<E, A2, In2, L2, E2, R2>(
f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>
): <A, In, L, R>(
self: Sink<A, In, L, E, R>
) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>
<A, In, L, E, R, A2, In2, L2, E2, R2>(
self: Sink<A, In, L, E, R>,
f: (error: E) => Sink<A2, In2, L2, E2, R2>
): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>Runs a fallback sink if this sink fails with a typed error.
Details
The fallback is built from the error and continues consuming from the same upstream stream. If the upstream stream had already ended, the fallback sees the upstream end instead.
error handling
Source effect/Sink.ts:201932 lines
export const const orElse: {
<E, A2, In2, L2, E2, R2>(
f: (
error: Types.NoInfer<E>
) => Sink<A2, In2, L2, E2, R2>
): <A, In, L, R>(
self: Sink<A, In, L, E, R>
) => Sink<
A2 | A,
In & In2,
L2 | L,
E2 | E,
R2 | R
>
<A, In, L, E, R, A2, In2, L2, E2, R2>(
self: Sink<A, In, L, E, R>,
f: (error: E) => Sink<A2, In2, L2, E2, R2>
): Sink<
A | A2,
In & In2,
L | L2,
E | E2,
R | R2
>
}
Runs a fallback sink if this sink fails with a typed error.
Details
The fallback is built from the error and continues consuming from the same
upstream stream. If the upstream stream had already ended, the fallback sees
the upstream end instead.
orElse: {
<function (type parameter) E in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>E, function (type parameter) A2 in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>A2, function (type parameter) In2 in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>In2, function (type parameter) L2 in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>L2, function (type parameter) E2 in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>E2, function (type parameter) R2 in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>R2>(
f: (
error: Types.NoInfer<E>
) => Sink<A2, In2, L2, E2, R2>
error: Types.NoInfer<E>error: import TypesTypes.type NoInfer<A> = [A][A extends any
? 0
: never]
Prevents TypeScript from inferring a type parameter from a specific
position.
When to use
Use when a function parameter must match an inferred type without becoming
an inference source.
Details
The parameter using NoInfer must still match the inferred type.
Example (Controlling inference)
import type { Types } from "effect"
declare function withDefault<T>(value: T, fallback: Types.NoInfer<T>): T
// T is inferred as "a" | "b" from the first argument only
const result = withDefault<"a" | "b">("a", "b")
NoInfer<function (type parameter) E in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>E>) => interface Sink<out A, in In = unknown, out L = never, out E = never, out R = never>A Sink<A, In, L, E, R> is used to consume elements produced by a Stream.
You can think of a sink as a function that will consume a variable amount of
In elements (could be 0, 1, or many), might fail with an error of type E,
and will eventually yield a value of type A together with a remainder of
type L (i.e. any leftovers).
Example (Running a sink with a stream)
import { Effect, Sink, Stream } from "effect"
// Create a simple sink that always succeeds with a value
const sink: Sink.Sink<number> = Sink.succeed(42)
// Use the sink to consume a stream
const stream = Stream.make(1, 2, 3)
const program = Stream.run(stream, sink)
Effect.runPromise(program).then(console.log)
// Output: 42
Namespace containing types and interfaces for Sink variance and type relationships.
Sink<function (type parameter) A2 in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>A2, function (type parameter) In2 in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>In2, function (type parameter) L2 in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>L2, function (type parameter) E2 in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>E2, function (type parameter) R2 in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>R2>
): <function (type parameter) A in <A, In, L, R>(self: Sink<A, In, L, E, R>): Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>A, function (type parameter) In in <A, In, L, R>(self: Sink<A, In, L, E, R>): Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>In, function (type parameter) L in <A, In, L, R>(self: Sink<A, In, L, E, R>): Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>L, function (type parameter) R in <A, In, L, R>(self: Sink<A, In, L, E, R>): Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>R>(self: Sink<A, In, L, E, R>(parameter) self: {
transform: (upstream: Pull.Pull<NonEmptyReadonlyArray<In>, never, void>, scope: Scope.Scope) => Effect.Effect<End<A, L>, E, R>;
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; <…;
}
interface Sink<out A, in In = unknown, out L = never, out E = never, out R = never>A Sink<A, In, L, E, R> is used to consume elements produced by a Stream.
