From c6dc925c6cf7eeff9237ee07c55927a7bbc14cb7 Mon Sep 17 00:00:00 2001
From: fecqs <466712071@qq.com>
Date: Mon, 21 Jun 2021 00:33:09 +0800
Subject: [PATCH] Remove duplicate global property check (#2985)

---
 .changeset/witty-bananas-care.md | 5 +++++
 packages/mobx/src/mobx.ts        | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/witty-bananas-care.md

diff --git a/.changeset/witty-bananas-care.md b/.changeset/witty-bananas-care.md
new file mode 100644
index 000000000..6d0d27e5f
--- /dev/null
+++ b/.changeset/witty-bananas-care.md
@@ -0,0 +1,5 @@
+---
+"mobx": patch
+---
+
+Remove duplicate global property check
diff --git a/packages/mobx/src/mobx.ts b/packages/mobx/src/mobx.ts
index c858bc1de..315ee4a63 100644
--- a/packages/mobx/src/mobx.ts
+++ b/packages/mobx/src/mobx.ts
@@ -17,7 +17,7 @@
  */
 import { die } from "./errors"
 import { getGlobal } from "./utils/global"
-;["Symbol", "Map", "Set", "Symbol"].forEach(m => {
+;["Symbol", "Map", "Set"].forEach(m => {
     let g = getGlobal()
     if (typeof g[m] === "undefined") {
         die(`MobX requires global '${m}' to be available or polyfilled`)