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variable / @typed/fx

Fx.take

Takes the first n elements from an Fx and then completes.

Package version
2.0.0-beta.7
Category
Selecting values
Since
1.0.0
Member of
Fx

Follow one execution

Takes the first n elements from an Fx and then completes.

Fx timelinetake completes after its fixed prefixtake
Operatortake(2)
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.

A per-run counter owns no external resource. Reaching the limit interrupts/stops upstream work; source failures before that point and consumer interruption remain observable.

Source implementation · Learn the surrounding model

Compare all Fx timelines →

Import

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

Access Fx.take 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 take: {
    (n: number): <A, E, R>(fx: Fx<A, E, R>) => Fx<A, E, R>;
    <A, E, R>(fx: Fx<A, E, R>, n: number): Fx<A, E, R>;
};

Why

take bounds cardinality without buffering: it forwards at most the first n values in order and then completes the run early.

Ownership and lifetime

A per-run counter owns no external resource. Reaching the limit interrupts/stops upstream work; source failures before that point and consumer interruption remain observable.

Examples

import { Fx } from "@typed/fx"

const firstTwo = Fx.fromIterable([1, 2, 3]).pipe(Fx.take(2))

Other public imports

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

Source