<E, E2, A, A2>(options: {
readonly onFailure: (e: E) => E2
readonly onSuccess: (a: A) => A2
}): <R>(self: Effect<A, E, R>) => Effect<A2, E2, R>
<A, E, R, E2, A2>(
self: Effect<A, E, R>,
options: {
readonly onFailure: (e: E) => E2
readonly onSuccess: (a: A) => A2
}
): Effect<A2, E2, R>Applies mapBoth eagerly when an effect is already resolved.
When to use
Use when an already-resolved effect should transform either success or failure immediately while pending effects still use regular channel mapping.
Details
Success effects apply onSuccess immediately, and failure effects apply
onFailure immediately. Pending effects fall back to regular mapBoth
behavior.
Example (Mapping both channels eagerly when possible)
import { Effect } from "effect"
// For resolved effects, the appropriate mapping is applied immediately
const success = Effect.succeed(5)
const mapped = Effect.mapBothEager(success, {
onFailure: (err: string) => `Failed: ${err}`,
onSuccess: (n: number) => n * 2
}) // onSuccess applied eagerly
const failure = Effect.fail("error")
const mappedError = Effect.mapBothEager(failure, {
onFailure: (err: string) => `Failed: ${err}`,
onSuccess: (n: number) => n * 2
}) // onFailure applied eagerlyexport const const mapBothEager: {
<E, E2, A, A2>(options: {
readonly onFailure: (e: E) => E2
readonly onSuccess: (a: A) => A2
}): <R>(
self: Effect<A, E, R>
) => Effect<A2, E2, R>
<A, E, R, E2, A2>(
self: Effect<A, E, R>,
options: {
readonly onFailure: (e: E) => E2
readonly onSuccess: (a: A) => A2
}
): Effect<A2, E2, R>
}
Applies mapBoth eagerly when an effect is already resolved.
When to use
Use when an already-resolved effect should transform either success or
failure immediately while pending effects still use regular channel mapping.
Details
Success effects apply onSuccess immediately, and failure effects apply
onFailure immediately. Pending effects fall back to regular mapBoth
behavior.
Example (Mapping both channels eagerly when possible)
import { Effect } from "effect"
// For resolved effects, the appropriate mapping is applied immediately
const success = Effect.succeed(5)
const mapped = Effect.mapBothEager(success, {
onFailure: (err: string) => `Failed: ${err}`,
onSuccess: (n: number) => n * 2
}) // onSuccess applied eagerly
const failure = Effect.fail("error")
const mappedError = Effect.mapBothEager(failure, {
onFailure: (err: string) => `Failed: ${err}`,
onSuccess: (n: number) => n * 2
}) // onFailure applied eagerly
mapBothEager: {
<function (type parameter) E in <E, E2, A, A2>(options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): <R>(self: Effect<A, E, R>) => Effect<A2, E2, R>
function (type parameter) E2 in <E, E2, A, A2>(options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): <R>(self: Effect<A, E, R>) => Effect<A2, E2, R>
function (type parameter) A in <E, E2, A, A2>(options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): <R>(self: Effect<A, E, R>) => Effect<A2, E2, R>
function (type parameter) A2 in <E, E2, A, A2>(options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): <R>(self: Effect<A, E, R>) => Effect<A2, E2, R>
options: {
readonly onFailure: (e: E) => E2
readonly onSuccess: (a: A) => A2
}
onFailure: (e: E) => E2onFailure: (e: Ee: function (type parameter) E in <E, E2, A, A2>(options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): <R>(self: Effect<A, E, R>) => Effect<A2, E2, R>
function (type parameter) E2 in <E, E2, A, A2>(options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): <R>(self: Effect<A, E, R>) => Effect<A2, E2, R>
onSuccess: (a: A) => A2onSuccess: (a: Aa: function (type parameter) A in <E, E2, A, A2>(options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): <R>(self: Effect<A, E, R>) => Effect<A2, E2, R>
function (type parameter) A2 in <E, E2, A, A2>(options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): <R>(self: Effect<A, E, R>) => Effect<A2, E2, R>
function (type parameter) R in <R>(self: Effect<A, E, R>): Effect<A2, E2, 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 <E, E2, A, A2>(options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): <R>(self: Effect<A, E, R>) => Effect<A2, E2, R>
function (type parameter) E in <E, E2, A, A2>(options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): <R>(self: Effect<A, E, R>) => Effect<A2, E2, R>
function (type parameter) R in <R>(self: Effect<A, E, R>): Effect<A2, E2, 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, E2, A, A2>(options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): <R>(self: Effect<A, E, R>) => Effect<A2, E2, R>
function (type parameter) E2 in <E, E2, A, A2>(options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): <R>(self: Effect<A, E, R>) => Effect<A2, E2, R>
function (type parameter) R in <R>(self: Effect<A, E, R>): Effect<A2, E2, R>R>
<function (type parameter) A in <A, E, R, E2, A2>(self: Effect<A, E, R>, options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): Effect<A2, E2, R>
function (type parameter) E in <A, E, R, E2, A2>(self: Effect<A, E, R>, options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): Effect<A2, E2, R>
function (type parameter) R in <A, E, R, E2, A2>(self: Effect<A, E, R>, options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): Effect<A2, E2, R>
function (type parameter) E2 in <A, E, R, E2, A2>(self: Effect<A, E, R>, options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): Effect<A2, E2, R>
function (type parameter) A2 in <A, E, R, E2, A2>(self: Effect<A, E, R>, options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): Effect<A2, E2, 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, E2, A2>(self: Effect<A, E, R>, options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): Effect<A2, E2, R>
function (type parameter) E in <A, E, R, E2, A2>(self: Effect<A, E, R>, options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): Effect<A2, E2, R>
function (type parameter) R in <A, E, R, E2, A2>(self: Effect<A, E, R>, options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): Effect<A2, E2, R>
options: {
readonly onFailure: (e: E) => E2
readonly onSuccess: (a: A) => A2
}
onFailure: (e: E) => E2onFailure: (e: Ee: function (type parameter) E in <A, E, R, E2, A2>(self: Effect<A, E, R>, options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): Effect<A2, E2, R>
function (type parameter) E2 in <A, E, R, E2, A2>(self: Effect<A, E, R>, options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): Effect<A2, E2, R>
onSuccess: (a: A) => A2onSuccess: (a: Aa: function (type parameter) A in <A, E, R, E2, A2>(self: Effect<A, E, R>, options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): Effect<A2, E2, R>
function (type parameter) A2 in <A, E, R, E2, A2>(self: Effect<A, E, R>, options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): Effect<A2, E2, 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 <A, E, R, E2, A2>(self: Effect<A, E, R>, options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): Effect<A2, E2, R>
function (type parameter) E2 in <A, E, R, E2, A2>(self: Effect<A, E, R>, options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): Effect<A2, E2, R>
function (type parameter) R in <A, E, R, E2, A2>(self: Effect<A, E, R>, options: {
readonly onFailure: (e: E) => E2;
readonly onSuccess: (a: A) => A2;
}): Effect<A2, E2, R>
import internalinternal.const mapBothEager: {
<E, E2, A, A2>(options: {
readonly onFailure: (e: E) => E2
readonly onSuccess: (a: A) => A2
}): <R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<A2, E2, R>
<A, E, R, E2, A2>(
self: Effect.Effect<A, E, R>,
options: {
readonly onFailure: (e: E) => E2
readonly onSuccess: (a: A) => A2
}
): Effect.Effect<A2, E2, R>
}