SubscriptionRef.getAndUpdateEffect — API

SubscriptionRef.getAndUpdateEffectconsteffect/SubscriptionRef.ts:313

<A, E, R>(update: (a: A) => Effect.Effect<A, E, R>): (
  self: SubscriptionRef<A>
) => Effect.Effect<A, E, R>
<A, E, R>(
  self: SubscriptionRef<A>,
  update: (a: A) => Effect.Effect<A, E, R>
): Effect.Effect<A, E, R>

Retrieves the current value and updates it atomically with the result of applying an effectful function, notifying subscribers of the change.

Example (Getting and updating with an effect)

import { Effect, SubscriptionRef } from "effect"

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

  const oldValue = yield* SubscriptionRef.getAndUpdateEffect(
    ref,
    (n) => Effect.succeed(n + 5)
  )
  console.log("Old value:", oldValue)

  const newValue = yield* SubscriptionRef.get(ref)
  console.log("New value:", newValue)
})

getters

Source effect/SubscriptionRef.ts:31314 lines

export const getAndUpdateEffect: {
  <A, E, R>(update: (a: A) => Effect.Effect<A, E, R>): (self: SubscriptionRef<A>) => Effect.Effect<A, E, R>
  <A, E, R>(self: SubscriptionRef<A>, update: (a: A) => Effect.Effect<A, E, R>): Effect.Effect<A, E, R>
} = dual(2, <A, E, R>(
  self: SubscriptionRef<A>,
  update: (a: A) => Effect.Effect<A, E, R>
) =>
  self.semaphore.withPermit(Effect.sync(() => {
    const current = self.value
    return Effect.map(update(current), (newValue) => {
      setUnsafe(self, newValue)
      return current
    })
  })))