<const Layers extends [Layer.Any, ...Array<Layer.Any>]>(
layers: Layers,
options?: { readonly local?: boolean | undefined } | undefined
): <A, E, R>(
self: Effect<A, E, R>
) => Effect<
A,
E | Layer.Error<Layers[number]>,
| Layer.Services<Layers[number]>
| Exclude<R, Layer.Success<Layers[number]>>
>
<ROut, E2, RIn>(
layer: Layer.Layer<ROut, E2, RIn>,
options?: { readonly local?: boolean | undefined } | undefined
): <A, E, R>(
self: Effect<A, E, R>
) => Effect<A, E | E2, RIn | Exclude<R, ROut>>
<R2>(context: Context.Context<R2>): <A, E, R>(
self: Effect<A, E, R>
) => Effect<A, E, Exclude<R, R2>>
<A, E, R, const Layers extends [Layer.Any, ...Array<Layer.Any>]>(
self: Effect<A, E, R>,
layers: Layers,
options?: { readonly local?: boolean | undefined } | undefined
): Effect<
A,
E | Layer.Error<Layers[number]>,
| Layer.Services<Layers[number]>
| Exclude<R, Layer.Success<Layers[number]>>
>
<A, E, R, ROut, E2, RIn>(
self: Effect<A, E, R>,
layer: Layer.Layer<ROut, E2, RIn>,
options?: { readonly local?: boolean | undefined } | undefined
): Effect<A, E | E2, RIn | Exclude<R, ROut>>
<A, E, R, R2>(
self: Effect<A, E, R>,
context: Context.Context<R2>
): Effect<A, E, Exclude<R, R2>>Provides dependencies to an effect using layers or a context. Use options.local
to build the layer every time; by default, layers are shared between provide
calls.
Example (Providing dependencies with a layer)
import { Context, Effect, Layer } from "effect"
interface Database {
readonly query: (sql: string) => Effect.Effect<string>
}
const Database = Context.Service<Database>("Database")
const DatabaseLive = Layer.succeed(Database)({
query: Effect.fn("Database.query")((sql: string) => Effect.succeed(`Result for: ${sql}`))
})
const program = Effect.gen(function*() {
const db = yield* Database
return yield* db.query("SELECT * FROM users")
})
const provided = Effect.provide(program, DatabaseLive)
Effect.runPromise(provided).then(console.log)
// Output: "Result for: SELECT * FROM users"export const const provide: {
<
Layers extends [
Layer.Any,
...Array<Layer.Any>
]
>(
layers: Layers,
options?:
| { readonly local?: boolean | undefined }
| undefined
): <A, E, R>(
self: Effect<A, E, R>
) => Effect<
A,
E | Layer.Error<Layers[number]>,
| Layer.Services<Layers[number]>
| Exclude<R, Layer.Success<Layers[number]>>
>
<ROut, E2, RIn>(
layer: Layer.Layer<ROut, E2, RIn>,
options?:
| { readonly local?: boolean | undefined }
| undefined
): <A, E, R>(
self: Effect<A, E, R>
) => Effect<A, E | E2, RIn | Exclude<R, ROut>>
<R2>(context: Context.Context<R2>): <A, E, R>(
self: Effect<A, E, R>
) => Effect<A, E, Exclude<R, R2>>
<
A,
E,
R,
Layers extends [
Layer.Any,
...Array<Layer.Any>
]
>(
self: Effect<A, E, R>,
layers: Layers,
options?:
| { readonly local?: boolean | undefined }
| undefined
): Effect<
A,
E | Layer.Error<Layers[number]>,
| Layer.Services<Layers[number]>
| Exclude<R, Layer.Success<Layers[number]>>
>
<A, E, R, ROut, E2, RIn>(
self: Effect<A, E, R>,
layer: Layer.Layer<ROut, E2, RIn>,
options?:
| { readonly local?: boolean | undefined }
| undefined
): Effect<A, E | E2, RIn | Exclude<R, ROut>>
<A, E, R, R2>(
self: Effect<A, E, R>,
context: Context.Context<R2>
): Effect<A, E, Exclude<R, R2>>
}
Provides dependencies to an effect using layers or a context. Use options.local
to build the layer every time; by default, layers are shared between provide
calls.
