diff --git a/app/assets/javascripts/alert.js b/app/assets/javascripts/alert.js
index 53b21d7..9523597 100644
--- a/app/assets/javascripts/alert.js
+++ b/app/assets/javascripts/alert.js
@@ -33,9 +33,7 @@
       methods: {
         fetchAlertsData: function() {
           return new Promise(function(resolve, reject) {
-            $.getJSON(POLLING_URL, function(data){
-              resolve(data);
-            }).fail(reject);
+            $.getJSON(POLLING_URL, resolve).fail(reject);
           });
         }
       }
diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index d505276..990dff9 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -23,23 +23,23 @@ class ApplicationController < ActionController::Base
   end
 
   def installing_gem?
-    installing_gems.length > 0
+    installing_gems.present?
   end
 
   def installing_gems
     Plugin::WORKING.find_all do |data|
       data[:type] == :install && data[:state] == :running
-    end.map{|data| data[:plugin]} || []
+    end.map{|data| data[:plugin]}
   end
 
   def uninstalling_gem?
-    uninstalling_gems.length > 0
+    uninstalling_gems.present?
   end
 
   def uninstalling_gems
     Plugin::WORKING.find_all do |data|
       data[:type] == :uninstall && data[:state] == :running
-    end.map{|data| data[:plugin]} || []
+    end.map{|data| data[:plugin]}
   end
 
   private