You can think of a sink as a function that will consume a variable amount of
In elements (could be 0, 1, or many), might fail with an error of type E,
and will eventually yield a value of type A together with a remainder of
type L (i.e. any leftovers).
Example (Running a sink with a stream)
import { Effect, Sink, Stream } from "effect"
// Create a simple sink that always succeeds with a value
const sink: Sink.Sink<number> = Sink.succeed(42)
// Use the sink to consume a stream
const stream = Stream.make(1, 2, 3)
const program = Stream.run(stream, sink)
Effect.runPromise(program).then(console.log)
// Output: 42
Namespace containing types and interfaces for Sink variance and type relationships.
Sink<function (type parameter) A in <A, In, L, R>(self: Sink<A, In, L, E, R>): Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>A, function (type parameter) In in <A, In, L, R>(self: Sink<A, In, L, E, R>): Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>In, function (type parameter) L in <A, In, L, R>(self: Sink<A, In, L, E, R>): Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>L, function (type parameter) E in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>E, function (type parameter) R in <A, In, L, R>(self: Sink<A, In, L, E, R>): Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>R>) => interface Sink<out A, in In = unknown, out L = never, out E = never, out R = never>A Sink<A, In, L, E, R> is used to consume elements produced by a Stream.
You can think of a sink as a function that will consume a variable amount of
In elements (could be 0, 1, or many), might fail with an error of type E,
and will eventually yield a value of type A together with a remainder of
type L (i.e. any leftovers).
Example (Running a sink with a stream)
import { Effect, Sink, Stream } from "effect"
// Create a simple sink that always succeeds with a value
const sink: Sink.Sink<number> = Sink.succeed(42)
// Use the sink to consume a stream
const stream = Stream.make(1, 2, 3)
const program = Stream.run(stream, sink)
Effect.runPromise(program).then(console.log)
// Output: 42
Namespace containing types and interfaces for Sink variance and type relationships.
Sink<function (type parameter) A2 in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>A2 | function (type parameter) A in <A, In, L, R>(self: Sink<A, In, L, E, R>): Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>A, function (type parameter) In in <A, In, L, R>(self: Sink<A, In, L, E, R>): Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>In & function (type parameter) In2 in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>In2, function (type parameter) L2 in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>L2 | function (type parameter) L in <A, In, L, R>(self: Sink<A, In, L, E, R>): Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>L, function (type parameter) E2 in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>E2 | function (type parameter) E in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>E, function (type parameter) R2 in <E, A2, In2, L2, E2, R2>(f: (error: Types.NoInfer<E>) => Sink<A2, In2, L2, E2, R2>): <A, In, L, R>(self: Sink<A, In, L, E, R>) => Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>R2 | function (type parameter) R in <A, In, L, R>(self: Sink<A, In, L, E, R>): Sink<A2 | A, In & In2, L2 | L, E2 | E, R2 | R>R>
<function (type parameter) A in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>A, function (type parameter) In in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>In, function (type parameter) L in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>L, function (type parameter) E in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>E, function (type parameter) R in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>R, function (type parameter) A2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>A2, function (type parameter) In2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>In2, function (type parameter) L2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>L2, function (type parameter) E2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>E2, function (type parameter) R2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>R2>(
self: Sink<A, In, L, E, R>(parameter) self: {
transform: (upstream: Pull.Pull<NonEmptyReadonlyArray<In>, never, void>, scope: Scope.Scope) => Effect.Effect<End<A, L>, E, R>;
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; <…;
}
interface Sink<out A, in In = unknown, out L = never, out E = never, out R = never>A Sink<A, In, L, E, R> is used to consume elements produced by a Stream.
