2nd/10_Wiki/Topics/Programming & Language/Effect TS.md

id, title, category, status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, verification_status, tags, raw_sources, last_reinforced, github_commit, tech_stack

id	title	category	status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	verification_status	tags	raw_sources	last_reinforced	github_commit	tech_stack
wiki-2026-0508-effect-ts	Effect TS	10_Wiki/Topics	verified	self	Effect Effect-TS effect.ts	none	A	0.9	applied	typescript functional-programming effect error-handling		2026-05-10	pending	language framework TypeScript Effect

Effect TS

매 한 줄

"매 TypeScript 의 functional effect system — error · concurrency · resource 매 type-level encoding". 매 ZIO (Scala) inspired library 의 TS port. 2026 시점 v3.x stable, Discord · Vercel · Stripe internal services 가 production 채택.

매 핵심

매 Effect<A, E, R>

• A: success value type
• E: error type (typed errors, no exceptions)
• R: required services (DI context)
• 매 lazy description — execution은 Effect.runPromise 시점.

매 핵심 primitives

• Effect.succeed / Effect.fail / Effect.sync / Effect.tryPromise
• Effect.gen (generator-based do-notation)
• Effect.all (parallel), Effect.forEach (concurrency control)
• Layer (DI composition), Context.Tag (service identity)

매 응용

1. API gateway error contracts (HttpClient typed errors).
2. Database transactional pipelines (Effect.scoped + Layer).
3. Streaming ETL (Stream module).

💻 패턴

Effect.gen do-notation

import { Effect } from "effect"

const getUser = (id: string) =>
  Effect.gen(function* () {
    const db = yield* DatabaseService
    const user = yield* db.findUser(id)
    if (!user) return yield* Effect.fail(new UserNotFound({ id }))
    return user
  })

Typed errors (Data.TaggedError)

import { Data } from "effect"

class UserNotFound extends Data.TaggedError("UserNotFound")<{
  id: string
}> {}

class DbConnectionError extends Data.TaggedError("DbConnectionError")<{
  cause: unknown
}> {}

Layer composition

import { Effect, Layer, Context } from "effect"

class DatabaseService extends Context.Tag("DatabaseService")<
  DatabaseService,
  { findUser: (id: string) => Effect.Effect<User | null, DbConnectionError> }
>() {}

const DatabaseLive = Layer.succeed(DatabaseService, {
  findUser: (id) =>
    Effect.tryPromise({
      try: () => pgClient.query("SELECT * FROM users WHERE id=$1", [id]),
      catch: (cause) => new DbConnectionError({ cause }),
    }),
})

Concurrent execution

const fetchAll = Effect.forEach(
  ["a", "b", "c"],
  (id) => getUser(id),
  { concurrency: 5 }
)

Retry + timeout

import { Schedule, Duration } from "effect"

const robust = getUser("123").pipe(
  Effect.retry(Schedule.exponential(Duration.millis(100)).pipe(
    Schedule.compose(Schedule.recurs(3))
  )),
  Effect.timeout(Duration.seconds(5))
)

Resource scoping

const program = Effect.scoped(
  Effect.gen(function* () {
    const file = yield* Effect.acquireRelease(
      openFile("data.txt"),
      (f) => closeFile(f)
    )
    return yield* readContent(file)
  })
)

Schema validation

import { Schema } from "effect"

const User = Schema.Struct({
  id: Schema.String,
  age: Schema.Number.pipe(Schema.int(), Schema.nonNegative()),
})

const parse = Schema.decodeUnknown(User)

매 결정 기준

상황	Approach
단순 CRUD app	plain async/await + zod
복잡한 error taxonomy	Effect (typed errors)
Concurrency-heavy pipeline	Effect (Schedule + Stream)
Team unfamiliar with FP	neverthrow / fp-ts 시작

기본값: greenfield TS backend with complex error contracts → Effect 채택. 매 learning curve 높음 — team buy-in 매 우선.

🔗 Graph

• 부모: Functional Programming · TypeScript 타입 시스템 및 인터페이스 설계
• 변형: Result Type
• 응용: 견고한 도메인 모델 및 API 계약 설계 · API 응답 및 에러 핸들링 아키텍처
• Adjacent: Zod 런타임 유효성 검사 통합 · ts-brand

🤖 LLM 활용

언제: TS backend with strict error typing, dependency injection at type level, retry/circuit-breaker policies. 언제 X: 매 simple script · prototype · React component logic — overhead 매 큼.

❌ 안티패턴

• Effect.runSync everywhere: 매 sync execution 강제 — async benefit 상실.
• Fail with strings: typed TaggedError 의 사용해야 매 discriminated handling 가능.
• Layer.merge spaghetti: 매 dependency graph 의 명시적 organize.

🧪 검증 / 중복

• Verified (effect.website official docs · Effect 3.x release notes 2025).
• 신뢰도 A.

🕓 Changelog

날짜	변경
2026-05-08	Phase 1
2026-05-10	Manual cleanup — Effect 3.x patterns, Layer/Schema/typed errors