Ported rest of Code ops & enabled/fixed some tests

src/core/operations/XPathExpression.mjs

@@ -0,0 +1,72 @@
+/**
+ * @author Mikescher (https://github.com/Mikescher | https://mikescher.com)
+ * @copyright Crown Copyright 2016
+ * @license Apache-2.0
+ */
+
+import xpath from "xpath";
+import Operation from "../Operation";
+import OperationError from "../errors/OperationError";
+
+/**
+ * XPath expression operation
+ */
+class XPathExpression extends Operation {
+
+    /**
+     * XPathExpression constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "XPath expression";
+        this.module = "Code";
+        this.description = "Extract information from an XML document with an XPath query";
+        this.inputType = "string";
+        this.outputType = "string";
+        this.args = [
+            {
+                "name": "XPath",
+                "type": "string",
+                "value": ""
+            },
+            {
+                "name": "Result delimiter",
+                "type": "binaryShortString",
+                "value": "\\n"
+            }
+        ];
+    }
+
+    /**
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        const [query, delimiter] = args;
+
+        let doc;
+        try {
+            doc = new DOMParser().parseFromString(input, "application/xml");
+        } catch (err) {
+            throw new OperationError("Invalid input XML.");
+        }
+
+        let nodes;
+        try {
+            nodes = xpath.select(query, doc);
+        } catch (err) {
+            throw new OperationError(`Invalid XPath. Details:\n${err.message}.`);
+        }
+
+        const nodeToString = function(node) {
+            return node.toString();
+        };
+
+        return nodes.map(nodeToString).join(delimiter);
+    }
+
+}
+
+export default XPathExpression;