<E, A2>(f: (error: E) => A2): <A, R>(
self: Stream<A, E, R>
) => Stream<A | A2, never, R>
<A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<
A | A2,
never,
R
>Returns a stream that emits a fallback value when this stream fails.
Example (Recovering with a fallback value)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const stream = Stream.fail("NetworkError").pipe(
Stream.orElseSucceed((error) => `Recovered: ${error}`)
)
const values = yield* Stream.runCollect(stream)
yield* Console.log(values)
})
Effect.runPromise(program)
// Output: [ "Recovered: NetworkError" ]error handling
Source effect/Stream.ts:595212 lines
export const const orElseSucceed: {
<E, A2>(f: (error: E) => A2): <A, R>(
self: Stream<A, E, R>
) => Stream<A | A2, never, R>
<A, E, R, A2>(
self: Stream<A, E, R>,
f: (error: E) => A2
): Stream<A | A2, never, R>
}
Returns a stream that emits a fallback value when this stream fails.
Example (Recovering with a fallback value)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const stream = Stream.fail("NetworkError").pipe(
Stream.orElseSucceed((error) => `Recovered: ${error}`)
)
const values = yield* Stream.runCollect(stream)
yield* Console.log(values)
})
Effect.runPromise(program)
// Output: [ "Recovered: NetworkError" ]
orElseSucceed: {
<function (type parameter) E in <E, A2>(f: (error: E) => A2): <A, R>(self: Stream<A, E, R>) => Stream<A | A2, never, R>E, function (type parameter) A2 in <E, A2>(f: (error: E) => A2): <A, R>(self: Stream<A, E, R>) => Stream<A | A2, never, R>A2>(
f: (error: E) => A2f: (error: Eerror: function (type parameter) E in <E, A2>(f: (error: E) => A2): <A, R>(self: Stream<A, E, R>) => Stream<A | A2, never, R>E) => function (type parameter) A2 in <E, A2>(f: (error: E) => A2): <A, R>(self: Stream<A, E, R>) => Stream<A | A2, never, R>A2
): <function (type parameter) A in <A, R>(self: Stream<A, E, R>): Stream<A | A2, never, R>A, function (type parameter) R in <A, R>(self: Stream<A, E, R>): Stream<A | A2, never, 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, R>(self: Stream<A, E, R>): Stream<A | A2, never, R>A, function (type parameter) E in <E, A2>(f: (error: E) => A2): <A, R>(self: Stream<A, E, R>) => Stream<A | A2, never, R>E, function (type parameter) R in <A, R>(self: Stream<A, E, R>): Stream<A | A2, never, 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, R>(self: Stream<A, E, R>): Stream<A | A2, never, R>A | function (type parameter) A2 in <E, A2>(f: (error: E) => A2): <A, R>(self: Stream<A, E, R>) => Stream<A | A2, never, R>A2, never, function (type parameter) R in <A, R>(self: Stream<A, E, R>): Stream<A | A2, never, R>R>
<function (type parameter) A in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>A, function (type parameter) E in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>E, function (type parameter) R in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>R, function (type parameter) A2 in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>A2>(
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>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>A, function (type parameter) E in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>E, function (type parameter) R in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>R>,
f: (error: E) => A2f: (error: Eerror: function (type parameter) E in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>E) => function (type parameter) A2 in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>A2
): 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>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>A | function (type parameter) A2 in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>A2, never, function (type parameter) R in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>R>
} = import dualdual(2, <function (type parameter) A in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>A, function (type parameter) E in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>E, function (type parameter) R in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>R, function (type parameter) A2 in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>A2>(
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>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>A, function (type parameter) E in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>E, function (type parameter) R in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>R>,
f: (error: E) => A2f: (error: Eerror: function (type parameter) E in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>E) => function (type parameter) A2 in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>A2
): 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>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>A | function (type parameter) A2 in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>A2, never, function (type parameter) R in <A, E, R, A2>(self: Stream<A, E, R>, f: (error: E) => A2): Stream<A | A2, never, R>R> => const catch_: {
<E, A2, E2, R2>(
f: (error: E) => Stream<A2, E2, R2>
): <A, R>(
self: Stream<A, E, R>
) => Stream<A | A2, E2, R2 | R>
<A, E, R, A2, E2, R2>(
self: Stream<A, E, R>,
f: (error: E) => Stream<A2, E2, R2>
): Stream<A | A2, 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; <…;
}
e: Ee) => const succeed: <A>(value: A) => Stream<A>Creates a single-valued pure stream.
Example (Creating a single-valued pure stream)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const values = yield* Stream.succeed(3).pipe(Stream.runCollect)
yield* Console.log(values)
})
Effect.runPromise(program)
// [ 3 ]
succeed(f: (error: E) => A2f(e: Ee))))