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variable / @typed/fx/Fx

undefined

An Fx that emits undefined exactly once and then completes.

Package version
2.0.0-beta.7
Category
Value sources
Since
1.0.0

Follow one execution

Exact export alias of succeedUndefined; the trace and lifecycle are identical. Deliver one undefined value and complete. This is a value pulse, distinct from empty.

Fx timelinesucceedUndefinedundefined
Operatorundefined (alias of succeedUndefined)
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 run performs one sink delivery and acquires no resources.

Source implementation · Learn the surrounding model

Compare all Fx timelines →

Import

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

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

Signatures

export { succeedUndefined as undefined };
export declare const succeedUndefined: Fx<undefined, never, never>;

Why

The shared constant avoids repeatedly spelling succeed(undefined) in optional compositions. It is also exported as undefined.

Ownership and lifetime

Each run performs one sink delivery and acquires no resources.

Examples

import { first, succeedUndefined } from "@typed/fx/Fx"

const program = first(succeedUndefined)

Other public imports

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

Source