Build an E-Commerce Orders API

Problem/Feature Description

Build the backend API for a simple e-commerce platform using Express and TypeScript.

Resources:

• Product: { id, name, price, stock }
• Order: { id, customerEmail, items: [{productId, quantity}], status, total, createdAt }

Endpoints:

• GET /api/products -- list all products
• GET /api/products/:id -- get a single product
• POST /api/products -- create a product (name required, price > 0, stock >= 0)
• POST /api/orders -- place an order:
  • customerEmail is required and must contain @
  • items array must be non-empty
  • each item must reference an existing product ID
  • each item quantity must be > 0
  • each referenced product must have sufficient stock
  • deduct stock from products on successful order
  • calculate and store the order total
• GET /api/orders/:id -- get an order by ID

Seed the product store with 3-5 sample products. Use in-memory storage.

Output Specification

Produce:

• src/server.ts -- server entry point
• src/app.ts -- Express application setup
• src/routes/products.ts -- product route handlers
• src/routes/orders.ts -- order route handlers
• package.json -- with dependencies listed

You may create additional files as needed.