fp-async

Practical Async Patterns with fp-ts

Stop writing nested try/catch blocks. Stop losing error context. Start building clean async pipelines that handle errors properly.

TaskEither is simply an async operation that tracks success or failure. That's it. No fancy terminology needed.

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 need async error handling in TypeScript with TaskEither.
• The task involves wrapping Promises, composing API calls, or replacing nested try/catch flows.
• You want practical fp-ts async patterns instead of academic explanations.

// TaskEither<Error, User> means:
// "An async operation that either fails with Error or succeeds with User"

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5. Real API Examples

Complete Fetch Wrapper

// types.ts
interface ApiError {
  code: string
  message: string
  status: number
  details?: unknown
}

// api.ts
const createApiError = (
  code: string,
  message: string,
  status: number,
  details?: unknown
): ApiError => ({ code, message, status, details })

const request = <T>(
  url: string,
  options: RequestIn