effect-io-ai

Package: effect
Module: Layer

Layer.build

Builds a layer into a scoped value.

Example (Building a layer into a context)

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

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

// Build a layer to get its services
const program = Effect.gen(function*() {
  const dbLayer = Layer.succeed(Database, {
    query: Effect.fn("Database.query")((sql: string) => Effect.succeed("result"))
  })

  // Build the layer into Context - automatically manages scope and memoization
  const context = yield* Layer.build(dbLayer)

  // Extract the specific service from the built layer
  const database = Context.get(context, Database)

  return yield* database.query("SELECT * FROM users")
})

Signature

declare const build: <RIn, E, ROut>(self: Layer<ROut, E, RIn>) => Effect<Context.Context<ROut>, E, RIn | Scope.Scope>

Source

Since v2.0.0