From 0c467d007df5f44cbdc99e9d8bad93769a36e2f4 Mon Sep 17 00:00:00 2001
From: uhyo <uhyo@uhy.ooo>
Date: Mon, 15 Jul 2024 22:33:30 +0900
Subject: [PATCH 1/2] test: add failing test

---
 tests/src/dom.ts | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tests/src/dom.ts b/tests/src/dom.ts
index 59f4d12..c0b9617 100644
--- a/tests/src/dom.ts
+++ b/tests/src/dom.ts
@@ -137,3 +137,14 @@ const test = async (url: string) => {
     }
   }
 }
+
+// NodeListOf
+{
+  // https://github.com/uhyo/better-typescript-lib/issues/43
+  const list: NodeListOf<HTMLDivElement> = document.querySelectorAll("div");
+
+  const item = list.item(100);
+  expectType<HTMLDivElement | null>(item);
+  // @ts-expect-error
+  item.append("a");
+}

From 61a3aad9a97aeae7362522f80942a08ba1cc498a Mon Sep 17 00:00:00 2001
From: uhyo <uhyo@uhy.ooo>
Date: Mon, 15 Jul 2024 22:39:41 +0900
Subject: [PATCH 2/2] fix: improve NodeListOf#item return type

---
 docs/diff/dom.generated.d.ts.md | 11 +++++++++++
 generated/lib.dom.d.ts          |  3 ++-
 lib/lib.dom.d.ts                |  4 ++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/docs/diff/dom.generated.d.ts.md b/docs/diff/dom.generated.d.ts.md
index cb1bb4a..27010ee 100644
--- a/docs/diff/dom.generated.d.ts.md
+++ b/docs/diff/dom.generated.d.ts.md
@@ -151,6 +151,17 @@ Index: dom.generated.d.ts
  }
  
  declare var MIDIOutputMap: {
+@@ -19085,9 +19107,9 @@
+   new (): NodeList;
+ };
+ 
+ interface NodeListOf<TNode extends Node> extends NodeList {
+-  item(index: number): TNode;
++  item(index: number): TNode | null;
+   /**
+    * Performs the specified action for each node in an list.
+    * @param callbackfn  A function that accepts up to three arguments. forEach calls the callbackfn function one time for each element in the list.
+    * @param thisArg  An object to which the this keyword can refer in the callbackfn function. If thisArg is omitted, undefined is used as the this value.
 @@ -21527,11 +21549,11 @@
  };
  
diff --git a/generated/lib.dom.d.ts b/generated/lib.dom.d.ts
index 75031a1..393c6e0 100644
--- a/generated/lib.dom.d.ts
+++ b/generated/lib.dom.d.ts
@@ -19118,7 +19118,7 @@ declare var NodeList: {
 };
 
 interface NodeListOf<TNode extends Node> extends NodeList {
-  item(index: number): TNode;
+  item(index: number): TNode | null;
   /**
    * Performs the specified action for each node in an list.
    * @param callbackfn  A function that accepts up to three arguments. forEach calls the callbackfn function one time for each element in the list.
@@ -19130,6 +19130,7 @@ interface NodeListOf<TNode extends Node> extends NodeList {
   ): void;
   [index: number]: TNode;
 }
+//     item(index: number): TNode;
 
 interface NonDocumentTypeChildNode {
   /**
diff --git a/lib/lib.dom.d.ts b/lib/lib.dom.d.ts
index 29397eb..0c61ce1 100644
--- a/lib/lib.dom.d.ts
+++ b/lib/lib.dom.d.ts
@@ -218,3 +218,7 @@ declare function structuredClone<
   value: T,
   options?: StructuredSerializeOptions,
 ): BetterTypeScriptLibInternals.StructuredClone.StructuredCloneOutput<T>;
+
+interface NodeListOf<TNode extends Node> extends NodeList {
+  item(index: number): TNode | null;
+}