From 8b35db3fc162ef24bc154f09669828fafb1e110d Mon Sep 17 00:00:00 2001
From: Alf Eaton <75253002+aeaton-overleaf@users.noreply.github.com>
Date: Wed, 21 Apr 2021 10:57:29 +0100
Subject: [PATCH] Merge pull request #3928 from overleaf/ae-safari-error

Check for existence of elements before attaching event listeners in SafariScrollPatcher

GitOrigin-RevId: 67338581878871cf67fc050dc233da93f14753a7
---
 .../web/frontend/js/ide/SafariScrollPatcher.js    | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/services/web/frontend/js/ide/SafariScrollPatcher.js b/services/web/frontend/js/ide/SafariScrollPatcher.js
index 6768ac236a..b75d990872 100644
--- a/services/web/frontend/js/ide/SafariScrollPatcher.js
+++ b/services/web/frontend/js/ide/SafariScrollPatcher.js
@@ -76,13 +76,14 @@ export default SafariScrollPatcher = class SafariScrollPatcher {
       this.aceDiv = document.querySelector('.ace_content') // Also the editor.
 
       // Set hover-related listeners.
-      this.pdfDiv.addEventListener('mouseleave', this.handlePdfDivMouseLeave)
-      this.pdfDiv.addEventListener('mouseenter', this.handlePdfDivMouseEnter)
-      this.aceDiv.addEventListener('mouseleave', this.handleAceDivMouseLeave)
-      return this.aceDiv.addEventListener(
-        'mouseenter',
-        this.handleAceDivMouseEnter
-      )
+      if (this.pdfDiv != null) {
+        this.pdfDiv.addEventListener('mouseleave', this.handlePdfDivMouseLeave)
+        this.pdfDiv.addEventListener('mouseenter', this.handlePdfDivMouseEnter)
+      }
+      if (this.aceDiv != null) {
+        this.aceDiv.addEventListener('mouseleave', this.handleAceDivMouseLeave)
+        this.aceDiv.addEventListener('mouseenter', this.handleAceDivMouseEnter)
+      }
     }
 
     // Handler for wheel events on the PDF.