<
const Layers extends Record<string, Layer.Layer<any, any, any>>,
const Preload extends boolean = false
>(
layers: Layers,
options?:
| {
readonly idleTimeToLive?:
| IdleTimeToLiveInput<keyof Layers>
| undefined
readonly preload?: Preload | undefined
}
| undefined
): Effect.Effect<
LayerMap<
keyof Layers,
Layer.Success<Layers[keyof Layers]>,
Layer.Error<Layers[keyof Layers]>
>,
Preload extends true ? Layer.Error<Layers[keyof Layers]> : never,
| Scope.Scope
| (Layers[keyof Layers] extends Layer.Layer<
infer _A,
infer _E,
infer _R
>
? _R
: never)
>Creates a LayerMap from a record of predefined layers.
Details
The record keys become the keys accepted by the returned LayerMap, and the
record values are the layers built for those keys.
Example (Creating a layer map from a record)
import { Context, Effect, Layer, LayerMap } from "effect"
// Define service keys
const DevDatabase = Context.Service<{
readonly query: (sql: string) => Effect.Effect<string>
}>("DevDatabase")
const ProdDatabase = Context.Service<{
readonly query: (sql: string) => Effect.Effect<string>
}>("ProdDatabase")
// Create predefined layers
const layers = {
development: Layer.succeed(DevDatabase)({
query: Effect.fn("DevDatabase.query")((sql) => Effect.succeed(`DEV: ${sql}`))
}),
production: Layer.succeed(ProdDatabase)({
query: Effect.fn("ProdDatabase.query")((sql) => Effect.succeed(`PROD: ${sql}`))
})
} as const
// Create a LayerMap from the record
const program = Effect.gen(function*() {
const layerMap = yield* LayerMap.fromRecord(layers, {
idleTimeToLive: "10 seconds"
})
// Get layers by key
const devLayer = layerMap.get("development")
const prodLayer = layerMap.get("production")
console.log("LayerMap created from record")
})constructors
Source effect/LayerMap.ts:22422 lines
export const const fromRecord: <
Layers extends Record<
string,
Layer.Layer<any, any, any>
>,
Preload extends boolean = false
>(
layers: Layers,
options?:
| {
readonly idleTimeToLive?:
| IdleTimeToLiveInput<keyof Layers>
| undefined
readonly preload?: Preload | undefined
}
| undefined
) => Effect.Effect<
LayerMap<
keyof Layers,
Layer.Success<Layers[keyof Layers]>,
Layer.Error<Layers[keyof Layers]>
>,
Preload extends true
? Layer.Error<Layers[keyof Layers]>
: never,
| Scope.Scope
| (Layers[keyof Layers] extends Layer.Layer<
infer _A,
infer _E,
infer _R
>
? _R
: never)
>
Creates a LayerMap from a record of predefined layers.
Details
The record keys become the keys accepted by the returned LayerMap, and the
record values are the layers built for those keys.
Example (Creating a layer map from a record)
import { Context, Effect, Layer, LayerMap } from "effect"
// Define service keys
const DevDatabase = Context.Service<{
readonly query: (sql: string) => Effect.Effect<string>
}>("DevDatabase")
const ProdDatabase = Context.Service<{
readonly query: (sql: string) => Effect.Effect<string>
}>("ProdDatabase")
// Create predefined layers
const layers = {
development: Layer.succeed(DevDatabase)({
query: Effect.fn("DevDatabase.query")((sql) => Effect.succeed(`DEV: ${sql}`))
}),
production: Layer.succeed(ProdDatabase)({
query: Effect.fn("ProdDatabase.query")((sql) => Effect.succeed(`PROD: ${sql}`))
})
} as const
// Create a LayerMap from the record
const program = Effect.gen(function*() {
const layerMap = yield* LayerMap.fromRecord(layers, {
idleTimeToLive: "10 seconds"
})
// Get layers by key
const devLayer = layerMap.get("development")
const prodLayer = layerMap.get("production")
console.log("LayerMap created from record")
})
fromRecord = <
const function (type parameter) Layers in <const Layers extends Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
type Record<K extends keyof any, T> = {
[P in K]: T
}
Construct a type with a set of properties K of type T
Record<string, 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<any, any, any>>,
const function (type parameter) Preload in <const Layers extends Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
layers: const Layers extends Record<string, Layer.Layer<any, any, any>>layers: function (type parameter) Layers in <const Layers extends Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
options: | {
readonly idleTimeToLive?:
| IdleTimeToLiveInput<keyof Layers>
| undefined
readonly preload?: Preload | undefined
}
| undefined
idleTimeToLive?: | IdleTimeToLiveInput<keyof Layers>
| undefined
type IdleTimeToLiveInput<K> =
| Duration.Input
| ((key: K) => Duration.Input)
function (type parameter) Layers in <const Layers extends Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
preload?: Preload | undefinedpreload?: function (type parameter) Preload in <const Layers extends Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
import EffectEffect.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<
interface LayerMap<in out K, in out I, in out E = never>A scoped, keyed map of layer-built service contexts.
