feat: add Escape Smart Characters operation

Converts smart characters (curly quotes, em/en dashes, arrows,
copyright signs, ellipses, etc.) to plain ASCII equivalents.

For characters with no obvious ASCII mapping, the user can choose
to Include (keep as-is), Remove, or Replace with '.'.

Closes #419
Ref: #1291 (closed due to inactivity)

src/core/config/Categories.json

@@ -82,7 +82,8 @@
             "Rison Decode",
             "To Modhex",
             "From Modhex",
-            "MIME Decoding"
+            "MIME Decoding",
+            "Escape Smart Characters"
         ]
     },
     {

src/core/operations/EscapeSmartCharacters.mjs

@@ -0,0 +1,152 @@
+/**
+ * @author min23asdw
+ * @copyright Crown Copyright 2026
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+
+/**
+ * Map of smart characters to their plain ASCII equivalents.
+ */
+const ESCAPE_MAP = {
+    // Quotation marks
+    "\u2018": "'",     // ' LEFT SINGLE QUOTATION MARK
+    "\u2019": "'",     // ' RIGHT SINGLE QUOTATION MARK
+    "\u201A": "'",     // ‚ SINGLE LOW-9 QUOTATION MARK
+    "\u201B": "'",     // ‛ SINGLE HIGH-REVERSED-9 QUOTATION MARK
+    "\u201C": "\"",    // " LEFT DOUBLE QUOTATION MARK
+    "\u201D": "\"",    // " RIGHT DOUBLE QUOTATION MARK
+    "\u201E": "\"",    // „ DOUBLE LOW-9 QUOTATION MARK
+    "\u201F": "\"",    // ‟ DOUBLE HIGH-REVERSED-9 QUOTATION MARK
+    "\u2039": "<",     // ‹ SINGLE LEFT-POINTING ANGLE QUOTATION MARK
+    "\u203A": ">",     // › SINGLE RIGHT-POINTING ANGLE QUOTATION MARK
+    "\u00AB": "<<",    // « LEFT-POINTING DOUBLE ANGLE QUOTATION MARK
+    "\u00BB": ">>",    // » RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK
+
+    // Primes
+    "\u2032": "'",     // ′ PRIME
+    "\u2033": "''",    // ″ DOUBLE PRIME
+    "\u2034": "'''",   // ‴ TRIPLE PRIME
+    "\u2035": "'",     // ‵ REVERSED PRIME
+    "\u2036": "''",    // ‶ REVERSED DOUBLE PRIME
+    "\u2037": "'''",   // ‷ REVERSED TRIPLE PRIME
+    "\u2057": "''''",  // ⁗ QUADRUPLE PRIME
+
+    // Dashes and hyphens
+    "\u2010": "-",     // ‐ HYPHEN
+    "\u2011": "-",     // ‑ NON-BREAKING HYPHEN
+    "\u2012": "-",     // ‒ FIGURE DASH
+    "\u2013": "-",     // – EN DASH
+    "\u2014": "--",    // — EM DASH
+    "\u2015": "--",    // ― HORIZONTAL BAR
+
+    // Symbols
+    "\u00A9": "(C)",   // © COPYRIGHT SIGN
+    "\u00AE": "(R)",   // ® REGISTERED SIGN
+    "\u2122": "(TM)",  // ™ TRADE MARK SIGN
+
+    // Arrows
+    "\u2190": "<--",   // ← LEFTWARDS ARROW
+    "\u2192": "-->",   // → RIGHTWARDS ARROW
+    "\u2194": "<->",   // ↔ LEFT RIGHT ARROW
+    "\u21D0": "<==",   // ⇐ LEFTWARDS DOUBLE ARROW
+    "\u21D2": "==>",   // ⇒ RIGHTWARDS DOUBLE ARROW
+    "\u21D4": "<=>",   // ⇔ LEFT RIGHT DOUBLE ARROW
+
+    // Dots, bullets, and ellipsis
+    "\u2022": ".",     // • BULLET
+    "\u2023": ">",     // ‣ TRIANGULAR BULLET
+    "\u2024": ".",     // ․ ONE DOT LEADER
+    "\u2025": "..",    // ‥ TWO DOT LEADER
+    "\u2026": "...",   // … HORIZONTAL ELLIPSIS
+    "\u2027": ".",     // ‧ HYPHENATION POINT
+
+    // Misc punctuation
+    "\u2016": "||",    // ‖ DOUBLE VERTICAL LINE
+    "\u2017": "==",    // ‗ DOUBLE LOW LINE
+    "\u2030": "%0",    // ‰ PER MILLE SIGN
+    "\u2031": "%00",   // ‱ PER TEN THOUSAND SIGN
+    "\u2038": "^",     // ‸ CARET
+    "\u203C": "!!",    // ‼ DOUBLE EXCLAMATION MARK
+    "\u203D": "?!",    // ‽ INTERROBANG
+    "\u2043": "-",     // ⁃ HYPHEN BULLET
+    "\u2044": "/",     // ⁄ FRACTION SLASH
+    "\u2045": "[-",    // ⁅ LEFT SQUARE BRACKET WITH QUILL
+    "\u2046": "-]",    // ⁆ RIGHT SQUARE BRACKET WITH QUILL
+    "\u2047": "??",    // ⁇ DOUBLE QUESTION MARK
+    "\u2048": "?!",    // ⁈ QUESTION EXCLAMATION MARK
+    "\u2049": "!?",    // ⁉ EXCLAMATION QUESTION MARK
+    "\u204E": "*",     // ⁎ LOW ASTERISK
+    "\u204F": ";",     // ⁏ REVERSED SEMICOLON
+    "\u2052": "%",     // ⁒ COMMERCIAL MINUS SIGN
+    "\u2053": "~",     // ⁓ SWUNG DASH
+    "\u2055": "*",     // ⁕ FLOWER PUNCTUATION MARK
+
+    // Invisible operators
+    "\u2062": "*",     // INVISIBLE TIMES
+    "\u2064": "+",     // INVISIBLE PLUS
+
+    // Spaces
+    "\u00A0": " ",     // NO-BREAK SPACE
+};
+
+/**
+ * Escape Smart Characters operation
+ */
+class EscapeSmartCharacters extends Operation {
+
+    /**
+     * EscapeSmartCharacters constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "Escape Smart Characters";
+        this.module = "Default";
+        this.description = "Converts smart characters (quotes, dashes, apostrophes, arrows, copyright signs, ellipses etc.) to their plain ASCII equivalents.<br><br>For characters with no obvious ASCII equivalent, the specified action will be applied.";
+        this.infoURL = "https://wikipedia.org/wiki/Smart_quotes";
+        this.inputType = "string";
+        this.outputType = "string";
+        this.args = [
+            {
+                name: "Unrecognised characters",
+                type: "option",
+                value: ["Include", "Remove", "Replace with '.'"]
+            }
+        ];
+    }
+
+    /**
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        const [unrecognisedAction] = args;
+        const result = [];
+
+        for (const char of input) {
+            if (char in ESCAPE_MAP) {
+                result.push(ESCAPE_MAP[char]);
+            } else if (char.codePointAt(0) > 0x7F) {
+                switch (unrecognisedAction) {
+                    case "Remove":
+                        break;
+                    case "Replace with '.'":
+                        result.push(".");
+                        break;
+                    default:
+                        result.push(char);
+                }
+            } else {
+                result.push(char);
+            }
+        }
+
+        return result.join("");
+    }
+
+}
+
+export default EscapeSmartCharacters;

