effect-io-ai

Package: effect
Module: Stream

Stream.mergeResult

Merges this stream and the specified stream together, tagging values from the left stream as Result.succeed and values from the right stream as Result.fail.

When to use

Use when values from both streams should be emitted and downstream code needs left values wrapped as successful Result values and right values wrapped as failed Result values.

Example (Merging streams into results)

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

const left = Stream.fromEffect(Effect.succeed("left"))
const right = Stream.fromEffect(Effect.delay(Effect.succeed("right"), "10 millis"))

const merged = left.pipe(
  Stream.mergeResult(right),
  Stream.map(
    Result.match({
      onFailure: (value) => `right:${value}`,
      onSuccess: (value) => `left:${value}`
    })
  )
)

const program = Effect.gen(function*() {
  const result = yield* Stream.runCollect(merged)
  yield* Console.log(result)
})

Effect.runPromise(program)
// Output: [ "left:left", "right:right" ]

Signature

declare const mergeResult: { <A2, E2, R2>(that: Stream<A2, E2, R2>): <A, E, R>(self: Stream<A, E, R>) => Stream<Result.Result<A, A2>, E2 | E, R2 | R>; <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>): Stream<Result.Result<A, A2>, E | E2, R | R2>; }

Source

Since v4.0.0