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variable / @typed/fx

Sink.loop

Threads pure state through successful inputs and forwards one derived value per input.

Package version
2.0.0-beta.7
Category
Stateful delivery
Since
1.0.0
Member of
Sink

Import

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

Access Sink.loop through the imported Sink 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 const loop: {
    <B, A, C>(seed: B, f: (acc: B, a: A) => readonly [
        C,
        B
    ]): <E, R>(sink: Sink<C, E, R>) => Sink<A, E, R>;
    <A, E, R, B, C>(sink: Sink<C, E, R>, seed: B, f: (acc: B, a: A) => readonly [
        C,
        B
    ]): Sink<A, E, R>;
};

Why

loop implements an ordered consumer-side state machine without exposing mutable state to the producer.

Ownership and lifetime

Each adapted sink owns its seed. Updates are synchronous and follow callback invocation order; every input produces exactly one downstream success. Failures bypass the state machine. Reusing the same sink for another producer run continues from its retained seed; create a new sink to reset.

Examples

import { Effect } from "effect"
import * as Sink from "@typed/fx/Sink"
const totals = Sink.loop(Sink.make(Effect.logError, Effect.log), 0, (sum, n: number) => [sum + n, sum + n])

Other public imports

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

Source