<A2, E2, R2>(
that: Stream<A2, E2, R2>,
options?:
| { readonly haltStrategy?: HaltStrategy | undefined }
| undefined
): <A, E, R>(self: Stream<A, E, R>) => Stream<A | A2, E | E2, R | R2>
<A, E, R, A2, E2, R2>(
self: Stream<A, E, R>,
that: Stream<A2, E2, R2>,
options?:
| { readonly haltStrategy?: HaltStrategy | undefined }
| undefined
): Stream<A | A2, E | E2, R | R2>Merges two streams, emitting elements from both as they arrive.
Details
By default, the merged stream ends when both streams end. Use
haltStrategy to change the termination behavior.
Example (Merging stream values)
import { Console, Effect, Stream } from "effect"
const fast = Stream.make(1, 2, 3)
const slow = Stream.fromEffect(Effect.delay(Effect.succeed(4), "50 millis"))
const program = Effect.gen(function*() {
const result = yield* Stream.runCollect(Stream.merge(fast, slow))
yield* Console.log(result)
})
Effect.runPromise(program)
// Output: [ 1, 2, 3, 4 ]merging
Source effect/Stream.ts:312824 lines
export const const merge: {
<A2, E2, R2>(
that: Stream<A2, E2, R2>,
options?:
| {
readonly haltStrategy?:
| HaltStrategy
| undefined
}
| undefined
): <A, E, R>(
self: Stream<A, E, R>
) => Stream<A | A2, E | E2, R | R2>
<A, E, R, A2, E2, R2>(
self: Stream<A, E, R>,
that: Stream<A2, E2, R2>,
options?:
| {
readonly haltStrategy?:
| HaltStrategy
| undefined
}
| undefined
): Stream<A | A2, E | E2, R | R2>
}
Merges two streams, emitting elements from both as they arrive.
Details
By default, the merged stream ends when both streams end. Use
haltStrategy to change the termination behavior.
Example (Merging stream values)
import { Console, Effect, Stream } from "effect"
const fast = Stream.make(1, 2, 3)
const slow = Stream.fromEffect(Effect.delay(Effect.succeed(4), "50 millis"))
const program = Effect.gen(function*() {
const result = yield* Stream.runCollect(Stream.merge(fast, slow))
yield* Console.log(result)
})
Effect.runPromise(program)
// Output: [ 1, 2, 3, 4 ]
merge: {
<function (type parameter) A2 in <A2, E2, R2>(that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): <A, E, R>(self: Stream<A, E, R>) => Stream<A | A2, E | E2, R | R2>
function (type parameter) E2 in <A2, E2, R2>(that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): <A, E, R>(self: Stream<A, E, R>) => Stream<A | A2, E | E2, R | R2>
function (type parameter) R2 in <A2, E2, R2>(that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): <A, E, R>(self: Stream<A, E, R>) => Stream<A | A2, E | E2, R | R2>
that: Stream<A2, E2, R2>(parameter) that: {
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) A2 in <A2, E2, R2>(that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): <A, E, R>(self: Stream<A, E, R>) => Stream<A | A2, E | E2, R | R2>
function (type parameter) E2 in <A2, E2, R2>(that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): <A, E, R>(self: Stream<A, E, R>) => Stream<A | A2, E | E2, R | R2>
function (type parameter) R2 in <A2, E2, R2>(that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): <A, E, R>(self: Stream<A, E, R>) => Stream<A | A2, E | E2, R | R2>
options: | {
readonly haltStrategy?:
| HaltStrategy
| undefined
}
| undefined
haltStrategy?: HaltStrategy | undefinedhaltStrategy?: type HaltStrategy =
| "left"
| "right"
| "both"
| "either"
Describes how merged streams decide when to halt.
HaltStrategy | undefined
} | undefined
): <function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<A | A2, E | E2, R | R2>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A | A2, E | E2, R | R2>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<A | A2, E | E2, R | R2>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 | A2, E | E2, R | R2>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A | A2, E | E2, R | R2>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<A | A2, E | E2, R | 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) A in <A, E, R>(self: Stream<A, E, R>): Stream<A | A2, E | E2, R | R2>A | function (type parameter) A2 in <A2, E2, R2>(that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): <A, E, R>(self: Stream<A, E, R>) => Stream<A | A2, E | E2, R | R2>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A | A2, E | E2, R | R2>E | function (type parameter) E2 in <A2, E2, R2>(that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): <A, E, R>(self: Stream<A, E, R>) => Stream<A | A2, E | E2, R | R2>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<A | A2, E | E2, R | R2>R | function (type parameter) R2 in <A2, E2, R2>(that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): <A, E, R>(self: Stream<A, E, R>) => Stream<A | A2, E | E2, R | R2>
function (type parameter) A in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) E in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) R in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) A2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | 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>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) E in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) R in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
that: Stream<A2, E2, R2>(parameter) that: {
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) A2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
options: | {
readonly haltStrategy?:
| HaltStrategy
| undefined
}
| undefined
haltStrategy?: HaltStrategy | undefinedhaltStrategy?: type HaltStrategy =
| "left"
| "right"
| "both"
| "either"
Describes how merged streams decide when to halt.
