Skip to content
Josh Deeden

Solution Overview

Code Refactor Exercise

Project Summary

This project entailed a comprehensive refactor of the executeStandardPTOperations function in a Node.js environment, focusing on enhancing code quality, particularly in the context of RDS database transactions. The objective was to improve the codebase across readability, maintainability, testability, and architecture.

Requirements

  • Objective: Refactor and unit test the executeStandardPTOperations function.
  • Key Areas: Emphasis on readability, maintainability, testability, and understandability.
  • Testing: Implement mocking for RDS calls and ensure comprehensive unit test coverage.

Assumptions

  • Language: TypeScript, chosen for type safety.
  • Environment: Node.js runtime.
  • Database Details: Database schema specifics deemed non-critical.
  • Transactional Handling: External management of transactions.
  • Testing Aim: Behavioral validation of executeStandardPTOperations.

Technical Approach

TypeScript Integration

  • Type Safety: Early detection of errors, proper data structure usage, and correct parameter passing.
  • Developer Experience: Tooling support such as autocompletion and informative error messages.
  • Readability and Maintainability: Clear type annotations for better code comprehension and maintenance.

Separation of Concerns

  • Modular Structure: Specific database functions like insertPayment for focused database interaction.
  • Database Interaction Abstraction: The DB interface simplifies the business logic by abstracting SQL query construction.
  • Input Validation with Zod: Ensures data integrity before processing.
  • Configuration Management: Independent management of environmental variables.
  • Testing Isolation: Unit tests written in separate files, targeting individual components.

Testability Enhancements

  • Modular Design: Facilitates isolated testing of smaller components.
  • Defined Inputs/Outputs: Simplifies test creation and understanding.
  • Mocking External Dependencies: Enables behavior testing without real database dependencies.
  • Robust Error Handling: Supports testing under varied failure scenarios.
  • Stateless Design: Reduces complexity in test setup and cleanup.

Design Patterns

  • Factory Pattern: Used in creating database operations, enhancing modularity.
  • Module Pattern: TypeScript modules for cohesive and encapsulated code organization.
  • Strategy Pattern: Demonstrated in interchangeable database operations.
  • Facade Pattern: DB interface acts as a simplified gateway to complex database logic.

Code Quality

  • ESLint: Used for enforcing coding standards and identifying potential issues.
  • Automated Testing: Continuous quality checks and prevention of regression errors.
  • Performance Optimization: Focused on database interaction efficiency and response times.
  • Scalability Considerations: Modular and abstracted design for easy scaling and modifications.