From 87a27216d011f1d02ac0fc0aeb3ae0400ecfbd8c Mon Sep 17 00:00:00 2001
From: Liam DeBeasi <liamdebeasi@users.noreply.github.com>
Date: Wed, 11 Mar 2020 10:58:26 -0400
Subject: [PATCH] fix(header): collapsible header now works when navigating
 quickly (#20728)

fixes #20725
---
 core/src/components/header/header.tsx | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/core/src/components/header/header.tsx b/core/src/components/header/header.tsx
index f9f59a4862..17376a2e56 100644
--- a/core/src/components/header/header.tsx
+++ b/core/src/components/header/header.tsx
@@ -129,7 +129,9 @@ export class Header implements ComponentInterface {
       cloneElement('ion-title');
       cloneElement('ion-back-button');
 
-      this.collapsibleMainHeader!.classList.add('header-collapse-main');
+      if (this.collapsibleMainHeader !== undefined) {
+        this.collapsibleMainHeader.classList.add('header-collapse-main');
+      }
     });
 
     this.collapsibleHeaderInitialized = true;