<A, K, V, E2, R2>(
f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>,
options?: {
readonly bufferSize?: number | undefined
readonly idleTimeToLive?: Duration.Input | undefined
}
): <E, R>(
self: Stream<A, E, R>
) => Stream<readonly [K, Stream<V>], E | E2, R | R2>
<A, E, R, K, V, E2, R2>(
self: Stream<A, E, R>,
f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>,
options?: {
readonly bufferSize?: number | undefined
readonly idleTimeToLive?: Duration.Input | undefined
}
): Stream<readonly [K, Stream<V>], E | E2, R | R2>Groups elements into keyed substreams using an effectful classifier.
Example (Grouping elements into keyed substreams using an effectful classifier)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const grouped = yield* Stream.make(1, 2, 3, 4, 5).pipe(
Stream.groupBy((n) =>
Effect.succeed([n % 2 === 0 ? "even" : "odd", n] as const)
),
Stream.mapEffect(
Effect.fnUntraced(function*([key, stream]) {
return [key, yield* Stream.runCollect(stream)] as const
}),
{ concurrency: "unbounded" }
),
Stream.runCollect
)
yield* Console.log(grouped)
})
Effect.runPromise(program)
// Output: [ [ "odd", [ 1, 3, 5 ] ], [ "even", [ 2, 4 ] ] ]grouping
Source effect/Stream.ts:826339 lines
export const const groupBy: {
<A, K, V, E2, R2>(
f: (
a: NoInfer<A>
) => Effect.Effect<readonly [K, V], E2, R2>,
options?: {
readonly bufferSize?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
): <E, R>(
self: Stream<A, E, R>
) => Stream<
readonly [K, Stream<V>],
E | E2,
R | R2
>
<A, E, R, K, V, E2, R2>(
self: Stream<A, E, R>,
f: (
a: NoInfer<A>
) => Effect.Effect<readonly [K, V], E2, R2>,
options?: {
readonly bufferSize?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
): Stream<
readonly [K, Stream<V>],
E | E2,
R | R2
>
}
Groups elements into keyed substreams using an effectful classifier.
Example (Grouping elements into keyed substreams using an effectful classifier)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const grouped = yield* Stream.make(1, 2, 3, 4, 5).pipe(
Stream.groupBy((n) =>
Effect.succeed([n % 2 === 0 ? "even" : "odd", n] as const)
),
Stream.mapEffect(
Effect.fnUntraced(function*([key, stream]) {
return [key, yield* Stream.runCollect(stream)] as const
}),
{ concurrency: "unbounded" }
),
Stream.runCollect
)
yield* Console.log(grouped)
})
Effect.runPromise(program)
// Output: [ [ "odd", [ 1, 3, 5 ] ], [ "even", [ 2, 4 ] ] ]
groupBy: {
<function (type parameter) A in <A, K, V, E2, R2>(f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) K in <A, K, V, E2, R2>(f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) V in <A, K, V, E2, R2>(f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E2 in <A, K, V, E2, R2>(f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) R2 in <A, K, V, E2, R2>(f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<readonly [K, Stream<V>], E | E2, R | R2>
f: (
a: NoInfer<A>
) => Effect.Effect<readonly [K, V], E2, R2>
a: NoInfer<A>a: type NoInfer<A> = [A][A extends any ? 0 : never]Prevents TypeScript from inferring a type parameter from a specific
position.
When to use
Use when a function parameter must match an inferred type without becoming
an inference source.
Details
The parameter using NoInfer must still match the inferred type.
