From 6d46b691cd64b3912c016844ba706b38de77ced0 Mon Sep 17 00:00:00 2001
From: Mario Pabon <restlessbit@users.noreply.github.com>
Date: Mon, 10 Dec 2018 12:10:30 -0500
Subject: [PATCH] fix: prevent calling setState in TransitionGroup if it has
 been unmounted (#435)

---
 src/TransitionGroup.js | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/TransitionGroup.js b/src/TransitionGroup.js
index 919c5e92..1e1e0fa9 100644
--- a/src/TransitionGroup.js
+++ b/src/TransitionGroup.js
@@ -104,6 +104,11 @@ class TransitionGroup extends React.Component {
 
   componentDidMount() {
     this.appeared = true
+    this.mounted = true
+  }
+
+  componentWillUnmount() {
+    this.mounted = false
   }
 
   static getDerivedStateFromProps(
@@ -127,12 +132,14 @@ class TransitionGroup extends React.Component {
       child.props.onExited(node)
     }
 
-    this.setState(state => {
-      let children = { ...state.children }
+    if (this.mounted) {
+      this.setState(state => {
+        let children = { ...state.children }
 
-      delete children[child.key]
-      return { children }
-    })
+        delete children[child.key]
+        return { children }
+      })
+    }
   }
 
   render() {