effect-io-ai

Package: effect
Module: SubscriptionRef

SubscriptionRef.updateSomeAndGet

Applies an optional update and returns the current value afterward.

When to use

Use to conditionally update a SubscriptionRef and read the value that is current after the update decision.

Details

If the function returns Option.some, the new value is set, published, and returned. If it returns Option.none, the unchanged current value is returned without publishing.

Example (Conditionally updating and reading the new value)

import { Effect, Option, SubscriptionRef } from "effect"

const program = Effect.gen(function*() {
  const ref = yield* SubscriptionRef.make(10)

  const newValue = yield* SubscriptionRef.updateSomeAndGet(
    ref,
    (n) => n > 5 ? Option.some(n * 2) : Option.none()
  )
  console.log("New value:", newValue)
})

Signature

declare const updateSomeAndGet: { <A>(update: (a: A) => Option.Option<A>): (self: SubscriptionRef<A>) => Effect.Effect<A>; <A>(self: SubscriptionRef<A>, update: (a: A) => Option.Option<A>): Effect.Effect<A>; }

Source

Since v2.0.0