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function / @typed/fx

Sink.filter

Filters values before they reach the sink using a predicate function.

Package version
2.0.0-beta.7
Category
Selecting inputs
Since
1.0.0
Member of
Sink

Import

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

Access Sink.filter 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 filter<A, E, R>(sink: Sink<A, E, R>, f: (a: A) => boolean): Sink<A, E, R>;

Why

Predicate filtering narrows consumer traffic without changing the producer.

Ownership and lifetime

The predicate runs synchronously in arrival order. Matching values invoke the wrapped sink once; non-matches invoke it zero times. The adapter acquires no resources.

Examples

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

const program = Effect.gen(function* () {
  const sink = Sink.make(
    (cause) => Effect.void,
    (value: number) => Effect.sync(() => console.log("Positive:", value))
  )

  // Only pass through positive numbers
  const filtered = Sink.filter(sink, (n) => n > 0)

  yield* Fx.fromIterable([-2, -1, 0, 1, 2]).run(filtered)
  // Output: "Positive: 1", "Positive: 2"
})

Other public imports

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

Source