effect-io-ai

Package: effect
Module: RcMap

RcMap.make

Creates an RcMap that can contain multiple reference counted resources that can be indexed by a key. The resources are lazily acquired on the first call to get and released when the last reference is released.

When to use

Use to create a scoped reference-counted map for resources that should be acquired once per key and shared while in use.

Details

Complex keys can extend Equal and Hash to allow lookups by value.

• capacity: The maximum number of resources that can be held in the map.
• idleTimeToLive: When the reference count reaches zero, the resource will be released after this duration.

Example (Creating a reference-counted map)

import { Effect, RcMap } from "effect"

Effect.gen(function*() {
  const map = yield* RcMap.make({
    lookup: (key: string) =>
      Effect.acquireRelease(
        Effect.succeed(`acquired ${key}`),
        () => Effect.log(`releasing ${key}`)
      )
  })

  // Get "foo" from the map twice, which will only acquire it once.
  // It will then be released once the scope closes.
  yield* RcMap.get(map, "foo").pipe(
    Effect.andThen(RcMap.get(map, "foo")),
    Effect.scoped
  )
})

See

• get for acquiring or retaining a resource by key
• invalidate for removing a resource from the map

Signature

declare const make: { <K, A, E, R>(options: { readonly lookup: (key: K) => Effect.Effect<A, E, R>; readonly idleTimeToLive?: Duration.Input | ((key: K) => Duration.Input) | undefined; readonly capacity?: undefined; }): Effect.Effect<RcMap<K, A, E>, never, Scope.Scope | R>; <K, A, E, R>(options: { readonly lookup: (key: K) => Effect.Effect<A, E, R>; readonly idleTimeToLive?: Duration.Input | ((key: K) => Duration.Input) | undefined; readonly capacity: number; }): Effect.Effect<RcMap<K, A, E | Cause.ExceededCapacityError>, never, Scope.Scope | R>; }

Source

Since v3.5.0