effect-io-ai

Package: effect
Module: Layer

Layer.mergeAll

Combines all the provided layers concurrently, creating a new layer with merged input, error, and output types.

When to use

Use when you need to combine multiple independent layers.

Details

All layers are built concurrently, and their outputs are merged into a single layer.

If multiple merged layers depend on the same layer value, that dependency is shared by default. Reuse a named layer value when you want services to share the same resource, such as one database pool.

Example (Merging independent layers)

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

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

class Logger extends Context.Service<Logger, {
  readonly log: (msg: string) => Effect.Effect<void>
}>()("Logger") {}

const dbLayer = Layer.succeed(Database, {
  query: Effect.fn("Database.query")((sql: string) => Effect.succeed("result"))
})
const loggerLayer = Layer.succeed(Logger, {
  log: Effect.fn("Logger.log")((msg: string) => Effect.sync(() => console.log(msg)))
})

const mergedLayer = Layer.mergeAll(dbLayer, loggerLayer)

See

• merge for merging one layer with another layer or array

Signature

declare const mergeAll: <Layers extends [Layer<never, any, any>, ...Array<Layer<never, any, any>>]>(...layers: Layers) => Layer<Success<Layers[number]>, Error<Layers[number]>, Services<Layers[number]>>

Source

Since v2.0.0