You can think of a sink as a function that will consume a variable amount of
In elements (could be 0, 1, or many), might fail with an error of type E,
and will eventually yield a value of type A together with a remainder of
type L (i.e. any leftovers).
Example (Running a sink with a stream)
import { Effect, Sink, Stream } from "effect"
// Create a simple sink that always succeeds with a value
const sink: Sink.Sink<number> = Sink.succeed(42)
// Use the sink to consume a stream
const stream = Stream.make(1, 2, 3)
const program = Stream.run(stream, sink)
Effect.runPromise(program).then(console.log)
// Output: 42
Namespace containing types and interfaces for Sink variance and type relationships.
Sink<function (type parameter) A in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>A, function (type parameter) In in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>In, function (type parameter) L in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>L, function (type parameter) E in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>E, function (type parameter) R in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>R>,
f: (error: E) => Sink<A2, In2, L2, E2, R2>f: (error: Eerror: function (type parameter) E in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>E) => interface Sink<out A, in In = unknown, out L = never, out E = never, out R = never>A Sink<A, In, L, E, R> is used to consume elements produced by a Stream.
You can think of a sink as a function that will consume a variable amount of
In elements (could be 0, 1, or many), might fail with an error of type E,
and will eventually yield a value of type A together with a remainder of
type L (i.e. any leftovers).
Example (Running a sink with a stream)
import { Effect, Sink, Stream } from "effect"
// Create a simple sink that always succeeds with a value
const sink: Sink.Sink<number> = Sink.succeed(42)
// Use the sink to consume a stream
const stream = Stream.make(1, 2, 3)
const program = Stream.run(stream, sink)
Effect.runPromise(program).then(console.log)
// Output: 42
Namespace containing types and interfaces for Sink variance and type relationships.
Sink<function (type parameter) A2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>A2, function (type parameter) In2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>In2, function (type parameter) L2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>L2, function (type parameter) E2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>E2, function (type parameter) R2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>R2>
): interface Sink<out A, in In = unknown, out L = never, out E = never, out R = never>A Sink<A, In, L, E, R> is used to consume elements produced by a Stream.
You can think of a sink as a function that will consume a variable amount of
In elements (could be 0, 1, or many), might fail with an error of type E,
and will eventually yield a value of type A together with a remainder of
type L (i.e. any leftovers).
Example (Running a sink with a stream)
import { Effect, Sink, Stream } from "effect"
// Create a simple sink that always succeeds with a value
const sink: Sink.Sink<number> = Sink.succeed(42)
// Use the sink to consume a stream
const stream = Stream.make(1, 2, 3)
const program = Stream.run(stream, sink)
Effect.runPromise(program).then(console.log)
// Output: 42
Namespace containing types and interfaces for Sink variance and type relationships.
Sink<function (type parameter) A in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>A | function (type parameter) A2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>A2, function (type parameter) In in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>In & function (type parameter) In2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>In2, function (type parameter) L in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>L | function (type parameter) L2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>L2, function (type parameter) E in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>E | function (type parameter) E2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>E2, function (type parameter) R in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>R | function (type parameter) R2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>R2>
} = dual<(...args: Array<any>) => any, <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>) => Sink<A | A2, In & In2, L | L2, E | E2, R | R2>>(arity: 2, body: <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>) => Sink<A | A2, In & In2, L | L2, E | E2, R | R2>): ((...args: Array<any>) => any) & (<A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>) => Sink<A | A2, In & In2, L | L2, E | E2, R | R2>) (+1 overload)Creates a function that can be called in data-first style or data-last
(pipe-friendly) style.
When to use
Use to expose one implementation through both direct and pipe-friendly
call styles.
Details
Pass either the arity of the uncurried function or a predicate that decides
whether the current call is data-first. Arity is the common case. Use a
predicate when optional arguments make arity ambiguous.
