effect-io-ai

Package: effect
Module: RcMap

RcMap.RcMap

An RcMap is a reference-counted map data structure that manages the lifecycle of resources indexed by keys. Resources are lazily acquired and automatically released when no longer in use.

When to use

Use to share scoped resources by key while automatically releasing them after their last active reference is gone.

Example (Inspecting a reference-counted map)

import { Effect, RcMap } from "effect"

Effect.gen(function*() {
  // Create an RcMap that manages database connections
  const dbConnectionMap = yield* RcMap.make({
    lookup: (dbName: string) =>
      Effect.acquireRelease(
        Effect.succeed(`Connection to ${dbName}`),
        (conn) => Effect.log(`Closing ${conn}`)
      ),
    capacity: 10,
    idleTimeToLive: "5 minutes"
  })

  // The RcMap interface provides access to:
  // - lookup: Function to acquire resources
  // - capacity: Maximum number of resources
  // - idleTimeToLive: Time before idle resources are released
  // - state: Current state of the map

  console.log(`Capacity: ${dbConnectionMap.capacity}`)
}).pipe(Effect.scoped)

See

• make for creating an RcMap
• get for acquiring or retaining a resource by key

Signature

export interface RcMap<in out K, in out A, in out E = never> extends Pipeable {
  readonly [TypeId]: typeof TypeId
  readonly lookup: (key: K) => Effect.Effect<A, E, Scope.Scope>
  readonly context: Context.Context<never>
  readonly scope: Scope.Scope
  readonly idleTimeToLive: (key: K) => Duration.Duration
  readonly capacity: number
  state: State<K, A, E>
}

Source

Since v3.5.0