's a theme

app/views/layouts/application.html.haml

@@ -19,10 +19,11 @@
       = title
 
     = javascript_pack_tag "locales", integrity: true, crossorigin: 'anonymous'
-    - if @theme[:supported_locales].include? I18n.locale.to_s
-      = javascript_pack_tag "locales/#{@theme[:flavour]}/#{I18n.locale}", integrity: true, crossorigin: 'anonymous'
-    - elsif @theme[:supported_locales].include? 'en'
-      = javascript_pack_tag "locales/#{@theme[:flavour]}/en", integrity: true, crossorigin: 'anonymous'
+    - if @theme
+      - if @theme[:supported_locales].include? I18n.locale.to_s
+        = javascript_pack_tag "locales/#{@theme[:flavour]}/#{I18n.locale}", integrity: true, crossorigin: 'anonymous'
+      - elsif @theme[:supported_locales].include? 'en'
+        = javascript_pack_tag "locales/#{@theme[:flavour]}/en", integrity: true, crossorigin: 'anonymous'
     = csrf_meta_tags
 
     = yield :header_tags