diff --git a/src/event-manager.ts b/src/event-manager.ts
index 37c79cc..504eccc 100644
--- a/src/event-manager.ts
+++ b/src/event-manager.ts
@@ -250,7 +250,7 @@ export class EventManager {
       opts = handler;
       // If `event` is a map, call `on()` for each entry.
       for (const [eventName, eventHandler] of Object.entries(event)) {
-        this._addEventHandler(eventName, eventHandler!, opts, once, passive);
+        this._addEventHandler(eventName, eventHandler, opts, once, passive);
       }
       return;
     }
diff --git a/src/types.ts b/src/types.ts
index 972a0d1..2f84cbc 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -77,7 +77,9 @@ export type MjolnirEvent =
   | MjolnirWheelEvent
   | MjolnirKeyEvent;
 
-export type MjolnirEventHandler<EventT extends MjolnirEvent = MjolnirEvent> = (event: EventT) => void;
+export type MjolnirEventHandler<EventT extends MjolnirEvent = MjolnirEvent> = (
+  event: EventT
+) => void;
 
 export type MjolnirEventHandlers = {
   [type: string]: MjolnirEventHandler;