2. CRUD Operations

1. Simple CRUD Example

Here’s a full CRUD (Create, Read, Update, Delete) example in Express.js using an in-memory array as the data store — no database required.

1.1 📄 server.js

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

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

// In-memory data (acts like a fake DB)
let items = [
  { id: 1, name: 'Apple' },
  { id: 2, name: 'Banana' }
];

// 🔹 CREATE
app.post('/items', (req, res) => {
  const newItem = {
    id: items.length + 1,
    name: req.body.name
  };
  items.push(newItem);
  res.status(201).json(newItem);
});

// 🔹 READ all
app.get('/items', (req, res) => {
  res.json(items);
});

// 🔹 READ one
app.get('/items/:id', (req, res) => {
  const item = items.find(i => i.id === parseInt(req.params.id));
  if (!item) return res.status(404).send('Item not found');
  res.json(item);
});

// 🔹 UPDATE
app.put('/items/:id', (req, res) => {
  const item = items.find(i => i.id === parseInt(req.params.id));
  if (!item) return res.status(404).send('Item not found');

  item.name = req.body.name;
  res.json(item);
});

// 🔹 DELETE
app.delete('/items/:id', (req, res) => {
  const index = items.findIndex(i => i.id === parseInt(req.params.id));
  if (index === -1) return res.status(404).send('Item not found');

  const deleted = items.splice(index, 1);
  res.json(deleted[0]);
});

// 🔹 Start server
app.listen(3000, () => console.log('Server running on http://localhost:3000'));

1.2 🧪 Sample Requests

• GET /items → List all items
• GET /items/1 → Get item with id = 1
• POST /items → Add new item

  { "name": "Orange" }

• PUT /items/2 → Update item with id = 2

  { "name": "Grapes" }

• DELETE /items/1 → Delete item with id = 1

1.3 📝 Notes

• The id is incremented automatically here (simple logic).
• No database used — restarting the server will reset data.
• Use tools like Postman or cURL to test the API.