<A, E, XE = never, XR = never>(
f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>
): <R>(self: Effect<A, E, R>) => Effect<A, E | XE, R | XR>
<A, E, R, XE = never, XR = never>(
self: Effect<A, E, R>,
f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>
): Effect<A, E | XE, R | XR>Ensures that a cleanup function runs whether this effect succeeds, fails, or is interrupted.
Example (Observing every exit)
import { Console, Effect, Exit } from "effect"
const task = Effect.succeed(42)
const program = Effect.onExit(task, (exit) =>
Console.log(
Exit.isSuccess(exit)
? `Task succeeded with: ${exit.value}`
: `Task failed: ${Exit.isFailure(exit) ? exit.cause : "interrupted"}`
))
Effect.runPromise(program).then(console.log)
// Output:
// Task succeeded with: 42
// 42export const const onExit: {
<A, E, XE = never, XR = never>(
f: (
exit: Exit.Exit<A, E>
) => Effect<void, XE, XR>
): <R>(
self: Effect<A, E, R>
) => Effect<A, E | XE, R | XR>
<A, E, R, XE = never, XR = never>(
self: Effect<A, E, R>,
f: (
exit: Exit.Exit<A, E>
) => Effect<void, XE, XR>
): Effect<A, E | XE, R | XR>
}
Ensures that a cleanup function runs whether this effect succeeds, fails, or
is interrupted.
Example (Observing every exit)
import { Console, Effect, Exit } from "effect"
const task = Effect.succeed(42)
const program = Effect.onExit(task, (exit) =>
Console.log(
Exit.isSuccess(exit)
? `Task succeeded with: ${exit.value}`
: `Task failed: ${Exit.isFailure(exit) ? exit.cause : "interrupted"}`
))
Effect.runPromise(program).then(console.log)
// Output:
// Task succeeded with: 42
// 42
onExit: {
<function (type parameter) A in <A, E, XE = never, XR = never>(f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): <R>(self: Effect<A, E, R>) => Effect<A, E | XE, R | XR>A, function (type parameter) E in <A, E, XE = never, XR = never>(f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): <R>(self: Effect<A, E, R>) => Effect<A, E | XE, R | XR>E, function (type parameter) XE in <A, E, XE = never, XR = never>(f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): <R>(self: Effect<A, E, R>) => Effect<A, E | XE, R | XR>XE = never, function (type parameter) XR in <A, E, XE = never, XR = never>(f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): <R>(self: Effect<A, E, R>) => Effect<A, E | XE, R | XR>XR = never>(
f: (
exit: Exit.Exit<A, E>
) => Effect<void, XE, XR>
exit: Exit.Exit<A, E>exit: import ExitExit.type Exit<A, E = never> = Exit.Success<A, E> | Exit.Failure<A, E>Represents the result of an Effect computation.
When to use
Use when you need to synchronously inspect whether an Effect computation
succeeded or failed.
Details
An Exit<A, E> is either Success<A, E> containing a value of type A, or
Failure<A, E> containing a Cause<E> describing why the computation
failed.
Since Exit is also an Effect, you can yield it inside Effect.gen.
Example (Pattern matching on an Exit)
import { Exit } from "effect"
const success: Exit.Exit<number> = Exit.succeed(42)
const failure: Exit.Exit<number, string> = Exit.fail("error")
const result = Exit.match(success, {
onSuccess: (value) => `Got value: ${value}`,
onFailure: (cause) => `Got error: ${cause}`
})
Namespace containing helper types shared by Exit values.
When to use
Use to reference helper types that describe the shared structure of Exit
values.
