Introduction

Building a REST API is a crucial skill for modern web developers, and using Express.js with MongoDB provides a flexible and scalable approach. This guide will help you create a REST API step-by-step.

Setting Up the Environment

Installing Node.js and Express.js

Begin by setting up Node.js and Express.js. If Node.js isn't installed, download it from the official site. Initialize a new Node.js project using:

npm init -y

Then, install Express.js:

npm install express

Setting Up MongoDB

MongoDB is a popular NoSQL database. You can download it from the MongoDB website and install it following their official guide. For a simpler approach, consider using MongoDB Atlas, their cloud solution.

Creating the REST API

Project Structure

Organize your files for clarity:

your-app-name/
├── node_modules/
├── package.json
├── server.js
└── routes/
    └── api.js

Connecting to MongoDB

Use Mongoose to connect to MongoDB, making schema creation simple. First, install Mongoose:

npm install mongoose

Create a connection in your server.js:

const mongoose = require('mongoose');
const dbURI = 'your_mongodb_connection_string';

mongoose.connect(dbURI, { useNewUrlParser: true, useUnifiedTopology: true })
    .then(() => console.log('MongoDB connected...'))
    .catch(err => console.log(err));

Implementing Routes

Creating Basic CRUD Operations

Define routes in routes/api.js for CRUD operations:

const express = require('express');
const router = express.Router();

// Example Model
const Item = require('../models/item');

// GET: Fetch all items
router.get('/', async (req, res) => {
    try {
        const items = await Item.find();
        res.json(items);
    } catch (err) {
        res.status(500).send(err);
    }
});

// POST: Create a new item
router.post('/', async (req, res) => {
    const newItem = new Item(req.body);
    try {
        const item = await newItem.save();
        res.status(201).json(item);
    } catch (err) {
        res.status(400).send(err);
    }
});

module.exports = router;

Attach these routes in server.js:

const express = require('express');
const app = express();

// Middleware
app.use(express.json());

// Routes
app.use('/api/items', require('./routes/api'));

const PORT = process.env.PORT || 5000;
app.listen(PORT, () => console.log(`Server running on port ${PORT}`));

FAQ

What is Express.js?

Express.js is a minimal and flexible Node.js web application framework that provides a robust set of features to build web and mobile applications.

Why use MongoDB with Express.js?

MongoDB's flexible schema design makes it a perfect match for the fast and scalable nature of Express.js applications.

How do I handle errors in Express.js?

You can handle errors using middleware. For example:

app.use((err, req, res, next) => {
    console.error(err.stack);
    res.status(500).send('Something broke!');
});

Conclusion

By combining Express.js and MongoDB, you've built a flexible REST API that can grow with your application's needs. Keep optimizing and iterating to improve performance.