<A, A2, E2, R2>(
f: (a: A) => Stream<A2, E2, R2>,
options?:
| {
readonly concurrency?: number | "unbounded" | undefined
readonly bufferSize?: number | undefined
}
| undefined
): <E, R>(self: Stream<A, E, R>) => Stream<A2, E2 | E, R2 | R>
<A, E, R, A2, E2, R2>(
self: Stream<A, E, R>,
f: (a: A) => Stream<A2, E2, R2>,
options?:
| {
readonly concurrency?: number | "unbounded" | undefined
readonly bufferSize?: number | undefined
}
| undefined
): Stream<A2, E | E2, R | R2>Maps each element to a stream and flattens the resulting streams.
Details
With the default sequential concurrency, inner streams are concatenated in
input order. When concurrency is greater than 1 or "unbounded",
multiple inner streams may run at the same time and their outputs are merged
as they arrive.
Example (Flat mapping stream values)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const values = yield* Stream.make(1, 2, 3).pipe(
Stream.flatMap((n) => Stream.make(n, n * 2)),
Stream.runCollect
)
yield* Console.log(values)
})
Effect.runPromise(program)
// Output: [ 1, 2, 2, 4, 3, 6 ]mapping
Source effect/Stream.ts:243629 lines
export const const flatMap: {
<A, A2, E2, R2>(
f: (a: A) => Stream<A2, E2, R2>,
options?:
| {
readonly concurrency?:
| number
| "unbounded"
| undefined
readonly bufferSize?: number | undefined
}
| undefined
): <E, R>(
self: Stream<A, E, R>
) => Stream<A2, E2 | E, R2 | R>
<A, E, R, A2, E2, R2>(
self: Stream<A, E, R>,
f: (a: A) => Stream<A2, E2, R2>,
options?:
| {
readonly concurrency?:
| number
| "unbounded"
| undefined
readonly bufferSize?: number | undefined
}
| undefined
): Stream<A2, E | E2, R | R2>
}
Maps each element to a stream and flattens the resulting streams.
Details
With the default sequential concurrency, inner streams are concatenated in
input order. When concurrency is greater than 1 or "unbounded",
multiple inner streams may run at the same time and their outputs are merged
as they arrive.
Example (Flat mapping stream values)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const values = yield* Stream.make(1, 2, 3).pipe(
Stream.flatMap((n) => Stream.make(n, n * 2)),
Stream.runCollect
)
yield* Console.log(values)
})
Effect.runPromise(program)
// Output: [ 1, 2, 2, 4, 3, 6 ]
flatMap: {
<function (type parameter) A in <A, A2, E2, R2>(f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): <E, R>(self: Stream<A, E, R>) => Stream<A2, E2 | E, R2 | R>
function (type parameter) A2 in <A, A2, E2, R2>(f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): <E, R>(self: Stream<A, E, R>) => Stream<A2, E2 | E, R2 | R>
function (type parameter) E2 in <A, A2, E2, R2>(f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): <E, R>(self: Stream<A, E, R>) => Stream<A2, E2 | E, R2 | R>
function (type parameter) R2 in <A, A2, E2, R2>(f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): <E, R>(self: Stream<A, E, R>) => Stream<A2, E2 | E, R2 | R>
f: (a: A) => Stream<A2, E2, R2>f: (a: Aa: function (type parameter) A in <A, A2, E2, R2>(f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): <E, R>(self: Stream<A, E, R>) => Stream<A2, E2 | E, R2 | 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) A2 in <A, A2, E2, R2>(f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): <E, R>(self: Stream<A, E, R>) => Stream<A2, E2 | E, R2 | R>
function (type parameter) E2 in <A, A2, E2, R2>(f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): <E, R>(self: Stream<A, E, R>) => Stream<A2, E2 | E, R2 | R>
function (type parameter) R2 in <A, A2, E2, R2>(f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): <E, R>(self: Stream<A, E, R>) => Stream<A2, E2 | E, R2 | R>
options: | {
readonly concurrency?:
| number
| "unbounded"
| undefined
readonly bufferSize?: number | undefined
}
| undefined
concurrency?: number | "unbounded" | undefinedconcurrency?: number | "unbounded" | undefined
readonly bufferSize?: number | undefinedbufferSize?: number | undefined
} | undefined
): <function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<A2, E2 | E, R2 | R>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<A2, E2 | E, R2 | 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, A2, E2, R2>(f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): <E, R>(self: Stream<A, E, R>) => Stream<A2, E2 | E, R2 | R>
function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<A2, E2 | E, R2 | R>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<A2, E2 | E, R2 | 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) A2 in <A, A2, E2, R2>(f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): <E, R>(self: Stream<A, E, R>) => Stream<A2, E2 | E, R2 | R>
function (type parameter) E2 in <A, A2, E2, R2>(f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): <E, R>(self: Stream<A, E, R>) => Stream<A2, E2 | E, R2 | R>
function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<A2, E2 | E, R2 | R>E, function (type parameter) R2 in <A, A2, E2, R2>(f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): <E, R>(self: Stream<A, E, R>) => Stream<A2, E2 | E, R2 | R>
function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<A2, E2 | E, R2 | R>R>
<function (type parameter) A in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) E in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) R in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) A2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
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, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) E in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) R in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
f: (a: A) => Stream<A2, E2, R2>f: (a: Aa: function (type parameter) A in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
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) A2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
options: | {
readonly concurrency?:
| number
| "unbounded"
| undefined
readonly bufferSize?: number | undefined
}
| undefined
concurrency?: number | "unbounded" | undefinedconcurrency?: number | "unbounded" | undefined
readonly bufferSize?: number | undefinedbufferSize?: number | undefined
} | 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) A2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) E in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) R in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
import dualdual((args: anyargs) => const isStream: (
u: unknown
) => u is Stream<unknown, unknown, unknown>
Checks whether a value is a Stream.
Example (Checking whether a value is a Stream)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const stream = Stream.make(1, 2, 3)
const notStream = { data: [1, 2, 3] }
yield* Console.log(Stream.isStream(stream))
// true
yield* Console.log(Stream.isStream(notStream))
// false
})
Effect.runPromise(program)
isStream(args: anyargs[0]), <function (type parameter) A in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) E in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) R in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) A2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
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, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) E in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) R in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
f: (a: A) => Stream<A2, E2, R2>f: (a: Aa: function (type parameter) A in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
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) A2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
options: | {
readonly concurrency?:
| number
| "unbounded"
| undefined
readonly bufferSize?: number | undefined
}
| undefined
concurrency?: number | "unbounded" | undefinedconcurrency?: number | "unbounded" | undefined
readonly bufferSize?: number | undefinedbufferSize?: number | undefined
} | 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) A2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) E in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) R in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, f: (a: A) => Stream<A2, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
} | undefined): Stream<A2, E | E2, R | R2>
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; <…;
}
import ChannelChannel.flattenArray,
import ChannelChannel.flatMap((a: anya) => f: (a: A) => Stream<A2, E2, R2>f(a: anya).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 concurrency?:
| number
| "unbounded"
| undefined
readonly bufferSize?: number | undefined
}
| undefined
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
))Referenced by 5 symbols