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variable / @typed/fx/Fx

skipRepeatsWith

Drops elements that are equal to the previous element using a custom equivalence function.

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

Follow one execution

Compare against the last emitted value using the supplied equivalence; a changed payload with the same id is suppressed.

Fx timelineskipRepeatsWith(sameId)skipRepeatsWith
OperatorskipRepeatsWith(sameId)
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 per-run previous-value state is updated atomically and released when observation ends. The pure equivalence adds no failures or services and acquires no resource.

Source implementation · Learn the surrounding model

Compare all Fx timelines →

Import

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

Signatures

export declare const skipRepeatsWith: <A>(Eq: Equivalence.Equivalence<A>) => <E, R>(fx: Fx<A, E, R>) => Fx<A, E, R>;

Why

skipRepeatsWith defines consecutive equality for values that need domain-specific comparison. It compares against the last emitted value, emits the first value, and otherwise preserves order.

Ownership and lifetime

The per-run previous-value state is updated atomically and released when observation ends. The pure equivalence adds no failures or services and acquires no resource.

Examples

import { Fx } from "@typed/fx"

const byId = Fx.skipRepeatsWith<{ id: number }>((a, b) => a.id === b.id)
const changes = Fx.fromIterable([{ id: 1 }, { id: 1 }, { id: 2 }]).pipe(byId)

Other public imports

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

Source