<A, E, R>(self: Stream<A, E, R>): Stream<
[Option.Option<A>, A, Option.Option<A>],
E,
R
>Zips each element with its previous and next values.
Example (Zipping elements with neighbors)
import { Console, Effect, Option, Stream } from "effect"
const program = Effect.gen(function*() {
const values = yield* Stream.make(1, 2, 3).pipe(
Stream.zipWithPreviousAndNext,
Stream.runCollect
)
yield* Console.log(values)
})
Effect.runPromise(program)
// Output: [ [Option.none(), 1, Option.some(2)], [Option.some(1), 2, Option.some(3)], [Option.some(2), 3, Option.none()] ]zipping
Source effect/Stream.ts:396530 lines
export const const zipWithPreviousAndNext: <A, E, R>(
self: Stream<A, E, R>
) => Stream<
[Option.Option<A>, A, Option.Option<A>],
E,
R
>
Zips each element with its previous and next values.
Example (Zipping elements with neighbors)
import { Console, Effect, Option, Stream } from "effect"
const program = Effect.gen(function*() {
const values = yield* Stream.make(1, 2, 3).pipe(
Stream.zipWithPreviousAndNext,
Stream.runCollect
)
yield* Console.log(values)
})
Effect.runPromise(program)
// Output: [ [Option.none(), 1, Option.some(2)], [Option.some(1), 2, Option.some(3)], [Option.some(2), 3, Option.none()] ]
zipWithPreviousAndNext = <function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<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<[Option.Option<A>, A, Option.Option<A>], E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<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 OptionOption.type Option.Option = /*unresolved*/ anyOption<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>A>, function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>A, import OptionOption.type Option.Option = /*unresolved*/ anyOption<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>A>], function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>R> =>
const mapAccumArray: {
<S, A, B>(
initial: LazyArg<S>,
f: (
s: S,
a: Arr.NonEmptyReadonlyArray<A>
) => readonly [
state: S,
values: ReadonlyArray<B>
],
options?: {
readonly onHalt?:
| ((state: S) => ReadonlyArray<B>)
| undefined
}
): <E, R>(
self: Stream<A, E, R>
) => Stream<B, E, R>
<A, E, R, S, B>(
self: Stream<A, E, R>,
initial: LazyArg<S>,
f: (
s: S,
a: Arr.NonEmptyReadonlyArray<A>
) => readonly [
state: S,
values: ReadonlyArray<B>
],
options?: {
readonly onHalt?:
| ((state: S) => Array<B>)
| undefined
}
): Stream<B, 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; <…;
}
prev: Option.Option<A>prev: import OptionOption.none<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>A>(),
current: Option.Option<A>current: import OptionOption.none<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>A>()
}), (acc: unknown(parameter) acc: {
prev: Option.Option<A>;
current: Option.Option<A>;
}
arr: Arr.NonEmptyReadonlyArray<A>(parameter) arr: {
0: A;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<A>>): Array<A>; (...items: Array<A | ConcatArray<A>>): Array<A> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<A>;
indexOf: (searchElement: A, fromIndex?: number) => number;
lastIndexOf: (searchElement: A, fromIndex?: number) => number;
every: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => void, thisArg?: any) => void;
map: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): Array<S>; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): Array<A> };
reduce: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
reduceRight: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
find: { (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findIndex: (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, A]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<A>;
includes: (searchElement: A, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: A, index: number, array: Array<A>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => A | undefined;
findLast: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findLastIndex: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
toReversed: () => Array<A>;
toSorted: (compareFn?: ((a: A, b: A) => number) | undefined) => Array<A>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<A>): Array<A>; (start: number, deleteCount?: number): Array<A> };
with: (index: number, value: A) => Array<A>;
}
let i: numberi = 0
let let current: Acurrent: function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>A
if (acc: unknown(parameter) acc: {
prev: Option.Option<A>;
current: Option.Option<A>;
}
let i: numberi = 1
let current: Acurrent = arr: Arr.NonEmptyReadonlyArray<A>(parameter) arr: {
0: A;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<A>>): Array<A>; (...items: Array<A | ConcatArray<A>>): Array<A> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<A>;
indexOf: (searchElement: A, fromIndex?: number) => number;
lastIndexOf: (searchElement: A, fromIndex?: number) => number;
every: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => void, thisArg?: any) => void;
map: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): Array<S>; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): Array<A> };
reduce: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
reduceRight: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
find: { (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findIndex: (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, A]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<A>;
includes: (searchElement: A, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: A, index: number, array: Array<A>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => A | undefined;
