<In>(): Sink<Option.Option<In>, In, In>Creates a sink containing the first value.
Details
Returns Option.some(first) for non-empty input, or Option.none when the
upstream ends without input. The first element is consumed; later elements
from the same pulled array are emitted as leftovers.
export const const head: <In>() => Sink<
Option.Option<In>,
In,
In
>
Creates a sink containing the first value.
Details
Returns Option.some(first) for non-empty input, or Option.none when the
upstream ends without input. The first element is consumed; later elements
from the same pulled array are emitted as leftovers.
head = <function (type parameter) In in <In>(): Sink<Option.Option<In>, In, In>In>(): interface Sink<out A, in In = unknown, out L = never, out E = never, out R = never>A Sink<A, In, L, E, R> is used to consume elements produced by a Stream.
You can think of a sink as a function that will consume a variable amount of
In elements (could be 0, 1, or many), might fail with an error of type E,
and will eventually yield a value of type A together with a remainder of
type L (i.e. any leftovers).
Example (Running a sink with a stream)
import { Effect, Sink, Stream } from "effect"
// Create a simple sink that always succeeds with a value
const sink: Sink.Sink<number> = Sink.succeed(42)
// Use the sink to consume a stream
const stream = Stream.make(1, 2, 3)
const program = Stream.run(stream, sink)
Effect.runPromise(program).then(console.log)
// Output: 42
Namespace containing types and interfaces for Sink variance and type relationships.
Sink<import OptionOption.type Option.Option = /*unresolved*/ anyOption<function (type parameter) In in <In>(): Sink<Option.Option<In>, In, In>In>, function (type parameter) In in <In>(): Sink<Option.Option<In>, In, In>In, function (type parameter) In in <In>(): Sink<Option.Option<In>, In, In>In> => const head_: Sink<
Option.Option<unknown>,
unknown,
unknown,
never,
never
>
const head_: {
transform: (upstream: Pull.Pull<NonEmptyReadonlyArray<In>, never, void>, scope: Scope.Scope) => Effect.Effect<End<A, L>, E, R>;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}