In this tutorial, we’ll walk you through the process of creating a RESTful API using Node.js and the Express framework. REST APIs are essential for building web applications and mobile backends. We’ll cover setting up your project, creating a basic server, and implementing CRUD (Create, Read, Update, Delete) operations. Let’s get started!

1. Setting Up your Project

First, ensure you have Node.js and npm (Node Package Manager) installed. Create a new project directory and navigate to it in your terminal. Then, initialize a new Node.js project using npm:

mkdir my-rest-api
cd my-rest-api
npm init -y

This command creates a package.json file with default settings. Next, install the necessary dependencies:

npm install express mongoose body-parser

• express: A fast, minimalist web framework for Node.js.
• mongoose: An elegant MongoDB object modeling tool for Node.js.
• body-parser: Middleware for parsing incoming request bodies.

2. Creating the Server

Now, create a file named server.js (or any name you prefer) and add the following code to set up a basic Express server:

const express = require('express');
const bodyParser = require('body-parser');
const mongoose = require('mongoose');
const app = express();
const port = 3000;

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

// Basic route to check if the server is running
app.get('/', (req, res) => {
    res.send('API is running!');
});

app.listen(port, () => {
    console.log(`Server running on port ${port}`);
});

// Connect to MongoDB
mongoose.connect('mongodb://localhost:27017/myDatabase', {
    useNewUrlParser: true,
    useUnifiedTopology: true,
})
.then(() => console.log('MongoDB Connected'))
.catch(err => console.log(err));

• bodyParser.json(): Added middleware to parse JSON requests, which is essential for handling POST and PUT requests.
• Basic Route (/): Included a basic route to verify that the server is running.
• MongoDB Connection: Added code to connect to a local MongoDB database. Replace 'mongodb://localhost:27017/myDatabase' with your MongoDB connection string.
• Error Handling for MongoDB: added .then and .catch for MongoDB connection.

3. Implementing CRUD Operations

Let’s define a simple model for our items and implement CRUD operations.

3.1 Defining the Model (Create a file named models/item.js):

// models/item.js
const mongoose = require('mongoose');

const itemSchema = new mongoose.Schema({
    name: { type: String, required: true },
    description: String,
});

module.exports = mongoose.model('Item', itemSchema);

3.2 Implementing CRUD Routes (Modify server.js):

// ... (previous code)

const Item = require('./models/item'); // Import the Item model

// GET all items
app.get('/api/items', async (req, res) => {
    try {
        const items = await Item.find();
        res.json(items);
    } catch (error) {
        res.status(500).json({ message: error.message });
    }
});

// GET a single item by ID
app.get('/api/items/:id', async (req, res) => {
    try {
        const item = await Item.findById(req.params.id);
        if (!item) {
            return res.status(404).json({ message: 'Item not found' });
        }
        res.json(item);
    } catch (error) {
        res.status(500).json({ message: error.message });
    }
});

// POST a new item
app.post('/api/items', async (req, res) => {
    const item = new Item({
        name: req.body.name,
        description: req.body.description,
    });
    try {
        const newItem = await item.save();
        res.status(201).json(newItem);
    } catch (error) {
        res.status(400).json({ message: error.message });
    }
});

// PUT (update) an existing item
app.put('/api/items/:id', async (req, res) => {
    try {
        const updatedItem = await Item.findByIdAndUpdate(req.params.id, req.body, { new: true });
        if (!updatedItem) {
            return res.status(404).json({ message: 'Item not found' });
        }
        res.json(updatedItem);
    } catch (error) {
        res.status(400).json({ message: error.message });
    }
});

// DELETE an item
app.delete('/api/items/:id', async (req, res) => {
    try {
        const deletedItem = await Item.findByIdAndDelete(req.params.id);
        if (!deletedItem) {
            return res.status(404).json({ message: 'Item not found' });
        }
        res.json({ message: 'Item deleted' });
    } catch (error) {
        res.status(500).json({ message: error.message });
    }
});