From 0ec580475872d700b7ba650b0093cb531c0a425f Mon Sep 17 00:00:00 2001
From: morning <chenxuanincn@gmail.com>
Date: Fri, 13 Nov 2020 15:14:15 +0800
Subject: [PATCH] feat: avoid install installed plugin

---
 src/index.js | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/index.js b/src/index.js
index 439a392f9..6bf5ee656 100644
--- a/src/index.js
+++ b/src/index.js
@@ -387,7 +387,12 @@ dayjs.prototype = proto;
 })
 
 dayjs.extend = (plugin, option) => {
+  if (plugin.installed) {
+    return dayjs
+  }
+
   plugin(option, Dayjs, dayjs)
+  plugin.installed = true
   return dayjs
 }