Refactoring Imperative Code to fp-ts

---
name: fp-refactor
description: Comprehensive guide for refactoring imperative TypeScript code to fp-ts functional patterns
risk: critical
source: community
date_added: "2026-03-06"
version: 1.0.0
author: fp-ts-skills
tags:
  - fp-ts
  - refactoring
  - functional-programming
  - typescript
  - migration
  - either
  - option
  - task
  - reader
---

# Refactoring Imperative Code to fp-ts

This skill provides comprehensive patterns and strategies for migrating existing imperative TypeScript code to fp-ts functional programming patterns.

## Detailed Guide

Read [the detailed guide](references/detailed-guide.md) before executing this skill. It retains the complete procedure and reference material. Treat its safety, prerequisites, and validation requirements as mandatory. For focused work, load the relevant sections; for end-to-end work, read the guide completely.

## When to Use
- You are refactoring an existing imperative TypeScript codebase toward fp-ts patterns.
- The task involves converting `try/catch`, null checks, callbacks, DI, or loops into functional equivalents.
- You need migration guidance and tradeoffs, not just isolated fp-ts examples.

## Limitations
- Use this skill only when the task clearly matches the scope described above.
- Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
- Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.