effect-io-ai

Package: effect
Module: Ref

Ref.updateAndGet

Updates the value of the Ref atomically using the given function and returns the new value.

When to use

Use to apply a Ref state transition and return the new stored value.

Example (Updating and returning the new value)

import { Effect, Ref } from "effect"

const program = Effect.gen(function*() {
  const counter = yield* Ref.make(5)

  // Update and get the new value in one operation
  const newValue = yield* Ref.updateAndGet(counter, (n) => n * 3)
  console.log(newValue) // 15

  // Verify the ref contains the new value
  const current = yield* Ref.get(counter)
  console.log(current) // 15
})

See

• update for updating without returning the new value
• getAndUpdate for returning the previous value instead

Signature

declare const updateAndGet: (<A>(f: (a: A) => A) => (self: Ref<A>) => Effect.Effect<A>) & (<A>(self: Ref<A>, f: (a: A) => A) => Effect.Effect<A>)

Source

Since v2.0.0