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function / @typed/fx

Sink.filterMap

Filters and transforms values before they reach the sink using a function that returns an Option.

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.filterMap 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 filterMap<A, E, R, B>(sink: Sink<A, E, R>, f: (b: B) => Option.Option<A>): Sink<B, E, R>;

Why

Selection and transformation happen at the consumer boundary without constructing another Fx.

Ownership and lifetime

Inputs are inspected synchronously in arrival order. Some invokes the wrapped sink once; None invokes it zero times. The adapter acquires no resources and failures pass through.

Examples

import { Effect, Option } 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("Even:", value))
  )

  // Only pass through even numbers
  const filtered = Sink.filterMap(sink, (n: number) =>
    n % 2 === 0 ? Option.some(n) : Option.none()
  )

  yield* Fx.fromIterable([1, 2, 3, 4, 5]).run(filtered)
  // Output: "Even: 2", "Even: 4"
})

Other public imports

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

Source