<A, A1, L, In1 extends L, L1, E1, R1>(
f: (a: A) => Sink<A1, In1, L1, E1, R1>
): <In, E, R>(
self: Sink<A, In, L, E, R>
) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>
<A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(
self: Sink<A, In, L, E, R>,
f: (a: A) => Sink<A1, In1, L1, E1, R1>
): Sink<A1, In & In1, L | L1, E | E1, R | R1>Runs this sink until it yields a result, then uses that result to create another sink from the provided function which will continue to run until it yields a result.
When to use
Use to compose sinks when the next sink depends on the result produced by the previous sink.
Details
Leftovers from the first sink are fed to the sink returned by f before more
upstream input is pulled.
Source effect/Sink.ts:117436 lines
export const const flatMap: {
<A, A1, L, In1 extends L, L1, E1, R1>(
f: (a: A) => Sink<A1, In1, L1, E1, R1>
): <In, E, R>(
self: Sink<A, In, L, E, R>
) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>
<A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(
self: Sink<A, In, L, E, R>,
f: (a: A) => Sink<A1, In1, L1, E1, R1>
): Sink<A1, In & In1, L | L1, E | E1, R | R1>
}
Runs this sink until it yields a result, then uses that result to create
another sink from the provided function which will continue to run until it
yields a result.
When to use
Use to compose sinks when the next sink depends on the result produced by the
previous sink.
Details
Leftovers from the first sink are fed to the sink returned by f before more
upstream input is pulled.
flatMap: {
<function (type parameter) A in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>A, function (type parameter) A1 in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>A1, function (type parameter) L in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>L, function (type parameter) In1 in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>In1 extends function (type parameter) L in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>L, function (type parameter) L1 in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>L1, function (type parameter) E1 in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>E1, function (type parameter) R1 in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>R1>(
f: (a: A) => Sink<A1, In1, L1, E1, R1>f: (a: Aa: function (type parameter) A in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>A) => 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) A1 in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>A1, function (type parameter) In1 in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>In1, function (type parameter) L1 in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>L1, function (type parameter) E1 in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>E1, function (type parameter) R1 in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>R1>
): <function (type parameter) In in <In, E, R>(self: Sink<A, In, L, E, R>): Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>In, function (type parameter) E in <In, E, R>(self: Sink<A, In, L, E, R>): Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>E, function (type parameter) R in <In, E, R>(self: Sink<A, In, L, E, R>): Sink<A1, In & In1, L1 | L, E1 | E, R1 | 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, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>A, function (type parameter) In in <In, E, R>(self: Sink<A, In, L, E, R>): Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>In, function (type parameter) L in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>L, function (type parameter) E in <In, E, R>(self: Sink<A, In, L, E, R>): Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>E, function (type parameter) R in <In, E, R>(self: Sink<A, In, L, E, R>): Sink<A1, In & In1, L1 | L, E1 | E, R1 | 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) A1 in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>A1, function (type parameter) In in <In, E, R>(self: Sink<A, In, L, E, R>): Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>In & function (type parameter) In1 in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>In1, function (type parameter) L1 in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>L1 | function (type parameter) L in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>L, function (type parameter) E1 in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>E1 | function (type parameter) E in <In, E, R>(self: Sink<A, In, L, E, R>): Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>E, function (type parameter) R1 in <A, A1, L, In1 extends L, L1, E1, R1>(f: (a: A) => Sink<A1, In1, L1, E1, R1>): <In, E, R>(self: Sink<A, In, L, E, R>) => Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>R1 | function (type parameter) R in <In, E, R>(self: Sink<A, In, L, E, R>): Sink<A1, In & In1, L1 | L, E1 | E, R1 | R>R>
<function (type parameter) A in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>A, function (type parameter) In in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>In, function (type parameter) L in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>L, function (type parameter) E in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>E, function (type parameter) R in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>R, function (type parameter) A1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>A1, function (type parameter) In1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>In1 extends function (type parameter) L in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>L, function (type parameter) L1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>L1, function (type parameter) E1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>E1, function (type parameter) R1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>R1>(
