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variable / @typed/fx/Fx

genScoped

Builds an Fx with a subscription-owned Scope shared by setup and streaming.

Package version
2.0.0-beta.13
Category
Generator composition
Since
1.0.0

Follow one execution

Builds an Fx with a subscription-owned Scope shared by setup and streaming.

Fx timelinegenScoped keeps a resource alive through its subscription and releases it afterwardgenScoped
OperatorgenScoped(function*)
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.

Every subscription creates one child Scope, runs the generator inside it, then runs the returned Fx in the same Scope. Normal completion, failure, defect, or interruption closes the Scope and its finalizers. Setup failures prevent streaming; all non-Scope errors and services remain in the result.

Source implementation · Learn the surrounding model

Compare all Fx timelines →

Import

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

Signatures

export declare const genScoped: <Yield extends Effect.Effect<any, any, any>, Return extends Fx.Any>(f: () => Generator<Yield, Return, any>) => Fx<Fx.Success<Return>, Fx.Error<Return> | ([
    Yield
] extends [
    never
] ? never : Effect.Error<Yield>), Exclude<Fx.Services<Return> | ([
    Yield
] extends [
    never
] ? never : Effect.Services<Yield>), Scope.Scope>>;

Why

Resourceful setup must remain alive while the returned producer runs and be released when that subscription ends. genScoped supplies that exact acquisition-to-stream lifetime while removing Scope from the public service requirement.

Ownership and lifetime

Every subscription creates one child Scope, runs the generator inside it, then runs the returned Fx in the same Scope. Normal completion, failure, defect, or interruption closes the Scope and its finalizers. Setup failures prevent streaming; all non-Scope errors and services remain in the result.

Examples

import { Effect } from "effect"
import { genScoped } from "@typed/fx/Fx"
import { succeed } from "@typed/fx/Fx"

const resourceful = genScoped(function* () {
  const handle = yield* Effect.acquireRelease(
    Effect.succeed({ open: true }),
    () => Effect.void
  )
  return succeed(handle.open)
})

Other public imports

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

Source