effect-io-ai

Package: effect
Module: Layer

Layer.sync

Constructs a layer lazily that provides a single service.

When to use

Use when you need a Layer that provides one service whose value is created synchronously, but creation should be deferred until the layer is built.

Details

This is a lazy version of succeed where the service value is computed synchronously only when the layer is built.

Example (Lazily providing a service)

import { Context, Effect, Layer } from "effect"

class Database extends Context.Service<Database, {
  readonly query: (sql: string) => Effect.Effect<string>
}>()("Database") {}

const layer = Layer.sync(Database, () => ({
  query: (sql: string) => Effect.succeed(`Query: ${sql}`)
}))

See

• succeed for constructing layers from static values

Signature

declare const sync: { <I, S>(service: Context.Key<I, S>): (evaluate: LazyArg<S>) => Layer<I>; <I, S>(service: Context.Key<I, S>, evaluate: LazyArg<Types.NoInfer<S>>): Layer<I>; }

Source

Since v2.0.0