(
options:
| {
readonly capacity: "unbounded"
readonly replay?: number | undefined
readonly idleTimeToLive?: Duration.Input | undefined
}
| {
readonly capacity: number
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined
readonly replay?: number | undefined
readonly idleTimeToLive?: Duration.Input | undefined
}
): <A, E, R>(
self: Stream<A, E, R>
) => Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
<A, E, R>(
self: Stream<A, E, R>,
options:
| {
readonly capacity: "unbounded"
readonly replay?: number | undefined
readonly idleTimeToLive?: Duration.Input | undefined
}
| {
readonly capacity: number
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined
readonly replay?: number | undefined
readonly idleTimeToLive?: Duration.Input | undefined
}
): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>Returns a new Stream that multicasts the original stream, subscribing when the first consumer starts.
Details
The upstream continues running while there is at least one consumer and is finalized after the last one exits.
If idleTimeToLive is set, the upstream is kept alive for that duration so a later subscriber can continue from
the next element instead of restarting.
Example (Sharing a stream)
import { Console, Effect, Stream } from "effect"
Effect.runPromise(
Effect.scoped(
Effect.gen(function*() {
const shared = yield* Stream.make(1, 2, 3).pipe(
Stream.share({ capacity: 16 })
)
const first = yield* shared.pipe(Stream.take(1), Stream.runCollect)
const second = yield* shared.pipe(Stream.take(1), Stream.runCollect)
yield* Console.log([first, second])
})
)
)
// output: [[1], [1]]export const const share: {
(
options:
| {
readonly capacity: "unbounded"
readonly replay?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
| {
readonly capacity: number
readonly strategy?:
| "sliding"
| "dropping"
| "suspend"
| undefined
readonly replay?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
): <A, E, R>(
self: Stream<A, E, R>
) => Effect.Effect<
Stream<A, E>,
never,
Scope.Scope | R
>
<A, E, R>(
self: Stream<A, E, R>,
options:
| {
readonly capacity: "unbounded"
readonly replay?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
| {
readonly capacity: number
readonly strategy?:
| "sliding"
| "dropping"
| "suspend"
| undefined
readonly replay?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
): Effect.Effect<
Stream<A, E>,
never,
Scope.Scope | R
>
}
Returns a new Stream that multicasts the original stream, subscribing when the first consumer starts.
Details
The upstream continues running while there is at least one consumer and is finalized after the last one exits.
If idleTimeToLive is set, the upstream is kept alive for that duration so a later subscriber can continue from
the next element instead of restarting.
Example (Sharing a stream)
import { Console, Effect, Stream } from "effect"
Effect.runPromise(
Effect.scoped(
Effect.gen(function*() {
const shared = yield* Stream.make(1, 2, 3).pipe(
Stream.share({ capacity: 16 })
)
const first = yield* shared.pipe(Stream.take(1), Stream.runCollect)
const second = yield* shared.pipe(Stream.take(1), Stream.runCollect)
yield* Console.log([first, second])
})
)
)
// output: [[1], [1]]
share: {
(
options: | {
readonly capacity: "unbounded"
readonly replay?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
| {
readonly capacity: number
readonly strategy?:
| "sliding"
| "dropping"
| "suspend"
| undefined
readonly replay?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
capacity: "unbounded"capacity: "unbounded"
readonly replay?: number | undefinedreplay?: 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
} | {
readonly capacity: numbercapacity: number
readonly strategy?: | "sliding"
| "dropping"
| "suspend"
| undefined
replay?: number | undefinedreplay?: 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) A in <A, E, R>(self: Stream<A, E, R>): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Effect.Effect<Stream<A, E>, never, Scope.Scope | 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, E, R>(self: Stream<A, E, R>): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>R>) => 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<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>): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>E>, never, import ScopeScope.Scope | function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>R>
<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | 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>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
options: | {
readonly capacity: "unbounded"
readonly replay?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
| {
readonly capacity: number
readonly strategy?:
| "sliding"
| "dropping"
| "suspend"
| undefined
readonly replay?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
capacity: "unbounded"capacity: "unbounded"
readonly replay?: number | undefinedreplay?: 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
} | {
readonly capacity: numbercapacity: number
readonly strategy?: | "sliding"
| "dropping"
| "suspend"
| undefined
replay?: number | undefinedreplay?: 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
}
): 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<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>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
import ScopeScope.Scope | function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
dual<(...args: Array<any>) => any, <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}) => Effect.Effect<Stream<A, E>, never, Scope.Scope | R>>(arity: 2, body: <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}) => Effect.Effect<Stream<A, E>, never, Scope.Scope | R>): ((...args: Array<any>) => any) & (<A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}) => Effect.Effect<Stream<A, E>, never, Scope.Scope | R>) (+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(2, <function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | 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>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
options: | {
readonly capacity: "unbounded"
readonly replay?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
| {
readonly capacity: number
readonly strategy?:
| "sliding"
| "dropping"
| "suspend"
| undefined
readonly replay?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
capacity: "unbounded"capacity: "unbounded"
readonly replay?: number | undefinedreplay?: 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
} | {
readonly capacity: numbercapacity: number
readonly strategy?: | "sliding"
| "dropping"
| "suspend"
| undefined
replay?: number | undefinedreplay?: 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
}
): 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<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>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
import ScopeScope.Scope | function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, options: {
readonly capacity: "unbounded";
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
} | {
readonly capacity: number;
readonly strategy?: "sliding" | "dropping" | "suspend" | undefined;
readonly replay?: number | undefined;
readonly idleTimeToLive?: Duration.Input | undefined;
}): Effect.Effect<Stream<A, E>, never, Scope.Scope | R>
import EffectEffect.const map: {
<A, B>(f: (a: A) => B): <E, R>(
self: Effect<A, E, R>
) => Effect<B, E, R>
<A, E, R, B>(
self: Effect<A, E, R>,
f: (a: A) => B
): Effect<B, E, R>
}
import RcRefRcRef.const make: <A, E, R>(options: {
readonly acquire: Effect.Effect<A, E, R>
readonly idleTimeToLive?:
| Duration.Input
| undefined
}) => Effect.Effect<RcRef<A, E>, never, R | Scope>
Creates an RcRef from an acquire effect.
