From: zhufengzhufeng <894918097@qq.com>
Date: Thu, 25 Feb 2021 19:57:35 +0000 (+0800)
Subject: perf(reactivity): only call Set.add if doesn't already have value (#3307)
X-Git-Tag: v3.0.7~8
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9cd988342cfa32ddd9479585244eb317d74c9712;p=thirdparty%2Fvuejs%2Fcore.git

perf(reactivity): only call Set.add if doesn't already have value (#3307)
---

diff --git a/packages/reactivity/src/collectionHandlers.ts b/packages/reactivity/src/collectionHandlers.ts
index e43d3ac59f..149bcb54d2 100644
--- a/packages/reactivity/src/collectionHandlers.ts
+++ b/packages/reactivity/src/collectionHandlers.ts
@@ -76,8 +76,8 @@ function add(this: SetTypes, value: unknown) {
   const target = toRaw(this)
   const proto = getProto(target)
   const hadKey = proto.has.call(target, value)
-  target.add(value)
   if (!hadKey) {
+    target.add(value)
     trigger(target, TriggerOpTypes.ADD, value, value)
   }
   return this