<A, E = never>(): Effect<Deferred<A, E>>Creates a new Deferred.
When to use
Use to allocate an empty Deferred inside an Effect workflow.
Example (Creating a Deferred)
import { Deferred, Effect } from "effect"
const program = Effect.gen(function*() {
const deferred = yield* Deferred.make<number>()
yield* Deferred.succeed(deferred, 42)
const value = yield* Deferred.await(deferred)
console.log(value) // 42
})export const const make: <A, E = never>() => Effect<
Deferred<A, E>
>
Creates a new Deferred.
When to use
Use to allocate an empty Deferred inside an Effect workflow.
Example (Creating a Deferred)
import { Deferred, Effect } from "effect"
const program = Effect.gen(function*() {
const deferred = yield* Deferred.make<number>()
yield* Deferred.succeed(deferred, 42)
const value = yield* Deferred.await(deferred)
console.log(value) // 42
})
make = <function (type parameter) A in <A, E = never>(): Effect<Deferred<A, E>>A, function (type parameter) E in <A, E = never>(): Effect<Deferred<A, E>>E = never>(): interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<interface Deferred<in out A, in out E = never>A Deferred represents an asynchronous variable that can be set exactly
once, with the ability for an arbitrary number of fibers to suspend (by
calling Deferred.await) and automatically resume when the variable is set.
When to use
Use to coordinate multiple fibers around a value or failure that will be
supplied exactly once.
Example (Creating a Deferred for inter-fiber communication)
import { Deferred, Effect, Fiber } from "effect"
// Create and use a Deferred for inter-fiber communication
const program = Effect.gen(function*() {
// Create a Deferred that will hold a string value
const deferred: Deferred.Deferred<string> = yield* Deferred.make<string>()
// Fork a fiber that will set the deferred value
const producer = yield* Effect.forkChild(
Effect.gen(function*() {
yield* Effect.sleep("100 millis")
yield* Deferred.succeed(deferred, "Hello, World!")
})
)
// Fork a fiber that will await the deferred value
const consumer = yield* Effect.forkChild(
Effect.gen(function*() {
const value = yield* Deferred.await(deferred)
console.log("Received:", value)
return value
})
)
// Wait for both fibers to complete
yield* Fiber.join(producer)
const result = yield* Fiber.join(consumer)
return result
})
Companion namespace containing type-level metadata for Deferred.
When to use
Use to reference type-level metadata associated with Deferred.
Deferred<function (type parameter) A in <A, E = never>(): Effect<Deferred<A, E>>A, function (type parameter) E in <A, E = never>(): Effect<Deferred<A, E>>E>> => import internalEffectinternalEffect.const sync: <A>(
thunk: LazyArg<A>
) => Effect.Effect<A>
const makeUnsafe: <
A,
E = never
>() => Deferred<A, E>
Creates an empty Deferred synchronously outside the Effect runtime.
When to use
Use to allocate a Deferred synchronously when direct allocation outside
Effect is required.
Example (Creating a Deferred unsafely)
import { Deferred } from "effect"
const deferred = Deferred.makeUnsafe<number>()
console.log(deferred)
makeUnsafe())