<A, E>(deferred: Deferred<A, E>): <R>(
self: Effect<A, E, R>
) => Effect<boolean, never, R>
<A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<
boolean,
never,
R
>Runs an Effect and attempts to complete a Deferred with the effect's
result.
When to use
Use to pipe an effect result into a Deferred while preserving success,
failure, defects, and interruption.
Details
If the effect succeeds, fails, dies, or is interrupted, that result is used
as the attempted completion. The returned effect cannot fail; it succeeds
with true if it completed the Deferred, or false if the Deferred was
already completed.
Example (Completing a Deferred from an effect result)
import { Deferred, Effect } from "effect"
// Define an effect that succeeds
const successEffect = Effect.succeed(42)
const program = Effect.gen(function*() {
// Create a deferred
const deferred = yield* Deferred.make<number, string>()
// Complete the deferred using the successEffect
const isCompleted = yield* Deferred.into(successEffect, deferred)
// Access the value of the deferred
const value = yield* Deferred.await(deferred)
console.log(value)
return isCompleted
})
Effect.runPromise(program).then(console.log)
// Output:
// 42
// trueexport const const into: {
<A, E>(deferred: Deferred<A, E>): <R>(
self: Effect<A, E, R>
) => Effect<boolean, never, R>
<A, E, R>(
self: Effect<A, E, R>,
deferred: Deferred<A, E>
): Effect<boolean, never, R>
}
Runs an Effect and attempts to complete a Deferred with the effect's
result.
When to use
Use to pipe an effect result into a Deferred while preserving success,
failure, defects, and interruption.
Details
If the effect succeeds, fails, dies, or is interrupted, that result is used
as the attempted completion. The returned effect cannot fail; it succeeds
with true if it completed the Deferred, or false if the Deferred was
already completed.
Example (Completing a Deferred from an effect result)
import { Deferred, Effect } from "effect"
// Define an effect that succeeds
const successEffect = Effect.succeed(42)
const program = Effect.gen(function*() {
// Create a deferred
const deferred = yield* Deferred.make<number, string>()
// Complete the deferred using the successEffect
const isCompleted = yield* Deferred.into(successEffect, deferred)
// Access the value of the deferred
const value = yield* Deferred.await(deferred)
console.log(value)
return isCompleted
})
Effect.runPromise(program).then(console.log)
// Output:
// 42
// true
into: {
<function (type parameter) A in <A, E>(deferred: Deferred<A, E>): <R>(self: Effect<A, E, R>) => Effect<boolean, never, R>A, function (type parameter) E in <A, E>(deferred: Deferred<A, E>): <R>(self: Effect<A, E, R>) => Effect<boolean, never, R>E>(deferred: Deferred<A, E>(parameter) deferred: {
effect: Effect<A, E>;
resumes: Array<(effect: Effect<A, E>) => void> | undefined;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
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>(deferred: Deferred<A, E>): <R>(self: Effect<A, E, R>) => Effect<boolean, never, R>A, function (type parameter) E in <A, E>(deferred: Deferred<A, E>): <R>(self: Effect<A, E, R>) => Effect<boolean, never, R>E>): <function (type parameter) R in <R>(self: Effect<A, E, R>): Effect<boolean, never, R>R>(self: Effect<A, E, R>(parameter) self: {
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
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<function (type parameter) A in <A, E>(deferred: Deferred<A, E>): <R>(self: Effect<A, E, R>) => Effect<boolean, never, R>A, function (type parameter) E in <A, E>(deferred: Deferred<A, E>): <R>(self: Effect<A, E, R>) => Effect<boolean, never, R>E, function (type parameter) R in <R>(self: Effect<A, E, R>): Effect<boolean, never, R>R>) => 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<boolean, never, function (type parameter) R in <R>(self: Effect<A, E, R>): Effect<boolean, never, R>R>
<function (type parameter) A in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>R>(self: Effect<A, E, R>(parameter) self: {
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
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<function (type parameter) A in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>R>, deferred: Deferred<A, E>(parameter) deferred: {
effect: Effect<A, E>;
resumes: Array<(effect: Effect<A, E>) => void> | undefined;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
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, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>E>): 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<boolean, never, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>R>
} = dual<(...args: Array<any>) => any, <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>) => Effect<boolean, never, R>>(arity: 2, body: <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>) => Effect<boolean, never, R>): ((...args: Array<any>) => any) & (<A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>) => Effect<boolean, never, R>) (+1 overload)Creates a function that can be called in data-first style or data-last
(pipe-friendly) style.
When to use
Use to expose one implementation through both direct and pipe-friendly
call styles.
Details
Pass either the arity of the uncurried function or a predicate that decides
whether the current call is data-first. Arity is the common case. Use a
predicate when optional arguments make arity ambiguous.
Example (Selecting data-first or data-last style by arity)
import { Function, pipe } from "effect"
const sum = Function.dual<
(that: number) => (self: number) => number,
(self: number, that: number) => number
>(2, (self, that) => self + that)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
Example (Defining overloads with call signatures)
import { Function, pipe } from "effect"
const sum: {
(that: number): (self: number) => number
(self: number, that: number): number
} = Function.dual(2, (self: number, that: number): number => self + that)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
Example (Selecting data-first or data-last style with a predicate)
import { Function, pipe } from "effect"
const sum = Function.dual<
(that: number) => (self: number) => number,
(self: number, that: number) => number
>(
(args) => args.length === 2,
(self, that) => self + that
)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
dual(
2,
<function (type parameter) A in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>R>(self: Effect<A, E, R>(parameter) self: {
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
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<function (type parameter) A in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>R>, deferred: Deferred<A, E>(parameter) deferred: {
effect: Effect<A, E>;
resumes: Array<(effect: Effect<A, E>) => void> | undefined;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
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, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>E>): 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<boolean, never, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>, deferred: Deferred<A, E>): Effect<boolean, never, R>R> =>
import internalEffectinternalEffect.const uninterruptibleMask: <A, E, R>(
f: (
restore: <A, E, R>(
effect: Effect.Effect<A, E, R>
) => Effect.Effect<A, E, R>
) => Effect.Effect<A, E, R>
) => Effect.Effect<A, E, R>
restore: <A, E, R>(
effect: Effect.Effect<A, E, R>
) => Effect.Effect<A, E, R>
import internalEffectinternalEffect.const flatMap: {
<A, B, E2, R2>(
f: (a: A) => Effect.Effect<B, E2, R2>
): <E, R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<B, E | E2, R | R2>
<A, E, R, B, E2, R2>(
self: Effect.Effect<A, E, R>,
f: (a: A) => Effect.Effect<B, E2, R2>
): Effect.Effect<B, E | E2, R | R2>
}
import internalEffectinternalEffect.const exit: <A, E, R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<Exit.Exit<A, E>, never, R>
restore: <A, E, R>(
effect: Effect.Effect<A, E, R>
) => Effect.Effect<A, E, R>
self: Effect<A, E, R>(parameter) self: {
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
exit: Exit.Exit<A, E>exit) => const done: {
<A, E>(exit: Exit.Exit<A, E>): (
self: Deferred<A, E>
) => Effect<boolean>
<A, E>(
self: Deferred<A, E>,
exit: Exit.Exit<A, E>
): Effect<boolean>
}
deferred: Deferred<A, E>(parameter) deferred: {
effect: Effect<A, E>;
resumes: Array<(effect: Effect<A, E>) => void> | undefined;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
exit: Exit.Exit<A, E>exit)
)
)
)