Why should I use Layers instead of standard imports?

Layers enable dependency injection, allowing you to swap production implementations with test mocks easily, leading to better modularity and testability.

Are Effect Layers memoized?

Yes, Layers are memoized by default, meaning a service is created only once even if it is shared by multiple dependent layers.

How does this skill help with unit testing?

It provides patterns for creating stateless and stateful test layers, allowing you to achieve 100% coverage by controlling all external I/O.

How do I handle resources that need cleanup, like database pools?

Use Layer.scoped to define services with a lifecycle, ensuring resources are automatically cleaned up when the scope is closed.

What is the 'R' parameter in Effect ?

The 'R' represents Requirements, which are the services or dependencies (such as databases, loggers, or APIs) an effect needs to access during execution.

Effect Requirements & Dependency Injection

Name: Effect Requirements & Dependency Injection
Author: andrueandersoncs

byandrueandersoncs

•

API 开发

Manage services and dependencies in Effect applications using tags and layers to ensure modularity and 100% testability.

This skill provides specialized guidance for handling the Requirements (R) type parameter in the Effect TS ecosystem. It assists developers in defining service interfaces with Context.Tag, constructing dependency graphs via Layers, and implementing robust dependency injection patterns. By emphasizing the creation of test layers and mocking external dependencies like APIs or databases, it empowers developers to build highly maintainable, loosely coupled, and fully testable functional TypeScript applications. It covers everything from basic service definition to complex layer composition and resource lifecycle management.

主要功能

01Advanced layer composition using merge, provide, and provideMerge

02Implementation of stateful test layers and mock services for testing

033 GitHub stars

04Service definition using Effect.Tag and Context.Tag patterns

05Guidance on layer memoization and overriding default Effect services

06Layer construction for simple values, effects, and scoped resources

使用场景

01Managing complex resource lifecycles like database connection pools

02Architecting scalable TypeScript backends with clean dependency injection

03Mocking external APIs, databases, or file systems for 100% test coverage

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add andrueandersoncs/claude-skill-effect-ts requirements-management

For use in Claude.ai and ChatGPT

Download Skill