From bbfe5f81cbd938d4ca2f23088b1ff332cd82e7aa Mon Sep 17 00:00:00 2001
From: toasted-nutbread <toasted-nutbread@users.noreply.github.com>
Date: Mon, 24 Aug 2020 18:26:04 -0400
Subject: [PATCH] Fix sessionStorage not being supported when cookies are
 disabled (#756)

* Fix sessionStorage not being supported when cookies are disabled

* Update comment
---
 ext/mixed/js/display.js | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/ext/mixed/js/display.js b/ext/mixed/js/display.js
index 6e41a190..4a8605e5 100644
--- a/ext/mixed/js/display.js
+++ b/ext/mixed/js/display.js
@@ -1319,17 +1319,26 @@ class Display extends EventDispatcher {
     }
 
     _updateMode() {
-        const mode = sessionStorage.getItem('mode');
+        let mode = null;
+        try {
+            mode = sessionStorage.getItem('mode');
+        } catch (e) {
+            // Browsers can throw a SecurityError when cookie blocking is enabled.
+        }
         this._setMode(mode, false);
     }
 
     _setMode(mode, save) {
         if (mode === this._mode) { return; }
         if (save) {
-            if (mode === null) {
-                sessionStorage.removeItem('mode');
-            } else {
-                sessionStorage.setItem('mode', mode);
+            try {
+                if (mode === null) {
+                    sessionStorage.removeItem('mode');
+                } else {
+                    sessionStorage.setItem('mode', mode);
+                }
+            } catch (e) {
+                // Browsers can throw a SecurityError when cookie blocking is enabled.
             }
         }
         this._mode = mode;