typescript-functional

Expert guidance on functional programming patterns in TypeScript. Use when writing TypeScript code that emphasizes pure functions, immutability, composition, and declarative style. Prevents common imperative anti-patterns and promotes concise, maintainable code.

Principles

• Pure functions: No side effects, deterministic outputs
• Immutability: Data never mutates, create new values instead
• Composition: Build complex functions from simple ones
• Declarative: Express what to do, not how to do it
• Conciseness: Minimize boilerplate, maximize clarity

Style Guide

Prefer

• Ternary operators over if statements for simple conditionals
• Switch statements over if/else chains for multiple conditions
• Array methods (map, filter, reduce) over for loops
• Function expressions over function statements
• const over let, never use var
• Expression-based code over statement-based
• Early returns for guard clauses

Avoid

• Mutations of variables or objects
• For/while loops when array methods work
• Nested conditionals
• Multi-line if statements for simple logic
• Side effects in functions (prefer explicit effect handling)

Structure

• SKILL.md - Main skill instructions and quick reference
• references/ - Detailed documentation for specific patterns
• examples/ - TypeScript code examples demonstrating patterns

Usage

This skill is automatically discovered by Claude when working with TypeScript or when functional programming patterns are relevant to the task.