effect-io-ai

Package: effect
Module: Optic

Optic.none

Prism that focuses on Option.None, exposing undefined.

When to use

Use when you want to match or construct None values within an optic chain.

Details

• getResult succeeds with undefined when the option is None.
• getResult fails when the option is Some.
• set(undefined) produces Option.none().

Example (Matching None)

import { Optic, Option, Result } from "effect"

const _none = Optic.id<Option.Option<number>>().compose(Optic.none())

console.log(Result.isSuccess(_none.getResult(Option.none())))
// Output: true

console.log(Result.isFailure(_none.getResult(Option.some(1))))
// Output: true

See

• some — focuses on Some instead
• Prism — the type this function returns

Signature

declare const none: <A>() => Prism<Option.Option<A>, undefined>

Source

Since v4.0.0