Case Study: E-Commerce Application

User Features

Admin Features

Model Layer

User Model: defines username, email, password, and role.

Product Model: defines name, price, description, category, and stock quantity.

Order Model: defines user, order items, shipping address, payment method, and order status.

// User Model (models/User.js)
const mongoose = require('mongoose');
const bcrypt = require('bcryptjs');
const userSchema = mongoose.Schema({
  name: { type: String, required: true },
  email: { type: String, required: true, unique: true },
  password: { type: String, required: true },
  isAdmin: { type: Boolean, default: false }
}, {
  timestamps: true
});
userSchema.methods.matchPassword = async function (enteredPassword) {
  return await bcrypt.compare(enteredPassword, this.password);
};
const User = mongoose.model('User', userSchema);
module.exports = User;

View Layer

React Components: structured to separate concerns, with components for the homepage, product listing, product details, cart, and admin dashboard.

Redux: manages application state, including auth status, product data, and cart contents.

// ProductList Component (components/ProductList.js)
import React, { useEffect } from 'react';
import { useDispatch, useSelector } from 'react-redux';
import { listProducts } from '../actions/productActions';
import Product from './Product';

const ProductList = () => {
  const dispatch = useDispatch();
  const { loading, error, products } = useSelector((state) => state.productList);

  useEffect(() => {
    dispatch(listProducts());
  }, [dispatch]);

  return loading ? (
    
Loading...
  ) : error ? (
    
{error}
  ) : (
    

      {products.map((product) => (
        
      ))}
    
  );
};

export default ProductList;

Controller Layer

Express Routes: define API endpoints for CRUD operations on products, user authentication, and order processing.

Middleware: JWT middleware protects routes that require authentication.

// Product Controller (controllers/productController.js)
const asyncHandler = require('express-async-handler');
const Product = require('../models/Product');

// @desc    Fetch all products
// @route   GET /api/products
// @access  Public
const getProducts = asyncHandler(async (req, res) => {
  const products = await Product.find({});
  res.json(products);
});

// @desc    Fetch single product
// @route   GET /api/products/:id
// @access  Public
const getProductById = asyncHandler(async (req, res) => {
  const product = await Product.findById(req.params.id);
  if (product) {
    res.json(product);
  } else {
    res.status(404);
    throw new Error('Product not found');
  }
});

module.exports = { getProducts, getProductById };