(chunkSize: number): <A, E, R>(
self: Stream<A, E, R>
) => Stream<Arr.NonEmptyReadonlyArray<A>, E, R>
<A, E, R>(self: Stream<A, E, R>, chunkSize: number): Stream<
Arr.NonEmptyReadonlyArray<A>,
E,
R
>Emits a sliding window of n elements.
Example (Emitting sliding windows)
import { Console, Effect, pipe, Stream } from "effect"
Effect.gen(function*() {
const result = yield* pipe(
Stream.make(1, 2, 3, 4, 5),
Stream.sliding(2),
Stream.runCollect
)
yield* Console.log(result)
})
// Output: [ [1, 2], [2, 3], [3, 4], [4, 5] ]export const const sliding: {
(chunkSize: number): <A, E, R>(
self: Stream<A, E, R>
) => Stream<Arr.NonEmptyReadonlyArray<A>, E, R>
<A, E, R>(
self: Stream<A, E, R>,
chunkSize: number
): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>
}
Emits a sliding window of n elements.
Example (Emitting sliding windows)
import { Console, Effect, pipe, Stream } from "effect"
Effect.gen(function*() {
const result = yield* pipe(
Stream.make(1, 2, 3, 4, 5),
Stream.sliding(2),
Stream.runCollect
)
yield* Console.log(result)
})
// Output: [ [1, 2], [2, 3], [3, 4], [4, 5] ]
sliding: {
(chunkSize: numberchunkSize: 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>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, chunkSize: 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>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>R>, chunkSize: numberchunkSize: 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>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>A>, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>R>
} = dual<(...args: Array<any>) => any, <A, E, R>(self: Stream<A, E, R>, chunkSize: number) => Stream<Arr.NonEmptyReadonlyArray<A>, E, R>>(arity: 2, body: <A, E, R>(self: Stream<A, E, R>, chunkSize: number) => Stream<Arr.NonEmptyReadonlyArray<A>, E, R>): ((...args: Array<any>) => any) & (<A, E, R>(self: Stream<A, E, R>, chunkSize: 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>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, chunkSize: 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>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>R>, chunkSize: numberchunkSize: 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>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>A>, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, chunkSize: number): Stream<Arr.NonEmptyReadonlyArray<A>, E, R>R> =>
const slidingSize: {
(chunkSize: number, stepSize: number): <
A,
E,
R
>(
self: Stream<A, E, R>
) => Stream<Arr.NonEmptyReadonlyArray<A>, E, R>
<A, E, R>(
self: Stream<A, E, R>,
chunkSize: number,
stepSize: number
): Stream<Arr.NonEmptyReadonlyArray<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; <…;
}
chunkSize: numberchunkSize, 1)
)