From 37e097dd5f987410603d08f2cea066f4978f1e40 Mon Sep 17 00:00:00 2001
From: Filip Skokan <panva.ip@gmail.com>
Date: Mon, 21 Feb 2022 18:45:25 +0100
Subject: [PATCH] Fix NaN .is() return

---
 source/index.ts | 3 ++-
 test/test.ts    | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/source/index.ts b/source/index.ts
index fcd66a0..0d4bc0a 100644
--- a/source/index.ts
+++ b/source/index.ts
@@ -50,6 +50,7 @@ const objectTypeNames = [
 	'FormData',
 	'URLSearchParams',
 	'HTMLElement',
+	'NaN',
 	...typedArrayTypeNames
 ] as const;
 
@@ -110,7 +111,7 @@ function is(value: unknown): TypeName {
 		case 'string':
 			return 'string';
 		case 'number':
-			return 'number';
+			return Number.isNaN(value) ? 'NaN' : 'number';
 		case 'boolean':
 			return 'boolean';
 		case 'function':
diff --git a/test/test.ts b/test/test.ts
index 734fd27..a177e87 100644
--- a/test/test.ts
+++ b/test/test.ts
@@ -446,7 +446,7 @@ const types = new Map<string, Test>([
 			NaN,
 			Number.NaN
 		],
-		typename: 'number',
+		typename: 'NaN',
 		typeDescription: AssertionTypeDescription.nan
 	}],
 	['nullOrUndefined', {