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fp-ts-errors

fp-ts-errors

github.com/sickn33Development48.7k71 installsUpdated today
Repository

About fp-ts-errors

fp-ts-errors is a practical skill for TypeScript developers who need explicit, type-safe error handling. It presents fp-ts Either and TaskEither patterns for representing failures as values and handling validation errors.

Key features

  1. 01Either-based error values
  2. 02TaskEither side-effect patterns
  3. 03Explicit error types for APIs
  4. 04Accumulation of validation errors
  5. 05Guidance on retries and mutation safety

Use cases

  1. 01Replace try/catch flows with typed results
  2. 02Define explicit errors in an API
  3. 03Collect multiple input validation failures

Install

Copy the command and run it in a terminal.

$npx skills add https://github.com/sickn33/agentic-awesome-skills --skill fp-ts-errors

After installing, type/fp-ts-errorsin Claude Code to confirm it loaded.

Bundled filesreferences/detailed-guide.md

Details

From the project README

Practical Error Handling with fp-ts

This skill teaches you how to handle errors without try/catch spaghetti. No academic jargon - just practical patterns for real problems.

Detailed Guide

Read the detailed guide 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 This Skill

  • When you want type-safe error handling in TypeScript
  • When replacing try/catch with Either and TaskEither patterns
  • When building APIs or services that need explicit error types
  • When accumulating multiple validation errors

The core idea: Errors are just data. Instead of throwing them into the void and hoping someone catches them, return them as values that TypeScript can track.

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.

Type and side-effect boundaries

These are separate fragments, not one compilable module: imports, domain types and application helpers must be supplied. FormData means a custom record with email/password/age fields here, not the browser FormData class. Import Task as T wherever T.of is used and Array as A in the bulk fragment. fp-ts Either can still be ignored; a return type does not force a caller to inspect it. Functions inside map/chain must not throw outside an explicitly wrapped boundary, and TaskEither does not automatically catch every rejection.

JSON parsing or as T checks syntax/type assertions, not runtime shape; decode unknown data using a real schema. Do not use the default-user fallback for authentication/authorization failures. Retry only transient idempotent operations, validate positive integer attempt counts and finite bounded delay, and include SDK retries/deadlines. ApplyPar starts all operations and does not cancel siblings on Left; the bulk example uses sequential tasks to avoid unbounded parallel deletion. Actual mutations still need authorization, tenant checks, idempotency and partial-success reconciliation. Do not expose raw causes, credentials or submitted password values in logs/UI. No TypeScript compilation or service operation was performed.

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