From 4baa26336daa8c6a3565cefaf28ff5ccfb1dd807 Mon Sep 17 00:00:00 2001
From: MANDEM_VIGNESH_KUMAR_REDDY <welcometomvkr8985090256@gmail.com>
Date: Tue, 18 Feb 2025 18:30:50 +0530
Subject: [PATCH] Update vigenere.js

---
 vigenere.js | 97 +++++++++++++++++++++++++++--------------------------
 1 file changed, 50 insertions(+), 47 deletions(-)

diff --git a/vigenere.js b/vigenere.js
index e552d982..3a2be958 100644
--- a/vigenere.js
+++ b/vigenere.js
@@ -1,3 +1,9 @@
+/**
+ * Cleans the input text by removing spaces and ensuring it contains only alphanumeric characters.
+ * @param {string} text - The input text to be cleaned.
+ * @returns {string} The cleaned text without spaces or special characters.
+ * @throws Will throw an error if special characters are found.
+ */
 function cleanText(text) {
     const textNoSpaces = text.replace(/ /g, "");
     if (/[^A-Za-z0-9]/.test(textNoSpaces)) {
@@ -6,6 +12,12 @@ function cleanText(text) {
     return textNoSpaces;
 }
 
+/**
+ * Encrypts a message using a key with a substitution cipher.
+ * @param {string} message - The message to encrypt.
+ * @param {string} key - The encryption key.
+ * @returns {string} The encrypted message.
+ */
 function encrypt(message, key) {
     message = message.toLowerCase();
     key = key.toLowerCase();
@@ -14,23 +26,25 @@ function encrypt(message, key) {
     const encrypted = [];
     let keyIndex = 0;
 
-    try {
-        for (const char of message) {
-            if (combinedAlphabet.includes(char)) {
-                const mIndex = combinedAlphabet.indexOf(char);
-                const keyChar = key[keyIndex % key.length];
-                const shift = combinedAlphabet.indexOf(keyChar);
-                const newIndex = (mIndex + shift) % n;
-                encrypted.push(combinedAlphabet[newIndex]);
-                keyIndex++;
-            }
+    for (const char of message) {
+        if (combinedAlphabet.includes(char)) {
+            const mIndex = combinedAlphabet.indexOf(char);
+            const keyChar = key[keyIndex % key.length];
+            const shift = combinedAlphabet.indexOf(keyChar);
+            const newIndex = (mIndex + shift) % n;
+            encrypted.push(combinedAlphabet[newIndex]);
+            keyIndex++;
         }
-        return encrypted.join("");
-    } catch (e) {
-        throw new Error("Encryption error: " + e.message);
     }
+    return encrypted.join("");
 }
 
+/**
+ * Decrypts an encrypted message using a key with a substitution cipher.
+ * @param {string} cipherText - The encrypted message to decrypt.
+ * @param {string} key - The decryption key.
+ * @returns {string} The decrypted message.
+ */
 function decrypt(cipherText, key) {
     cipherText = cipherText.toLowerCase();
     key = key.toLowerCase();
@@ -39,50 +53,39 @@ function decrypt(cipherText, key) {
     const decrypted = [];
     let keyIndex = 0;
 
-    try {
-        for (const char of cipherText) {
-            if (combinedAlphabet.includes(char)) {
-                const cIndex = combinedAlphabet.indexOf(char);
-                const keyChar = key[keyIndex % key.length];
-                const shift = combinedAlphabet.indexOf(keyChar);
-                const originalIndex = (cIndex - shift + n) % n;
-                decrypted.push(combinedAlphabet[originalIndex]);
-                keyIndex++;
-            }
+    for (const char of cipherText) {
+        if (combinedAlphabet.includes(char)) {
+            const cIndex = combinedAlphabet.indexOf(char);
+            const keyChar = key[keyIndex % key.length];
+            const shift = combinedAlphabet.indexOf(keyChar);
+            const originalIndex = (cIndex - shift + n) % n;
+            decrypted.push(combinedAlphabet[originalIndex]);
+            keyIndex++;
         }
-        return decrypted.join("");
-    } catch (e) {
-        throw new Error("Decryption error: " + e.message);
     }
+    return decrypted.join("");
 }
 
+/**
+ * The main function to clean, encrypt, and decrypt messages.
+ */
 function main() {
     try {
         const rawMessage = prompt("Enter the message: ");
         const rawKey = prompt("Enter the key: ");
-        try {
-            const cleanedMessage = cleanText(rawMessage);
-            const cleanedKey = cleanText(rawKey);
-            if (!cleanedMessage) {
-                throw new Error("Message is empty after cleaning!");
-            }
-            if (!cleanedKey) {
-                throw new Error("Key is empty after cleaning!");
-            }
-            const encryptedMsg = encrypt(cleanedMessage, cleanedKey);
-            console.log("\nEncrypted Message:");
-            console.log(encryptedMsg);
-            const decryptedMsg = decrypt(encryptedMsg, cleanedKey);
-            console.log("\nDecrypted Message:");
-            console.log(decryptedMsg);
-        } catch (ve) {
-            console.log("Input error:", ve.message);
-            return;
-        }
+        const cleanedMessage = cleanText(rawMessage);
+        const cleanedKey = cleanText(rawKey);
+        
+        if (!cleanedMessage) throw new Error("Message is empty after cleaning!");
+        if (!cleanedKey) throw new Error("Key is empty after cleaning!");
+
+        const encryptedMsg = encrypt(cleanedMessage, cleanedKey);
+        alert(`Encrypted Message: ${encryptedMsg}`);
+        const decryptedMsg = decrypt(encryptedMsg, cleanedKey);
+        alert(`Decrypted Message: ${decryptedMsg}`);
     } catch (e) {
-        console.log("An error occurred:", e.message);
+        alert(`An error occurred: ${e.message}`);
     }
 }
 
 main();
-