effect-io-ai

Package: effect
Module: Option

Option.orElse

Returns the fallback Option if self is None; otherwise returns self.

When to use

Use when you need a lazy fallback Option, such as when building priority chains of optional values.

Details

• Some → returns self unchanged
• None → evaluates and returns that()
• that is lazily evaluated

Example (Providing a fallback Option)

import { Option } from "effect"

console.log(Option.none().pipe(Option.orElse(() => Option.some("b"))))
// Output: { _id: 'Option', _tag: 'Some', value: 'b' }

console.log(Option.some("a").pipe(Option.orElse(() => Option.some("b"))))
// Output: { _id: 'Option', _tag: 'Some', value: 'a' }

See

• orElseSome to wrap the fallback value in Some automatically
• firstSomeOf to pick the first Some from a collection

Signature

declare const orElse: { <B>(that: LazyArg<Option<B>>): <A>(self: Option<A>) => Option<B | A>; <A, B>(self: Option<A>, that: LazyArg<Option<B>>): Option<A | B>; }

Source

Since v2.0.0