server.js

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

const app = express();
app.use(express.json());

// Connect to MongoDB
mongoose.connect('mongodb://localhost:27017/crudapi', {
  useNewUrlParser: true,
  useUnifiedTopology: true,
});

// Define a simple schema and model for demonstration
const itemSchema = new mongoose.Schema({
  name: String,
  quantity: Number,
});

const Item = mongoose.model('Item', itemSchema);

// CRUD operations
// Create
app.post('/items', async (req, res) => {
  const item = new Item(req.body);
  await item.save();
  res.status(201).send(item);
});

// Read
app.get('/items', async (req, res) => {
  const items = await Item.find();
  res.send(items);
});

// Update
app.put('/items/:id', async (req, res) => {
  const item = await Item.findByIdAndUpdate(req.params.id, req.body, { new: true });
  res.send(item);
});

// Delete
app.delete('/items/:id', async (req, res) => {
  await Item.findByIdAndDelete(req.params.id);
  res.status(204).send();
});

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