Does this require a specific library?

The skill is designed to work with the @jagreehal/workflow library for composition, but the core Result pattern can be applied to any TypeScript project.

How does this skill handle third-party libraries that still throw errors?

It utilizes a step.try() utility that wraps throwing code (like JSON.parse or external SDKs) and maps those exceptions into typed Result objects for consistent processing.

What is the benefit of using Result types over throwing exceptions?

Result types make error cases explicit in the function signature, forcing developers to handle them at compile-time and preventing 'invisible' runtime crashes caused by unhandled exceptions.

What is railway-oriented programming in this context?

It is a pattern where functions are linked together like tracks; if one step returns an error, the execution 'switches tracks' to the error path and skips subsequent steps automatically.

Functional Result Types

Name: Functional Result Types
Author: jagreehal

byjagreehal

0•

API Development

Implements explicit error handling and workflow composition using Result types to replace hidden exceptions in TypeScript.

This skill guides Claude to adopt a functional approach to error handling by returning Result types instead of throwing exceptions. By making failure modes part of the function signature, it ensures that errors are visible, type-safe, and handled exhaustively. It leverages the @jagreehal/workflow library for railway-oriented programming, allowing complex business logic to be composed into clean, readable steps that automatically handle error propagation and short-circuiting.

Key Features

010 GitHub stars

02Replaces invisible exceptions with explicit Result<T, E> types

03Provides step.try() for bridging throwing third-party code into result pipelines

04Standardizes mapping between domain errors and HTTP status codes

05Integrates railway-oriented programming using createWorkflow

06Enforces exhaustive error handling via TypeScript discriminated unions

Use Cases

01Standardizing error responses across a REST or GraphQL API boundary

02Composing multi-step business logic that requires clean short-circuiting on failure

03Building mission-critical backend services where failure modes must be explicitly documented

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add jagreehal/jagreehal-claude-skills result-types

For use in Claude.ai and ChatGPT

Download Skill