Product Catalog API for an E-Commerce Platform

Problem Description

An e-commerce company needs a backend API for their product catalog. The catalog currently holds about 50,000 products and is growing. The frontend team and a mobile app team will consume this API.

Build a Node.js/Express REST API that supports:

• Listing products with the ability to filter by category, price range, and availability
• Getting the details of a single product by ID
• Creating a new product (admin use)
• Updating specific fields of an existing product (e.g., changing just the price without resending the entire product)
• Deleting a product (admin use)

Products have: id, name, description, price, category, in_stock (boolean), and created_at.

Output Specification

Implement the API in a src/ directory with an entry point at src/app.js (or src/app.ts). Use an in-memory array or SQLite for storage — no external database required.

Produce a package.json with all dependencies.

Do not start the server — just produce the source files.