<E, A2, E2, R2>(f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): <A, R>(
self: Effect<A, E, R>
) => Effect<A2 | A, E2, R2 | R>
<A, E, R, A2, E2, R2>(
self: Effect<A, E, R>,
f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>
): Effect<A | A2, E2, R | R2>Handles both recoverable and unrecoverable errors by providing a recovery effect.
When to use
Use when you need to recover from an Effect by inspecting the full Cause,
including recoverable failures, defects, and interruptions, instead of only
the typed error value.
Details
When to Recover from Defects:
Defects are unexpected errors that typically shouldn't be recovered from, as they often indicate serious issues. However, in some cases, such as dynamically loaded plugins, controlled recovery might be needed.
Example (Recovering from full failure causes)
import { Cause, Console, Effect } from "effect"
// An effect that might fail in different ways
const program = Effect.die("Something went wrong")
// Recover from any cause (including defects)
const recovered = Effect.catchCause(program, (cause) => {
if (Cause.hasDies(cause)) {
return Console.log("Caught defect").pipe(
Effect.as("Recovered from defect")
)
}
return Effect.succeed("Unknown error")
})export const const catchCause: {
<E, A2, E2, R2>(
f: (
cause: Cause.Cause<E>
) => Effect<A2, E2, R2>
): <A, R>(
self: Effect<A, E, R>
) => Effect<A2 | A, E2, R2 | R>
<A, E, R, A2, E2, R2>(
self: Effect<A, E, R>,
f: (
cause: Cause.Cause<E>
) => Effect<A2, E2, R2>
): Effect<A | A2, E2, R | R2>
}
Handles both recoverable and unrecoverable errors by providing a recovery
effect.
When to use
Use when you need to recover from an Effect by inspecting the full Cause,
including recoverable failures, defects, and interruptions, instead of only
the typed error value.
Details
When to Recover from Defects:
Defects are unexpected errors that typically shouldn't be recovered from, as
they often indicate serious issues. However, in some cases, such as
dynamically loaded plugins, controlled recovery might be needed.
Example (Recovering from full failure causes)
import { Cause, Console, Effect } from "effect"
// An effect that might fail in different ways
const program = Effect.die("Something went wrong")
// Recover from any cause (including defects)
const recovered = Effect.catchCause(program, (cause) => {
if (Cause.hasDies(cause)) {
return Console.log("Caught defect").pipe(
Effect.as("Recovered from defect")
)
}
return Effect.succeed("Unknown error")
})
catchCause: {
<function (type parameter) E in <E, A2, E2, R2>(f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): <A, R>(self: Effect<A, E, R>) => Effect<A2 | A, E2, R2 | R>E, function (type parameter) A2 in <E, A2, E2, R2>(f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): <A, R>(self: Effect<A, E, R>) => Effect<A2 | A, E2, R2 | R>A2, function (type parameter) E2 in <E, A2, E2, R2>(f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): <A, R>(self: Effect<A, E, R>) => Effect<A2 | A, E2, R2 | R>E2, function (type parameter) R2 in <E, A2, E2, R2>(f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): <A, R>(self: Effect<A, E, R>) => Effect<A2 | A, E2, R2 | R>R2>(
f: (
cause: Cause.Cause<E>
) => Effect<A2, E2, R2>
f: (cause: Cause.Cause<E>(parameter) cause: {
reasons: ReadonlyArray<Reason<E>>;
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;
}
cause: 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 <E, A2, E2, R2>(f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): <A, R>(self: Effect<A, E, R>) => Effect<A2 | A, E2, R2 | 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<function (type parameter) A2 in <E, A2, E2, R2>(f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): <A, R>(self: Effect<A, E, R>) => Effect<A2 | A, E2, R2 | R>A2, function (type parameter) E2 in <E, A2, E2, R2>(f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): <A, R>(self: Effect<A, E, R>) => Effect<A2 | A, E2, R2 | R>E2, function (type parameter) R2 in <E, A2, E2, R2>(f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): <A, R>(self: Effect<A, E, R>) => Effect<A2 | A, E2, R2 | R>R2>
): <function (type parameter) A in <A, R>(self: Effect<A, E, R>): Effect<A2 | A, E2, R2 | R>A, function (type parameter) R in <A, R>(self: Effect<A, E, R>): Effect<A2 | A, E2, R2 | 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;
}
self: 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, R>(self: Effect<A, E, R>): Effect<A2 | A, E2, R2 | R>A, function (type parameter) E in <E, A2, E2, R2>(f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): <A, R>(self: Effect<A, E, R>) => Effect<A2 | A, E2, R2 | R>E, function (type parameter) R in <A, R>(self: Effect<A, E, R>): Effect<A2 | A, E2, R2 | 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) A2 in <E, A2, E2, R2>(f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): <A, R>(self: Effect<A, E, R>) => Effect<A2 | A, E2, R2 | R>A2 | function (type parameter) A in <A, R>(self: Effect<A, E, R>): Effect<A2 | A, E2, R2 | R>A, function (type parameter) E2 in <E, A2, E2, R2>(f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): <A, R>(self: Effect<A, E, R>) => Effect<A2 | A, E2, R2 | R>E2, function (type parameter) R2 in <E, A2, E2, R2>(f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): <A, R>(self: Effect<A, E, R>) => Effect<A2 | A, E2, R2 | R>R2 | function (type parameter) R in <A, R>(self: Effect<A, E, R>): Effect<A2 | A, E2, R2 | R>R>
<function (type parameter) A in <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>A, function (type parameter) E in <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>E, function (type parameter) R in <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>R, function (type parameter) A2 in <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>A2, function (type parameter) E2 in <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>E2, function (type parameter) R2 in <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>R2>(
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;
}
self: 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, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>A, function (type parameter) E in <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>E, function (type parameter) R in <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>R>,
f: (
cause: Cause.Cause<E>
) => Effect<A2, E2, R2>
f: (cause: Cause.Cause<E>(parameter) cause: {
reasons: ReadonlyArray<Reason<E>>;
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;
}
cause: 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, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>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<function (type parameter) A2 in <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>A2, function (type parameter) E2 in <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>E2, function (type parameter) R2 in <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>R2>
): 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, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>A | function (type parameter) A2 in <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>A2, function (type parameter) E2 in <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>E2, function (type parameter) R in <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>R | function (type parameter) R2 in <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, f: (cause: Cause.Cause<E>) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R2>R2>
} = import internalinternal.const catchCause: {
<E, B, E2, R2>(
f: (
cause: NoInfer<Cause.Cause<E>>
) => Effect.Effect<B, E2, R2>
): <A, R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<A | B, E2, R | R2>
<A, E, R, B, E2, R2>(
self: Effect.Effect<A, E, R>,
f: (
cause: NoInfer<Cause.Cause<E>>
) => Effect.Effect<B, E2, R2>
): Effect.Effect<A | B, E2, R | R2>
}
catchCause