effect-io-ai

Package: effect
Module: Effect

Effect.transposeOption

Converts an Option of an Effect into an Effect of an Option.

When to use

Use when an effect should run only when an optional value is present, while preserving absence as a successful None.

Details

• None becomes an effect that succeeds with None
• Some(effect) runs the inner effect and wraps its success value in Some
• Inner failures are preserved in the resulting effect

Example (Transposing an Option of an Effect)

import { Effect, Option } from "effect"

const some = Option.some(Effect.succeed(42))

//      ┌─── Effect<Option<number>, never, never>
//      ▼
const program = Effect.transposeOption(some)

Effect.runPromise(program).then(console.log)
// Output: { _id: 'Option', _tag: 'Some', value: 42 }

Signature

declare const transposeOption: <A = never, E = never, R = never>(self: Option<Effect<A, E, R>>) => Effect<Option<A>, E, R>

Source

Since v3.13.0