Refactor advanced search component a bit

app/components/advanced_search_component.rb

@@ -10,7 +10,7 @@ def initialize(search_path)
 
     def official_level_search_options
       options_for_select((1..5).map { |i| [setting["official_level_#{i}_name"], i] },
-                         params[:advanced_search].try(:[], :official_level))
+                         search_params[:official_level])
     end
 
     def date_range_options
@@ -24,10 +24,14 @@ def date_range_options
     end
 
     def selected_date_range
-      custom_date_range? ? "custom" : params[:advanced_search].try(:[], :date_min)
+      custom_date_range? ? "custom" : search_params[:date_min]
     end
 
     def custom_date_range?
-      params[:advanced_search].try(:[], :date_max).present?
+      search_params[:date_max].present?
+    end
+
+    def search_params
+      params[:advanced_search] || {}
     end
 end