diff --git a/.oss-upstream b/.oss-upstream
new file mode 100644
index 00000000..4e304ffa
--- /dev/null
+++ b/.oss-upstream
@@ -0,0 +1 @@
+TheAlgorithms/TypeScript
diff --git a/ciphers/test/xor_cipher.test.ts b/ciphers/test/xor_cipher.test.ts
index 0607d6a3..38db6c14 100644
--- a/ciphers/test/xor_cipher.test.ts
+++ b/ciphers/test/xor_cipher.test.ts
@@ -5,4 +5,17 @@ describe('Testing XORCipher function', () => {
     expect(XORCipher('test', 32)).toBe('TEST')
     expect(XORCipher('TEST', 32)).toBe('test')
   })
+
+  it('encrypts newline and other line-terminator characters', () => {
+    // /./g without the s-flag skips \n, \r — Array.from handles them correctly
+    expect(XORCipher('\n', 1)).toBe(String.fromCharCode(10 ^ 1))
+    expect(XORCipher('\r', 1)).toBe(String.fromCharCode(13 ^ 1))
+    expect(XORCipher('A\nB', 1)).toBe(
+      String.fromCharCode(65 ^ 1) + String.fromCharCode(10 ^ 1) + String.fromCharCode(66 ^ 1)
+    )
+  })
+
+  it('XORCipher is its own inverse', () => {
+    expect(XORCipher(XORCipher('Hello\nWorld', 42), 42)).toBe('Hello\nWorld')
+  })
 })
diff --git a/ciphers/xor_cipher.ts b/ciphers/xor_cipher.ts
index 72d91e68..d6930191 100644
--- a/ciphers/xor_cipher.ts
+++ b/ciphers/xor_cipher.ts
@@ -10,6 +10,6 @@
  * @return {string} encrypted string
  */
 export const XORCipher = (str: string, key: number): string =>
-  str.replace(/./g, (char: string) =>
+  Array.from(str, (char: string) =>
     String.fromCharCode(char.charCodeAt(0) ^ key)
-  )
+  ).join('')