Beginner's Guide - CRUD System using NodeJS, ExpressJS and MongoDB

Step 1: Set Up Your NodeJs Project

Create a new project folder and initialize a NodeJs project:


mkdir node-crud-app
cd node-crud-app
npm init -y

Install required dependencies:


npm install express mongoose body-parser cors dotenv

Step 2: Create the Basic Server

Create a new file server.js and add the following code:


const express = require('express');
const mongoose = require('mongoose');
const cors = require('cors');
const bodyParser = require('body-parser');
require('dotenv').config();

const app = express();
const PORT = process.env.PORT || 5000;
app.use(cors());
app.use(bodyParser.json());
mongoose.connect(process.env.MONGO_URI, { useNewUrlParser: true, useUnifiedTopology: true })
.then(() => console.log('MongoDB Connected'))
.catch(err => console.log(err));

app.get('/', (req, res) => { res.send('Welcome to the CRUD API'); });
app.listen(PORT, () => { console.log(`Server running on port ${PORT}`); });

Step 3: Define a Mongoose Model

Create a folder models and inside it, create Item.js:


const mongoose = require('mongoose');
const ItemSchema = new mongoose.Schema({
    name: { type: String, required: true },
    description: String,
    createdAt: { type: Date, default: Date.now }
});
module.exports = mongoose.model('Item', ItemSchema);

Step 4: Implement CRUD Routes

Create a folder routes and inside it, create items.js:


const express = require('express');
const router = express.Router();
const Item = require('../models/Item');

// CREATE an item
router.post('/', async (req, res) => {
    try { const newItem = new Item(req.body); await newItem.save(); res.status(201).json(newItem); }
    catch (err) { res.status(400).json({ message: err.message }); }
});
// READ all items
router.get('/', async (req, res) => {
    try { const items = await Item.find(); res.json(items); }
    catch (err) { res.status(500).json({ message: err.message }); }
});
// UPDATE an item
router.put('/:id', async (req, res) => {
    try { const updatedItem = await Item.findByIdAndUpdate(req.params.id, req.body, { new: true }); res.json(updatedItem); }
    catch (err) { res.status(400).json({ message: err.message }); }
});
// DELETE an item
router.delete('/:id', async (req, res) => {
    try { await Item.findByIdAndDelete(req.params.id); res.json({ message: 'Item deleted' }); }
    catch (err) { res.status(500).json({ message: err.message }); }
});
module.exports = router;

Step 5: Connect Routes to Server

Modify server.js to include the new routes:


const itemRoutes = require('./routes/items');
app.use('/items', itemRoutes);

Step 6: Test the API

Start your server:


node server.js

Test CRUD operations using Postman or cURL:

Create an item (POST):


POST http://localhost:5000/items
Body (JSON): { "name": "Laptop", "description": "A powerful laptop" }

Get all items (GET):


GET http://localhost:5000/items

Update an item (PUT):


PUT http://localhost:5000/items/{item_id}
Body (JSON): { "name": "Updated Laptop" }

Delete an item (DELETE):


DELETE http://localhost:5000/items/{item_id}

Conclusion

You now have a fully functional CRUD API using NodeJs, ExpressJs, and MongoDB!