Example (Controlling inference)
import type { Types } from "effect"
declare function withDefault<T>(value: T, fallback: Types.NoInfer<T>): T
// T is inferred as "a" | "b" from the first argument only
const result = withDefault<"a" | "b">("a", "b")
NoInfer<function (type parameter) A in <A, K, V, E2, R2>(f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<readonly [K, Stream<V>], E | E2, R | R2>
import EffectEffect.interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<readonly [function (type parameter) K in <A, K, V, E2, R2>(f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) V in <A, K, V, E2, R2>(f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E2 in <A, K, V, E2, R2>(f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) R2 in <A, K, V, E2, R2>(f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<readonly [K, Stream<V>], E | E2, R | R2>
options: {
readonly bufferSize?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
bufferSize?: number | undefinedbufferSize?: number | undefined
readonly idleTimeToLive?: Duration.Input | undefinedidleTimeToLive?: import DurationDuration.type Input =
| number
| bigint
| Duration.Duration
| readonly [seconds: number, nanos: number]
| `${number} nano`
| `${number} nanos`
| `${number} micro`
| `${number} micros`
| `${number} milli`
| `${number} millis`
| `${number} second`
| `${number} seconds`
| `${number} minute`
| `${number} minutes`
| `${number} hour`
| `${number} hours`
| `${number} day`
| `${number} days`
| `${number} week`
| `${number} weeks`
| "Infinity"
| "-Infinity"
| Duration.DurationObject
Valid input types that can be converted to a Duration.
When to use
Use when an API should accept any value that Effect can convert into a
Duration, including existing durations, millisecond numbers, nanosecond
bigints, high-resolution tuples, duration strings, infinity strings, or
duration objects.
Details
String inputs accept values like "10 seconds", "500 millis",
"Infinity", and "-Infinity". Finite fractional values that are
normalized to nanoseconds are rounded to the nearest nanosecond, with ties
away from zero.
Input | undefined
}
): <function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<readonly [K, Stream<V>], E | E2, R | R2>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<readonly [K, Stream<V>], 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, K, V, E2, R2>(f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<readonly [K, Stream<V>], E | E2, R | R2>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<readonly [K, Stream<V>], 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<readonly [function (type parameter) K in <A, K, V, E2, R2>(f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<readonly [K, Stream<V>], 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) V in <A, K, V, E2, R2>(f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<readonly [K, Stream<V>], E | E2, R | R2>E | function (type parameter) E2 in <A, K, V, E2, R2>(f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<readonly [K, Stream<V>], E | E2, R | R2>R | function (type parameter) R2 in <A, K, V, E2, R2>(f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) A in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) R in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) K in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) V in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E2 in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) R2 in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], 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, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) R in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
f: (
a: NoInfer<A>
) => Effect.Effect<readonly [K, V], E2, R2>
a: NoInfer<A>a: type NoInfer<A> = [A][A extends any ? 0 : never]Prevents TypeScript from inferring a type parameter from a specific
position.
When to use
Use when a function parameter must match an inferred type without becoming
an inference source.
Details
The parameter using NoInfer must still match the inferred type.
Example (Controlling inference)
import type { Types } from "effect"
declare function withDefault<T>(value: T, fallback: Types.NoInfer<T>): T
// T is inferred as "a" | "b" from the first argument only
const result = withDefault<"a" | "b">("a", "b")
NoInfer<function (type parameter) A in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
import EffectEffect.interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<readonly [function (type parameter) K in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) V in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E2 in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) R2 in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
options: {
readonly bufferSize?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
bufferSize?: number | undefinedbufferSize?: number | undefined
readonly idleTimeToLive?: Duration.Input | undefinedidleTimeToLive?: import DurationDuration.type Input =
| number
| bigint
| Duration.Duration
| readonly [seconds: number, nanos: number]
| `${number} nano`
| `${number} nanos`
| `${number} micro`
| `${number} micros`
| `${number} milli`
| `${number} millis`
| `${number} second`
| `${number} seconds`
| `${number} minute`
| `${number} minutes`
| `${number} hour`
| `${number} hours`
| `${number} day`
| `${number} days`
| `${number} week`
| `${number} weeks`
| "Infinity"
| "-Infinity"
| Duration.DurationObject
Valid input types that can be converted to a Duration.
When to use
Use when an API should accept any value that Effect can convert into a
Duration, including existing durations, millisecond numbers, nanosecond
bigints, high-resolution tuples, duration strings, infinity strings, or
duration objects.
Details
String inputs accept values like "10 seconds", "500 millis",
"Infinity", and "-Infinity". Finite fractional values that are
normalized to nanoseconds are rounded to the nearest nanosecond, with ties
away from zero.