Example (Providing dependencies with a layer)
import { Context, Effect, Layer } from "effect"
interface Database {
readonly query: (sql: string) => Effect.Effect<string>
}
const Database = Context.Service<Database>("Database")
const DatabaseLive = Layer.succeed(Database)({
query: Effect.fn("Database.query")((sql: string) => Effect.succeed(`Result for: ${sql}`))
})
const program = Effect.gen(function*() {
const db = yield* Database
return yield* db.query("SELECT * FROM users")
})
const provided = Effect.provide(program, DatabaseLive)
Effect.runPromise(provided).then(console.log)
// Output: "Result for: SELECT * FROM users"
provide: {
<const function (type parameter) Layers in <const Layers extends [Layer.Any, ...Array<Layer.Any>]>(layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
import LayerLayer.Any, ...interface Array<T>Array<import LayerLayer.Any>]>(
layers: const Layers extends [Layer.Any, ...Array<Layer.Any>]layers: function (type parameter) Layers in <const Layers extends [Layer.Any, ...Array<Layer.Any>]>(layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
options: | {
readonly local?: boolean | undefined
}
| undefined
local?: boolean | undefinedlocal?: boolean | undefined
} | undefined
): <function (type parameter) A in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>R>(
self: Effect<A, E, R>(parameter) self: {
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; <…;
toString: () => string;
toJSON: () => unknown;
}
interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>R>
) => interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<
function (type parameter) A in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>A,
function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>E | import LayerLayer.type Error<T extends Layer.Any> =
T extends Layer.Layer<
infer _ROut,
infer _E,
infer _RIn
>
? _E
: never
Extracts the error type (E) from a Layer type.
When to use
Use to derive a layer construction error type for helper types, wrappers, or
APIs that preserve a layer failure channel.
Error<function (type parameter) Layers in <const Layers extends [Layer.Any, ...Array<Layer.Any>]>(layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
import LayerLayer.type Services<T extends Layer.Any> =
T extends infer L
? L extends Layer.Layer<
infer _ROut,
infer _E,
infer _RIn
>
? _RIn
: never
: never
Extracts the service requirements (RIn) from a Layer type.
When to use
Use to derive the dependency requirements of a generic or inferred Layer
without restating its RIn type parameter.
Services<function (type parameter) Layers in <const Layers extends [Layer.Any, ...Array<Layer.Any>]>(layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>R, import LayerLayer.type Success<T extends Layer.Any> =
T extends Layer.Layer<
infer _ROut,
infer _E,
infer _RIn
>
? _ROut
: never
Extracts the service output type (ROut) from a Layer type.
When to use
Use to derive the services provided by an existing or generic Layer without
restating its ROut type parameter.
Success<function (type parameter) Layers in <const Layers extends [Layer.Any, ...Array<Layer.Any>]>(layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
function (type parameter) ROut in <ROut, E2, RIn>(layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) E2 in <ROut, E2, RIn>(layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) RIn in <ROut, E2, RIn>(layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, RIn | Exclude<R, ROut>>
layer: Layer.Layer<ROut, E2, RIn>(parameter) layer: {
build: (memoMap: MemoMap, scope: Scope.Scope) => Effect<Context.Context<ROut>, E2, RIn>;
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; <…;
}
import LayerLayer.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) ROut in <ROut, E2, RIn>(layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) E2 in <ROut, E2, RIn>(layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) RIn in <ROut, E2, RIn>(layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, RIn | Exclude<R, ROut>>
options: | {
readonly local?: boolean | undefined
}
| undefined
local?: boolean | undefinedlocal?: boolean | undefined
} | undefined
): <function (type parameter) A in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, RIn | Exclude<R, ROut>>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, RIn | Exclude<R, ROut>>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, RIn | Exclude<R, ROut>>R>(
self: Effect<A, E, R>(parameter) self: {
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; <…;
toString: () => string;
toJSON: () => unknown;
}
interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, RIn | Exclude<R, ROut>>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, RIn | Exclude<R, ROut>>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, RIn | Exclude<R, ROut>>R>
) => interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, RIn | Exclude<R, ROut>>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, RIn | Exclude<R, ROut>>E | function (type parameter) E2 in <ROut, E2, RIn>(layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) RIn in <ROut, E2, RIn>(layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, RIn | Exclude<R, ROut>>
