From ba3c7ae1b2f72dbb02ed421e4574d8fe57165aac Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Newton/m=C2=B2?=
 <27069811+newtondividedbysqm@users.noreply.github.com>
Date: Mon, 30 Mar 2026 19:48:50 +0200
Subject: [PATCH 1/2] fix assertString to throw TypeErrors on objects with
 custom constructor property

---
 src/lib/util/assertString.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/lib/util/assertString.js b/src/lib/util/assertString.js
index 3baa4452f..e62e1a624 100644
--- a/src/lib/util/assertString.js
+++ b/src/lib/util/assertString.js
@@ -1,4 +1,4 @@
 export default function assertString(input) {
   if (input === undefined || input === null) throw new TypeError(`Expected a string but received a ${input}`);
-  if (input.constructor.name !== 'String') throw new TypeError(`Expected a string but received a ${input.constructor.name}`);
+  if (typeof input !== 'string' && !(input instanceof String)) throw new TypeError(`Expected a string but received a ${input?.constructor?.name ?? typeof input}`)
 }

From 5dc7d99b3641194d25e957ec33df4fe438b9152f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Newton/m=C2=B2?=
 <27069811+newtondividedbysqm@users.noreply.github.com>
Date: Mon, 30 Mar 2026 19:57:14 +0200
Subject: [PATCH 2/2] Add tests for boxed strings and Objects pretending to be
 a string

---
 test/util.test.js | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/test/util.test.js b/test/util.test.js
index 0146a4e2c..5edbf0441 100644
--- a/test/util.test.js
+++ b/test/util.test.js
@@ -54,11 +54,23 @@ describe('assertString', () => {
     assert.throws(() => { assertString([]); }, TypeError);
   });
 
+  it('Should throw an error if argument provided is an Object pretending to be a \'string\'', () => {
+    assert.throws(() => { assertString({constructor: {name: "string"}}); }, TypeError);
+  });
+
+  it('Should throw an error if argument provided is an Object pretending to be a \'String\'', () => {
+    assert.throws(() => { assertString({constructor: {name: "String"}}); }, TypeError);
+  });
+
   it('Should not throw an error if the argument is an empty string', () => {
     assert.doesNotThrow(() => { assertString(''); });
   });
-
+  
   it('Should not throw an error if the argument is a String', () => {
     assert.doesNotThrow(() => { assertString('antidisestablishmentarianism'); });
   });
+
+  it('Should not throw an error if the argument is a boxed string', () => {
+    assert.doesNotThrow(() => { assertString(new String('antidisestablishmentarianism')); });
+  });
 });