effect-io-ai

Package: effect
Module: Option

Option.isNone

Checks whether an Option is None (absent).

When to use

Use when you need to branch on an absent Option before accessing .value.

Details

• Acts as a type guard, narrowing to None<A>

Example (Checking for None)

import { Option } from "effect"

console.log(Option.isNone(Option.some(1)))
// Output: false

console.log(Option.isNone(Option.none()))
// Output: true

See

• isSome for the opposite check.

Signature

declare const isNone: <A>(self: Option<A>) => self is None<A>

Source

Since v2.0.0