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variable / @typed/fx/Fx

provideService

Provides one existing service value to the entire Fx run.

Package version
2.0.0-beta.13
Category
Providing services
Since
1.0.0

Follow one execution

Insert one caller-owned service instance; other requirements remain.

Fx timelineprovideService(Config, config)provideService
OperatorprovideService(Config, config)
Read this diagram

Follow each lane from left to right. Events stacked vertically share a tick; the green cursor marks the current time across every lane.

  • A value
    The text inside the pill is the emitted value.
  • Work starts
    The raised chevron starts an inner run (^ in the source).
  • The run returns
    The vertical bar ends this lane’s run.
  • A cause is delivered
    The exclamation mark belongs to this lane.
  • Work is interrupted
    The cross marks cancellation of this run.
  • Current time
    The line and diamond move together across all lanes.
  • Happening now
    A highlighted event is at the current tick.
  • Still ahead
    Muted, dashed values have not happened yet.
  • Time continues
    The lane’s arrow is not a return marker. An empty stretch can be quiet work that is still running.

Illustrated ticks start at 0. At 1×, one illustrated tick takes one second; captions specify real durations when timing matters. A cause or interruption belongs to its lane, and other work may continue. Scroll horizontally to inspect the rest of a long timeline.

The service value is captured and reused for every subscription. It is not acquired or finalized here; its caller owns its lifetime. The matching service identifier is removed from R, while values, errors, ordering, and interruption remain those of the source.

Source implementation · Learn the surrounding model

Compare all Fx timelines →

Import

import { provideService } from "@typed/fx/Fx";

Signatures

export declare const provideService: {
    <Id, S>(tag: Context.Service<Id, S>, service: S): <A, E, R>(fx: Fx<A, E, R>) => Fx<A, E, Exclude<R, Id>>;
    <A, E, R, Id, S>(fx: Fx<A, E, R>, tag: Context.Service<Id, S>, service: S): Fx<A, E, Exclude<R, Id>>;
};

Why

This is the precise single-service form of {@link provideContext}, useful for tests and application edges where the instance is already owned.

Ownership and lifetime

The service value is captured and reused for every subscription. It is not acquired or finalized here; its caller owns its lifetime. The matching service identifier is removed from R, while values, errors, ordering, and interruption remain those of the source.

Examples

import { Context, Effect } from "effect"
import { provideService } from "@typed/fx/Fx"
import { fromEffect } from "@typed/fx/Fx"

class Config extends Context.Service<Config, { readonly url: string }>()("Config") {}
const runnable = provideService(
  fromEffect(Effect.map(Config, (x) => x.url)),
  Config,
  { url: "/api" }
)

Other public imports

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

Source