opts can be undefined and throw error

Gemfile.lock

@@ -332,8 +332,5 @@ DEPENDENCIES
   uglifier
   uservoice-ruby
 
-RUBY VERSION
-   ruby 2.3.0p0
-
 BUNDLED WITH
    1.12.5

frontend/src/Metamaps/TopicCard.js

@@ -40,7 +40,7 @@ const TopicCard = {
    */
   showCard: function (node, opts) {
     var self = TopicCard
-
+    if (!opts) opts = {}
     var topic = node.getData('topic')
 
     self.openTopicCard = topic