effect-io-ai

Package: effect
Module: Stream

Stream.zipLatestWith

Combines the latest values from both streams whenever either emits, using the provided function.

When to use

Use when two streams should start emitting custom combined values after both have produced at least one value.

Gotchas

Note: tracking the latest value is done on a per-array basis. That means that emitted elements that are not the last value in arrays will never be used for zipping.

Example (Zipping latest values with a function)

import { Console, Effect, Stream } from "effect"

Effect.gen(function*() {
  const result = yield* Stream.make(1, 2, 3).pipe(
    Stream.rechunk(1),
    Stream.zipLatestWith(
      Stream.make(10, 20).pipe(Stream.rechunk(1)),
      (n, m) => n + m
    ),
    Stream.runCollect
  )

  yield* Console.log(result)
  // Output: [ 11, 12, 22, 23 ]
})

Signature

declare const zipLatestWith: { <AR, ER, RR, AL, A>(right: Stream<AR, ER, RR>, f: (left: AL, right: AR) => A): <EL, RL>(left: Stream<AL, EL, RL>) => Stream<A, EL | ER, RL | RR>; <AL, EL, RL, AR, ER, RR, A>(left: Stream<AL, EL, RL>, right: Stream<AR, ER, RR>, f: (left: AL, right: AR) => A): Stream<A, EL | ER, RL | RR>; }

Source

Since v2.0.0