Example (Selecting data-first or data-last style by arity)
import { Function, pipe } from "effect"
const sum = Function.dual<
(that: number) => (self: number) => number,
(self: number, that: number) => number
>(2, (self, that) => self + that)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
Example (Defining overloads with call signatures)
import { Function, pipe } from "effect"
const sum: {
(that: number): (self: number) => number
(self: number, that: number): number
} = Function.dual(2, (self: number, that: number): number => self + that)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
Example (Selecting data-first or data-last style with a predicate)
import { Function, pipe } from "effect"
const sum = Function.dual<
(that: number) => (self: number) => number,
(self: number, that: number) => number
>(
(args) => args.length === 2,
(self, that) => self + that
)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
dual(2, <function (type parameter) A in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>A, function (type parameter) In in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>In, function (type parameter) L in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>L, function (type parameter) E in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>E, function (type parameter) R in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>R, function (type parameter) A2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>A2, function (type parameter) In2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>In2, function (type parameter) L2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>L2, function (type parameter) E2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>E2, function (type parameter) R2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>R2>(
self: Sink<A, In, L, E, R>(parameter) self: {
transform: (upstream: Pull.Pull<NonEmptyReadonlyArray<In>, never, void>, scope: Scope.Scope) => Effect.Effect<End<A, L>, E, R>;
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; <…;
}
interface Sink<out A, in In = unknown, out L = never, out E = never, out R = never>A Sink<A, In, L, E, R> is used to consume elements produced by a Stream.
You can think of a sink as a function that will consume a variable amount of
In elements (could be 0, 1, or many), might fail with an error of type E,
and will eventually yield a value of type A together with a remainder of
type L (i.e. any leftovers).
Example (Running a sink with a stream)
import { Effect, Sink, Stream } from "effect"
// Create a simple sink that always succeeds with a value
const sink: Sink.Sink<number> = Sink.succeed(42)
// Use the sink to consume a stream
const stream = Stream.make(1, 2, 3)
const program = Stream.run(stream, sink)
Effect.runPromise(program).then(console.log)
// Output: 42
Namespace containing types and interfaces for Sink variance and type relationships.
Sink<function (type parameter) A in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>A, function (type parameter) In in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>In, function (type parameter) L in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>L, function (type parameter) E in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>E, function (type parameter) R in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>R>,
f: (error: E) => Sink<A2, In2, L2, E2, R2>f: (error: Eerror: function (type parameter) E in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>E) => interface Sink<out A, in In = unknown, out L = never, out E = never, out R = never>A Sink<A, In, L, E, R> is used to consume elements produced by a Stream.
You can think of a sink as a function that will consume a variable amount of
In elements (could be 0, 1, or many), might fail with an error of type E,
and will eventually yield a value of type A together with a remainder of
type L (i.e. any leftovers).
Example (Running a sink with a stream)
import { Effect, Sink, Stream } from "effect"
// Create a simple sink that always succeeds with a value
const sink: Sink.Sink<number> = Sink.succeed(42)
// Use the sink to consume a stream
const stream = Stream.make(1, 2, 3)
const program = Stream.run(stream, sink)
Effect.runPromise(program).then(console.log)
// Output: 42
Namespace containing types and interfaces for Sink variance and type relationships.
Sink<function (type parameter) A2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>A2, function (type parameter) In2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>In2, function (type parameter) L2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>L2, function (type parameter) E2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>E2, function (type parameter) R2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>R2>
): interface Sink<out A, in In = unknown, out L = never, out E = never, out R = never>A Sink<A, In, L, E, R> is used to consume elements produced by a Stream.
You can think of a sink as a function that will consume a variable amount of
In elements (could be 0, 1, or many), might fail with an error of type E,
and will eventually yield a value of type A together with a remainder of
type L (i.e. any leftovers).
Example (Running a sink with a stream)
import { Effect, Sink, Stream } from "effect"
// Create a simple sink that always succeeds with a value
const sink: Sink.Sink<number> = Sink.succeed(42)
// Use the sink to consume a stream
const stream = Stream.make(1, 2, 3)
const program = Stream.run(stream, sink)
Effect.runPromise(program).then(console.log)
// Output: 42
Namespace containing types and interfaces for Sink variance and type relationships.
