* Check if username exists * @param username Username to check * @returns Promise resolving to boolean indicating existence

* Create an order item * @param orderId Order ID * @param productId Product ID * @param quantity Quantity * @param priceAtTime Price at ti

* Check if email exists * @param email Email to check * @returns Promise resolving to boolean indicating existence

* Check if category exists by ID * @param id Category ID * @returns Promise resolving to boolean

* Find categories by parent ID * @param parentId Parent category ID (null for root categories) * @returns Promise resolving to array of Categori

* Get products by category * @param categoryId Category ID * @param page Page number * @param limit Items per page * @returns Promise reso

* Get products by seller * @param sellerId Seller ID * @param page Page number * @param limit Items per page * @returns Promise resolving

* Get count of items in cart * @param userId User ID * @returns Promise resolving to item count

Determine action based on error type and attempt count. Decision logic: 1. If error is permanent -> FAIL_IMMEDIATELY 2. If max retries re

Check if an error is due to throttling. Throttling errors include: - ProvisionedThroughputExceededException: DynamoDB throttling - Thrott

* Simulated payment processing service * In a real application, this would integrate with actual payment gateways * like Stripe, PayPal, Square,

* Simulated payment processing service * In a real application, this would integrate with actual payment gateways * like Stripe, PayPal, Square,

* Validate payment method and details

* Validate payment method and details

* Check if setting parent would create a cycle * @param categoryId Category ID * @param newParentId New parent ID * @returns Promise resolvin

* Create a new category

* Create a new category

* Find child categories of a parent * @param parentId Parent category ID * @returns Promise resolving to array of child Categories

* Get product with details (includes category and seller info) * @param productId Product ID * @returns Promise resolving to ProductWithDetails

Load CSV file into DynamoDB with shuffling and parallel processing. This method: 1. Reads all records from the CSV file 2. Sh

* Make request with reliability improvements

* Make request with reliability improvements

Calculate success rate percentage. Returns: Success rate as a percentage (0-100)

* Create a test product

* Create a test product

* Get orders by status * @param status Order status * @param limit Maximum number of orders to return * @returns Promise resolving to array o

* Get count of user orders * @param userId User ID * @returns Promise resolving to order count

Executes a request with hedging strategy. This method sends an initial request and then sends additional identical requests (hedged requests) after sp

Load CSV file into DynamoDB with shuffling and parallel processing. This method: 1. Reads all records from the CSV file 2. Sh

* Update an existing category

* Update an existing category

* Validate parent ID exists * @param parentId Parent ID to validate * @returns Promise resolving to boolean

Split records into batches. Args: records: List of records Returns: List of batches, where each batch is a l

* Clean up all test data created during tests

* Clean up all test data created during tests

* Find root categories (categories with no parent) * @returns Promise resolving to array of root Categories

* Handle errors consistently across components

* Handle errors consistently across components