From ac46b5400d7ae00fcc001467ddfda5f9624c4ce8 Mon Sep 17 00:00:00 2001
From: Sindre Sorhus <sindresorhus@gmail.com>
Date: Wed, 8 Apr 2026 14:54:37 +0700
Subject: [PATCH] Fix `isInRange` silently returning false when range contains
 `NaN`

---
 source/index.ts | 4 ++++
 test/test.ts    | 8 ++++++++
 2 files changed, 12 insertions(+)

diff --git a/source/index.ts b/source/index.ts
index 3131d02..9bfe2e6 100644
--- a/source/index.ts
+++ b/source/index.ts
@@ -599,6 +599,10 @@ export function isInRange(value: number, range: number | [number, number]): valu
 	}
 
 	if (isArray(range) && range.length === 2) {
+		if (Number.isNaN(range[0]) || Number.isNaN(range[1])) {
+			throw new TypeError(`Invalid range: ${JSON.stringify(range)}`);
+		}
+
 		return value >= Math.min(...range) && value <= Math.max(...range);
 	}
 
diff --git a/test/test.ts b/test/test.ts
index 31e661b..750858e 100644
--- a/test/test.ts
+++ b/test/test.ts
@@ -1274,6 +1274,14 @@ test('is.inRange', () => {
 		is.inRange(0, [1, 2, 3]);
 	});
 
+	assert.throws(() => {
+		is.inRange(5, [NaN, 10]);
+	}, TypeError);
+
+	assert.throws(() => {
+		is.inRange(5, [0, NaN]);
+	}, TypeError);
+
 	assert.doesNotThrow(() => {
 		isAssert.inRange(x, [0, 5]);
 	});