type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, RIn | Exclude<R, ROut>>R, function (type parameter) ROut in <ROut, E2, RIn>(layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) R2 in <R2>(context: Context.Context<R2>): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E, Exclude<R, R2>>R2>(
context: Context.Context<R2>(parameter) context: {
mapUnsafe: ReadonlyMap<string, any>;
mutable: boolean;
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; <…;
toString: () => string;
toJSON: () => unknown;
}
import ContextContext.type Context.Context = /*unresolved*/ anyContext<function (type parameter) R2 in <R2>(context: Context.Context<R2>): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E, Exclude<R, R2>>R2>
): <function (type parameter) A in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, R2>>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, R2>>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, R2>>R>(self: Effect<A, E, R>(parameter) self: {
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; <…;
toString: () => string;
toJSON: () => unknown;
}
interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, R2>>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, R2>>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, R2>>R>) => interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, R2>>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, R2>>E, type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, R2>>R, function (type parameter) R2 in <R2>(context: Context.Context<R2>): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E, Exclude<R, R2>>R2>>
<function (type parameter) A in <A, E, R, const Layers extends [Layer.Any, ...Array<Layer.Any>]>(self: Effect<A, E, R>, layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
function (type parameter) E in <A, E, R, const Layers extends [Layer.Any, ...Array<Layer.Any>]>(self: Effect<A, E, R>, layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
function (type parameter) R in <A, E, R, const Layers extends [Layer.Any, ...Array<Layer.Any>]>(self: Effect<A, E, R>, layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
function (type parameter) Layers in <A, E, R, const Layers extends [Layer.Any, ...Array<Layer.Any>]>(self: Effect<A, E, R>, layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
import LayerLayer.Any, ...interface Array<T>Array<import LayerLayer.Any>]>(
self: Effect<A, E, R>(parameter) self: {
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; <…;
toString: () => string;
toJSON: () => unknown;
}
interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R, const Layers extends [Layer.Any, ...Array<Layer.Any>]>(self: Effect<A, E, R>, layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
function (type parameter) E in <A, E, R, const Layers extends [Layer.Any, ...Array<Layer.Any>]>(self: Effect<A, E, R>, layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
function (type parameter) R in <A, E, R, const Layers extends [Layer.Any, ...Array<Layer.Any>]>(self: Effect<A, E, R>, layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
layers: const Layers extends [Layer.Any, ...Array<Layer.Any>]layers: function (type parameter) Layers in <A, E, R, const Layers extends [Layer.Any, ...Array<Layer.Any>]>(self: Effect<A, E, R>, layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
options: | {
readonly local?: boolean | undefined
}
| undefined
local?: boolean | undefinedlocal?: boolean | undefined
} | undefined
): interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<
function (type parameter) A in <A, E, R, const Layers extends [Layer.Any, ...Array<Layer.Any>]>(self: Effect<A, E, R>, layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
function (type parameter) E in <A, E, R, const Layers extends [Layer.Any, ...Array<Layer.Any>]>(self: Effect<A, E, R>, layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
import LayerLayer.type Error<T extends Layer.Any> =
T extends Layer.Layer<
infer _ROut,
infer _E,
infer _RIn
>
? _E
: never
Extracts the error type (E) from a Layer type.
When to use
Use to derive a layer construction error type for helper types, wrappers, or
APIs that preserve a layer failure channel.
Error<function (type parameter) Layers in <A, E, R, const Layers extends [Layer.Any, ...Array<Layer.Any>]>(self: Effect<A, E, R>, layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
import LayerLayer.type Services<T extends Layer.Any> =
T extends infer L
? L extends Layer.Layer<
infer _ROut,
infer _E,
infer _RIn
>
? _RIn
: never
: never
Extracts the service requirements (RIn) from a Layer type.
When to use
Use to derive the dependency requirements of a generic or inferred Layer
without restating its RIn type parameter.
Services<function (type parameter) Layers in <A, E, R, const Layers extends [Layer.Any, ...Array<Layer.Any>]>(self: Effect<A, E, R>, layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) R in <A, E, R, const Layers extends [Layer.Any, ...Array<Layer.Any>]>(self: Effect<A, E, R>, layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
import LayerLayer.type Success<T extends Layer.Any> =
T extends Layer.Layer<
infer _ROut,
infer _E,
infer _RIn
>
? _ROut
: never
Extracts the service output type (ROut) from a Layer type.
When to use
Use to derive the services provided by an existing or generic Layer without
restating its ROut type parameter.