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, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>A, function (type parameter) In in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>In, function (type parameter) L in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>L, function (type parameter) E in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>E, function (type parameter) R in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>R>,
f: (a: A) => Sink<A1, In1, L1, E1, R1>f: (a: Aa: function (type parameter) A in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>A) => 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) A1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>A1, function (type parameter) In1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>In1, function (type parameter) L1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>L1, function (type parameter) E1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>E1, function (type parameter) R1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>R1>
): 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) A1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>A1, function (type parameter) In in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>In & function (type parameter) In1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>In1, function (type parameter) L in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>L | function (type parameter) L1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>L1, function (type parameter) E in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>E | function (type parameter) E1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>E1, function (type parameter) R in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>R | function (type parameter) R1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>R1>
} = dual<(...args: Array<any>) => any, <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>) => Sink<A1, In & In1, L | L1, E | E1, R | R1>>(arity: 2, body: <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>) => Sink<A1, In & In1, L | L1, E | E1, R | R1>): ((...args: Array<any>) => any) & (<A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>) => Sink<A1, In & In1, L | L1, E | E1, R | R1>) (+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, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>A, function (type parameter) In in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>In, function (type parameter) L in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>L, function (type parameter) E in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>E, function (type parameter) R in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>R, function (type parameter) A1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>A1, function (type parameter) In1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>In1 extends function (type parameter) L in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>L, function (type parameter) L1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>L1, function (type parameter) E1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>E1, function (type parameter) R1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>R1>(
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, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>A, function (type parameter) In in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>In, function (type parameter) L in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>L, function (type parameter) E in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>E, function (type parameter) R in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>R>,
f: (a: A) => Sink<A1, In1, L1, E1, R1>f: (a: Aa: function (type parameter) A in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>A) => 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) A1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>A1, function (type parameter) In1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>In1, function (type parameter) L1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>L1, function (type parameter) E1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>E1, function (type parameter) R1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>R1>
): 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) A1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>A1, function (type parameter) In in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>In & function (type parameter) In1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>In1, function (type parameter) L in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>L | function (type parameter) L1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>L1, function (type parameter) E in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>E | function (type parameter) E1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>E1, function (type parameter) R in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>R | function (type parameter) R1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>R1> =>
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 & In1, ...(In & In1)[]],
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 & In1, ...(In & In1)[]],
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 & In1, ...(In & In1)[]],
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.const flatMap: {
<A, B, E1, R1>(
f: (a: A) => Effect<B, E1, R1>
): <E, R>(
self: Effect<A, E, R>
) => Effect<B, E1 | E, R1 | R>
<A, E, R, B, E1, R1>(
self: Effect<A, E, R>,
f: (a: A) => Effect<B, E1, R1>
): Effect<B, E | E1, R | R1>
}
