diff --git a/JavaScript/8-methods.js b/JavaScript/8-methods.js
index eaa478d..3061d5b 100644
--- a/JavaScript/8-methods.js
+++ b/JavaScript/8-methods.js
@@ -38,7 +38,7 @@ const emitter = () => {
     },
     listeners: (name) => {
       const event = events[name];
-      return event.slice();
+      return event ? event.slice() : [];
     },
     names: () => Object.keys(events)
   };
diff --git a/JavaScript/a-prod.js b/JavaScript/a-prod.js
index 7a2a4c1..d16fdbb 100644
--- a/JavaScript/a-prod.js
+++ b/JavaScript/a-prod.js
@@ -49,7 +49,7 @@ const emitter = () => {
     },
     listeners: (name) => {
       const event = events.get(name);
-      return event.slice();
+      return event ? event.slice() : [];
     },
     names: () => [...events.keys()]
   };