Input | 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<readonly [function (type parameter) K in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], 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) V in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E2 in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) R in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) R2 in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
dual<(...args: Array<any>) => any, <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}) => Stream<readonly [K, Stream<V>], E | E2, R | R2>>(isDataFirst: (args: IArguments) => boolean, body: <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}) => Stream<readonly [K, Stream<V>], E | E2, R | R2>): ((...args: Array<any>) => any) & (<A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}) => Stream<readonly [K, Stream<V>], 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]), <function (type parameter) A in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) R in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) K in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) V in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E2 in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) R2 in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], 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, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) R in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
f: (
a: NoInfer<A>
) => Effect.Effect<readonly [K, V], E2, R2>
a: NoInfer<A>a: type NoInfer<A> = [A][A extends any ? 0 : never]Prevents TypeScript from inferring a type parameter from a specific
position.
When to use
Use when a function parameter must match an inferred type without becoming
an inference source.
Details
The parameter using NoInfer must still match the inferred type.
Example (Controlling inference)
import type { Types } from "effect"
declare function withDefault<T>(value: T, fallback: Types.NoInfer<T>): T
// T is inferred as "a" | "b" from the first argument only
const result = withDefault<"a" | "b">("a", "b")
NoInfer<function (type parameter) A in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
import EffectEffect.interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<readonly [function (type parameter) K in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) V in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E2 in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) R2 in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
options: {
readonly bufferSize?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
bufferSize?: number | undefinedbufferSize?: number | undefined
readonly idleTimeToLive?: Duration.Input | undefinedidleTimeToLive?: import DurationDuration.type Input =
| number
| bigint
| Duration.Duration
| readonly [seconds: number, nanos: number]
| `${number} nano`
| `${number} nanos`
| `${number} micro`
| `${number} micros`
| `${number} milli`
| `${number} millis`
| `${number} second`
| `${number} seconds`
| `${number} minute`
| `${number} minutes`
| `${number} hour`
| `${number} hours`
| `${number} day`
| `${number} days`
| `${number} week`
| `${number} weeks`
| "Infinity"
| "-Infinity"
| Duration.DurationObject
Valid input types that can be converted to a Duration.
When to use
Use when an API should accept any value that Effect can convert into a
Duration, including existing durations, millisecond numbers, nanosecond
bigints, high-resolution tuples, duration strings, infinity strings, or
duration objects.
Details
String inputs accept values like "10 seconds", "500 millis",
"Infinity", and "-Infinity". Finite fractional values that are
normalized to nanoseconds are rounded to the nearest nanosecond, with ties
away from zero.
Input | 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<readonly [function (type parameter) K in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], 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) V in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) E2 in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) R in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
function (type parameter) R2 in <A, E, R, K, V, E2, R2>(self: Stream<A, E, R>, f: (a: NoInfer<A>) => Effect.Effect<readonly [K, V], E2, R2>, options?: {
readonly bufferSize?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Stream<readonly [K, Stream<V>], E | E2, R | R2>
const groupByImpl: <
A,
E,
R,
K,
V,
E2,
R2
>(
self: Stream<A, E, R>,
f: (
arr: Arr.NonEmptyReadonlyArray<A>,
queues: RcMap.RcMap<
K,
Queue.Queue<V, Cause.Done>
>,
queueMap: MutableHashMap.MutableHashMap<
K,
Queue.Queue<V, Cause.Done>
>
) => Effect.Effect<void, E2, R2>,
options?: {
readonly bufferSize?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
) => Stream<
readonly [K, Stream<V>],
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; <…;
}
import EffectEffect.const fnUntraced: <Effect.Effect<void, never, never> | Effect.Effect<readonly [K, V], E2, R2>, void, [arr: readonly [A, ...A[]], queues: RcMap.RcMap<K, Queue.Queue<V, Cause.Done<void>>, never>, queueMap: MutableHashMap.MutableHashMap<K, Queue.Queue<V, Cause.Done<void>>>]>(body: (this: unassigned, arr: readonly [A, ...A[]], queues: RcMap.RcMap<K, Queue.Queue<V, Cause.Done<void>>, never>, queueMap: MutableHashMap.MutableHashMap<K, Queue.Queue<V, Cause.Done<void>>>) => Generator<...>) => (arr: readonly [...], queues: RcMap.RcMap<...>, queueMap: MutableHashMap.MutableHashMap<...>) => Effect.Effect<...> (+41 overloads)fnUntraced(function*(arr: readonly [A, ...A[]](parameter) arr: {
0: A;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<A>>): Array<A>; (...items: Array<A | ConcatArray<A>>): Array<A> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<A>;
