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variable / @typed/fx/Fx

takeUntilEffect

Takes elements from an Fx until an effectful predicate returns true. The element that satisfies the predicate is not included in the output.

Package version
2.0.0-beta.13
Category
Selecting values
Since
1.0.0

Follow one execution

Each predicate Effect takes one turn in this serialized source. Its failure is forwarded rather than treated as false. The boundary input is excluded and the source stops.

Fx timelinetakeUntilEffect(oneTurnCheck)takeUntilEffect
OperatortakeUntilEffect(oneTurnCheck)
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.

Predicate effects run in the consumer and expose their failures and services. A match or interruption stops upstream and cancels active work.

Source implementation · Learn the surrounding model

Compare all Fx timelines →

Import

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

Signatures

export declare const takeUntilEffect: {
    <A, E2, R2>(predicate: (a: A) => Effect.Effect<boolean, E2, R2>): <E, R>(fx: Fx<A, E, R>) => Fx<A, E | E2, R | R2>;
    <A, E, R, E2, R2>(fx: Fx<A, E, R>, predicate: (a: A) => Effect.Effect<boolean, E2, R2>): Fx<A, E | E2, R | R2>;
};

Why

takeUntilEffect makes the stopping decision Effectful and ordered. A successful match completes before that input is emitted; a false result forwards it.

Ownership and lifetime

Predicate effects run in the consumer and expose their failures and services. A match or interruption stops upstream and cancels active work.

Examples

import { Effect } from "effect"
import { Fx } from "@typed/fx"
const values = Fx.fromIterable([1, 2]).pipe(Fx.takeUntilEffect((n) => Effect.succeed(n === 2)))

Other public imports

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

Source