add_palindrome_function

.gitignore

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+# Node dependencies
+node_modules/
+
+# Logs
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+
+# Environment files
+.env
+.env.local
+.env.*.local
+
+# OS files
+.DS_Store
+Thumbs.db
+
+# Editor / IDE settings
+.vscode/
+.idea/
+
+# Coverage reports
+coverage/
+
+# Build output (if applicable)
+dist/
+build/

README.md

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-# nodejs-practice-repository
+# Node.js Practice Repository
+
+This repository contains small Node.js utility functions with automated unit tests.  
+Each feature is developed on its own branch and submitted via a Pull Request.
+
+---
+
+## Palindrome Function
+
+### Description
+
+Adds a utility function that checks whether a given string is a palindrome.  
+The function ignores spaces, punctuation, and letter casing.
+
+Example:
+
+- `"racecar"` → `true`
+- `"A man a plan a canal Panama"` → `true`
+- `"hello"` → `false`
+
+---
+
+## Setup Instructions
+
+### Prerequisites
+
+- Node.js (LTS version recommended)
+- npm (included with Node.js)
+
+### Install Dependencies
+
+Clone the repository and install dependencies:
+
+```bash
+git clone https://github.com/tink012184/nodejs-practice-repository.git
+cd nodejs-practice-repository
+npm install
+```

src/palindrome.js

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+/**
+ * Checks if a string is a palindrome.
+ * Ignores spaces, punctuation, and letter casing.
+ *
+ * @param {string} input
+ * @returns {boolean}
+ */
+function isPalindrome(input) {
+  if (typeof input !== "string") {
+    return false;
+  }
+
+  const cleaned = input.toLowerCase().replace(/[^a-z0-9]/g, "");
+
+  const reversed = cleaned.split("").reverse().join("");
+
+  return cleaned === reversed;
+}
+
+module.exports = { isPalindrome };

test/palindrome.test.js

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+const { isPalindrome } = require("../src/palindrome");
+
+describe("isPalindrome", () => {
+  test("returns true for a simple palindrome", () => {
+    expect(isPalindrome("racecar")).toBe(true);
+  });
+
+  test("returns true for a palindrome with spaces and capitalization", () => {
+    expect(isPalindrome("A man a plan a canal Panama")).toBe(true);
+  });
+
+  test("returns false for a non-palindrome string", () => {
+    expect(isPalindrome("hello world")).toBe(false);
+  });
+});