effect-ts

Implement idiomatic Effect v4 TypeScript patterns with ServiceMap, Layer, and Schema.

38|1|Updated Mar 19, 2026

Search Tags:#typescript #testing #error-handling #data-modeling #effect #layer #service-map

Ready to run

npx skills add https://github.com/joelhooks/effectts-skills --skill effect-ts-joelhooks

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: effect-ts
Source: https://github.com/joelhooks/effectts-skills/tree/main/skills/effect-ts
Command: npx skills add https://github.com/joelhooks/effectts-skills --skill effect-ts-joelhooks

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Effect-TS Skill helps developers write idiomatic Effect v4 TypeScript patterns by providing proven patterns, examples, and scaffolding for services, layers, error handling, data modeling, and testing.

Core Features & Use Cases

ServiceMap.Service for strongly-typed service interfaces and Layer-based dependency injection
Data modeling with Schema.Class, branded types, and tagged errors
End-to-end guidance for building Effect v4 apps including testing, HTTP clients, and CLI integrations
Clear examples and references to real-world patterns

Quick Start

Create a minimal Effect v4 project and implement a simple service using ServiceMap and Layer, then test it with a simple runner.

Frequently Asked Questions about effect-ts

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I structure dependency injection in TypeScript using Effect layers?▼

Structure dependency injection in TypeScript using Effect layers by defining strongly-typed service interfaces with ServiceMap.Service and composing them via Layer. This approach provides modular, testable dependency management for real-world applications.

What is the best way to model data and handle errors in Effect v4?▼

Model data and handle errors in Effect v4 by using Schema.Class for data modeling alongside branded types, and TaggedErrorClass for typed errors. This ensures type-safe data validation and explicit error management.

How do I test services built with Effect v4 in TypeScript?▼

Test services built with Effect v4 by leveraging Layer composition to swap real implementations with test mocks. The Skill provides end-to-end testing guidance and concrete examples for running Effect-based service tests.

Can I use Effect.gen and Effect.fn for asynchronous workflows in TypeScript?▼

Yes, you can use Effect.gen and Effect.fn to structure asynchronous workflows in TypeScript. These idiomatic Effect v4 patterns allow you to write sequential-style code that handles complex concurrent operations safely.

Does Effect v4 work for building HTTP clients and CLI utilities?▼

Effect v4 works for building HTTP clients and CLI utilities by applying its modular service composition and error handling patterns. The Skill provides end-to-end guidance for integrating these utilities into TypeScript projects.