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variable / @typed/fx/Fx

zipRight

Zips two Fx streams in strict lockstep and emits only the right value. Completes when the first of the two streams completes.

Package version
2.0.0-beta.13
Category
Combining sources
Since
1.0.0

Follow one execution

Each fresh left value permits one right value; the left payload is discarded.

Fx timelinezipRight(left, right)zipRight
OperatorzipRight(left, right)
Read this diagram

Follow each lane from left to right. Events stacked vertically share a tick; the green cursor marks the current time across every lane.

  • A value
    The text inside the pill is the emitted value.
  • Work starts
    The raised chevron starts an inner run (^ in the source).
  • The run returns
    The vertical bar ends this lane’s run.
  • A cause is delivered
    The exclamation mark belongs to this lane.
  • Work is interrupted
    The cross marks cancellation of this run.
  • Current time
    The line and diamond move together across all lanes.
  • Happening now
    A highlighted event is at the current tick.
  • Still ahead
    Muted, dashed values have not happened yet.
  • Time continues
    The lane’s arrow is not a return marker. An empty stretch can be quiet work that is still running.

Illustrated ticks start at 0. At 1×, one illustrated tick takes one second; captions specify real durations when timing matters. A cause or interruption belongs to its lane, and other work may continue. Scroll horizontally to inspect the rest of a long timeline.

Both runs belong to the consumer. The first completion or consumer interruption cancels the remaining run and releases the lockstep queues. Failure is Sink delivery, not an automatic stop; pairing can continue when the failing producer remains active and later emits a value.

Source implementation · Learn the surrounding model

Compare all Fx timelines →

Import

import { zipRight } from "@typed/fx/Fx";

Signatures

export declare const zipRight: {
    <A2, E2, R2>(that: Fx<A2, E2, R2>): <A, E, R>(self: Fx<A, E, R>) => Fx<A2, E | E2, R | R2>;
    <A, E, R, A2, E2, R2>(self: Fx<A, E, R>, that: Fx<A2, E2, R2>): Fx<A2, E | E2, R | R2>;
};

Why

zipRight pairs both sources but deliberately keeps the right payload. It emits once per pair, in pairing order, and never emits an unmatched right value.

Ownership and lifetime

Both runs belong to the consumer. The first completion or consumer interruption cancels the remaining run and releases the lockstep queues. Failure is Sink delivery, not an automatic stop; pairing can continue when the failing producer remains active and later emits a value.

Examples

import { Cause, Effect } from "effect"
import { Fx, Sink } from "@typed/fx"

const left = Fx.make<number, string>((sink) =>
  sink.onFailure(Cause.fail("warning")).pipe(Effect.andThen(sink.onSuccess(1)))
)
const program = Fx.zipRight(left, Fx.succeed("paired")).run(
  Sink.make(Effect.logError, Effect.log)
) // logs the failure and then "paired"

Other public imports

These import paths expose the same declaration. Each page retains its own public name and signature.

Source