Certainly! Here's a simple example of how you can create a REST API endpoint using Node.js and Express:

// Import required modules
const express = require('express');
const bodyParser = require('body-parser');

// Create an instance of Express
const app = express();

// Middleware to parse JSON bodies
app.use(bodyParser.json());

// Sample data (you can replace this with your own data source)
let books = [
    { id: 1, title: 'Book 1', author: 'Author 1' },
    { id: 2, title: 'Book 2', author: 'Author 2' },
    { id: 3, title: 'Book 3', author: 'Author 3' }
];

// GET endpoint to retrieve all books
app.get('/api/books', (req, res) => {
    res.json(books);
});

// GET endpoint to retrieve a specific book by ID
app.get('/api/books/:id', (req, res) => {
    const bookId = parseInt(req.params.id);
    const book = books.find(book => book.id === bookId);
    if (!book) {
        return res.status(404).json({ error: 'Book not found' });
    }
    res.json(book);
});

// POST endpoint to add a new book
app.post('/api/books', (req, res) => {
    const { title, author } = req.body;
    if (!title || !author) {
        return res.status(400).json({ error: 'Title and author are required' });
    }
    const newBook = {
        id: books.length + 1,
        title,
        author
    };
    books.push(newBook);
    res.status(201).json(newBook);
});

// Set up the server to listen on port 3000
const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
    console.log(`Server is running on port ${PORT}`);
});

To run this code:

1. Make sure you have Node.js installed on your machine.
2. Create a new directory for your project and navigate into it using your terminal.
3. Create a new file, e.g., app.js, and paste the code above into it.
4. Run npm init -y to initialize a new Node.js project.
5. Run npm install express body-parser to install the required dependencies.
6. Run node app.js to start the server.

Now you have a simple REST API with three endpoints:

• GET /api/books: Retrieves all books.
• GET /api/books/:id: Retrieves a specific book by ID.
• POST /api/books: Adds a new book to the collection.