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 & In1, ...(In & In1)[]],
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;
}
a: Aa, leftover: readonly [L, ...L[]] | undefinedleftover]) =>
f: (a: A) => Sink<A1, In1, L1, E1, R1>f(a: Aa).Sink<A1, In1, L1, E1, R1>.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 (leftover: readonly [L, ...L[]] | undefinedleftover) {
const const arr: readonly [In1, ...In1[]]const arr: {
0: In1;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<In1>>): Array<In1>; (...items: Array<In1 | ConcatArray<In1>>): Array<In1> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<In1>;
indexOf: (searchElement: In1, fromIndex?: number) => number;
lastIndexOf: (searchElement: In1, fromIndex?: number) => number;
every: { (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: In1, index: number, array: ReadonlyArray<In1>) => void, thisArg?: any) => void;
map: (callbackfn: (value: In1, index: number, array: ReadonlyArray<In1>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => value is S, thisArg?: any): Array<S>; (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => unknown, thisArg?: any): Array<In1> };
reduce: { (callbackfn: (previousValue: In1, currentValue: In1, currentIndex: number, array: ReadonlyArray<In1>) => In1): In1; (callbackfn: (previousValue: In1, currentValue: In1, currentIndex: number, array: ReadonlyArray<In1>) => In1, initialValu…;
reduceRight: { (callbackfn: (previousValue: In1, currentValue: In1, currentIndex: number, array: ReadonlyArray<In1>) => In1): In1; (callbackfn: (previousValue: In1, currentValue: In1, currentIndex: number, array: ReadonlyArray<In1>) => In1, initialValu…;
find: { (predicate: (value: In1, index: number, obj: ReadonlyArray<In1>) => value is S, thisArg?: any): S | undefined; (predicate: (value: In1, index: number, obj: ReadonlyArray<In1>) => unknown, thisArg?: any): In1 | undefined };
findIndex: (predicate: (value: In1, index: number, obj: ReadonlyArray<In1>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, In1]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<In1>;
includes: (searchElement: In1, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: In1, index: number, array: Array<In1>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => In1 | undefined;
findLast: { (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => value is S, thisArg?: any): S | undefined; (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => unknown, thisArg?: any): In1 | undefined };
findLastIndex: (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => unknown, thisArg?: any) => number;
toReversed: () => Array<In1>;
toSorted: (compareFn?: ((a: In1, b: In1) => number) | undefined) => Array<In1>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<In1>): Array<In1>; (start: number, deleteCount?: number): Array<In1> };
with: (index: number, value: In1) => Array<In1>;
}
leftover: readonly [L, ...L[]](parameter) leftover: {
0: L;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<L>>): Array<L>; (...items: Array<L | ConcatArray<L>>): Array<L> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<L>;
indexOf: (searchElement: L, fromIndex?: number) => number;
lastIndexOf: (searchElement: L, fromIndex?: number) => number;
every: { (predicate: (value: L, index: number, array: ReadonlyArray<L>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: L, index: number, array: ReadonlyArray<L>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: L, index: number, array: ReadonlyArray<L>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: L, index: number, array: ReadonlyArray<L>) => void, thisArg?: any) => void;
map: (callbackfn: (value: L, index: number, array: ReadonlyArray<L>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: L, index: number, array: ReadonlyArray<L>) => value is S, thisArg?: any): Array<S>; (predicate: (value: L, index: number, array: ReadonlyArray<L>) => unknown, thisArg?: any): Array<L> };
reduce: { (callbackfn: (previousValue: L, currentValue: L, currentIndex: number, array: ReadonlyArray<L>) => L): L; (callbackfn: (previousValue: L, currentValue: L, currentIndex: number, array: ReadonlyArray<L>) => L, initialValue: L): L; (callbac…;
reduceRight: { (callbackfn: (previousValue: L, currentValue: L, currentIndex: number, array: ReadonlyArray<L>) => L): L; (callbackfn: (previousValue: L, currentValue: L, currentIndex: number, array: ReadonlyArray<L>) => L, initialValue: L): L; (callbac…;
find: { (predicate: (value: L, index: number, obj: ReadonlyArray<L>) => value is S, thisArg?: any): S | undefined; (predicate: (value: L, index: number, obj: ReadonlyArray<L>) => unknown, thisArg?: any): L | undefined };
findIndex: (predicate: (value: L, index: number, obj: ReadonlyArray<L>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, L]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<L>;
includes: (searchElement: L, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: L, index: number, array: Array<L>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => L | undefined;
findLast: { (predicate: (value: L, index: number, array: ReadonlyArray<L>) => value is S, thisArg?: any): S | undefined; (predicate: (value: L, index: number, array: ReadonlyArray<L>) => unknown, thisArg?: any): L | undefined };
findLastIndex: (predicate: (value: L, index: number, array: ReadonlyArray<L>) => unknown, thisArg?: any) => number;
toReversed: () => Array<L>;
toSorted: (compareFn?: ((a: L, b: L) => number) | undefined) => Array<L>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<L>): Array<L>; (start: number, deleteCount?: number): Array<L> };
with: (index: number, value: L) => Array<L>;
}
import ArrArr.type NonEmptyReadonlyArray<A> = readonly [
A,
...A[]
]
A readonly array guaranteed to have at least one element.