findLast: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findLastIndex: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
toReversed: () => Array<A>;
toSorted: (compareFn?: ((a: A, b: A) => number) | undefined) => Array<A>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<A>): Array<A>; (start: number, deleteCount?: number): Array<A> };
with: (index: number, value: A) => Array<A>;
}
acc: unknown(parameter) acc: {
prev: Option.Option<A>;
current: Option.Option<A>;
}
import OptionOption.some(let current: Acurrent)
} else {
let current: Acurrent = acc: unknown(parameter) acc: {
prev: Option.Option<A>;
current: Option.Option<A>;
}
const pairs: anypairs = import ArrArr.empty<[import OptionOption.type Option.Option = /*unresolved*/ anyOption<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>A>, function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>A, import OptionOption.type Option.Option = /*unresolved*/ anyOption<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>A>]>()
for (; let i: numberi < arr: Arr.NonEmptyReadonlyArray<A>(parameter) arr: {
0: A;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<A>>): Array<A>; (...items: Array<A | ConcatArray<A>>): Array<A> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<A>;
indexOf: (searchElement: A, fromIndex?: number) => number;
lastIndexOf: (searchElement: A, fromIndex?: number) => number;
every: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => void, thisArg?: any) => void;
map: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): Array<S>; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): Array<A> };
reduce: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
reduceRight: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
find: { (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findIndex: (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, A]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<A>;
includes: (searchElement: A, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: A, index: number, array: Array<A>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => A | undefined;
findLast: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findLastIndex: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
toReversed: () => Array<A>;
toSorted: (compareFn?: ((a: A, b: A) => number) | undefined) => Array<A>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<A>): Array<A>; (start: number, deleteCount?: number): Array<A> };
with: (index: number, value: A) => Array<A>;
}
let i: numberi++) {
const const element: Arr.NonEmptyReadonlyArray<A>element = arr: Arr.NonEmptyReadonlyArray<A>(parameter) arr: {
0: A;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<A>>): Array<A>; (...items: Array<A | ConcatArray<A>>): Array<A> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<A>;
indexOf: (searchElement: A, fromIndex?: number) => number;
lastIndexOf: (searchElement: A, fromIndex?: number) => number;
every: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => void, thisArg?: any) => void;
map: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): Array<S>; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): Array<A> };
reduce: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
reduceRight: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
find: { (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findIndex: (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, A]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<A>;
includes: (searchElement: A, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: A, index: number, array: Array<A>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => A | undefined;
findLast: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findLastIndex: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
toReversed: () => Array<A>;
toSorted: (compareFn?: ((a: A, b: A) => number) | undefined) => Array<A>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<A>): Array<A>; (start: number, deleteCount?: number): Array<A> };
with: (index: number, value: A) => Array<A>;
}
let i: numberi]
acc: unknown(parameter) acc: {
prev: Option.Option<A>;
current: Option.Option<A>;
}
import OptionOption.some(const element: Arr.NonEmptyReadonlyArray<A>element) as import OptionOption.type Option.Some = /*unresolved*/ anySome<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>A>
const pairs: anypairs.push([acc: unknown(parameter) acc: {
prev: Option.Option<A>;
current: Option.Option<A>;
}
let current: Acurrent, acc: unknown(parameter) acc: {
prev: Option.Option<A>;
current: Option.Option<A>;
}
acc: unknown(parameter) acc: {
prev: Option.Option<A>;
current: Option.Option<A>;
}
import OptionOption.some(let current: Acurrent)
let current: Acurrent = const element: Arr.NonEmptyReadonlyArray<A>element
}
return [acc: unknown(parameter) acc: {
prev: Option.Option<A>;
current: Option.Option<A>;
}
const pairs: anypairs]
}, {
onHalt?: | ((state: unknown) => [any, any, any][])
| undefined
acc: unknown(parameter) acc: {
prev: Option.Option<A>;
current: Option.Option<A>;
}
acc: unknown(parameter) acc: {
prev: Option.Option<A>;
current: Option.Option<A>;
}
acc: unknown(parameter) acc: {
prev: Option.Option<A>;
current: Option.Option<A>;
}
acc: unknown(parameter) acc: {
prev: Option.Option<A>;
current: Option.Option<A>;
}
import OptionOption.none<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<[Option.Option<A>, A, Option.Option<A>], E, R>A>()]] : []
}
})