<A, E = never, R = never>(
register: (
this: Scheduler,
resume: (effect: Effect<A, E, R>) => void,
signal: AbortSignal
) => void | Effect<void, never, R>
): Effect<A, E, R>Creates an Effect from a callback-based asynchronous API.
When to use
Use when you need to integrate APIs that complete through callbacks instead
of returning a Promise.
Details
The registration function receives a resume callback and, when requested,
an AbortSignal. Call resume at most once with the effect that should
complete the fiber; later calls are ignored. Return an optional cleanup
effect from the registration function to run if the fiber is interrupted.
Example (Integrating callback APIs)
import { Effect } from "effect"
const delay = (ms: number) =>
Effect.callback<void>((resume) => {
const timeoutId = setTimeout(() => {
resume(Effect.void)
}, ms)
// Cleanup function for interruption
return Effect.sync(() => clearTimeout(timeoutId))
})
const program = delay(1000)export const const callback: <A, E = never, R = never>(
register: (
this: Scheduler,
resume: (effect: Effect<A, E, R>) => void,
signal: AbortSignal
) => void | Effect<void, never, R>
) => Effect<A, E, R>
Creates an Effect from a callback-based asynchronous API.
When to use
Use when you need to integrate APIs that complete through callbacks instead
of returning a Promise.
Details
The registration function receives a resume callback and, when requested,
an AbortSignal. Call resume at most once with the effect that should
complete the fiber; later calls are ignored. Return an optional cleanup
effect from the registration function to run if the fiber is interrupted.
Example (Integrating callback APIs)
import { Effect } from "effect"
const delay = (ms: number) =>
Effect.callback<void>((resume) => {
const timeoutId = setTimeout(() => {
resume(Effect.void)
}, ms)
// Cleanup function for interruption
return Effect.sync(() => clearTimeout(timeoutId))
})
const program = delay(1000)
callback: <function (type parameter) A in <A, E = never, R = never>(register: (this: Scheduler, resume: (effect: Effect<A, E, R>) => void, signal: AbortSignal) => void | Effect<void, never, R>): Effect<A, E, R>A, function (type parameter) E in <A, E = never, R = never>(register: (this: Scheduler, resume: (effect: Effect<A, E, R>) => void, signal: AbortSignal) => void | Effect<void, never, R>): Effect<A, E, R>E = never, function (type parameter) R in <A, E = never, R = never>(register: (this: Scheduler, resume: (effect: Effect<A, E, R>) => void, signal: AbortSignal) => void | Effect<void, never, R>): Effect<A, E, R>R = never>(
register: (
this: Scheduler,
resume: (effect: Effect<A, E, R>) => void,
signal: AbortSignal
) => void | Effect<void, never, R>
this: Scheduler(parameter) this: {
executionMode: "sync" | "async";
shouldYield: (fiber: Fiber.Fiber<unknown, unknown>) => boolean;
makeDispatcher: () => SchedulerDispatcher;
}
resume: (effect: Effect<A, E, R>) => voidresume: (effect: Effect<A, E, R>(parameter) effect: {
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 = never, R = never>(register: (this: Scheduler, resume: (effect: Effect<A, E, R>) => void, signal: AbortSignal) => void | Effect<void, never, R>): Effect<A, E, R>A, function (type parameter) E in <A, E = never, R = never>(register: (this: Scheduler, resume: (effect: Effect<A, E, R>) => void, signal: AbortSignal) => void | Effect<void, never, R>): Effect<A, E, R>E, function (type parameter) R in <A, E = never, R = never>(register: (this: Scheduler, resume: (effect: Effect<A, E, R>) => void, signal: AbortSignal) => void | Effect<void, never, R>): Effect<A, E, R>R>) => void,
signal: AbortSignalsignal: AbortSignal
) => void | 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<void, never, function (type parameter) R in <A, E = never, R = never>(register: (this: Scheduler, resume: (effect: Effect<A, E, R>) => void, signal: AbortSignal) => void | Effect<void, never, R>): Effect<A, E, 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<function (type parameter) A in <A, E = never, R = never>(register: (this: Scheduler, resume: (effect: Effect<A, E, R>) => void, signal: AbortSignal) => void | Effect<void, never, R>): Effect<A, E, R>A, function (type parameter) E in <A, E = never, R = never>(register: (this: Scheduler, resume: (effect: Effect<A, E, R>) => void, signal: AbortSignal) => void | Effect<void, never, R>): Effect<A, E, R>E, function (type parameter) R in <A, E = never, R = never>(register: (this: Scheduler, resume: (effect: Effect<A, E, R>) => void, signal: AbortSignal) => void | Effect<void, never, R>): Effect<A, E, R>R> = import internalinternal.const callback: <A, E = never, R = never>(
register: (
this: Scheduler.Scheduler,
resume: (
effect: Effect.Effect<A, E, R>
) => void,
signal: AbortSignal
) => void | Effect.Effect<void, never, R>
) => Effect.Effect<A, E, R>