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Fx.timeoutTo

Switches to fallback if the source does not produce a value within duration of the previous event. Matches Effect Stream.timeoutOrElse and RxJS timeoutTo.

Package version
2.0.0-beta.7
Category
Time and rate
Since
1.0.0
Member of
Fx

Follow one execution

Switches to fallback if the source does not produce a value within duration of the previous event. Matches Effect Stream.timeoutOrElse and RxJS timeoutTo.

Fx timelinetimeoutTo cancels the source and hands off to its fallbacktimeoutTo
OperatortimeoutTo(2 seconds, fallback)
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.

The source and resettable timer start first. On timeout the source is interrupted, then one fallback subscription starts; the two producers never overlap. A source failure before timeout propagates and does not start the fallback. Interruption stops the active producer and timer. Infinite duration returns the source unchanged; zero duration returns the fallback without starting the source.

Source implementation · Learn the surrounding model

Compare all Fx timelines →

Import

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

Access Fx.timeoutTo through the imported Fx export. Its declaration below describes the member.

This public exposure is a re-export. Its import path is supported; declaration documentation is shared with the other public exposures below.

Signatures

export declare const timeoutTo: {
    <B, E2, R2>(duration: Duration.Input, fallback: Fx<B, E2, R2>): <A, E, R>(self: Fx<A, E, R>) => Fx<A | B, E | E2, R | R2 | Scope.Scope>;
    <A, E, R, B, E2, R2>(self: Fx<A, E, R>, duration: Duration.Input, fallback: Fx<B, E2, R2>): Fx<A | B, E | E2, R | R2 | Scope.Scope>;
};

Why

A fallback lets an idle producer hand ownership to another push source while preserving both sources’ precise values, failures, and services.

Ownership and lifetime

The source and resettable timer start first. On timeout the source is interrupted, then one fallback subscription starts; the two producers never overlap. A source failure before timeout propagates and does not start the fallback. Interruption stops the active producer and timer. Infinite duration returns the source unchanged; zero duration returns the fallback without starting the source.

Examples

import { timeoutTo } from "@typed/fx/Fx"
import { periodic, succeed } from "@typed/fx/Fx"

const available = timeoutTo(periodic("1 second"), "250 millis", succeed("offline"))

Other public imports

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

Source