Add yaml beautify

package.json

@@ -140,6 +140,7 @@
     "jq-web": "^0.5.1",
     "jquery": "3.7.1",
     "js-sha3": "^0.9.3",
+    "js-yaml": "^4.1.0",
     "jsesc": "^3.0.2",
     "json5": "^2.2.3",
     "jsonata": "^2.0.3",

src/core/config/Categories.json

@@ -470,6 +470,7 @@
             "SQL Beautify",
             "SQL Minify",
             "CSS Beautify",
+            "YAML Beautify",
             "CSS Minify",
             "XPath expression",
             "JPath expression",

src/core/operations/YAMLBeautify.mjs

@@ -0,0 +1,51 @@
+/**
+ * @author MrMadFox [[email protected]]
+ * @copyright Crown Copyright 2025
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+import YAML from "js-yaml";
+import OperationError from "../errors/OperationError.mjs";
+
+/**
+ * YAMLBeautify operation
+ */
+class YAMLBeautify extends Operation {
+
+    /**
+     * YAMLBeautify constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "YAML Beautify";
+        this.module = "Code";
+        this.description = "Indents and prettifies YAML code.";
+        this.infoURL = "https://yaml.org/";
+        this.inputType = "string";
+        this.outputType = "string";
+        this.args = [];
+    }
+
+    /**
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        try {
+            return YAML.dump(YAML.load(input), {
+                styles: {
+                    "!!null": "empty"
+                }
+            });
+        } catch (err) {
+            if (err instanceof YAML.YAMLException) {
+                throw new OperationError(err.message);
+            }
+        }
+    }
+}
+
+export default YAMLBeautify;

tests/operations/tests/YAMLBeautify.mjs

@@ -0,0 +1,45 @@
+/**
+ * YamlBeautifier tests.
+ *
+ * @author MrMadFox [[email protected]]
+ * @copyright Crown Copyright 2018
+ * @license Apache-2.0
+ */
+
+import TestRegister from "../../lib/TestRegister.mjs";
+
+TestRegister.addTests(
+    [{
+        name: "YAML Beautify: basic YAML",
+        input: "key1: value1\nkey2: value2",
+        expectedOutput: "key1: value1\nkey2: value2\n",
+        recipeConfig: [{
+            "op": "YAML Beautify",
+            "args": []
+        }]
+    }, {
+        name: "YAML Beautify: nested YAML",
+        input: "key1:\n  subkey1: value1\n  subkey2: value2\nkey2: value3",
+        expectedOutput: "key1:\n  subkey1: value1\n  subkey2: value2\nkey2: value3\n",
+        recipeConfig: [{
+            "op": "YAML Beautify",
+            "args": []
+        }]
+    }, {
+        name: "YAML Beautify: empty YAML",
+        input: "",
+        expectedOutput: "",
+        recipeConfig: [{
+            "op": "YAML Beautify",
+            "args": []
+        }]
+    }, {
+        name: "YAML Beautify: malformed YAML",
+        input: "key1: value1\nkey2: value2\nkey3",
+        expectedOutput: "key1: value",
+        recipeConfig: [{
+            "op": "YAML Beautify",
+            "args": []
+        }]
+    }
+    ]);