Import
import { head } from "@typed/fx/Sink";Signatures
export declare function head<A, E>(ref: Ref.Ref<Option.Option<A>>): Sink<A, E, never>;Why
The first observed value can be retained in a caller-owned location without stopping the producer.
Ownership and lifetime
The caller owns the Ref. Each success returns a lazy atomic update. The first update Effect to
execute while the Ref is None stores its value; that is the first callback only when the producer
executes callback Effects serially. Later updates leave Some unchanged. Failures are ignored.
Examples
import { Effect, Option, Ref } from "effect"
import * as Sink from "@typed/fx/Sink"
const program = Effect.gen(function* () {
const first = yield* Ref.make<Option.Option<number>>(Option.none())
return Sink.head(first)
})Other public imports
These import paths expose the same declaration. Each page retains its own public name and signature.