Success<function (type parameter) Layers in <A, E, R, const Layers extends [Layer.Any, ...Array<Layer.Any>]>(self: Effect<A, E, R>, layers: Layers, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | Layer.Error<Layers[number]>, Layer.Services<Layers[number]> | Exclude<R, Layer.Success<Layers[number]>>>
function (type parameter) A in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) E in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) R in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) ROut in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) E2 in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) RIn in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
self: Effect<A, E, R>(parameter) self: {
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; <…;
toString: () => string;
toJSON: () => unknown;
}
interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) E in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) R in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
layer: Layer.Layer<ROut, E2, RIn>(parameter) layer: {
build: (memoMap: MemoMap, scope: Scope.Scope) => Effect<Context.Context<ROut>, E2, RIn>;
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; <…;
}
import LayerLayer.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) ROut in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) E2 in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) RIn in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
options: | {
readonly local?: boolean | undefined
}
| undefined
local?: boolean | undefinedlocal?: boolean | undefined
} | undefined
): interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) E in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) E2 in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) RIn in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) R in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) ROut in <A, E, R, ROut, E2, RIn>(self: Effect<A, E, R>, layer: Layer.Layer<ROut, E2, RIn>, options?: {
readonly local?: boolean | undefined;
} | undefined): Effect<A, E | E2, RIn | Exclude<R, ROut>>
function (type parameter) A in <A, E, R, R2>(self: Effect<A, E, R>, context: Context.Context<R2>): Effect<A, E, Exclude<R, R2>>A, function (type parameter) E in <A, E, R, R2>(self: Effect<A, E, R>, context: Context.Context<R2>): Effect<A, E, Exclude<R, R2>>E, function (type parameter) R in <A, E, R, R2>(self: Effect<A, E, R>, context: Context.Context<R2>): Effect<A, E, Exclude<R, R2>>R, function (type parameter) R2 in <A, E, R, R2>(self: Effect<A, E, R>, context: Context.Context<R2>): Effect<A, E, Exclude<R, R2>>R2>(
self: Effect<A, E, R>(parameter) self: {
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; <…;
toString: () => string;
toJSON: () => unknown;
}
interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R, R2>(self: Effect<A, E, R>, context: Context.Context<R2>): Effect<A, E, Exclude<R, R2>>A, function (type parameter) E in <A, E, R, R2>(self: Effect<A, E, R>, context: Context.Context<R2>): Effect<A, E, Exclude<R, R2>>E, function (type parameter) R in <A, E, R, R2>(self: Effect<A, E, R>, context: Context.Context<R2>): Effect<A, E, Exclude<R, R2>>R>,
context: Context.Context<R2>(parameter) context: {
mapUnsafe: ReadonlyMap<string, any>;
mutable: boolean;
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; <…;
toString: () => string;
toJSON: () => unknown;
}
import ContextContext.type Context.Context = /*unresolved*/ anyContext<function (type parameter) R2 in <A, E, R, R2>(self: Effect<A, E, R>, context: Context.Context<R2>): Effect<A, E, Exclude<R, R2>>R2>
): interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R, R2>(self: Effect<A, E, R>, context: Context.Context<R2>): Effect<A, E, Exclude<R, R2>>A, function (type parameter) E in <A, E, R, R2>(self: Effect<A, E, R>, context: Context.Context<R2>): Effect<A, E, Exclude<R, R2>>E, type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) R in <A, E, R, R2>(self: Effect<A, E, R>, context: Context.Context<R2>): Effect<A, E, Exclude<R, R2>>R, function (type parameter) R2 in <A, E, R, R2>(self: Effect<A, E, R>, context: Context.Context<R2>): Effect<A, E, Exclude<R, R2>>R2>>
} = import internalLayerinternalLayer.const provide: {
<
Layers extends [
Layer.Any,
...Array<Layer.Any>
]
>(
layers: Layers,
options?:
| { readonly local?: boolean | undefined }
| undefined
): <A, E, R>(
self: Effect<A, E, R>
) => Effect<
A,
E | Layer.Error<Layers[number]>,
| Layer.Services<Layers[number]>
| Exclude<R, Layer.Success<Layers[number]>>
>
<ROut, E2, RIn>(
layer: Layer.Layer<ROut, E2, RIn>,
options?:
| { readonly local?: boolean | undefined }
| undefined
): <A, E, R>(
self: Effect<A, E, R>
) => Effect<A, E | E2, RIn | Exclude<R, ROut>>
<R2>(context: Context.Context<R2>): <A, E, R>(
self: Effect<A, E, R>
) => Effect<A, E, Exclude<R, R2>>
} & {
<
A,
E,
R,
Layers extends [
Layer.Any,
...Array<Layer.Any>
]
>(
self: Effect<A, E, R>,
layers: Layers,
options?:
| { readonly local?: boolean | undefined }
| undefined
): Effect<
A,
E | Layer.Error<Layers[number]>,
| Layer.Services<Layers[number]>
| Exclude<R, Layer.Success<Layers[number]>>
>
<A, E, R, ROut, E2, RIn>(
self: Effect<A, E, R>,
layer: Layer.Layer<ROut, E2, RIn>,
options?:
| { readonly local?: boolean | undefined }
| undefined
): Effect<A, E | E2, RIn | Exclude<R, ROut>>
<A, E, R, R2>(
self: Effect<A, E, R>,
context: Context.Context<R2>
): Effect<A, E, Exclude<R, R2>>
}