<A, E, R>(self: Effect<A, E, R>): Effect<A, Cause.Cause<E>, R>Exposes an effect's full failure cause in the error channel as Cause<E>.
Details
Use sandbox when downstream error handling needs to distinguish typed
failures, defects, and interruptions. Use unsandbox to restore the original
typed error channel after cause-level handling.
Example (Exposing failures as causes)
import { Cause, Effect } from "effect"
const task = Effect.fail("Something went wrong")
// Sandbox exposes the full cause as the error type
const program = Effect.gen(function*() {
const result = yield* Effect.flip(Effect.sandbox(task))
return `Caught cause: ${Cause.squash(result)}`
})
Effect.runPromise(program).then(console.log)
// Output: "Caught cause: Something went wrong"export const const sandbox: <A, E, R>(
self: Effect<A, E, R>
) => Effect<A, Cause.Cause<E>, R>
Exposes an effect's full failure cause in the error channel as Cause<E>.
Details
Use sandbox when downstream error handling needs to distinguish typed
failures, defects, and interruptions. Use unsandbox to restore the original
typed error channel after cause-level handling.
Example (Exposing failures as causes)
import { Cause, Effect } from "effect"
const task = Effect.fail("Something went wrong")
// Sandbox exposes the full cause as the error type
const program = Effect.gen(function*() {
const result = yield* Effect.flip(Effect.sandbox(task))
return `Caught cause: ${Cause.squash(result)}`
})
Effect.runPromise(program).then(console.log)
// Output: "Caught cause: Something went wrong"
sandbox: <function (type parameter) A in <A, E, R>(self: Effect<A, E, R>): Effect<A, Cause.Cause<E>, R>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, Cause.Cause<E>, R>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, Cause.Cause<E>, 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>): Effect<A, Cause.Cause<E>, R>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, Cause.Cause<E>, R>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, Cause.Cause<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, R>(self: Effect<A, E, R>): Effect<A, Cause.Cause<E>, R>A, import CauseCause.interface Cause<out E>A structured representation of how an Effect failed.
When to use
Use to preserve the full structured failure information for an effect instead
of collapsing it to a single error value.
Details
Access the individual failure entries through the reasons array, then
narrow each entry with
isFailReason
,
isDieReason
, or
- Use
hasFails
/
hasDies
/
hasInterrupts
to test
for the presence of specific reason kinds without iterating.
- Use
findError
/
findDefect
to extract the first value
of a given kind.
- Use
combine
to merge two causes.
Cause implements Equal — two causes with the same reasons (by value)
compare as equal.
Example (Creating and inspecting a cause)
import { Cause } from "effect"
const cause = Cause.fail("Something went wrong")
console.log(cause.reasons.length) // 1
console.log(Cause.isFailReason(cause.reasons[0])) // true
Companion namespace for the Cause interface.
Cause<function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, Cause.Cause<E>, R>E>, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, Cause.Cause<E>, R>R> = import internalinternal.const sandbox: <A, E, R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<A, Cause.Cause<E>, R>