indexOf: (searchElement: A, fromIndex?: number) => number;
lastIndexOf: (searchElement: A, fromIndex?: number) => number;
every: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => void, thisArg?: any) => void;
map: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): Array<S>; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): Array<A> };
reduce: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
reduceRight: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
find: { (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findIndex: (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, A]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<A>;
includes: (searchElement: A, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: A, index: number, array: Array<A>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => A | undefined;
findLast: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findLastIndex: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
toReversed: () => Array<A>;
toSorted: (compareFn?: ((a: A, b: A) => number) | undefined) => Array<A>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<A>): Array<A>; (start: number, deleteCount?: number): Array<A> };
with: (index: number, value: A) => Array<A>;
}
queues: RcMap.RcMap<
K,
Queue.Queue<V, Cause.Done<void>>,
never
>
(parameter) queues: {
lookup: (key: K) => Effect.Effect<A, E, Scope.Scope>;
context: Context.Context<never>;
scope: Scope.Scope;
idleTimeToLive: (key: K) => Duration.Duration;
capacity: number;
state: State<K, A, E>;
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; <…;
}
queueMap: MutableHashMap.MutableHashMap<
K,
Queue.Queue<V, Cause.Done<void>>
>
(parameter) queueMap: {
backing: Map<K, V>;
buckets: Map<number, NonEmptyArray<K>>;
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;
}
let i: numberi = 0; let i: numberi < arr: readonly [A, ...A[]](parameter) arr: {
0: A;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<A>>): Array<A>; (...items: Array<A | ConcatArray<A>>): Array<A> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<A>;
indexOf: (searchElement: A, fromIndex?: number) => number;
lastIndexOf: (searchElement: A, fromIndex?: number) => number;
every: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => void, thisArg?: any) => void;
map: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): Array<S>; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): Array<A> };
reduce: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
reduceRight: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
find: { (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findIndex: (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, A]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<A>;
includes: (searchElement: A, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: A, index: number, array: Array<A>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => A | undefined;
findLast: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findLastIndex: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
toReversed: () => Array<A>;
toSorted: (compareFn?: ((a: A, b: A) => number) | undefined) => Array<A>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<A>): Array<A>; (start: number, deleteCount?: number): Array<A> };
with: (index: number, value: A) => Array<A>;
}
length: numberlength; let i: numberi++) {
const [const key: Kkey, const value: Vvalue] = yield* f: (
a: NoInfer<A>
) => Effect.Effect<readonly [K, V], E2, R2>
arr: readonly [A, ...A[]](parameter) arr: {
0: A;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<A>>): Array<A>; (...items: Array<A | ConcatArray<A>>): Array<A> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<A>;
indexOf: (searchElement: A, fromIndex?: number) => number;
lastIndexOf: (searchElement: A, fromIndex?: number) => number;
every: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => void, thisArg?: any) => void;
map: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): Array<S>; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): Array<A> };
reduce: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
reduceRight: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
find: { (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findIndex: (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, A]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<A>;
includes: (searchElement: A, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: A, index: number, array: Array<A>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => A | undefined;
findLast: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findLastIndex: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
toReversed: () => Array<A>;
toSorted: (compareFn?: ((a: A, b: A) => number) | undefined) => Array<A>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<A>): Array<A>; (start: number, deleteCount?: number): Array<A> };
with: (index: number, value: A) => Array<A>;
}
let i: numberi])
const const oentry: Option.Option<
Queue.Queue<V, Cause.Done<void>>
>
import MutableHashMapMutableHashMap.const get: {
<K>(key: K): <V>(
self: MutableHashMap<K, V>
) => Option.Option<V>
<K, V>(
self: MutableHashMap<K, V>,
key: K
): Option.Option<V>
}
queueMap: MutableHashMap.MutableHashMap<
K,
Queue.Queue<V, Cause.Done<void>>
>
(parameter) queueMap: {
backing: Map<K, V>;
buckets: Map<number, NonEmptyArray<K>>;
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;
}
const key: Kkey)
const const queue: Queue.Queue<
V,
Cause.Done<void>
>
const queue: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
import OptionOption.const isSome: <A>(
self: Option<A>
) => self is Some<A>
Checks whether an Option contains a value (Some).
