Product Catalog Pagination API

Build a product catalog API that efficiently retrieves products with pagination support.

Overview

You need to create a module that fetches products from a database with pagination capabilities. The system should support two pagination strategies: limit-based pagination for simple page sizes and range-based pagination for more precise control over result sets.

Requirements

Core Functionality

Implement a ProductCatalog class with the following methods:

1. getProductsWithLimit(pageSize)

   • Fetches products limited to a specific page size
   • Returns an array of product objects
   • Should retrieve only the specified number of products

2. getProductsInRange(startIndex, endIndex)

   • Fetches products within a specific index range (inclusive)
   • Returns an array of product objects
   • The range should be zero-based and inclusive on both ends

3. getPagedProducts(page, pageSize)

   • Fetches a specific page of products
   • Page numbers start at 1
   • Returns an array of product objects for the requested page

Database Schema

The database contains a products table with the following structure:

• id (integer): Product ID
• name (string): Product name
• price (number): Product price
• category (string): Product category
• created_at (timestamp): Creation timestamp

Error Handling

• Handle cases where the range or limit parameters are invalid
• Return appropriate error responses for database connection issues

Test Cases

Implement the following test cases in product-catalog.test.ts:

Test 1: Fetch products with limit { @test }

// Given a database with 100 products
// When fetching with a limit of 10
const products = await catalog.getProductsWithLimit(10);
// Then exactly 10 products should be returned
assert(products.length === 10);

Test 2: Fetch products in a range { @test }

// Given a database with 100 products
// When fetching products from index 20 to 29 (inclusive)
const products = await catalog.getProductsInRange(20, 29);
// Then exactly 10 products should be returned (indices 20-29)
assert(products.length === 10);

Test 3: Fetch a specific page { @test }

// Given a database with 100 products and pageSize of 25
// When fetching page 2
const products = await catalog.getPagedProducts(2, 25);
// Then exactly 25 products should be returned (items 26-50)
assert(products.length === 25);

Implementation Notes

• Focus on implementing efficient pagination queries
• Ensure the range-based method correctly handles zero-based inclusive ranges
• The paged products method should internally calculate the correct range based on page number and page size

Dependencies { .dependencies }

@supabase/supabase-js { .dependency }

Provides database client for querying the PostgreSQL database with pagination support.

Deliverables

• product-catalog.ts: Main implementation file with the ProductCatalog class
• product-catalog.test.ts: Test file with all test cases passing