When to use
Use to create a lazily acquired, reference-counted resource from an acquire
effect.
Details
The resource is acquired lazily on the first get and shared by subsequent
gets while it remains cached. Each get adds a reference to the current
Scope. When the last reference is released, the resource is closed
immediately by default, or after idleTimeToLive when that option is
provided.
Example (Creating a reference-counted resource)
import { Effect, RcRef } from "effect"
Effect.gen(function*() {
const ref = yield* RcRef.make({
acquire: Effect.acquireRelease(
Effect.succeed("foo"),
() => Effect.log("release foo")
)
})
// will only acquire the resource once, and release it
// when the scope is closed
yield* RcRef.get(ref).pipe(
Effect.andThen(RcRef.get(ref)),
Effect.scoped
)
})
make({
acquire: Effect.Effect<
Stream<A, E, never>,
never,
Scope.Scope | R
>
(property) acquire: {
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 broadcast: {
(
options:
| {
readonly capacity: "unbounded"
readonly replay?: number | undefined
}
| {
readonly capacity: number
readonly strategy?:
| "sliding"
| "dropping"
| "suspend"
| undefined
readonly replay?: number | undefined
}
): <A, E, R>(
self: Stream<A, E, R>
) => Effect.Effect<
Stream<A, E>,
never,
Scope.Scope | R
>
<A, E, R>(
self: Stream<A, E, R>,
options:
| {
readonly capacity: "unbounded"
readonly replay?: number | undefined
}
| {
readonly capacity: number
readonly strategy?:
| "sliding"
| "dropping"
| "suspend"
| undefined
readonly replay?: number | undefined
}
): Effect.Effect<
Stream<A, E>,
never,
Scope.Scope | 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; <…;
}
options: | {
readonly capacity: "unbounded"
readonly replay?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
| {
readonly capacity: number
readonly strategy?:
| "sliding"
| "dropping"
| "suspend"
| undefined
readonly replay?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
idleTimeToLive?: Duration.Input | undefinedWhen the reference count reaches zero, the resource will be released
after this duration.
idleTimeToLive: options: | {
readonly capacity: "unbounded"
readonly replay?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
| {
readonly capacity: number
readonly strategy?:
| "sliding"
| "dropping"
| "suspend"
| undefined
readonly replay?: number | undefined
readonly idleTimeToLive?:
| Duration.Input
| undefined
}
idleTimeToLive?: Duration.Input | undefinedidleTimeToLive
}),
(ref: RcRef.RcRef<Stream<A, E, never>, never>(parameter) ref: {
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 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(import RcRefRcRef.const get: <A, E>(
self: RcRef<A, E>
) => Effect.Effect<A, E, Scope>
Gets the value from an RcRef, acquiring it first if needed.
When to use
Use to borrow the current resource within a Scope, acquiring it first if
necessary.
Details
The reference count is incremented for the current Scope, and a release
finalizer is added to that scope. When the current scope closes, the
reference is released; the resource is closed when the final reference is
released, subject to any configured idle time-to-live.
Example (Sharing one acquired value)
import { Effect, RcRef } from "effect"
const program = Effect.gen(function*() {
// Create an RcRef with a resource
const ref = yield* RcRef.make({
acquire: Effect.acquireRelease(
Effect.succeed("shared resource"),
(resource) => Effect.log(`Releasing ${resource}`)
)
})
// Get the value from the RcRef
const value1 = yield* RcRef.get(ref)
const value2 = yield* RcRef.get(ref)
// Both values are the same instance
console.log(value1 === value2) // true
return value1
})
get(ref: RcRef.RcRef<Stream<A, E, never>, never>(parameter) ref: {
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; <…;
}