<A, E, R, X, AS extends A, ES, RS>(
effect: Effect.Effect<A, E, R>,
schedule: Schedule.Schedule<X, AS, ES, RS>
): Stream<A, E | ES, R | RS>Creates a stream from an effect producing a value of type A, which is
repeated using the specified schedule.
Example (Repeating an effect with a schedule)
import { Console, Effect, Schedule, Stream } from "effect"
const program = Effect.gen(function*() {
const stream = Stream.fromEffectSchedule(
Effect.succeed("ping"),
Schedule.recurs(2)
)
const result = yield* Stream.runCollect(stream)
yield* Console.log(result)
})
Effect.runPromise(program)
// Output: [ "ping", "ping", "ping" ]constructors
Source effect/Stream.ts:52223 lines
export const const fromEffectSchedule: <
A,
E,
R,
X,
AS extends A,
ES,
RS
>(
effect: Effect.Effect<A, E, R>,
schedule: Schedule.Schedule<X, AS, ES, RS>
) => Stream<A, E | ES, R | RS>
Creates a stream from an effect producing a value of type A, which is
repeated using the specified schedule.
Example (Repeating an effect with a schedule)
import { Console, Effect, Schedule, Stream } from "effect"
const program = Effect.gen(function*() {
const stream = Stream.fromEffectSchedule(
Effect.succeed("ping"),
Schedule.recurs(2)
)
const result = yield* Stream.runCollect(stream)
yield* Console.log(result)
})
Effect.runPromise(program)
// Output: [ "ping", "ping", "ping" ]
fromEffectSchedule = <function (type parameter) A in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>A, function (type parameter) E in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>E, function (type parameter) R in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>R, function (type parameter) X in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>X, function (type parameter) AS in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>AS extends function (type parameter) A in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>A, function (type parameter) ES in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>ES, function (type parameter) RS in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>RS>(
effect: Effect.Effect<A, E, R>(parameter) effect: {
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<function (type parameter) A in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>A, function (type parameter) E in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>E, function (type parameter) R in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>R>,
schedule: Schedule.Schedule<X, AS, ES, RS>(parameter) schedule: {
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 ScheduleSchedule.type Schedule.Schedule = /*unresolved*/ anySchedule<function (type parameter) X in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>X, function (type parameter) AS in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>AS, function (type parameter) ES in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>ES, function (type parameter) RS in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>RS>
): 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, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>A, function (type parameter) E in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>E | function (type parameter) ES in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>ES, function (type parameter) R in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>R | function (type parameter) RS in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>RS> =>
const fromPull: <A, E, R, EX, RX>(
pull: Effect.Effect<
Pull.Pull<
Arr.NonEmptyReadonlyArray<A>,
E,
void,
R
>,
EX,
RX
>
) => Stream<A, Pull.ExcludeDone<E> | EX, R | RX>
Creates a stream from a pull effect, such as one produced by Stream.toPull.
Details
A pull effect yields chunks on demand and completes when the upstream stream ends.
See Stream.toPull for a matching producer.
Example (Creating a stream from a pull effect)
import { Console, Effect, Stream } from "effect"
const program = Effect.scoped(
Effect.gen(function*() {
const source = Stream.make(1, 2, 3)
const pull = yield* Stream.toPull(source)
const stream = Stream.fromPull(Effect.succeed(pull))
const values = yield* Stream.runCollect(stream)
yield* Console.log(values)
})
)
Effect.runPromise(program)
// Output: [1, 2, 3]
fromPull(import EffectEffect.gen(function*() {
const const step: anystep = yield* import ScheduleSchedule.toStepWithMetadata(schedule: Schedule.Schedule<X, AS, ES, RS>(parameter) schedule: {
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; <…;
}
let s: anys = yield* import EffectEffect.provideService(effect: Effect.Effect<A, E, R>(parameter) effect: {
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 ScheduleSchedule.CurrentMetadata, import ScheduleSchedule.CurrentMetadata.defaultValue())
let let initial: booleaninitial = true
const const pull: Pull.Pull<
readonly [A, ...A[]],
E | ES,
void,
R | RS
>
const pull: {
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.suspend(() => const step: anystep(let s: anys as function (type parameter) AS in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>AS)).pipe(
import EffectEffect.flatMap((meta: Schedule.Metadata<X, AS>(parameter) meta: {
output: Output;
duration: Duration.Duration;
input: Input;
attempt: number;
start: number;
now: number;
elapsed: number;
elapsedSincePrevious: number;
}
import EffectEffect.provideService(effect: Effect.Effect<A, E, R>(parameter) effect: {
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 ScheduleSchedule.CurrentMetadata, meta: Schedule.Metadata<X, AS>(parameter) meta: {
output: Output;
duration: Duration.Duration;
input: Input;
attempt: number;
start: number;
now: number;
elapsed: number;
elapsedSincePrevious: number;
}
import EffectEffect.map((next: anynext) => {
let s: anys = next: anynext
return import ArrArr.of(next: anynext)
})
) as import PullPull.type Pull.Pull = /*unresolved*/ anyPull<import ArrArr.type Arr.NonEmptyReadonlyArray = /*unresolved*/ anyNonEmptyReadonlyArray<function (type parameter) A in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>A>, function (type parameter) E in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>E | function (type parameter) ES in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>ES, void, function (type parameter) R in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>R | function (type parameter) RS in <A, E, R, X, AS extends A, ES, RS>(effect: Effect.Effect<A, E, R>, schedule: Schedule.Schedule<X, AS, ES, RS>): Stream<A, E | ES, R | RS>RS>
return import EffectEffect.suspend(() => {
if (let initial: booleaninitial) {
let initial: booleaninitial = false
return import EffectEffect.succeed(import ArrArr.of(let s: anys))
}
return const pull: Pull.Pull<
readonly [A, ...A[]],
E | ES,
void,
R | RS
>
const pull: {
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;
}