From 28227bc1f7a6ba0f1eaa1f30a406105f88c8ef07 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=8E=9F=E7=BD=AA?= <531362022@qq.com>
Date: Thu, 25 Feb 2021 23:10:23 +0800
Subject: [PATCH] fix: subscribeOnce unsubscribe from undefined object

---
 index.test.ts | 17 +++++++++++++++++
 index.ts      | 12 +++++++++++-
 package.json  |  2 +-
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/index.test.ts b/index.test.ts
index 579a828..043d9b5 100644
--- a/index.test.ts
+++ b/index.test.ts
@@ -236,3 +236,20 @@ it ('can release keeped handle', async () => {
   await sleep(5);
   expect(counter).to.equal(23);
 });
+
+it ('can compose keep and subscribeOnce', async () => {
+  const topic = new Topic<{
+    hello: (num: number) => void;
+  }>();
+
+  let counter = 0;
+
+  const token1 = topic.keep('hello', true, 1);
+  topic.subscribeOnce('hello', (num) => {
+    counter += num;
+  });
+
+  expect(counter).to.equal(1);
+
+  token1.release();
+});
diff --git a/index.ts b/index.ts
index 73f9ec3..b0f216f 100644
--- a/index.ts
+++ b/index.ts
@@ -52,11 +52,21 @@ export class Topic<T extends CommonObject> {
   }
 
   subscribeOnce<K extends keyof T>(name: K, fn: Callback<T, K>): SubscribeToken {
+    let executed = false;
+
     const token = this.subscribe(name, function () {
       fn.apply(null, arguments as unknown as Parameters<T[K]>);
-      token.unsubscribe();
+      if (token) {
+        token.unsubscribe();
+      } else {
+        executed = true;
+      }
     });
 
+    if (executed) {
+      token.unsubscribe();
+    }
+
     return token;
   }
 
diff --git a/package.json b/package.json
index a74913f..49a3bfb 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "topic",
-  "version": "2.1.0",
+  "version": "2.1.2",
   "description": "subscribe and publish your business.",
   "main": "index.cjs.js",
   "module": "index.module.js",