From a074b32dc892c3d0c48bd9cc99012dbb8e5822aa Mon Sep 17 00:00:00 2001
From: greymoth <246701683+greymoth-jp@users.noreply.github.com>
Date: Tue, 30 Jun 2026 08:50:41 +0900
Subject: [PATCH] fix(isByteLength): default min to 0 in the legacy positional
 signature

The backwards-compatibility branch assigned min = arguments[1] with no
default, so omitting min (e.g. isByteLength('abc') or
isByteLength(str, undefined, max)) left min undefined and made the final
len >= min check evaluate as len >= NaN, which is always false. The object
branch already defaults min to 0, the README documents the default as
{ min: 0 }, and the sibling isLength uses arguments[1] || 0 in the same
legacy branch.
---
 src/lib/isByteLength.js | 2 +-
 test/validators.test.js | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/lib/isByteLength.js b/src/lib/isByteLength.js
index 619d7f604..99f0d25ad 100644
--- a/src/lib/isByteLength.js
+++ b/src/lib/isByteLength.js
@@ -9,7 +9,7 @@ export default function isByteLength(str, options) {
     min = options.min || 0;
     max = options.max;
   } else { // backwards compatibility: isByteLength(str, min [, max])
-    min = arguments[1];
+    min = arguments[1] || 0;
     max = arguments[2];
   }
   const len = encodeURI(str).split(/%..|./).length - 1;
diff --git a/test/validators.test.js b/test/validators.test.js
index 9c867efae..610e76605 100644
--- a/test/validators.test.js
+++ b/test/validators.test.js
@@ -5727,6 +5727,12 @@ describe('Validators', () => {
       valid: [''],
       invalid: ['ｇ', 'a'],
     });
+    test({
+      validator: 'isByteLength',
+      args: [undefined, 3],
+      valid: ['abc', 'de', 'ｇ', 'a', ''],
+      invalid: ['abcd', 'ｇｍ'],
+    });
   });