<A, E, R>(self: Layer<A, E, R>): Layer<A, never, R>Converts layer construction failures into defects, removing them from the layer's error type.
Details
Use this only when failures should be treated as unrecoverable defects rather than typed errors that callers can handle.
Example (Converting layer failures to defects)
import { Context, Data, Effect, Layer } from "effect"
class DatabaseError extends Data.TaggedError("DatabaseError")<{
message: string
}> {}
class Database extends Context.Service<Database, {
readonly query: (sql: string) => Effect.Effect<string>
}>()("Database") {}
// Layer that can fail during construction
const flakyDatabaseLayer = Layer.effect(Database, Effect.gen(function*() {
console.log("connecting")
return yield* new DatabaseError({ message: "Connection failed" })
}))
// Convert failures to fiber death - removes error from type
const reliableDatabaseLayer = flakyDatabaseLayer.pipe(Layer.orDie)
// Now the layer type is Layer<Database, never, never> - no error in type
const program = Effect.gen(function*() {
const database = yield* Database
return yield* database.query("SELECT * FROM users")
}).pipe(
Effect.provide(reliableDatabaseLayer)
)
// Running the program prints "connecting", then the DatabaseError is
// converted into a fiber defect instead of remaining a typed error.export const const orDie: <A, E, R>(
self: Layer<A, E, R>
) => Layer<A, never, R>
Converts layer construction failures into defects, removing them from the
layer's error type.
Details
Use this only when failures should be treated as unrecoverable defects rather
than typed errors that callers can handle.
Example (Converting layer failures to defects)
import { Context, Data, Effect, Layer } from "effect"
class DatabaseError extends Data.TaggedError("DatabaseError")<{
message: string
}> {}
class Database extends Context.Service<Database, {
readonly query: (sql: string) => Effect.Effect<string>
}>()("Database") {}
// Layer that can fail during construction
const flakyDatabaseLayer = Layer.effect(Database, Effect.gen(function*() {
console.log("connecting")
return yield* new DatabaseError({ message: "Connection failed" })
}))
// Convert failures to fiber death - removes error from type
const reliableDatabaseLayer = flakyDatabaseLayer.pipe(Layer.orDie)
// Now the layer type is Layer<Database, never, never> - no error in type
const program = Effect.gen(function*() {
const database = yield* Database
return yield* database.query("SELECT * FROM users")
}).pipe(
Effect.provide(reliableDatabaseLayer)
)
// Running the program prints "connecting", then the DatabaseError is
// converted into a fiber defect instead of remaining a typed error.
orDie = <function (type parameter) A in <A, E, R>(self: Layer<A, E, R>): Layer<A, never, R>A, function (type parameter) E in <A, E, R>(self: Layer<A, E, R>): Layer<A, never, R>E, function (type parameter) R in <A, E, R>(self: Layer<A, E, R>): Layer<A, never, R>R>(self: Layer<A, E, R>(parameter) self: {
build: (memoMap: MemoMap, scope: Scope.Scope) => Effect<Context.Context<A>, E, R>;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
interface Layer<in ROut, out E = never, out RIn = never>A Layer describes how to build one or more services for dependency injection.
When to use
Use to model construction of application services for dependency injection,
especially when services have dependencies, can fail during construction, or
need scoped setup and release.
Details
A Layer<ROut, E, RIn> represents ROut as the services this layer
provides, E as the possible errors during layer construction, and RIn as
the services this layer requires as dependencies.
Layer<function (type parameter) A in <A, E, R>(self: Layer<A, E, R>): Layer<A, never, R>A, function (type parameter) E in <A, E, R>(self: Layer<A, E, R>): Layer<A, never, R>E, function (type parameter) R in <A, E, R>(self: Layer<A, E, R>): Layer<A, never, R>R>): interface Layer<in ROut, out E = never, out RIn = never>A Layer describes how to build one or more services for dependency injection.
When to use
Use to model construction of application services for dependency injection,
especially when services have dependencies, can fail during construction, or
need scoped setup and release.
Details
A Layer<ROut, E, RIn> represents ROut as the services this layer
provides, E as the possible errors during layer construction, and RIn as
the services this layer requires as dependencies.
Layer<function (type parameter) A in <A, E, R>(self: Layer<A, E, R>): Layer<A, never, R>A, never, function (type parameter) R in <A, E, R>(self: Layer<A, E, R>): Layer<A, never, R>R> =>
const fromBuildUnsafe: <ROut, E, RIn>(
build: (
memoMap: MemoMap,
scope: Scope.Scope
) => Effect<Context.Context<ROut>, E, RIn>
) => Layer<ROut, E, RIn>
memoMap: MemoMap(parameter) memoMap: {
get: <RIn, E, ROut>(layer: Layer<ROut, E, RIn>, scope: Scope.Scope) => Effect<Context.Context<ROut>, E, RIn> | undefined;
getOrElseMemoize: <RIn, E, ROut>(layer: Layer<ROut, E, RIn>, scope: Scope.Scope, build: (memoMap: MemoMap, scope: Scope.Scope) => Effect<Context.Context<ROut>, E, RIn>) => Effect<Context.Context<ROut>, E, RIn>;
}
scope: Scope.Scope(parameter) scope: {
strategy: "sequential" | "parallel";
state: State.Open | State.Closed | State.Empty;
}
import internalEffectinternalEffect.const orDie: <A, E, R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<A, never, R>
self: Layer<A, E, R>(parameter) self: {
build: (memoMap: MemoMap, scope: Scope.Scope) => Effect<Context.Context<A>, E, R>;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
function Layer(memoMap: MemoMap, scope: Scope.Scope): Effect<Context.Context<A>, E, R>build(memoMap: MemoMap(parameter) memoMap: {
get: <RIn, E, ROut>(layer: Layer<ROut, E, RIn>, scope: Scope.Scope) => Effect<Context.Context<ROut>, E, RIn> | undefined;
getOrElseMemoize: <RIn, E, ROut>(layer: Layer<ROut, E, RIn>, scope: Scope.Scope, build: (memoMap: MemoMap, scope: Scope.Scope) => Effect<Context.Context<ROut>, E, RIn>) => Effect<Context.Context<ROut>, E, RIn>;
}
scope: Scope.Scope(parameter) scope: {
strategy: "sequential" | "parallel";
state: State.Open | State.Closed | State.Empty;
}