When to use
Use when you need to branch on a present Option before accessing .value.
Details
- Acts as a type guard, narrowing to
Some<A>
Example (Checking for Some)
import { Option } from "effect"
console.log(Option.isSome(Option.some(1)))
// Output: true
console.log(Option.isSome(Option.none()))
// Output: false
isSome(const oentry: Option.Option<
Queue.Queue<V, Cause.Done<void>>
>
const oentry: Option.Some<
Queue.Queue<V, Cause.Done<void>>
>
const oentry: {
_tag: "Some";
_op: "Some";
value: A;
valueOrUndefined: A;
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;
}
Some<Queue<V, Done<void>>>.value: Queue.Queue<V, Cause.Done<void>>(property) Some<Queue<V, Done<void>>>.value: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
import EffectEffect.const scoped: <A, E, R>(
self: Effect<A, E, R>
) => Effect<A, E, Exclude<R, Scope>>
Runs an effect with a scope that closes when the effect completes.
When to use
Use to acquire scoped resources for the duration of a single workflow.
Details
Finalizers for resources acquired inside the workflow run as soon as the
workflow completes, whether by success, failure, or interruption.
Example (Running a scoped acquisition)
import { Console, Effect } from "effect"
const resource = Effect.acquireRelease(
Console.log("Acquiring resource").pipe(Effect.as("resource")),
() => Console.log("Releasing resource")
)
const program = Effect.scoped(
Effect.gen(function*() {
const res = yield* resource
yield* Console.log(`Using ${res}`)
return res
})
)
Effect.runFork(program)
// Output: "Acquiring resource"
// Output: "Using resource"
// Output: "Releasing resource"
scoped(import RcMapRcMap.const get: {
<K>(key: K): <A, E>(
self: RcMap<K, A, E>
) => Effect.Effect<A, E, Scope.Scope>
<K, A, E>(
self: RcMap<K, A, E>,
key: K
): Effect.Effect<A, E, Scope.Scope>
}
queues: RcMap.RcMap<
K,
Queue.Queue<V, Cause.Done<void>>,
never
>
(parameter) queues: {
lookup: (key: K) => Effect.Effect<A, E, Scope.Scope>;
context: Context.Context<never>;
scope: Scope.Scope;
idleTimeToLive: (key: K) => Duration.Duration;
capacity: number;
state: State<K, A, E>;
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 key: Kkey))
yield* import RcMapRcMap.const touch: {
<K>(key: K): <A, E>(
self: RcMap<K, A, E>
) => Effect.Effect<void>
<K, A, E>(
self: RcMap<K, A, E>,
key: K
): Effect.Effect<void>
}
queues: RcMap.RcMap<
K,
Queue.Queue<V, Cause.Done<void>>,
never
>
(parameter) queues: {
lookup: (key: K) => Effect.Effect<A, E, Scope.Scope>;
context: Context.Context<never>;
scope: Scope.Scope;
idleTimeToLive: (key: K) => Duration.Duration;
capacity: number;
state: State<K, A, E>;
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 key: Kkey)
yield* import QueueQueue.const offer: <A, E>(
self: Enqueue<A, E>,
message: Types.NoInfer<A>
) => Effect<boolean>
Adds a message to the queue. Returns false if the queue is done.
Details
For bounded queues, this operation may suspend if the queue is at capacity,
depending on the backpressure strategy. For dropping/sliding queues, it may
return false or succeed immediately by dropping/sliding existing messages.
Example (Offering a value)
import { Effect, Queue } from "effect"
const program = Effect.gen(function*() {
const queue = yield* Queue.bounded<number>(3)
// Successfully add messages to queue
const success1 = yield* Queue.offer(queue, 1)
const success2 = yield* Queue.offer(queue, 2)
console.log(success1, success2) // true, true
// Queue state
const size = yield* Queue.size(queue)
console.log(size) // 2
})
offer(const queue: Queue.Queue<
V,
Cause.Done<void>
>
const queue: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
const value: Vvalue)
}
}),
options: {
readonly bufferSize?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}