architecture-paradigm-functional-core

What problem does it solve?

Business logic often gets entangled with I/O operations, making testing brittle and refactoring difficult. This skill guides you in applying the Functional Core, Imperative Shell pattern to separate deterministic logic from side-effect orchestration.

Core Features & Use Cases

• Side-Effect Inventory: Identify and map all I/O operations as shell responsibilities.
• Pure Core Modeling: Represent business policies as pure functions transforming data.
• Command Schema Design: Define clear command structures for the shell to interpret.
• Use Case: Refactor a complex e-commerce checkout process where payment processing (I/O) is mixed with pricing calculations (pure logic), making the pricing logic easily testable in isolation.

Quick Start

Inventory all side-effects in your module, then model your core business policies as pure functions that transform data.