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function / @typed/fx

Sink.reduceEffect

Reduces values into a single result using an effectful function. Pass a Ref<B>; after running, read the result with Ref.get(ref). If the reducer effect fails, the ref is left unchanged (Sink onSuccess is typed as never failing).

Package version
2.0.0-beta.7
Category
Collecting values
Since
1.0.0
Member of
Sink

Import

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

Access Sink.reduceEffect 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 function reduceEffect<A, B, E, E2, R2>(ref: Ref.Ref<B>, f: (b: B, a: A) => Effect.Effect<B, E2, R2>): Sink<A, E | E2, R2>;

Why

Aggregation may require Effect services or asynchronous work while the result remains explicitly available through a caller-owned Ref.

Ownership and lifetime

The caller owns the Ref. Each success returns a lazy read/reduce/write Effect; invocation alone does no work. The three steps are not one atomic operation. Serialized producers preserve execution order, while overlapping executions can read the same value and commit in completion order. Reducer failures, producer failures, and interrupted writes are ignored. Use withStateSemaphore when the whole effectful transition must be serialized.

Examples

import { Effect, Ref } from "effect"
import * as Sink from "@typed/fx/Sink"
const program = Effect.gen(function* () {
  const total = yield* Ref.make(0)
  return Sink.reduceEffect(total, (sum, n: number) => Effect.succeed(sum + n))
})

Other public imports

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

Source