HaltStrategy | 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) A in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) A2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) E in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) R in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
dual<(...args: Array<any>) => any, <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined) => Stream<A | A2, E | E2, R | R2>>(isDataFirst: (args: IArguments) => boolean, body: <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined) => Stream<A | A2, E | E2, R | R2>): ((...args: Array<any>) => any) & (<A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined) => Stream<A | A2, E | E2, R | R2>) (+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(
(args: IArgumentsargs) => 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: IArgumentsargs[0]) && 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: IArgumentsargs[1]),
<function (type parameter) A in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) E in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) R in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) A2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | 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>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) E in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) R in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
that: Stream<A2, E2, R2>(parameter) that: {
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) A2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
options: | {
readonly haltStrategy?:
| HaltStrategy
| undefined
}
| undefined
haltStrategy?: HaltStrategy | undefinedhaltStrategy?: type HaltStrategy =
| "left"
| "right"
| "both"
| "either"
Describes how merged streams decide when to halt.
HaltStrategy | 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) A in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) A2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) E in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) R in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, A2, E2, R2>(self: Stream<A, E, R>, that: Stream<A2, E2, R2>, options?: {
readonly haltStrategy?: HaltStrategy | undefined;
} | undefined): Stream<A | A2, E | E2, R | R2>
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.const merge: {
<
OutElem1,
OutErr1,
OutDone1,
InElem1,
InErr1,
InDone1,
Env1
>(
right: Channel<
OutElem1,
OutErr1,
OutDone1,
InElem1,
InErr1,
InDone1,
Env1
>,
options?:
| {
readonly haltStrategy?:
| HaltStrategy
| undefined
}
| undefined
): <
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>(
left: Channel<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>
) => Channel<
OutElem1 | OutElem,
OutErr | OutErr1,
OutDone | OutDone1,
InElem & InElem1,
InErr & InErr1,
InDone & InDone1,
Env1 | Env
>
<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env,
OutElem1,
OutErr1,
OutDone1,
InElem1,
InErr1,
InDone1,
Env1
>(
left: Channel<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>,
right: Channel<
OutElem1,
OutErr1,
OutDone1,
InElem1,
InErr1,
InDone1,
Env1
>,
options?:
| {
readonly haltStrategy?:
| HaltStrategy
| undefined
}
| undefined
): Channel<
OutElem | OutElem1,
OutErr | OutErr1,
OutDone | OutDone1,
InElem & InElem1,
InErr & InErr1,
InDone & InDone1,
Env | Env1
>
}
const toChannel: <A, E, R>(
stream: Stream<A, E, R>
) => Channel.Channel<
Arr.NonEmptyReadonlyArray<A>,
E,
void,
unknown,
unknown,
unknown,
R
>
Creates a channel from a stream.
Example (Converting a stream to a channel)
import { Channel, Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const stream = Stream.make(1, 2, 3)
const channel = Stream.toChannel(stream)
const values = yield* Channel.runCollect(channel)
yield* Console.log(values.flat())
})
Effect.runPromise(program)
// Output: [ 1, 2, 3 ]
toChannel(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; <…;
}
const toChannel: <A, E, R>(
stream: Stream<A, E, R>
) => Channel.Channel<
Arr.NonEmptyReadonlyArray<A>,
E,
void,
unknown,
unknown,
unknown,
R
>
Creates a channel from a stream.
Example (Converting a stream to a channel)
import { Channel, Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const stream = Stream.make(1, 2, 3)
const channel = Stream.toChannel(stream)
const values = yield* Channel.runCollect(channel)
yield* Console.log(values.flat())
})
Effect.runPromise(program)
// Output: [ 1, 2, 3 ]
toChannel(that: Stream<A2, E2, R2>(parameter) that: {
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; <…;
}
options: | {
readonly haltStrategy?:
| HaltStrategy
| undefined
}
| undefined
Referenced by 4 symbols