Optional

Optional<S, A> = object

Defined in: Core/Optional.ts:27

Optional<S, A> focuses on a value A inside a structure S that may or may not be present. Like a Lens, but get returns Option.

Compose with other Optionals via andThen, or with a Lens via andThenLens. Convert a Lens to an Optional with Lens.toOptional.

Example

type Profile = { username: string; bio?: string };

const bioOpt = Optional.prop<Profile>()("bio");

pipe(profile, Optional.get(bioOpt));               // Some("hello") or None
pipe(profile, Optional.set(bioOpt)("hello"));      // new Profile with bio set
pipe(profile, Optional.modify(bioOpt)(s => s + "!")); // appends if present

Type Parameters

S

S

A

A

Properties

get()

readonly get: (s) => Option<A>

Defined in: Core/Optional.ts:28

Parameters

s

S

Returns

Option<A>

---

set()

readonly set: (a) => (s) => S

Defined in: Core/Optional.ts:29

Parameters

a

A

Returns

(s): S

Parameters

s

S

Returns

S