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debounce

Emits a value only after no newer source value arrives for duration.

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

Follow one execution

Emits a value only after no newer source value arrives for duration.

Fx timelinedebounce emits 250ms after the final value (50ms slots)debounce
Operatordebounce(250ms)
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.

Each value starts a scoped sleep. A newer value interrupts the previous sleep and replaces its pending value, so at most the latest value is emitted after a quiet period. Source errors terminate the result. Interruption stops both source and pending timer; Scope owns those switching lifetimes.

Source implementation · Learn the surrounding model

Compare all Fx timelines →

Import

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

Signatures

export declare const debounce: {
    (duration: Duration.Input): <A, E, R>(fx: Fx<A, E, R>) => Fx<A, E, R | Scope.Scope>;
    <A, E, R>(fx: Fx<A, E, R>, duration: Duration.Input): Fx<A, E, R | Scope.Scope>;
};

Why

Bursty producers such as text input should often trigger work only after they settle. Debouncing represents that quiet-period rule in the Fx graph.

Ownership and lifetime

Each value starts a scoped sleep. A newer value interrupts the previous sleep and replaces its pending value, so at most the latest value is emitted after a quiet period. Source errors terminate the result. Interruption stops both source and pending timer; Scope owns those switching lifetimes.

Examples

import { debounce } from "@typed/fx/Fx"
import { fromIterable } from "@typed/fx/Fx"

const settled = debounce(fromIterable(["t", "ty", "typed"]), "250 millis")

Other public imports

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

Source