From 18b687e46a68854c35fc2f0e75f101d59b0804cd Mon Sep 17 00:00:00 2001
From: sealice <15445553+sealice@users.noreply.github.com>
Date: Mon, 4 Jan 2021 10:02:11 +0800
Subject: [PATCH] Add new features of emitter.off. Fixes #123

If mitt.off provides only the event, remove all listeners for that event.
---
 src/index.ts | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index ae85607..394a5ed 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -18,7 +18,7 @@ export interface Emitter {
 	on<T = any>(type: EventType, handler: Handler<T>): void;
 	on(type: '*', handler: WildcardHandler): void;
 
-	off<T = any>(type: EventType, handler: Handler<T>): void;
+	off<T = any>(type: EventType, handler?: Handler<T>): void;
 	off(type: '*', handler: WildcardHandler): void;
 
 	emit<T = any>(type: EventType, event?: T): void;
@@ -60,10 +60,14 @@ export default function mitt(all?: EventHandlerMap): Emitter {
 		 * @param {Function} handler Handler function to remove
 		 * @memberOf mitt
 		 */
-		off<T = any>(type: EventType, handler: Handler<T>) {
+		off<T = any>(type: EventType, handler?: Handler<T>) {
 			const handlers = all.get(type);
 			if (handlers) {
+		            if(handler){
 				handlers.splice(handlers.indexOf(handler) >>> 0, 1);
+		            } else {
+		                all.delete(type);
+		            }
 			}
 		},