Layers & Services

effect-layers-services

Define services, provide layers, compose dependencies, and switch live/test. Use for DI boundaries and app composition.

diegosouzapw/awesome-omni-skill·0installs62stars

SKILL.md

Full skill instructions

Layers & Services

When to use

You need DI boundaries or swapping test/live implementations
You want to compose infra (logger, db, http) once for the app

Define Service

class UserRepo extends Effect.Service<UserRepo>()("UserRepo", {
  sync: () => ({ find: (id: string) => Effect.succeed({ id }) })
}) {}

Provide Layer

const program = Effect.gen(function* () {
  const repo = yield* UserRepo
  return yield* repo.find("123")
}).pipe(Effect.provide(UserRepo.Default))

Compose

const AppLayer = Layer.merge(UserRepo.Default, Logger.Default)

Test vs Live

const layer = process.env.NODE_ENV === "test" ? UserRepoTest : UserRepo.Default

Guidance

Services define interfaces; Layers bind implementations
Compose layers at the app boundary; keep handlers unaware of wiring
Use .Default for quick live/test setup; add custom layers as needed

Pitfalls

Circular layer dependencies → split modules, provide from above
Providing layers too deep → centralize to avoid duplication and confusion

Cross-links

Foundations: requirement channel R and provisioning
Resources: scoped resources exposed via layers
EffectPatterns inspiration: https://github.com/PaulJPhilp/EffectPatterns

Local Source Reference

CRITICAL: Search local Effect source before implementing

The full Effect source code is available at docs/effect-source/. Always search the actual implementation before writing Effect code.

Key Source Files

Layer: docs/effect-source/effect/src/Layer.ts
Effect: docs/effect-source/effect/src/Effect.ts
Context: docs/effect-source/effect/src/Context.ts

Example Searches

# Find Layer composition patterns
grep -F "Layer.merge" docs/effect-source/effect/src/Layer.ts
grep -F "Layer.provide" docs/effect-source/effect/src/Layer.ts

# Study Effect.Service patterns
grep -F "Effect.Service" docs/effect-source/effect/src/Effect.ts

# Find Context usage
grep -F "Tag" docs/effect-source/effect/src/Context.ts
grep -F "make" docs/effect-source/effect/src/Context.ts

# Look at Layer test examples
grep -F "Layer." docs/effect-source/effect/test/Layer.test.ts

Workflow

Identify the Layer or Service API you need
Search docs/effect-source/effect/src/Layer.ts for the implementation
Study the types and composition patterns
Look at test files for usage examples
Write your code based on real implementations

Real source code > documentation > assumptions

References

Agent Skills overview: https://www.anthropic.com/news/skills
Skills guide: https://docs.claude.com/en/docs/claude-code/skills

Install skill

Copy and run in your terminal

npx -y skills add https://github.com/diegosouzapw/awesome-omni-skill --skill effect-layers-services-majiayu000

View on GitHub

skills/development/effect-layers-services-majiayu000/SKILL.md

ui-ux-design-system
Expert in building premium, accessible UI/UX design systems for SaaS apps. Covers design tokens, component architecture with shadcn/ui and Radix, dark mode, glassmorphism, micro-animations, responsive layouts, and accessibility. Use when: ui, ux, design system, shadcn, radix, tailwind, dark mode,...
1 installs
frontend
Defines frontend standards for Next.js App Router, React 19, React Query, shadcn/ui. Use when building components, pages, hooks, or frontend state management.
1 installs
design-ui-ux-pro-max
UI/UX design intelligence. 50 styles, 21 palettes, 50 font pairings, 20 charts, 9 stacks (React, Next.js, Vue, Svelte, SwiftUI, React Native, Flutter, Tailwind, shadcn/ui). Actions: plan, build, create, design, implement, review, fix, improve, optimize, enhance, refactor, check UI/UX code. Projec...
1 installs
sql-and-database
SQL writing and database engineering patterns, standards, and procedures. Use for designing database schemas, writing performant SQL queries, normalisation strategies, indexing, joins optimisation, locking mechanics, transactions, query debugging with EXPLAIN, and ORM integration. Applies to Post...
1 installs