effect-io-ai

Package: effect
Module: Exit

Exit.mapError

Transforms the typed error of a failed Exit using the given function.

When to use

Use to remap typed errors while preserving the Exit structure

Details

Successes pass through unchanged.

Allocates a new Exit if the error is transformed.

Gotchas

Only transforms typed errors (Fail reasons). If the Cause contains only defects or interruptions, the failure passes through unchanged.

Example (Mapping over an error)

import { Data, Exit } from "effect"

class ExitError extends Data.TaggedError("ExitError")<{ readonly input: string }> {}

const exit = Exit.fail("bad input")
const mapped = Exit.mapError(exit, (e) => new ExitError({ input: e }))
console.log(Exit.isFailure(mapped)) // true

See

• map to transform the success value
• mapBoth to transform both success and error

Signature

declare const mapError: { <E, E2>(f: (a: NoInfer<E>) => E2): <A>(self: Exit<A, E>) => Exit<A, E2>; <A, E, E2>(self: Exit<A, E>, f: (a: NoInfer<E>) => E2): Exit<A, E2>; }

Source

Since v2.0.0