Sink<function (type parameter) A in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>A | function (type parameter) A2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>A2, function (type parameter) In in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>In & function (type parameter) In2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>In2, function (type parameter) L in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>L | function (type parameter) L2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>L2, function (type parameter) E in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>E | function (type parameter) E2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>E2, function (type parameter) R in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>R | function (type parameter) R2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>R2> =>
const fromTransform: <
In,
A,
E,
R,
L = never
>(
transform: (
upstream: Pull.Pull<
NonEmptyReadonlyArray<In>,
never,
void
>,
scope: Scope.Scope
) => Effect.Effect<End<A, L>, E, R>
) => Sink<A, In, L, E, R>
Creates a Sink from a low-level transform function.
Details
The transform receives the upstream pull of non-empty input arrays and the
active scope, and returns an effect that completes with the sink's End
value.
fromTransform((upstream: Pull.Pull<
readonly [In & In2, ...(In & In2)[]],
never,
void,
never
>
(parameter) upstream: {
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;
}
scope: Scope.Scope(parameter) scope: {
strategy: "sequential" | "parallel";
state: State.Open | State.Closed | State.Empty;
}
let upstreamDone: booleanupstreamDone = false
const const pull: Effect.Effect<
readonly [In & In2, ...(In & In2)[]],
Cause.Done<void>,
never
>
const pull: {
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;
}
import EffectEffect.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>
}
upstream: Pull.Pull<
readonly [In & In2, ...(In & In2)[]],
never,
void,
never
>
(parameter) upstream: {
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: Cause.Cause<Cause.Done<void>>(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;
}
let upstreamDone: booleanupstreamDone = true
return import EffectEffect.const failCause: <E>(
cause: Cause.Cause<E>
) => Effect<never, E>
Creates an Effect that represents a failure with a specific Cause.
When to use
Use when you already have a full Cause and need to preserve defects,
interruptions, annotations, or combined failures in the effect's failure
channel.
Details
This function allows you to create effects that fail with complex error
structures, including multiple errors, defects, interruptions, and more.
Example (Failing with a full Cause)
import { Cause, Effect } from "effect"
const program = Effect.failCause(
Cause.fail("Network error")
)
Effect.runPromiseExit(program).then(console.log)
// Output: { _id: 'Exit', _tag: 'Failure', cause: ... }
failCause(cause: Cause.Cause<Cause.Done<void>>(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;
}
import EffectEffect.catch<End<A | A2, L | L2>, E, R, End<A2, L2>, E2, R2>(self: Effect.Effect<End<A | A2, L | L2>, E, R>, f: (e: E) => Effect.Effect<End<A2, L2>, E2, R2>): Effect.Effect<End<A | A2, L | L2> | End<A2, L2>, E2, R | R2> (+1 overload)
export catch
self: Sink<A, In, L, E, R>(parameter) self: {
transform: (upstream: Pull.Pull<NonEmptyReadonlyArray<In>, never, void>, scope: Scope.Scope) => Effect.Effect<End<A, L>, E, R>;
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; <…;
}
Sink<A, In, L, E, R>.transform: (upstream: Pull.Pull<NonEmptyReadonlyArray<In>, never, void>, scope: Scope.Scope) => Effect.Effect<End<A, L>, E, R>transform(const pull: Effect.Effect<
readonly [In & In2, ...(In & In2)[]],
Cause.Done<void>,
never
>
const pull: {
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;
}
scope: Scope.Scope(parameter) scope: {
strategy: "sequential" | "parallel";
state: State.Open | State.Closed | State.Empty;
}
import EffectEffect.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<type End<A, L = never> = readonly [
value: A,
leftover?: readonly [L, ...L[]] | undefined
]
Tuple returned when a Sink finishes.
Details
The first element is the sink result. The optional second element contains a
non-empty array of leftover input that was pulled but not consumed.
