(
options:
| { readonly capacity: "unbounded" }
| {
readonly capacity: number
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined
}
): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E, R>
<A, E, R>(
self: Stream<A, E, R>,
options:
| { readonly capacity: "unbounded" }
| {
readonly capacity: number
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined
}
): Stream<A, E, R>Buffers up to capacity elements so a faster producer can progress
independently of a slower consumer.
Details
Finite buffers use the configured queue strategy: "suspend" applies
backpressure, while "dropping" and "sliding" may discard elements when
the buffer is full. This combinator destroys chunking; use Stream.rechunk
afterward if you need fixed chunk sizes.
Example (Buffering stream elements)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const values = yield* Stream.make(1, 2, 3).pipe(
Stream.buffer({ capacity: 1 }),
Stream.runCollect
)
yield* Console.log(values)
})
Effect.runPromise(program)
// Output: [ 1, 2, 3 ]rate limiting
Source effect/Stream.ts:483621 lines
export const const buffer: {
(
options:
| { readonly capacity: "unbounded" }
| {
readonly capacity: number
readonly strategy?:
| "dropping"
| "sliding"
| "suspend"
| undefined
}
): <A, E, R>(
self: Stream<A, E, R>
) => Stream<A, E, R>
<A, E, R>(
self: Stream<A, E, R>,
options:
| { readonly capacity: "unbounded" }
| {
readonly capacity: number
readonly strategy?:
| "dropping"
| "sliding"
| "suspend"
| undefined
}
): Stream<A, E, R>
}
Buffers up to capacity elements so a faster producer can progress
independently of a slower consumer.
Details
Finite buffers use the configured queue strategy: "suspend" applies
backpressure, while "dropping" and "sliding" may discard elements when
the buffer is full. This combinator destroys chunking; use Stream.rechunk
afterward if you need fixed chunk sizes.
Example (Buffering stream elements)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const values = yield* Stream.make(1, 2, 3).pipe(
Stream.buffer({ capacity: 1 }),
Stream.runCollect
)
yield* Console.log(values)
})
Effect.runPromise(program)
// Output: [ 1, 2, 3 ]
buffer: {
(
options: | {
readonly capacity: "unbounded"
}
| {
readonly capacity: number
readonly strategy?:
| "dropping"
| "sliding"
| "suspend"
| undefined
}
capacity: "unbounded"capacity: "unbounded" } | {
readonly capacity: numbercapacity: number
readonly strategy?: | "suspend"
| "sliding"
| "dropping"
| undefined
function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<A, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<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<A, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<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<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<A, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<A, E, R>R>
<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): 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; <…;
}
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>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
options: | {
readonly capacity: "unbounded"
}
| {
readonly capacity: number
readonly strategy?:
| "dropping"
| "sliding"
| "suspend"
| undefined
}
capacity: "unbounded"capacity: "unbounded" } | {
readonly capacity: numbercapacity: number
readonly strategy?: | "suspend"
| "sliding"
| "dropping"
| undefined
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>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
import dualdual(2, <function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): 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; <…;
}
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>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
options: | {
readonly capacity: "unbounded"
}
| {
readonly capacity: number
readonly strategy?:
| "dropping"
| "sliding"
| "suspend"
| undefined
}
capacity: "unbounded"capacity: "unbounded" } | {
readonly capacity: numbercapacity: number
readonly strategy?: | "suspend"
| "sliding"
| "dropping"
| undefined
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>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Stream<A, E, R>
const fromChannel: <
Arr extends Arr.NonEmptyReadonlyArray<any>,
E,
R
>(
channel: Channel.Channel<
Arr,
E,
void,
unknown,
unknown,
unknown,
R
>
) => Stream<
Arr extends Arr.NonEmptyReadonlyArray<infer A>
? A
: never,
E,
R
>
Creates a stream from a array-emitting Channel.
Example (Creating a stream from an array-emitting channel)
import { Channel, Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const channel = Channel.succeed([1, 2, 3] as const)
const stream = Stream.fromChannel(channel)
const result = yield* Stream.runCollect(stream)
yield* Console.log(result)
})
// Output: [ 1, 2, 3 ]
fromChannel(import ChannelChannel.bufferArray(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; <…;
}
Stream<out A, out E = never, out R = never>.channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, R>(property) Stream<out A, out E = never, out R = never>.channel: {
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; <…;
}
options: | {
readonly capacity: "unbounded"
}
| {
readonly capacity: number
readonly strategy?:
| "dropping"
| "sliding"
| "suspend"
| undefined
}