From 7a663162975a7193f1d77abf9cb0e574e4017d8e Mon Sep 17 00:00:00 2001
From: Jim Broadbent <jim.r.broadbent@gmail.com>
Date: Sun, 20 Oct 2024 20:40:17 +0100
Subject: [PATCH] LibWeb/Storage: Return undefined for non-existent key/index
 access

All tests at now pass: http://wpt.live/webstorage/defineProperty.window.html
---
 Tests/LibWeb/Text/expected/localStorage.txt | 4 ++++
 Tests/LibWeb/Text/input/localStorage.html   | 7 +++++++
 Userland/Libraries/LibWeb/HTML/Storage.cpp  | 4 +++-
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/Tests/LibWeb/Text/expected/localStorage.txt b/Tests/LibWeb/Text/expected/localStorage.txt
index a5ea54de542..37bc923eb44 100644
--- a/Tests/LibWeb/Text/expected/localStorage.txt
+++ b/Tests/LibWeb/Text/expected/localStorage.txt
@@ -1,6 +1,10 @@
+undefined
+null
 value
 value
 other
 other
+undefined
+null
 foo
 foo
diff --git a/Tests/LibWeb/Text/input/localStorage.html b/Tests/LibWeb/Text/input/localStorage.html
index 32715a3ecf2..85fc7b4df29 100644
--- a/Tests/LibWeb/Text/input/localStorage.html
+++ b/Tests/LibWeb/Text/input/localStorage.html
@@ -1,6 +1,10 @@
 <script src="include.js"></script>
 <script>
     test(() => {
+
+        println(localStorage["test"])
+        println(localStorage.getItem("test"))
+
         localStorage["test"] = "value";
         println(localStorage["test"]);
         println(localStorage.getItem("test"));
@@ -10,6 +14,9 @@
         println(localStorage.getItem("test"));
 
         // Ensure indexed properties work
+        println(localStorage[0])
+        println(localStorage.getItem(0))
+
         localStorage[0] = "foo";
         println(localStorage[0]);
         println(localStorage.getItem("0"));
diff --git a/Userland/Libraries/LibWeb/HTML/Storage.cpp b/Userland/Libraries/LibWeb/HTML/Storage.cpp
index fd884f8f1aa..8c18f29f6da 100644
--- a/Userland/Libraries/LibWeb/HTML/Storage.cpp
+++ b/Userland/Libraries/LibWeb/HTML/Storage.cpp
@@ -182,7 +182,9 @@ JS::Value Storage::named_item_value(FlyString const& name) const
 {
     auto value = get_item(name);
     if (!value.has_value())
-        return JS::js_null();
+        // AD-HOC: Spec leaves open to a description at: https://html.spec.whatwg.org/multipage/webstorage.html#the-storage-interface
+        // However correct behavior expected here: https://github.com/whatwg/html/issues/8684
+        return JS::js_undefined();
     return JS::PrimitiveString::create(vm(), value.release_value());
 }