Add operation to normalise unicode

src/core/config/Categories.json

@@ -39,6 +39,7 @@
             "URL Decode",
             "Escape Unicode Characters",
             "Unescape Unicode Characters",
+            "Normalise Unicode",
             "To Quoted Printable",
             "From Quoted Printable",
             "To Punycode",

src/core/lib/ChrEnc.mjs

@@ -164,3 +164,15 @@ export const IO_FORMAT = {
     "Simplified Chinese GB18030 (54936)": 54936,
 };
 
+/**
+ * Unicode Normalisation Forms
+ *
+ * @author Matthieu [m@tthieu.xyz]
+ * @copyright Crown Copyright 2016
+ * @license Apache-2.0
+ */
+
+/**
+ * Character encoding format mappings.
+ */
+export const UNICODE_NORMALISATION_FORMS = ["NFD", "NFC", "NFKD", "NFKC"];

src/core/operations/NormaliseUnicode.mjs

@@ -0,0 +1,60 @@
+/**
+ * @author Matthieu [m@tthieu.xyz]
+ * @copyright Crown Copyright 2019
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+import OperationError from "../errors/OperationError.mjs";
+import unorm from "unorm";
+import {UNICODE_NORMALISATION_FORMS} from "../lib/ChrEnc";
+
+/**
+ * Normalise Unicode operation
+ */
+class NormaliseUnicode extends Operation {
+
+    /**
+     * NormaliseUnicode constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "Normalise Unicode";
+        this.module = "UnicodeNormalisation";
+        this.description = "Transform Unicode to one of the Normalisation Form";
+        this.infoURL = "http://www.unicode.org/reports/tr15/";
+        this.inputType = "string";
+        this.outputType = "string";
+        this.args = [
+            {
+                name: "Normal Form",
+                type: "option",
+                value: UNICODE_NORMALISATION_FORMS
+            }
+        ];
+    }
+
+    /**
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        const [normalForm] = args;
+        if (normalForm === "NFD") {
+            return unorm.nfd(input);
+        } else if (normalForm === "NFC") {
+            return unorm.nfc(input);
+        } else if (normalForm === "NFKD") {
+            return unorm.nfkd(input);
+        } else if (normalForm === "NFKC") {
+            return unorm.nfc(input);
+        }
+
+        throw new OperationError("Unknown Normalisation Form");
+    }
+
+}
+
+export default NormaliseUnicode;