Sink · API reference

Import

import { Sink } from "@typed/fx/Sink";

Signatures

export interface Sink<A, E = never, R = never> {
    readonly onSuccess: (value: A) => Effect<unknown, never, R>;
    readonly onFailure: (cause: Cause.Cause<E>) => Effect<unknown, never, R>;
}

export declare namespace Sink {
    type Any = Sink<any, any, any>;
    type Success<T> = T extends Sink<infer _A, infer _E, infer _R> ? _A : never;
    type Error<T> = T extends Sink<infer _A, infer _E, infer _R> ? _E : never;
    type Services<T> = T extends Sink<infer _A, infer _E, infer _R> ? _R : never;
    interface Service<Self, Id extends string, A, E> extends Sink<A, E, Self> {
        readonly id: Id;
        readonly service: Context.Service<Self, Sink<A, E>>;
        readonly make: <R = never>(onFailure: (cause: Cause.Cause<E>) => Effect<unknown, never, R>, onSuccess: (value: A) => Effect<unknown, never, R>) => Layer<Self, never, Exclude<R, Scope>>;
    }
    interface Class<Self, Id extends string, A, E> extends Service<Self, Id, A, E> {
        new (): Service<Self, Id, A, E>;
    }
}

Why

Sink gives an Fx producer one uniform destination while retaining Effect’s typed service requirements and complete failure Cause. Callback Effects have no typed failure channel, but they may still defect or be interrupted. Handling an incoming Cause is the consumer’s policy; accepting it successfully does not mean the failed producer operation succeeded.

Ownership and lifetime

A sink is inert until a producer invokes one of its callbacks. The producer’s fiber controls ordering, interruption, and callback lifetime; services in R must be available when callbacks run. Sink itself acquires no resources.

Property: onFailure

Handles the producer’s complete typed failure, defect, or interruption cause.

Property: onFailure: Why

Accepting Cause retains information that would be lost by an error-only callback.

Property: onFailure: Ownership and lifetime

The invoking producer owns ordering and interruption. The returned Effect acquires and releases any resources according to its own services and Scope.

Property: onSuccess

Handles one successful value.

Property: onSuccess: Why

The success callback is the value-side consumer boundary used by Fx producers.

Property: onSuccess: Ownership and lifetime