effect-io-ai

Package: effect
Module: Stream

Stream.when

Returns the specified stream if the given condition is satisfied, otherwise returns an empty stream.

Example (Conditionally keeping a stream)

import { Console, Effect, Stream } from "effect"

const program = Effect.gen(function*() {
  const result = yield* Stream.runCollect(
    Stream.when(Stream.make(1, 2, 3), Effect.succeed(false))
  )
  yield* Console.log(result)
})

Effect.runPromise(program)
// Output: []

Signature

declare const when: { <EX = never, RX = never>(test: Effect.Effect<boolean, EX, RX>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | EX, R | RX>; <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>; }

Source

Since v2.0.0