End<function (type parameter) A in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>A | function (type parameter) A2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>A2, function (type parameter) L in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>L | function (type parameter) L2 in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>L2>, function (type parameter) E in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>E, function (type parameter) R in <A, In, L, E, R, A2, In2, L2, E2, R2>(self: Sink<A, In, L, E, R>, f: (error: E) => Sink<A2, In2, L2, E2, R2>): Sink<A | A2, In & In2, L | L2, E | E2, R | R2>R>,
(error: Eerror) =>
f: (error: E) => Sink<A2, In2, L2, E2, R2>f(error: Eerror).Sink<A2, In2, L2, E2, R2>.transform: (upstream: Pull.Pull<NonEmptyReadonlyArray<In>, never, void>, scope: Scope.Scope) => Effect.Effect<End<A, L>, E, R>transform(
import EffectEffect.const suspend: <A, E, R>(
effect: LazyArg<Effect<A, E, R>>
) => Effect<A, E, R>
Creates an Effect lazily, delaying construction until it is needed.
When to use
Use when you need to defer the evaluation of an effect until it is required.
Details
suspend takes a thunk that represents an effect and delays creating it
until the suspended effect is evaluated. This is useful for optimizing
expensive computations, managing circular dependencies such as recursive
functions, and helping TypeScript unify return types when branches construct
different effects. Any side effects or scoped captures inside the thunk are
re-executed on each invocation.
Example (Lazily evaluating side effects)
import { Effect } from "effect"
let i = 0
const bad = Effect.succeed(i++)
const good = Effect.suspend(() => Effect.succeed(i++))
console.log(Effect.runSync(bad)) // Output: 0
console.log(Effect.runSync(bad)) // Output: 0
console.log(Effect.runSync(good)) // Output: 1
console.log(Effect.runSync(good)) // Output: 2
Example (Suspending recursive Fibonacci evaluation)
import { Effect } from "effect"
const blowsUp = (n: number): Effect.Effect<number> =>
n < 2
? Effect.succeed(1)
: Effect.zipWith(blowsUp(n - 1), blowsUp(n - 2), (a, b) => a + b)
// console.log(Effect.runSync(blowsUp(32)))
// crash: JavaScript heap out of memory
const allGood = (n: number): Effect.Effect<number> =>
n < 2
? Effect.succeed(1)
: Effect.zipWith(
Effect.suspend(() => allGood(n - 1)),
Effect.suspend(() => allGood(n - 2)),
(a, b) => a + b
)
console.log(Effect.runSync(allGood(32)))
// Output: 3524578
Example (Helping TypeScript infer recursive effect types)
import { Effect } from "effect"
// Without suspend, TypeScript may struggle with type inference.
// Inferred type:
// (a: number, b: number) =>
// Effect<never, Error, never> | Effect<number, never, never>
const withoutSuspend = (a: number, b: number) =>
b === 0
? Effect.fail(new Error("Cannot divide by zero"))
: Effect.succeed(a / b)
// Using suspend to unify return types.
// Inferred type:
// (a: number, b: number) => Effect<number, Error, never>
const withSuspend = (a: number, b: number) =>
Effect.suspend(() =>
b === 0
? Effect.fail(new Error("Cannot divide by zero"))
: Effect.succeed(a / b)
)
suspend(() => {
if (let upstreamDone: booleanupstreamDone) {
return import CauseCause.const done: <A = void>(
value?: A
) => Effect.Effect<never, Done<A>>
Creates an Effect that fails with a Done error. Shorthand for
Effect.fail(Cause.Done(value)).
When to use
Use when you model stream or queue completion through the error channel.
Example (Failing with Done)
import { Cause, Effect } from "effect"
const program = Cause.done("finished")
Effect.runPromiseExit(program).then((exit) => {
console.log(exit._tag) // "Failure"
})
done()
}
return upstream: Pull.Pull<
readonly [In & In2, ...(In & In2)[]],
never,
void,
never
>
(parameter) upstream: {
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;
}
scope: Scope.Scope(parameter) scope: {
strategy: "sequential" | "parallel";
state: State.Open | State.Closed | State.Empty;
}