<A>(
pubsub: PubSub.PubSub<A>,
options?: { readonly shutdownOnEnd?: boolean | undefined } | undefined
): <E, R>(self: Stream<A, E, R>) => Effect.Effect<void, E, R>
<A, E, R>(
self: Stream<A, E, R>,
pubsub: PubSub.PubSub<A>,
options?: { readonly shutdownOnEnd?: boolean | undefined } | undefined
): Effect.Effect<void, never, R>Runs the stream, publishing elements into the provided PubSub.
Details
shutdownOnEnd controls whether the PubSub is shut down when the stream ends.
It only shuts down when set to true.
Example (Running a stream into a PubSub)
import { Console, Effect, PubSub, Stream } from "effect"
const program = Effect.scoped(Effect.gen(function* () {
const pubsub = yield* PubSub.unbounded<number>()
const subscription = yield* PubSub.subscribe(pubsub)
yield* Stream.runIntoPubSub(Stream.fromIterable([1, 2]), pubsub)
const first = yield* PubSub.take(subscription)
const second = yield* PubSub.take(subscription)
yield* Console.log(first)
yield* Console.log(second)
}))
Effect.runPromise(program)
//=> 1
//=> 2export const const runIntoPubSub: {
<A>(
pubsub: PubSub.PubSub<A>,
options?:
| {
readonly shutdownOnEnd?:
| boolean
| undefined
}
| undefined
): <E, R>(
self: Stream<A, E, R>
) => Effect.Effect<void, E, R>
<A, E, R>(
self: Stream<A, E, R>,
pubsub: PubSub.PubSub<A>,
options?:
| {
readonly shutdownOnEnd?:
| boolean
| undefined
}
| undefined
): Effect.Effect<void, never, R>
}
Runs the stream, publishing elements into the provided PubSub.
Details
shutdownOnEnd controls whether the PubSub is shut down when the stream ends.
It only shuts down when set to true.
Example (Running a stream into a PubSub)
import { Console, Effect, PubSub, Stream } from "effect"
const program = Effect.scoped(Effect.gen(function* () {
const pubsub = yield* PubSub.unbounded<number>()
const subscription = yield* PubSub.subscribe(pubsub)
yield* Stream.runIntoPubSub(Stream.fromIterable([1, 2]), pubsub)
const first = yield* PubSub.take(subscription)
const second = yield* PubSub.take(subscription)
yield* Console.log(first)
yield* Console.log(second)
}))
Effect.runPromise(program)
//=> 1
//=> 2
runIntoPubSub: {
<function (type parameter) A in <A>(pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): <E, R>(self: Stream<A, E, R>) => Effect.Effect<void, E, R>
pubsub: PubSub.PubSub<A>(parameter) pubsub: {
pubsub: PubSub.Atomic<A>;
subscribers: PubSub.Subscribers<A>;
scope: Scope.Closeable;
shutdownHook: Latch.Latch;
shutdownFlag: MutableRef.MutableRef<boolean>;
strategy: PubSub.Strategy<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; <…;
}
import PubSubPubSub.interface PubSub<in out A>A PubSub<A> is an asynchronous message hub into which publishers can publish
messages of type A and subscribers can subscribe to take messages of type
A.
Example (Publishing and subscribing to messages)
import { Effect, PubSub } from "effect"
const program = Effect.gen(function*() {
// Create a bounded PubSub with capacity 10
const pubsub = yield* PubSub.bounded<string>(10)
// Subscribe and consume messages
yield* Effect.scoped(Effect.gen(function*() {
const subscription = yield* PubSub.subscribe(pubsub)
// Publish messages
yield* PubSub.publish(pubsub, "Hello")
yield* PubSub.publish(pubsub, "World")
const message1 = yield* PubSub.take(subscription)
const message2 = yield* PubSub.take(subscription)
console.log(message1, message2) // "Hello", "World"
}))
})
Companion namespace containing the low-level building blocks used by
PubSub, including atomic implementations, backing subscriptions, replay
windows, and delivery strategies.
PubSub<function (type parameter) A in <A>(pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): <E, R>(self: Stream<A, E, R>) => Effect.Effect<void, E, R>
options: | {
readonly shutdownOnEnd?: boolean | undefined
}
| undefined
shutdownOnEnd?: boolean | undefinedshutdownOnEnd?: boolean | undefined
} | undefined
): <function (type parameter) E in <E, R>(self: Stream<A, E, R>): Effect.Effect<void, E, R>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Effect.Effect<void, E, 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>(pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): <E, R>(self: Stream<A, E, R>) => Effect.Effect<void, E, R>
function (type parameter) E in <E, R>(self: Stream<A, E, R>): Effect.Effect<void, E, R>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Effect.Effect<void, E, 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<void, function (type parameter) E in <E, R>(self: Stream<A, E, R>): Effect.Effect<void, E, R>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Effect.Effect<void, E, R>R>
<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, never, R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, never, R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, never, 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>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, never, R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, never, R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, never, R>
pubsub: PubSub.PubSub<A>(parameter) pubsub: {
pubsub: PubSub.Atomic<A>;
subscribers: PubSub.Subscribers<A>;
scope: Scope.Closeable;
shutdownHook: Latch.Latch;
shutdownFlag: MutableRef.MutableRef<boolean>;
strategy: PubSub.Strategy<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; <…;
}
import PubSubPubSub.interface PubSub<in out A>A PubSub<A> is an asynchronous message hub into which publishers can publish
messages of type A and subscribers can subscribe to take messages of type
A.
