From 71531802a76296d1532c6a04ffed858c84ef0614 Mon Sep 17 00:00:00 2001
From: kevin9327 <5299031+kevin9327@users.noreply.github.com>
Date: Thu, 12 Nov 2026 11:50:57 +0900
Subject: [PATCH] fix: reject non-binary input in BinaryToDecimal

Digits other than 0 and 1 were coerced into the place-value sum,
so binaryToDecimal('2') returned 2 and binaryToDecimal('102')
returned 6.
---
 Conversions/BinaryToDecimal.js           |  8 ++++++++
 Conversions/test/BinaryToDecimal.test.js | 11 +++++++++++
 2 files changed, 19 insertions(+)

diff --git a/Conversions/BinaryToDecimal.js b/Conversions/BinaryToDecimal.js
index d149de0df2..3193783b80 100644
--- a/Conversions/BinaryToDecimal.js
+++ b/Conversions/BinaryToDecimal.js
@@ -1,4 +1,12 @@
 export default function binaryToDecimal(binaryString) {
+  if (typeof binaryString !== 'string') {
+    throw new TypeError('Argument is not a string type')
+  }
+
+  if (!/^[01]+$/.test(binaryString)) {
+    throw new Error('Argument is not a valid binary string!')
+  }
+
   let decimalNumber = 0
   const binaryDigits = binaryString.split('').reverse() // Splits the binary number into reversed single digits
   binaryDigits.forEach((binaryDigit, index) => {
diff --git a/Conversions/test/BinaryToDecimal.test.js b/Conversions/test/BinaryToDecimal.test.js
index 97f23aeb49..43a4a04896 100644
--- a/Conversions/test/BinaryToDecimal.test.js
+++ b/Conversions/test/BinaryToDecimal.test.js
@@ -12,4 +12,15 @@ describe('BinaryToDecimal', () => {
   it('expects to return correct hexadecimal value for padding-required binary', () => {
     expect(binaryToDecimal('1000101')).toBe(69)
   })
+
+  it('expects to throw for a non-string argument', () => {
+    expect(() => binaryToDecimal(1000)).toThrowError()
+    expect(() => binaryToDecimal(null)).toThrowError()
+  })
+
+  it('expects to throw for a non-binary string', () => {
+    expect(() => binaryToDecimal('2')).toThrowError()
+    expect(() => binaryToDecimal('102')).toThrowError()
+    expect(() => binaryToDecimal('')).toThrowError()
+  })
 })