Add palindrome utility function and corresponding tests

src/utils/palindrome.js

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+/**
+ * Author: Niki Nielsen
+ * Date: 06/03/2026
+ * File: palindrome.js
+ * Description: isPalindrome function.
+ */
+
+"use strict";
+
+function isPalindrome(str) {
+  if (typeof str !== "string") return false;
+
+  const cleaned = str.toLowerCase().replace(/[^a-z0-9]/g, "");
+  return cleaned === cleaned.split("").reverse().join("");
+}
+
+module.exports = isPalindrome;

test/utils/palindrome.spec.js

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+/**
+ * Author: Niki Nielsen
+ * Date: 06/03/2026
+ * File: palindrome.spec.js
+ * Description: Tests for the isPalindrome function.
+ */
+"use strict";
+
+const isPalindrome = require("../../src/utils/palindrome");
+
+describe("palindrome.js", () => {
+  it("should return true for a simple palindrome", () => {
+    expect(isPalindrome("racecar")).toBe(true);
+  });
+
+  it("should return false for a non-palindrome", () => {
+    expect(isPalindrome("hello")).toBe(false);
+  });
+
+  it("should handle punctuation and mixed case", () => {
+    expect(isPalindrome("A man, a plan, a canal: Panama")).toBe(true);
+  });
+});