<A>(pubsub: PubSub.PubSub<A>): Stream<A>Creates a stream from a subscription to a PubSub.
Example (Creating a stream from a subscription to a PubSub)
import { Console, Effect, Fiber, PubSub, Stream } from "effect"
const program = Effect.gen(function*() {
const pubsub = yield* PubSub.unbounded<number>()
const fiber = yield* Stream.fromPubSub(pubsub).pipe(
Stream.take(3),
Stream.runCollect,
Effect.forkChild
)
yield* PubSub.publish(pubsub, 1)
yield* PubSub.publish(pubsub, 2)
yield* PubSub.publish(pubsub, 3)
const values = yield* Fiber.join(fiber)
yield* Console.log(values)
})
Effect.runPromise(program)
// Output: [ 1, 2, 3 ]constructors
Source effect/Stream.ts:13281 lines
export const const fromPubSub: <A>(
pubsub: PubSub.PubSub<A>
) => Stream<A>
Creates a stream from a subscription to a PubSub.
Example (Creating a stream from a subscription to a PubSub)
import { Console, Effect, Fiber, PubSub, Stream } from "effect"
const program = Effect.gen(function*() {
const pubsub = yield* PubSub.unbounded<number>()
const fiber = yield* Stream.fromPubSub(pubsub).pipe(
Stream.take(3),
Stream.runCollect,
Effect.forkChild
)
yield* PubSub.publish(pubsub, 1)
yield* PubSub.publish(pubsub, 2)
yield* PubSub.publish(pubsub, 3)
const values = yield* Fiber.join(fiber)
yield* Console.log(values)
})
Effect.runPromise(program)
// Output: [ 1, 2, 3 ]
fromPubSub = <function (type parameter) A in <A>(pubsub: PubSub.PubSub<A>): Stream<A>A>(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.type PubSub.PubSub = /*unresolved*/ anyPubSub<function (type parameter) A in <A>(pubsub: PubSub.PubSub<A>): Stream<A>A>): 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>): Stream<A>A> => const fromChannel: <
Arr extends Arr.NonEmptyReadonlyArray<any>,
E,
R
>(
channel: Channel.Channel<
Arr,
E,
void,
unknown,
unknown,
unknown,
R
>
) => Stream<
Arr extends Arr.NonEmptyReadonlyArray<infer A>
? A
: never,
E,
R
>
Creates a stream from a array-emitting Channel.
Example (Creating a stream from an array-emitting channel)
import { Channel, Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const channel = Channel.succeed([1, 2, 3] as const)
const stream = Stream.fromChannel(channel)
const result = yield* Stream.runCollect(stream)
yield* Console.log(result)
})
// Output: [ 1, 2, 3 ]
fromChannel(import ChannelChannel.fromPubSubArray(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; <…;
}
Referenced by 1 symbols