From 47415dc46aaa27ad491393af87978e873cb9fbb1 Mon Sep 17 00:00:00 2001
From: Sindre Sorhus <sindresorhus@gmail.com>
Date: Wed, 8 Apr 2026 05:21:23 +0700
Subject: [PATCH] Fix `isNumericString` incorrectly accepting strings with
 surrounding whitespace

---
 source/index.ts | 2 +-
 test/test.ts    | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/source/index.ts b/source/index.ts
index 8a510dd..3131d02 100644
--- a/source/index.ts
+++ b/source/index.ts
@@ -688,7 +688,7 @@ export function isNumber(value: unknown): value is number {
 }
 
 export function isNumericString(value: unknown): value is `${number}` {
-	return isString(value) && !isEmptyStringOrWhitespace(value) && !Number.isNaN(Number(value));
+	return isString(value) && !isEmptyStringOrWhitespace(value) && value === value.trim() && !Number.isNaN(Number(value));
 }
 
 // eslint-disable-next-line @typescript-eslint/no-restricted-types
diff --git a/test/test.ts b/test/test.ts
index c789fdb..31e661b 100644
--- a/test/test.ts
+++ b/test/test.ts
@@ -587,6 +587,10 @@ test('is.numericString supplemental', () => {
 	assert.strictEqual(is.numericString(' '), false);
 	assert.strictEqual(is.numericString(' \t\t\n'), false);
 	assert.strictEqual(is.numericString(1), false);
+	assert.strictEqual(is.numericString(' 5'), false);
+	assert.strictEqual(is.numericString('5 '), false);
+	assert.strictEqual(is.numericString(' 5 '), false);
+	assert.strictEqual(is.numericString('\t3'), false);
 	assert.throws(() => {
 		isAssert.numericString('');
 	});