Exit<function (type parameter) A in <A, E, XE = never, XR = never>(f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): <R>(self: Effect<A, E, R>) => Effect<A, E | XE, R | XR>A, function (type parameter) E in <A, E, XE = never, XR = never>(f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): <R>(self: Effect<A, E, R>) => Effect<A, E | XE, R | XR>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<void, function (type parameter) XE in <A, E, XE = never, XR = never>(f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): <R>(self: Effect<A, E, R>) => Effect<A, E | XE, R | XR>XE, function (type parameter) XR in <A, E, XE = never, XR = never>(f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): <R>(self: Effect<A, E, R>) => Effect<A, E | XE, R | XR>XR>
): <function (type parameter) R in <R>(self: Effect<A, E, R>): Effect<A, E | XE, R | XR>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, XE = never, XR = never>(f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): <R>(self: Effect<A, E, R>) => Effect<A, E | XE, R | XR>A, function (type parameter) E in <A, E, XE = never, XR = never>(f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): <R>(self: Effect<A, E, R>) => Effect<A, E | XE, R | XR>E, function (type parameter) R in <R>(self: Effect<A, E, R>): Effect<A, E | XE, R | XR>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, XE = never, XR = never>(f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): <R>(self: Effect<A, E, R>) => Effect<A, E | XE, R | XR>A, function (type parameter) E in <A, E, XE = never, XR = never>(f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): <R>(self: Effect<A, E, R>) => Effect<A, E | XE, R | XR>E | function (type parameter) XE in <A, E, XE = never, XR = never>(f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): <R>(self: Effect<A, E, R>) => Effect<A, E | XE, R | XR>XE, function (type parameter) R in <R>(self: Effect<A, E, R>): Effect<A, E | XE, R | XR>R | function (type parameter) XR in <A, E, XE = never, XR = never>(f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): <R>(self: Effect<A, E, R>) => Effect<A, E | XE, R | XR>XR>
<function (type parameter) A in <A, E, R, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>A, function (type parameter) E in <A, E, R, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>E, function (type parameter) R in <A, E, R, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>R, function (type parameter) XE in <A, E, R, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>XE = never, function (type parameter) XR in <A, E, R, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>XR = never>(
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, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>A, function (type parameter) E in <A, E, R, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>E, function (type parameter) R in <A, E, R, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>R>,
f: (
exit: Exit.Exit<A, E>
) => Effect<void, XE, XR>
exit: Exit.Exit<A, E>exit: import ExitExit.type Exit<A, E = never> = Exit.Success<A, E> | Exit.Failure<A, E>Represents the result of an Effect computation.
When to use
Use when you need to synchronously inspect whether an Effect computation
succeeded or failed.
Details
An Exit<A, E> is either Success<A, E> containing a value of type A, or
Failure<A, E> containing a Cause<E> describing why the computation
failed.
Since Exit is also an Effect, you can yield it inside Effect.gen.
Example (Pattern matching on an Exit)
import { Exit } from "effect"
const success: Exit.Exit<number> = Exit.succeed(42)
const failure: Exit.Exit<number, string> = Exit.fail("error")
const result = Exit.match(success, {
onSuccess: (value) => `Got value: ${value}`,
onFailure: (cause) => `Got error: ${cause}`
})
Namespace containing helper types shared by Exit values.
When to use
Use to reference helper types that describe the shared structure of Exit
values.
Exit<function (type parameter) A in <A, E, R, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>A, function (type parameter) E in <A, E, R, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>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<void, function (type parameter) XE in <A, E, R, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>XE, function (type parameter) XR in <A, E, R, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>XR>
): 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, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>A, function (type parameter) E in <A, E, R, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>E | function (type parameter) XE in <A, E, R, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>XE, function (type parameter) R in <A, E, R, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>R | function (type parameter) XR in <A, E, R, XE = never, XR = never>(self: Effect<A, E, R>, f: (exit: Exit.Exit<A, E>) => Effect<void, XE, XR>): Effect<A, E | XE, R | XR>XR>
} = import internalinternal.const onExit: {
<A, E, XE = never, XR = never>(
f: (
exit: Exit.Exit<A, E>
) => Effect.Effect<void, XE, XR>
): <R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<A, E | XE, R | XR>
<A, E, R, XE = never, XR = never>(
self: Effect.Effect<A, E, R>,
f: (
exit: Exit.Exit<A, E>
) => Effect.Effect<void, XE, XR>
): Effect.Effect<A, E | XE, R | XR>
}