From 8286066372b42ce7d5af950b8e885c8ae1937c16 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Wed, 12 Jan 2022 17:04:51 +0100
Subject: [PATCH] Prevent run-time errors in `BaseViewer` when it's falling
 back to `SimpleLinkService` (issue 14442, PR 14295 follow-up)

---
 web/base_viewer.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/web/base_viewer.js b/web/base_viewer.js
index f73d876ba..0492241c3 100644
--- a/web/base_viewer.js
+++ b/web/base_viewer.js
@@ -1541,7 +1541,7 @@ class BaseViewer {
       if (!pageView.pdfPage) {
         pageView.setPdfPage(pdfPage);
       }
-      if (!this.linkService._cachedPageNumber(pdfPage.ref)) {
+      if (!this.linkService._cachedPageNumber?.(pdfPage.ref)) {
         this.linkService.cachePageRef(pageView.id, pdfPage.ref);
       }
       return pdfPage;