Create vigenere.js

in these peice of code you can use it for the alphabets and including numbers and removing out all the traces of punctuation marks and special characters and making it easy to work with and along side these code has both the encryption and decryption codes

vigenere.js

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+function cleanText(text) {
+    const textNoSpaces = text.replace(/ /g, "");
+    if (/[^A-Za-z0-9]/.test(textNoSpaces)) {
+        throw new Error("Special characters detected. They must be removed.");
+    }
+    return textNoSpaces;
+}
+
+function encrypt(message, key) {
+    message = message.toLowerCase();
+    key = key.toLowerCase();
+    const combinedAlphabet = "abcdefghijklmnopqrstuvwxyz0123456789";
+    const n = combinedAlphabet.length;
+    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++;
+            }
+        }
+        return encrypted.join("");
+    } catch (e) {
+        throw new Error("Encryption error: " + e.message);
+    }
+}
+
+function decrypt(cipherText, key) {
+    cipherText = cipherText.toLowerCase();
+    key = key.toLowerCase();
+    const combinedAlphabet = "abcdefghijklmnopqrstuvwxyz0123456789";
+    const n = combinedAlphabet.length;
+    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++;
+            }
+        }
+        return decrypted.join("");
+    } catch (e) {
+        throw new Error("Decryption error: " + e.message);
+    }
+}
+
+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;
+        }
+    } catch (e) {
+        console.log("An error occurred:", e.message);
+    }
+}
+
+main();
+