diff --git a/ui/lib/core/addon/helpers/message-types.js b/ui/lib/core/addon/helpers/message-types.js
index cf89b1f0e..f1f6018a9 100644
--- a/ui/lib/core/addon/helpers/message-types.js
+++ b/ui/lib/core/addon/helpers/message-types.js
@@ -35,7 +35,7 @@ export const MESSAGE_TYPES = {
 };
 
 export function messageTypes([type]) {
-  if (!([type] in MESSAGE_TYPES)) {
+  if (!(type in MESSAGE_TYPES)) {
     assert('type is not a valid message type.');
   }
   return MESSAGE_TYPES[type];