Converted Vignere, added more tests and cleaned stuff up

src/core/operations/VigenèreDecode.mjs

@@ -0,0 +1,101 @@
+/**
+ * @author Matt C [matt@artemisbot.uk]
+ * @copyright Crown Copyright 2018
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation";
+
+/**
+ * Vigenère Decode operation
+ */
+class VigenèreDecode extends Operation {
+
+    /**
+     * VigenèreDecode constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "Vigenère Decode";
+        this.module = "Ciphers";
+        this.description = "The Vigenere cipher is a method of encrypting alphabetic text by using a series of different Caesar ciphers based on the letters of a keyword. It is a simple form of polyalphabetic substitution.";
+        this.inputType = "string";
+        this.outputType = "string";
+        this.args = [
+            {
+                "name": "Key",
+                "type": "string",
+                "value": ""
+            }
+        ];
+    }
+
+    /**
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        const alphabet = "abcdefghijklmnopqrstuvwxyz",
+            key = args[0].toLowerCase();
+        let output = "",
+            fail = 0,
+            keyIndex,
+            msgIndex,
+            chr;
+
+        if (!key) return "No key entered";
+        if (!/^[a-zA-Z]+$/.test(key)) return "The key must consist only of letters";
+
+        for (let i = 0; i < input.length; i++) {
+            if (alphabet.indexOf(input[i]) >= 0) {
+                chr = key[(i - fail) % key.length];
+                keyIndex = alphabet.indexOf(chr);
+                msgIndex = alphabet.indexOf(input[i]);
+                // Subtract indexes from each other, add 26 just in case the value is negative,
+                // modulo to remove if neccessary
+                output += alphabet[(msgIndex - keyIndex + alphabet.length) % 26];
+            } else if (alphabet.indexOf(input[i].toLowerCase()) >= 0) {
+                chr = key[(i - fail) % key.length].toLowerCase();
+                keyIndex = alphabet.indexOf(chr);
+                msgIndex = alphabet.indexOf(input[i].toLowerCase());
+                output += alphabet[(msgIndex + alphabet.length - keyIndex) % 26].toUpperCase();
+            } else {
+                output += input[i];
+                fail++;
+            }
+        }
+
+        return output;
+    }
+
+    /**
+     * Highlight Vigenère Decode
+     *
+     * @param {Object[]} pos
+     * @param {number} pos[].start
+     * @param {number} pos[].end
+     * @param {Object[]} args
+     * @returns {Object[]} pos
+     */
+    highlight(pos, args) {
+        return pos;
+    }
+
+    /**
+     * Highlight Vigenère Decode in reverse
+     *
+     * @param {Object[]} pos
+     * @param {number} pos[].start
+     * @param {number} pos[].end
+     * @param {Object[]} args
+     * @returns {Object[]} pos
+     */
+    highlightReverse(pos, args) {
+        return pos;
+    }
+
+}
+
+export default VigenèreDecode;