<EX = never, RX = never>(test: Effect.Effect<boolean, EX, RX>): <A, E, R>(
self: Stream<A, E, R>
) => Stream<A, E | EX, R | RX>
<A, E, R, EX = never, RX = never>(
self: Stream<A, E, R>,
test: Effect.Effect<boolean, EX, RX>
): Stream<A, E | EX, R | RX>Returns the specified stream if the given condition is satisfied, otherwise returns an empty stream.
Example (Conditionally keeping a stream)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const result = yield* Stream.runCollect(
Stream.when(Stream.make(1, 2, 3), Effect.succeed(false))
)
yield* Console.log(result)
})
Effect.runPromise(program)
// Output: []filtering
Source effect/Stream.ts:472416 lines
export const const when: {
<EX = never, RX = never>(
test: Effect.Effect<boolean, EX, RX>
): <A, E, R>(
self: Stream<A, E, R>
) => Stream<A, E | EX, R | RX>
<A, E, R, EX = never, RX = never>(
self: Stream<A, E, R>,
test: Effect.Effect<boolean, EX, RX>
): Stream<A, E | EX, R | RX>
}
Returns the specified stream if the given condition is satisfied, otherwise
returns an empty stream.
Example (Conditionally keeping a stream)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const result = yield* Stream.runCollect(
Stream.when(Stream.make(1, 2, 3), Effect.succeed(false))
)
yield* Console.log(result)
})
Effect.runPromise(program)
// Output: []
when: {
<function (type parameter) EX in <EX = never, RX = never>(test: Effect.Effect<boolean, EX, RX>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | EX, R | RX>EX = never, function (type parameter) RX in <EX = never, RX = never>(test: Effect.Effect<boolean, EX, RX>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | EX, R | RX>RX = never>(
test: Effect.Effect<boolean, EX, RX>(parameter) test: {
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; <…;
toString: () => string;
toJSON: () => unknown;
}
import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<boolean, function (type parameter) EX in <EX = never, RX = never>(test: Effect.Effect<boolean, EX, RX>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | EX, R | RX>EX, function (type parameter) RX in <EX = never, RX = never>(test: Effect.Effect<boolean, EX, RX>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | EX, R | RX>RX>
): <function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | EX, R | RX>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | EX, R | RX>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | EX, R | RX>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 | EX, R | RX>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | EX, R | RX>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | EX, R | RX>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 | EX, R | RX>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | EX, R | RX>E | function (type parameter) EX in <EX = never, RX = never>(test: Effect.Effect<boolean, EX, RX>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | EX, R | RX>EX, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | EX, R | RX>R | function (type parameter) RX in <EX = never, RX = never>(test: Effect.Effect<boolean, EX, RX>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | EX, R | RX>RX>
<function (type parameter) A in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>A, function (type parameter) E in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>E, function (type parameter) R in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>R, function (type parameter) EX in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>EX = never, function (type parameter) RX in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>RX = never>(
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, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>A, function (type parameter) E in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>E, function (type parameter) R in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>R>,
test: Effect.Effect<boolean, EX, RX>(parameter) test: {
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; <…;
toString: () => string;
toJSON: () => unknown;
}
import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<boolean, function (type parameter) EX in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>EX, function (type parameter) RX in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>RX>
): 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, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>A, function (type parameter) E in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>E | function (type parameter) EX in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>EX, function (type parameter) R in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>R | function (type parameter) RX in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>RX>
} = import dualdual(2, <function (type parameter) A in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>A, function (type parameter) E in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>E, function (type parameter) R in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>R, function (type parameter) EX in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>EX = never, function (type parameter) RX in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>RX = never>(
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, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>A, function (type parameter) E in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>E, function (type parameter) R in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>R>,
test: Effect.Effect<boolean, EX, RX>(parameter) test: {
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; <…;
toString: () => string;
toJSON: () => unknown;
}
import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<boolean, function (type parameter) EX in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>EX, function (type parameter) RX in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>RX>
): 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, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>A, function (type parameter) E in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>E | function (type parameter) EX in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>EX, function (type parameter) R in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>R | function (type parameter) RX in <A, E, R, EX = never, RX = never>(self: Stream<A, E, R>, test: Effect.Effect<boolean, EX, RX>): Stream<A, E | EX, R | RX>RX> =>
test: Effect.Effect<boolean, EX, RX>(parameter) test: {
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; <…;
toString: () => string;
toJSON: () => unknown;
}
import EffectEffect.map((pass: anypass) => pass: anypass ? 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 empty: Stream<never>const empty: {
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; <…;
}
Creates an empty stream.
Example (Creating an empty stream)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const values = yield* Stream.empty.pipe(Stream.runCollect)
yield* Console.log(values)
})
Effect.runPromise(program)
// []
empty),
const unwrap: <A, E2, R2, E, R>(
effect: Effect.Effect<Stream<A, E2, R2>, E, R>
) => Stream<
A,
E | E2,
R2 | Exclude<R, Scope.Scope>
>
Creates a stream produced from an Effect.
Example (Unwrapping a stream effect)
import { Console, Effect, Stream } from "effect"
const effect = Effect.succeed(Stream.make(1, 2, 3))
const stream = Stream.unwrap(effect)
const program = Effect.gen(function*() {
const chunk = yield* Stream.runCollect(stream)
yield* Console.log(chunk)
})
// [1, 2, 3]
unwrap
))