Details
A LayerMap builds resources for a key on demand, exposes them as a Layer
or scoped Context, and can invalidate cached resources for a key.
Example (Managing keyed layers)
import { Context, Effect, Layer, LayerMap } from "effect"
// Define a service key
const DatabaseService = Context.Service<{
readonly query: (sql: string) => Effect.Effect<string>
}>("Database")
// Create a LayerMap that provides different database configurations
const createDatabaseLayerMap = LayerMap.make((env: string) =>
Layer.succeed(DatabaseService)({
query: Effect.fn("DatabaseService.query")((sql) => Effect.succeed(`${env}: ${sql}`))
})
)
// Use the LayerMap
const program = Effect.gen(function*() {
const layerMap = yield* createDatabaseLayerMap
// Get a layer for a specific environment
const devLayer = layerMap.get("development")
// Get context directly
const context = yield* layerMap.contextEffect("production")
// Invalidate a cached layer
yield* layerMap.invalidate("development")
})
LayerMap<
keyof function (type parameter) Layers in <const Layers extends Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
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 Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
function (type parameter) Layers in <const Layers extends Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
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 Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
function (type parameter) Layers in <const Layers extends Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
function (type parameter) Preload in <const Layers extends Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
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 Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
function (type parameter) Layers in <const Layers extends Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
import ScopeScope.Scope | (function (type parameter) Layers in <const Layers extends Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
function (type parameter) Layers in <const Layers extends Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
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<infer function (type parameter) _A_A, infer function (type parameter) _E_E, infer function (type parameter) _R_R> ? function (type parameter) _R_R : never)
> =>
const make: <
K,
L extends Layer.Layer<any, any, any>,
PreloadKeys extends
| Iterable<K>
| undefined = undefined
>(
lookup: (key: K) => L,
options?:
| {
readonly idleTimeToLive?:
| IdleTimeToLiveInput<K>
| undefined
readonly preloadKeys?: PreloadKeys
}
| undefined
) => Effect.Effect<
LayerMap<K, Layer.Success<L>, Layer.Error<L>>,
PreloadKeys extends undefined
? never
: Layer.Error<L>,
Scope.Scope | Layer.Services<L>
>
Creates a LayerMap that dynamically provides resources based on a key.
Example (Creating a layer map)
import { Context, Effect, Layer, LayerMap } from "effect"
// Define a service key
const DatabaseService = Context.Service<{
readonly query: (sql: string) => Effect.Effect<string>
}>("Database")
// Create a LayerMap that provides different database configurations
const program = Effect.gen(function*() {
const layerMap = yield* LayerMap.make(
(env: string) =>
Layer.succeed(DatabaseService)({
query: Effect.fn("DatabaseService.query")((sql) => Effect.succeed(`${env}: ${sql}`))
}),
{ idleTimeToLive: "5 seconds" }
)
// Get a layer for a specific environment
const devLayer = layerMap.get("development")
// Use the layer to provide the service
const result = yield* Effect.provide(
Effect.gen(function*() {
const db = yield* DatabaseService
return yield* db.query("SELECT * FROM users")
}),
devLayer
)
console.log(result) // "development: SELECT * FROM users"
})
make((key: keyof Layerskey: keyof function (type parameter) Layers in <const Layers extends Record<string, Layer.Layer<any, any, any>>, const Preload extends boolean = false>(layers: Layers, options?: {
readonly idleTimeToLive?: IdleTimeToLiveInput<keyof Layers> | undefined;
readonly preload?: Preload | undefined;
} | undefined): Effect.Effect<LayerMap<keyof Layers, Layer.Success<Layers[keyof Layers]>, Layer.Error<Layers[keyof Layers]>>, Preload extends true ? Layer.Error<Layers[keyof Layers]> : never, Scope.Scope | (Layers[keyof Layers] extends Layer.Layer<infer _A, infer _E, infer _R> ? _R : never)>
layers: const Layers extends Record<string, Layer.Layer<any, any, any>>layers[key: keyof Layerskey], {
...options: | {
readonly idleTimeToLive?:
| IdleTimeToLiveInput<keyof Layers>
| undefined
readonly preload?: Preload | undefined
}
| undefined
preloadKeys?: string[] | undefinedpreloadKeys: options: | {
readonly idleTimeToLive?:
| IdleTimeToLiveInput<keyof Layers>
| undefined
readonly preload?: Preload | undefined
}
| undefined
preload?: Preload | undefinedpreload ? var Object: ObjectConstructorProvides functionality common to all JavaScript objects.
Object.ObjectConstructor.keys(o: {}): string[] (+1 overload)Returns the names of the enumerable string properties and methods of an object.
keys(layers: const Layers extends Record<string, Layer.Layer<any, any, any>>layers) : var undefinedundefined
}) as anyReferenced by 1 symbols