(
url: string | Effect.Effect<string>,
options?:
| {
readonly closeCodeIsError?:
| ((code: number) => boolean)
| undefined
readonly openTimeout?: Duration.Input | undefined
readonly protocols?: string | Array<string> | undefined
}
| undefined
): Layer.Layer<Socket.Socket, never, never>Creates a Socket.Socket layer for a WebSocket URL using the Node WebSocket
constructor layer, honoring protocol, open-timeout, and close-code error
options.
export const const layerWebSocket: (
url: string | Effect.Effect<string>,
options?:
| {
readonly closeCodeIsError?:
| ((code: number) => boolean)
| undefined
readonly openTimeout?:
| Duration.Input
| undefined
readonly protocols?:
| string
| Array<string>
| undefined
}
| undefined
) => Layer.Layer<Socket.Socket, never, never>
Creates a Socket.Socket layer for a WebSocket URL using the Node WebSocket
constructor layer, honoring protocol, open-timeout, and close-code error
options.
layerWebSocket: (
url: string | Effect.Effect<string>url: string | 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<string>,
options: | {
readonly closeCodeIsError?:
| ((code: number) => boolean)
| undefined
readonly openTimeout?:
| Duration.Input
| undefined
readonly protocols?:
| string
| Array<string>
| undefined
}
| undefined
closeCodeIsError?: ((code: number) => boolean) | undefinedcloseCodeIsError?: ((code: numbercode: number) => boolean) | undefined
readonly openTimeout?: Duration.Input | undefinedopenTimeout?: import DurationDuration.type Input =
| number
| bigint
| Duration.Duration
| readonly [seconds: number, nanos: number]
| `${number} nano`
| `${number} nanos`
| `${number} micro`
| `${number} micros`
| `${number} milli`
| `${number} millis`
| `${number} second`
| `${number} seconds`
| `${number} minute`
| `${number} minutes`
| `${number} hour`
| `${number} hours`
| `${number} day`
| `${number} days`
| `${number} week`
| `${number} weeks`
| "Infinity"
| "-Infinity"
| Duration.DurationObject
Valid input types that can be converted to a Duration.
When to use
Use when an API should accept any value that Effect can convert into a
Duration, including existing durations, millisecond numbers, nanosecond
bigints, high-resolution tuples, duration strings, infinity strings, or
duration objects.
Details
String inputs accept values like "10 seconds", "500 millis",
"Infinity", and "-Infinity". Finite fractional values that are
normalized to nanoseconds are rounded to the nearest nanosecond, with ties
away from zero.
Input | undefined
readonly protocols?: string | string[] | undefinedprotocols?: string | interface Array<T>Array<string> | undefined
} | undefined
) => 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<import SocketSocket.Socket, never, never> = flow<[url: string | Effect.Effect<string, never, never>, options?: {
readonly closeCodeIsError?: ((code: number) => boolean) | undefined;
readonly openTimeout?: Duration.Input | undefined;
readonly protocols?: string | Array<string> | undefined;
} | undefined], Effect.Effect<Socket.Socket, never, Socket.WebSocketConstructor>, Layer.Layer<Socket.Socket, never, Socket.WebSocketConstructor>, Layer.Layer<Socket.Socket, never, never>>(ab: (url: string | Effect.Effect<string, never, never>, options?: {
readonly closeCodeIsError?: ((code: number) => boolean) | undefined;
readonly openTimeout?: Duration.Input | undefined;
readonly protocols?: string | Array<string> | undefined;
} | undefined) => Effect.Effect<...>, bc: (b: Effect.Effect<...>) => Layer.Layer<...>, cd: (c: Layer.Layer<...>) => Layer.Layer<...>): (url: string | Effect.Effect<...>, options?: {
readonly closeCodeIsError?: ((code: number) => boolean) | undefined;
readonly openTimeout?: Duration.Input | undefined;
readonly protocols?: string | Array<string> | undefined;
} | undefined) => Layer.Layer<...> (+8 overloads)
Performs left-to-right function composition.
When to use
Use to build a reusable function from a left-to-right sequence of
transformations.
Details
The first function may have any arity. Every following function must be
unary.
Example (Composing functions left to right)
import { flow } from "effect"
import * as assert from "node:assert"
const len = (s: string): number => s.length
const double = (n: number): number => n * 2
const f = flow(len, double)
assert.strictEqual(f("aaa"), 6)
flow(
import SocketSocket.const makeWebSocket: (
url: string | Effect.Effect<string>,
options?: {
readonly closeCodeIsError?:
| ((code: number) => boolean)
| undefined
readonly openTimeout?:
| Duration.Input
| undefined
readonly protocols?:
| string
| Array<string>
| undefined
}
) => Effect.Effect<
Socket.Socket,
never,
Socket.WebSocketConstructor
>
Creates a Socket backed by a WebSocketConstructor, acquiring the
WebSocket for each run and using the close-code classifier to decide which
closes fail the run.
makeWebSocket,
import LayerLayer.const effect: {
<I, S>(service: Context.Key<I, S>): <E, R>(
effect: Effect<S, E, R>
) => Layer<I, E, Exclude<R, Scope.Scope>>
<I, S, E, R>(
service: Context.Key<I, S>,
effect: Effect<Types.NoInfer<S>, E, R>
): Layer<I, E, Exclude<R, Scope.Scope>>
}
Constructs a layer from an effect that produces a single service.
When to use
Use when you need to construct a Layer-provided service with an Effect,
dependencies, or scoped resource acquisition.
Details
This allows you to create a Layer from an Effect that produces a service.
The Effect is executed in the scope of the layer, allowing for proper
resource management.