tests/operations/index.mjs

@@ -189,6 +189,7 @@ import "./tests/JSONtoYAML.mjs";
 import "./tests/YARA.mjs";
 import "./tests/ParseCSR.mjs";
 import "./tests/XXTEA.mjs";
+import "./tests/EscapeSmartCharacters.mjs";
 
 const testStatus = {
     allTestsPassing: true,

tests/operations/tests/EscapeSmartCharacters.mjs

@@ -0,0 +1,111 @@
+/**
+ * Escape Smart Characters tests.
+ *
+ * @author min23asdw
+ * @copyright Crown Copyright 2026
+ * @license Apache-2.0
+ */
+
+import TestRegister from "../../lib/TestRegister.mjs";
+
+TestRegister.addTests([
+    {
+        name: "Escape Smart Characters: empty input",
+        input: "",
+        expectedOutput: "",
+        recipeConfig: [
+            {
+                op: "Escape Smart Characters",
+                args: ["Include"],
+            },
+        ],
+    },
+    {
+        name: "Escape Smart Characters: ASCII passthrough",
+        input: "Hello, World! 123",
+        expectedOutput: "Hello, World! 123",
+        recipeConfig: [
+            {
+                op: "Escape Smart Characters",
+                args: ["Include"],
+            },
+        ],
+    },
+    {
+        name: "Escape Smart Characters: smart quotes and dashes",
+        input: "\u201C\u201D\u2014\u2018\u2019 \u2192\u00A9\u2026",
+        expectedOutput: "\"\"--'' -->(C)...",
+        recipeConfig: [
+            {
+                op: "Escape Smart Characters",
+                args: ["Include"],
+            },
+        ],
+    },
+    {
+        name: "Escape Smart Characters: guillemets and arrows",
+        input: "\u00AB\u00BB \u2190\u2194\u21D2",
+        expectedOutput: "<<>> <--<->==>",
+        recipeConfig: [
+            {
+                op: "Escape Smart Characters",
+                args: ["Include"],
+            },
+        ],
+    },
+    {
+        name: "Escape Smart Characters: Remove unrecognised",
+        input: "\u201CHello\u201D \u2603",
+        expectedOutput: "\"Hello\" ",
+        recipeConfig: [
+            {
+                op: "Escape Smart Characters",
+                args: ["Remove"],
+            },
+        ],
+    },
+    {
+        name: "Escape Smart Characters: Replace unrecognised with '.'",
+        input: "\u201CHello\u201D \u2603",
+        expectedOutput: "\"Hello\" .",
+        recipeConfig: [
+            {
+                op: "Escape Smart Characters",
+                args: ["Replace with '.'"],
+            },
+        ],
+    },
+    {
+        name: "Escape Smart Characters: Include unrecognised",
+        input: "\u201CHello\u201D \u2603",
+        expectedOutput: "\"Hello\" \u2603",
+        recipeConfig: [
+            {
+                op: "Escape Smart Characters",
+                args: ["Include"],
+            },
+        ],
+    },
+    {
+        name: "Escape Smart Characters: copyright, registered, trademark",
+        input: "\u00A9 \u00AE \u2122",
+        expectedOutput: "(C) (R) (TM)",
+        recipeConfig: [
+            {
+                op: "Escape Smart Characters",
+                args: ["Include"],
+            },
+        ],
+    },
+    {
+        name: "Escape Smart Characters: non-breaking space",
+        input: "hello\u00A0world",
+        expectedOutput: "hello world",
+        recipeConfig: [
+            {
+                op: "Escape Smart Characters",
+                args: ["Include"],
+            },
+        ],
+    },
+]);