When to use
Use when non-emptiness must be tracked at the type level while preventing mutation.
Many Array module functions accept or return this type.
Example (Typing a non-empty array)
import type { Array } from "effect"
const nonEmpty: Array.NonEmptyReadonlyArray<number> = [1, 2, 3]
const head: number = nonEmpty[0] // guaranteed to exist
NonEmptyReadonlyArray<function (type parameter) In1 in <A, In, L, E, R, A1, In1 extends L, L1, E1, R1>(self: Sink<A, In, L, E, R>, f: (a: A) => Sink<A1, In1, L1, E1, R1>): Sink<A1, In & In1, L | L1, E | E1, R | R1>In1>
leftover: readonly [L, ...L[]] | undefinedleftover = var undefinedundefined
return import EffectEffect.const succeed: <A>(value: A) => Effect<A>Creates an Effect that always succeeds with a given value.
When to use
Use when an effect should complete successfully with a specific value without any errors
or external dependencies.
Example (Creating a successful effect)
import { Effect } from "effect"
// Creating an effect that represents a successful scenario
//
// ┌─── Effect<number, never, never>
// ▼
const success = Effect.succeed(42)
succeed(const arr: readonly [In1, ...In1[]]const arr: {
0: In1;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<In1>>): Array<In1>; (...items: Array<In1 | ConcatArray<In1>>): Array<In1> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<In1>;
indexOf: (searchElement: In1, fromIndex?: number) => number;
lastIndexOf: (searchElement: In1, fromIndex?: number) => number;
every: { (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: In1, index: number, array: ReadonlyArray<In1>) => void, thisArg?: any) => void;
map: (callbackfn: (value: In1, index: number, array: ReadonlyArray<In1>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => value is S, thisArg?: any): Array<S>; (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => unknown, thisArg?: any): Array<In1> };
reduce: { (callbackfn: (previousValue: In1, currentValue: In1, currentIndex: number, array: ReadonlyArray<In1>) => In1): In1; (callbackfn: (previousValue: In1, currentValue: In1, currentIndex: number, array: ReadonlyArray<In1>) => In1, initialValu…;
reduceRight: { (callbackfn: (previousValue: In1, currentValue: In1, currentIndex: number, array: ReadonlyArray<In1>) => In1): In1; (callbackfn: (previousValue: In1, currentValue: In1, currentIndex: number, array: ReadonlyArray<In1>) => In1, initialValu…;
find: { (predicate: (value: In1, index: number, obj: ReadonlyArray<In1>) => value is S, thisArg?: any): S | undefined; (predicate: (value: In1, index: number, obj: ReadonlyArray<In1>) => unknown, thisArg?: any): In1 | undefined };
findIndex: (predicate: (value: In1, index: number, obj: ReadonlyArray<In1>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, In1]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<In1>;
includes: (searchElement: In1, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: In1, index: number, array: Array<In1>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => In1 | undefined;
findLast: { (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => value is S, thisArg?: any): S | undefined; (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => unknown, thisArg?: any): In1 | undefined };
findLastIndex: (predicate: (value: In1, index: number, array: ReadonlyArray<In1>) => unknown, thisArg?: any) => number;
toReversed: () => Array<In1>;
toSorted: (compareFn?: ((a: In1, b: In1) => number) | undefined) => Array<In1>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<In1>): Array<In1>; (start: number, deleteCount?: number): Array<In1> };
with: (index: number, value: In1) => Array<In1>;
}
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 & In1, ...(In & In1)[]],
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;
}