From 2bce9498f9b1d03986b3b91f69d3c83c8095cb0f Mon Sep 17 00:00:00 2001
From: Aleksandar Todorov <101955939+AlexTodorov11@users.noreply.github.com>
Date: Tue, 8 Oct 2024 23:32:17 +0300
Subject: [PATCH 1/2] Enhancements to Caesar Cipher Implementation -
CaesarCipher.js
Improves the existing Caesar Cipher implementation to make it more robust, future-proof, and flexible. Key improvements include handling edge cases, optimizing performance, and adding support for custom alphabets. These changes enhance both the functionality and maintainability of the code.
---
Ciphers/CaesarCipher.js | 43 +++++++++++++++++++++++++++--------------
1 file changed, 28 insertions(+), 15 deletions(-)
diff --git a/Ciphers/CaesarCipher.js b/Ciphers/CaesarCipher.js
index 8a942564e9..000a3d676f 100644
--- a/Ciphers/CaesarCipher.js
+++ b/Ciphers/CaesarCipher.js
@@ -4,29 +4,42 @@
* @see - [wiki](https://en.wikipedia.org/wiki/Caesar_cipher)
* @param {string} str - string to be encrypted
* @param {number} rotation - the number of rotation, expect real number ( > 0)
+ * @param {string} [alphabet='abcdefghijklmnopqrstuvwxyz'] - Optional parameter to specify a custom alphabet
* @return {string} - decrypted string
*/
-const caesarCipher = (str, rotation) => {
+const caesarCipher = (str, rotation, alphabet = 'abcdefghijklmnopqrstuvwxyz') => {
if (typeof str !== 'string' || !Number.isInteger(rotation) || rotation < 0) {
- throw new TypeError('Arguments are invalid')
+ throw new TypeError('Arguments are invalid');
}
- const alphabets = new Array(26)
- .fill()
- .map((_, index) => String.fromCharCode(97 + index)) // generate all lower alphabets array a-z
+ const alphabets = Array.from(alphabet); // Allow custom alphabet
+ const alphabetLength = alphabets.length;
- const cipherMap = alphabets.reduce(
- (map, char, index) => map.set(char, alphabets[(rotation + index) % 26]),
- new Map()
- )
+ // Optimize rotation to handle rotations greater than alphabet length
+ const effectiveRotation = rotation % alphabetLength;
+
+ // Create cipher map to avoid recalculating for each character
+ const cipherMap = alphabets.reduce((map, char, index) => {
+ map.set(char, alphabets[(effectiveRotation + index) % alphabetLength]);
+ return map;
+ }, new Map());
return str.replace(/[a-z]/gi, (char) => {
- if (/[A-Z]/.test(char)) {
- return cipherMap.get(char.toLowerCase()).toUpperCase()
+ const isUpperCase = /[A-Z]/.test(char);
+ const lowerChar = char.toLowerCase();
+
+ // Check if the character is in the map (i.e., an alphabetic character)
+ if (cipherMap.has(lowerChar)) {
+ const cipheredChar = cipherMap.get(lowerChar);
+ return isUpperCase ? cipheredChar.toUpperCase() : cipheredChar;
}
- return cipherMap.get(char)
- })
-}
+ // Return non-alphabetic characters unchanged
+ return char;
+ });
+};
+
+// Example usage:
+console.log(caesarCipher('Hello World!', 3)); // Khoor Zruog!
-export default caesarCipher
+export default caesarCipher;
From ab9ba901c020caf7a3bea92ab6de5aaba05b02e6 Mon Sep 17 00:00:00 2001
From: Aleksandar Todorov <101955939+AlexTodorov11@users.noreply.github.com>
Date: Wed, 9 Oct 2024 00:02:41 +0300
Subject: [PATCH 2/2] Update CaesarCipher.js
---
Ciphers/CaesarCipher.js | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/Ciphers/CaesarCipher.js b/Ciphers/CaesarCipher.js
index 000a3d676f..3e4e4f44a6 100644
--- a/Ciphers/CaesarCipher.js
+++ b/Ciphers/CaesarCipher.js
@@ -32,11 +32,11 @@ const caesarCipher = (str, rotation, alphabet = 'abcdefghijklmnopqrstuvwxyz') =>
if (cipherMap.has(lowerChar)) {
const cipheredChar = cipherMap.get(lowerChar);
return isUpperCase ? cipheredChar.toUpperCase() : cipheredChar;
- }
+ }
+
+ return cipherMap.get(char);
+});
- // Return non-alphabetic characters unchanged
- return char;
- });
};
// Example usage: