diff --git a/wolfy87-eventemitter/wolfy87-eventemitter.d.ts b/wolfy87-eventemitter/wolfy87-eventemitter.d.ts
index 8291c50c11..d9af289d1a 100644
--- a/wolfy87-eventemitter/wolfy87-eventemitter.d.ts
+++ b/wolfy87-eventemitter/wolfy87-eventemitter.d.ts
@@ -405,14 +405,14 @@ declare namespace Wolfy87EventEmitter {
          *
          * Added to mirror the node API.
          */
-        removeAllListeners(event: string): EventEmitter;
+        removeAllListeners(event?: string): EventEmitter;
 
         /**
          * Alias of removeEvent.
          *
          * Added to mirror the node API.
          */
-        removeAllListeners(event: RegExp): EventEmitter;
+        removeAllListeners(event?: RegExp): EventEmitter;
 
         /**
          * Emits an event of your choice.