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function / @typed/fx

Subject.Service

Defines an Effect context service that is simultaneously a Subject, Fx, and Sink facade.

Package version
2.0.0-beta.13
Category
Subject services
Since
1.0.0
Member of
Subject

Import

import { Subject } from "@typed/fx";

Access Subject.Service through the imported Subject export. Its declaration below describes the member.

This public exposure is a re-export. Its import path is supported; declaration documentation is shared with the other public exposures below.

Signatures

export declare function Service<Self, A, E = never>(): <const Id extends string>(id: Id) => Subject.Class<Self, Id, A, E>;

Why

A named subject often represents an application-wide event boundary. Service keeps that boundary type-safe and lets producers, consumers, and layers compose through Effect’s normal service channel instead of a module-global mutable instance.

Ownership and lifetime

Defining the class acquires nothing. Calling its static make creates a layer backed by scoped Subject.make; releasing the layer interrupts subscriptions and clears replay. Static Fx and Sink operations require Self, then delegate to the installed subject. Invalid replay capacities fail layer construction with Cause.IllegalArgumentError.

Examples

import { Effect } from "effect"
import { Fx } from "@typed/fx"
import * as Subject from "@typed/fx/Subject"

class Notifications extends Subject.Service<Notifications, string>()("Notifications") {}

const program = Effect.gen(function* () {
  yield* Notifications.onSuccess("saved")
  return yield* Fx.first(Notifications)
}).pipe(Effect.provide(Notifications.make(1)), Effect.scoped)

Other public imports

These import paths expose the same declaration. Each page retains its own public name and signature.

Source