Example (Publishing and subscribing to messages)
import { Effect, PubSub } from "effect"
const program = Effect.gen(function*() {
// Create a bounded PubSub with capacity 10
const pubsub = yield* PubSub.bounded<string>(10)
// Subscribe and consume messages
yield* Effect.scoped(Effect.gen(function*() {
const subscription = yield* PubSub.subscribe(pubsub)
// Publish messages
yield* PubSub.publish(pubsub, "Hello")
yield* PubSub.publish(pubsub, "World")
const message1 = yield* PubSub.take(subscription)
const message2 = yield* PubSub.take(subscription)
console.log(message1, message2) // "Hello", "World"
}))
})
Companion namespace containing the low-level building blocks used by
PubSub, including atomic implementations, backing subscriptions, replay
windows, and delivery strategies.
PubSub<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, never, R>
options: | {
readonly shutdownOnEnd?: boolean | undefined
}
| undefined
shutdownOnEnd?: boolean | undefinedshutdownOnEnd?: boolean | undefined
} | 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<void, never, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, never, R>
dual<(...args: Array<any>) => any, <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined) => Effect.Effect<void, E, R>>(isDataFirst: (args: IArguments) => boolean, body: <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined) => Effect.Effect<void, E, R>): ((...args: Array<any>) => any) & (<A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined) => Effect.Effect<void, E, 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((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>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, E, R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, E, R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, E, 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>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, E, R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, E, R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, E, R>
pubsub: PubSub.PubSub<A>(parameter) pubsub: {
pubsub: PubSub.Atomic<A>;
subscribers: PubSub.Subscribers<A>;
scope: Scope.Closeable;
shutdownHook: Latch.Latch;
shutdownFlag: MutableRef.MutableRef<boolean>;
strategy: PubSub.Strategy<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; <…;
}
import PubSubPubSub.interface PubSub<in out A>A PubSub<A> is an asynchronous message hub into which publishers can publish
messages of type A and subscribers can subscribe to take messages of type
A.
Example (Publishing and subscribing to messages)
import { Effect, PubSub } from "effect"
const program = Effect.gen(function*() {
// Create a bounded PubSub with capacity 10
const pubsub = yield* PubSub.bounded<string>(10)
// Subscribe and consume messages
yield* Effect.scoped(Effect.gen(function*() {
const subscription = yield* PubSub.subscribe(pubsub)
// Publish messages
yield* PubSub.publish(pubsub, "Hello")
yield* PubSub.publish(pubsub, "World")
const message1 = yield* PubSub.take(subscription)
const message2 = yield* PubSub.take(subscription)
console.log(message1, message2) // "Hello", "World"
}))
})
Companion namespace containing the low-level building blocks used by
PubSub, including atomic implementations, backing subscriptions, replay
windows, and delivery strategies.
PubSub<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, E, R>
options: | {
readonly shutdownOnEnd?: boolean | undefined
}
| undefined
shutdownOnEnd?: boolean | undefinedshutdownOnEnd?: boolean | undefined
} | 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<void, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, E, R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, pubsub: PubSub.PubSub<A>, options?: {
readonly shutdownOnEnd?: boolean | undefined;
} | undefined): Effect.Effect<void, E, R>
import ChannelChannel.const runIntoPubSubArray: {
<OutElem>(
pubsub: PubSub.PubSub<OutElem>,
options?:
| {
readonly shutdownOnEnd?:
| boolean
| undefined
}
| undefined
): <OutErr, OutDone, Env>(
self: Channel<
Arr.NonEmptyReadonlyArray<OutElem>,
OutErr,
OutDone,
unknown,
unknown,
unknown,
Env
>
) => Effect.Effect<OutDone, OutErr, Env>
<OutElem, OutErr, OutDone, Env>(
self: Channel<
Arr.NonEmptyReadonlyArray<OutElem>,
OutErr,
OutDone,
unknown,
unknown,
unknown,
Env
>,
pubsub: PubSub.PubSub<OutElem>,
options?:
| {
readonly shutdownOnEnd?:
| boolean
| undefined
}
| undefined
): Effect.Effect<OutDone, OutErr, Env>
}
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; <…;
}
Stream<A, E, R>.channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, R>(property) Stream<A, E, R>.channel: {
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; <…;
}
pubsub: PubSub.PubSub<A>(parameter) pubsub: {
pubsub: PubSub.Atomic<A>;
subscribers: PubSub.Subscribers<A>;
scope: Scope.Closeable;
shutdownHook: Latch.Latch;
shutdownFlag: MutableRef.MutableRef<boolean>;
strategy: PubSub.Strategy<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; <…;
}
options: | {
readonly shutdownOnEnd?: boolean | undefined
}
| undefined