Example (Creating a layer from an effect)
import { Context, Effect, Layer } from "effect"
class Database extends Context.Service<Database, {
readonly query: (sql: string) => Effect.Effect<string>
}>()("Database") {}
const layer = Layer.effect(Database,
Effect.sync(() => ({
query: (sql: string) => Effect.succeed(`Query: ${sql}`)
}))
)
effect(import SocketSocket.const Socket: Context.Service<
Socket,
Socket
>
const Socket: {
key: string;
Service: {
run: <_, E = never, R = never>(handler: (_: Uint8Array) => Effect.Effect<_, E, R> | void, options?: { readonly onOpen?: Effect.Effect<void> | undefined }) => Effect.Effect<void, SocketError | E, R>;
runString: <_, E = never, R = never>(handler: (_: string) => Effect.Effect<_, E, R> | void, options?: { readonly onOpen?: Effect.Effect<void> | undefined }) => Effect.Effect<void, SocketError | E, R>;
runRaw: <_, E = never, R = never>(handler: (_: string | Uint8Array) => Effect.Effect<_, E, R> | void, options?: { readonly onOpen?: Effect.Effect<void> | undefined }) => Effect.Effect<void, SocketError | E, R>;
writer: Effect.Effect<(chunk: Uint8Array | string | CloseEvent) => Effect.Effect<void, SocketError>, never, Scope.Scope>;
};
of: (this: void, self: Socket.Socket) => Socket.Socket;
context: (self: Socket.Socket) => Context<Socket.Socket>;
use: (f: (service: Socket.Socket) => Effect.Effect<A, E, R>) => Effect.Effect<A, E, Socket.Socket | R>;
useSync: (f: (service: Socket.Socket) => A) => Effect.Effect<A, never, Socket.Socket>;
Identifier: Identifier;
stack: string | undefined;
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;
}
Service tag for bidirectional socket transports.
When to use
Use to access or provide the socket implementation used by programs that
read and write frames through the Effect environment.
Effect-based socket abstraction for running string or binary read handlers
and obtaining a scoped writer for outgoing frames and close events.
Socket),
import LayerLayer.const provide: {
<RIn, E, ROut>(that: Layer<ROut, E, RIn>): <
RIn2,
E2,
ROut2
>(
self: Layer<ROut2, E2, RIn2>
) => Layer<
ROut2,
E | E2,
RIn | Exclude<RIn2, ROut>
>
<Layers extends [Any, ...Array<Any>]>(
that: Layers
): <A, E, R>(
self: Layer<A, E, R>
) => Layer<
A,
E | Error<Layers[number]>,
| Services<Layers[number]>
| Exclude<R, Success<Layers[number]>>
>
<RIn2, E2, ROut2, RIn, E, ROut>(
self: Layer<ROut2, E2, RIn2>,
that: Layer<ROut, E, RIn>
): Layer<
ROut2,
E | E2,
RIn | Exclude<RIn2, ROut>
>
<A, E, R, Layers extends [Any, ...Array<Any>]>(
self: Layer<A, E, R>,
that: Layers
): Layer<
A,
E | Error<Layers[number]>,
| Services<Layers[number]>
| Exclude<R, Success<Layers[number]>>
>
}
Feeds the output services of the dependency layer into the requirements of
this layer, returning a layer that only provides the services from this layer.
When to use
Use when you need to hide an implementation dependency layer from callers.
Details
In serviceLayer.pipe(Layer.provide(dependencyLayer)), the dependency layer is
built first and is used to satisfy the requirements of serviceLayer.
Example (Providing layer dependencies)
import { Context, Effect, Layer } from "effect"
class Database extends Context.Service<Database, {
readonly query: (sql: string) => Effect.Effect<string>
}>()("Database") {}
class UserService extends Context.Service<UserService, {
readonly getUser: (id: string) => Effect.Effect<{
id: string
name: string
}>
}>()("UserService") {}
class Logger extends Context.Service<Logger, {
readonly log: (msg: string) => Effect.Effect<void>
}>()("Logger") {}
// Create dependency layers
const databaseLayer = Layer.succeed(Database, {
query: Effect.fn("Database.query")((sql: string) => Effect.succeed(`DB: ${sql}`))
})
const loggerLayer = Layer.succeed(Logger, {
log: Effect.fn("Logger.log")((msg: string) => Effect.sync(() => console.log(`[LOG] ${msg}`)))
})
// UserService depends on Database and Logger
const userServiceLayer = Layer.effect(UserService, Effect.gen(function*() {
const database = yield* Database
const logger = yield* Logger
return {
getUser: Effect.fn("UserService.getUser")(function*(id: string) {
yield* logger.log(`Looking up user ${id}`)
const result = yield* database.query(
`SELECT * FROM users WHERE id = ${id}`
)
return { id, name: result }
})
}
}))
// Provide dependencies to UserService layer
const userServiceWithDependencies = userServiceLayer.pipe(
Layer.provide(Layer.mergeAll(databaseLayer, loggerLayer))
)
// Now UserService layer has no dependencies
const program = Effect.gen(function*() {
const userService = yield* UserService
return yield* userService.getUser("123")
}).pipe(
Effect.provide(userServiceWithDependencies)
)
provide(const layerWebSocketConstructor: Layer.Layer<Socket.WebSocketConstructor>const layerWebSocketConstructor: {
build: (memoMap: MemoMap, scope: Scope.Scope) => Effect<Context.Context<WebSocketConstructor>, never, never>;
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; <…;
}
Provides a Socket.WebSocketConstructor, using globalThis.WebSocket when
available and falling back to the ws package otherwise.
layerWebSocketConstructor)
)