effect-io-ai

Package: effect
Module: Ref

Ref.update

Updates the value of the Ref atomically using the given function.

When to use

Use to apply a Ref state transition without returning a value.

Example (Updating a value)

import { Effect, Ref } from "effect"

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

  // Update the value
  yield* Ref.update(counter, (n) => n * 2)

  const value = yield* Ref.get(counter)
  console.log(value) // 10
})

// Using multiple operations
const program2 = Effect.gen(function*() {
  const counter = yield* Ref.make(5)
  yield* Ref.update(counter, (n: number) => n + 10)
  const value = yield* Ref.get(counter)
  console.log(value) // 15
})

See

• updateAndGet for returning the new value
• getAndUpdate for returning the previous value

Signature

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

Source

Since v2.0.0