(n: number): <A, E, R>(
self: Stream<A, E, R>
) => Stream<Arr.NonEmptyReadonlyArray<A>, E, R>
<A, E, R>(self: Stream<A, E, R>, n: number): Stream<
Arr.NonEmptyReadonlyArray<A>,
E,
R
>Partitions the stream into non-empty arrays of the specified size.
Details
The final array may be smaller if there are not enough elements to fill it.
Example (Grouping elements by size)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const grouped = yield* Stream.range(1, 8).pipe(
Stream.grouped(3),
Stream.runCollect
)
yield* Console.log(grouped)
})
Effect.runPromise(program)
// Output: [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8 ] ]export const const grouped: {
(n: number): <A, E, R>(
self: Stream<A, E, R>
) => Stream<Arr.NonEmptyReadonlyArray<A>, E, R>
<A, E, R>(
self: Stream<A, E, R>,
n: number
): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>
}
Partitions the stream into non-empty arrays of the specified size.
Details
The final array may be smaller if there are not enough elements to fill it.
Example (Grouping elements by size)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const grouped = yield* Stream.range(1, 8).pipe(
Stream.grouped(3),
Stream.runCollect
)
yield* Console.log(grouped)
})
Effect.runPromise(program)
// Output: [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8 ] ]
grouped: {
(n: numbern: number): <function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>R>(self: Stream<A, E, R>(parameter) self: {
channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, 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 Stream<out A, out E = never, out R = never>A Stream<A, E, R> describes a program that can emit many A values, fail
with E, and require R.
Details
Streams are pull-based with backpressure and emit chunks to amortize effect
evaluation. They support monadic composition and error handling similar to
Effect, adapted for multiple values.
Example (Creating and consuming streams)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
yield* Stream.make(1, 2, 3).pipe(
Stream.map((n) => n * 2),
Stream.runForEach((n) => Console.log(n))
)
})
Effect.runPromise(program)
// Output:
// 2
// 4
// 6
Stream<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>R>) => interface Stream<out A, out E = never, out R = never>A Stream<A, E, R> describes a program that can emit many A values, fail
with E, and require R.
Details
Streams are pull-based with backpressure and emit chunks to amortize effect
evaluation. They support monadic composition and error handling similar to
Effect, adapted for multiple values.
Example (Creating and consuming streams)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
yield* Stream.make(1, 2, 3).pipe(
Stream.map((n) => n * 2),
Stream.runForEach((n) => Console.log(n))
)
})
Effect.runPromise(program)
// Output:
// 2
// 4
// 6
Stream<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) A in <A, E, R>(self: Stream<A, E, R>): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>A>, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>R>
<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>R>(self: Stream<A, E, R>(parameter) self: {
channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, 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 Stream<out A, out E = never, out R = never>A Stream<A, E, R> describes a program that can emit many A values, fail
with E, and require R.
Details
Streams are pull-based with backpressure and emit chunks to amortize effect
evaluation. They support monadic composition and error handling similar to
Effect, adapted for multiple values.
Example (Creating and consuming streams)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
yield* Stream.make(1, 2, 3).pipe(
Stream.map((n) => n * 2),
Stream.runForEach((n) => Console.log(n))
)
})
Effect.runPromise(program)
// Output:
// 2
// 4
// 6
Stream<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>R>, n: numbern: number): interface Stream<out A, out E = never, out R = never>A Stream<A, E, R> describes a program that can emit many A values, fail
with E, and require R.
Details
Streams are pull-based with backpressure and emit chunks to amortize effect
evaluation. They support monadic composition and error handling similar to
Effect, adapted for multiple values.
Example (Creating and consuming streams)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
yield* Stream.make(1, 2, 3).pipe(
Stream.map((n) => n * 2),
Stream.runForEach((n) => Console.log(n))
)
})
Effect.runPromise(program)
// Output:
// 2
// 4
// 6
Stream<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) A in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>A>, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>R>
} = dual<(...args: Array<any>) => any, <A, E, R>(self: Stream<A, E, R>, n: number) => Stream<Arr.NonEmptyReadonlyArray<A>, E, R>>(arity: 2, body: <A, E, R>(self: Stream<A, E, R>, n: number) => Stream<Arr.NonEmptyReadonlyArray<A>, E, R>): ((...args: Array<any>) => any) & (<A, E, R>(self: Stream<A, E, R>, n: number) => Stream<Arr.NonEmptyReadonlyArray<A>, E, R>) (+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, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>R>(self: Stream<A, E, R>(parameter) self: {
channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, 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 Stream<out A, out E = never, out R = never>A Stream<A, E, R> describes a program that can emit many A values, fail
with E, and require R.
Details
Streams are pull-based with backpressure and emit chunks to amortize effect
evaluation. They support monadic composition and error handling similar to
Effect, adapted for multiple values.
Example (Creating and consuming streams)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
yield* Stream.make(1, 2, 3).pipe(
Stream.map((n) => n * 2),
Stream.runForEach((n) => Console.log(n))
)
})
Effect.runPromise(program)
// Output:
// 2
// 4
// 6
Stream<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>R>, n: numbern: number): interface Stream<out A, out E = never, out R = never>A Stream<A, E, R> describes a program that can emit many A values, fail
with E, and require R.
Details
Streams are pull-based with backpressure and emit chunks to amortize effect
evaluation. They support monadic composition and error handling similar to
Effect, adapted for multiple values.
Example (Creating and consuming streams)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
yield* Stream.make(1, 2, 3).pipe(
Stream.map((n) => n * 2),
Stream.runForEach((n) => Console.log(n))
)
})
Effect.runPromise(program)
// Output:
// 2
// 4
// 6
Stream<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) A in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>A>, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, n: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>R> => const chunks: <A, E, R>(
self: Stream<A, E, R>
) => Stream<Arr.NonEmptyReadonlyArray<A>, E, R>
Exposes the underlying chunks as a stream of non-empty arrays.
Example (Exposing stream chunks)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const chunks = yield* Stream.make(1, 2, 3, 4).pipe(
Stream.rechunk(2),
Stream.chunks,
Stream.runCollect
)
yield* Console.log(chunks)
})
Effect.runPromise(program)
// Output: [ [ 1, 2 ], [ 3, 4 ] ]
chunks(const rechunk: {
(size: number): <A, E, R>(
self: Stream<A, E, R>
) => Stream<A, E, R>
<A, E, R>(
self: Stream<A, E, R>,
size: number
): Stream<A, E, R>
}
self: Stream<A, E, R>(parameter) self: {
channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, 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; <…;
}
n: numbern))
)