effect-io-ai

Package: effect
Module: Effect

Effect.mapBoth

Applies transformations to both the success and error channels of an effect.

When to use

Use to transform both success and failure channels of an Effect without changing whether it succeeds or fails.

Details

This function takes two map functions as arguments: one for the error channel and one for the success channel. You can use it when you want to modify both the error and the success values without altering the overall success or failure status of the effect.

Example (Transforming success and failure channels)

import { Data, Effect } from "effect"

class TaskError extends Data.TaggedError("TaskError")<{ readonly message: string }> {}

//      ┌─── Effect<number, string, never>
//      ▼
const simulatedTask = Effect.fail("Oh no!").pipe(Effect.as(1))

//      ┌─── Effect<boolean, TaskError, never>
//      ▼
const modified = Effect.mapBoth(simulatedTask, {
  onFailure: (message) => new TaskError({ message }),
  onSuccess: (n) => n > 0
})

See

• map for a version that operates on the success channel.
• mapError for a version that operates on the error channel.

Signature

declare const mapBoth: { <E, E2, A, A2>(options: { readonly onFailure: (e: E) => E2; readonly onSuccess: (a: A) => A2; }): <R>(self: Effect<A, E, R>) => Effect<A2, E2, R>; <A, E, R, E2, A2>(self: Effect<A, E, R>, options: { readonly onFailure: (e: E) => E2; readonly onSuccess: (a: A) => A2; }): Effect<A2, E2, R>; }

Source

Since v2.0.0