<A>(self: PubSub<A>): Effect.Effect<void>Shuts down the PubSub, interrupting suspended publishers and subscribers
and finalizing active subscriptions.
Details
After shutdown, publish and publishAll succeed with false,
publishUnsafe returns false, and subscription operations such as take
interrupt.
Example (Shutting down a PubSub)
import { Effect, PubSub } from "effect"
const program = Effect.gen(function*() {
const pubsub = yield* PubSub.bounded<string>(1)
// Shutdown the PubSub
yield* PubSub.shutdown(pubsub)
const isShutdown = yield* PubSub.isShutdown(pubsub)
console.log("Is shutdown:", isShutdown) // true
// Publishing after shutdown returns false
const published = yield* PubSub.publish(pubsub, "msg1")
console.log("Published after shutdown:", published) // false
})lifecycle
Source effect/PubSub.ts:7579 lines
export const const shutdown: <A>(
self: PubSub<A>
) => Effect.Effect<void>
Shuts down the PubSub, interrupting suspended publishers and subscribers
and finalizing active subscriptions.
Details
After shutdown, publish and publishAll succeed with false,
publishUnsafe returns false, and subscription operations such as take
interrupt.
Example (Shutting down a PubSub)
import { Effect, PubSub } from "effect"
const program = Effect.gen(function*() {
const pubsub = yield* PubSub.bounded<string>(1)
// Shutdown the PubSub
yield* PubSub.shutdown(pubsub)
const isShutdown = yield* PubSub.isShutdown(pubsub)
console.log("Is shutdown:", isShutdown) // true
// Publishing after shutdown returns false
const published = yield* PubSub.publish(pubsub, "msg1")
console.log("Published after shutdown:", published) // false
})
shutdown = <function (type parameter) A in <A>(self: PubSub<A>): Effect.Effect<void>A>(self: PubSub<A>(parameter) self: {
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; <…;
}
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>(self: PubSub<A>): Effect.Effect<void>A>): 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> =>
import EffectEffect.const uninterruptible: <A, E, R>(
self: Effect<A, E, R>
) => Effect<A, E, R>
Returns a new effect that disables interruption for the given effect.
Example (Preventing interruption)
import { Console, Effect, Fiber } from "effect"
const criticalTask = Effect.gen(function*() {
yield* Console.log("Starting critical section...")
yield* Effect.sleep("2 seconds")
yield* Console.log("Critical section completed")
})
const program = Effect.uninterruptible(criticalTask)
const fiber = Effect.runFork(program)
// Even if interrupted, the critical task will complete
Effect.runPromise(Fiber.interrupt(fiber))
uninterruptible(import EffectEffect.const withFiber: <
A,
E = never,
R = never
>(
evaluate: (
fiber: Fiber<unknown, unknown>
) => Effect<A, E, R>
) => Effect<A, E, R>
Provides access to the current fiber within an effect computation.
Example (Reading the current fiber)
import { Effect } from "effect"
const program = Effect.withFiber((fiber) =>
Effect.succeed(`Fiber ID: ${fiber.id}`)
)
Effect.runPromise(program).then(console.log)
// Output: Fiber ID: 1
withFiber((fiber: Fiber<unknown, unknown>(parameter) fiber: {
id: number;
currentOpCount: number;
getRef: <A>(ref: Context.Reference<A>) => A;
context: Context.Context<never>;
setContext: (context: Context.Context<never>) => void;
currentScheduler: Scheduler;
currentDispatcher: SchedulerDispatcher;
currentSpan: AnySpan | undefined;
currentLogLevel: LogLevel;
minimumLogLevel: LogLevel;
currentStackFrame: StackFrame | undefined;
maxOpsBeforeYield: number;
currentPreventYield: boolean;
addObserver: (cb: (exit: Exit<A, E>) => void) => () => void;
interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => void;
pollUnsafe: () => Exit<A, E> | undefined;
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 MutableRefMutableRef.const set: {
<T>(value: T): (
self: MutableRef<T>
) => MutableRef<T>
<T>(
self: MutableRef<T>,
value: T
): MutableRef<T>
}
self: PubSub<A>(parameter) self: {
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; <…;
}
PubSub<in out A>.shutdownFlag: MutableRef.MutableRef<boolean>(property) PubSub<in out A>.shutdownFlag: {
current: T;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
import ScopeScope.const close: <A, E>(
self: Scope,
exit: Exit<A, E>
) => Effect<void>
Closes a scope and runs its registered finalizers.
When to use
Use to close a scope manually with a specific exit value.
Details
Finalizers run in the scope's configured order and receive the supplied
Exit.
Example (Running scope finalizers)
import { Console, Effect, Exit, Scope } from "effect"
const resourceManagement = Effect.gen(function*() {
const scope = yield* Scope.make("sequential")
// Add multiple finalizers
yield* Scope.addFinalizer(scope, Console.log("Close database connection"))
yield* Scope.addFinalizer(scope, Console.log("Close file handle"))
yield* Scope.addFinalizer(scope, Console.log("Release memory"))
// Do some work...
yield* Console.log("Performing operations...")
// Close scope - finalizers run in reverse order of registration
yield* Scope.close(scope, Exit.succeed("Success!"))
// Output: "Release memory", "Close file handle", "Close database connection"
})
close(self: PubSub<A>(parameter) self: {
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; <…;
}
PubSub<in out A>.scope: Scope.Closeable(property) PubSub<in out A>.scope: {
strategy: "sequential" | "parallel";
state: State.Open | State.Closed | State.Empty;
}
import ExitExit.const interrupt: (
fiberId?: number | undefined
) => Exit<never>
Creates a failed Exit representing fiber interruption.
When to use
Use to signal that a fiber was interrupted.
Details
Optionally pass a fiber ID to identify which fiber was interrupted. Returns
a Failure<never> with an Interrupt cause.
Example (Creating an interruption Exit)
import { Exit } from "effect"
const exit = Exit.interrupt(123)
console.log(Exit.isFailure(exit)) // true
console.log(Exit.hasInterrupts(exit)) // true
interrupt(fiber: Fiber<unknown, unknown>(parameter) fiber: {
id: number;
currentOpCount: number;
getRef: <A>(ref: Context.Reference<A>) => A;
context: Context.Context<never>;
setContext: (context: Context.Context<never>) => void;
currentScheduler: Scheduler;
currentDispatcher: SchedulerDispatcher;
currentSpan: AnySpan | undefined;
currentLogLevel: LogLevel;
minimumLogLevel: LogLevel;
currentStackFrame: StackFrame | undefined;
maxOpsBeforeYield: number;
currentPreventYield: boolean;
addObserver: (cb: (exit: Exit<A, E>) => void) => () => void;
interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => void;
pollUnsafe: () => Exit<A, E> | undefined;
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; <…;
}
Fiber<out A, out E = never>.id: numberid)).Pipeable.pipe<Effect.Effect<void, never, never>, Effect.Effect<void, never, never>, Effect.Effect<Option.Option<void>, never, never>, Effect.Effect<void, never, never>>(this: Effect.Effect<...>, ab: (_: Effect.Effect<void, never, never>) => Effect.Effect<void, never, never>, bc: (_: Effect.Effect<void, never, never>) => Effect.Effect<Option.Option<void>, never, never>, cd: (_: Effect.Effect<Option.Option<void>, never, never>) => Effect.Effect<void, never, never>): Effect.Effect<...> (+21 overloads)pipe(
import EffectEffect.const andThen: {
<A, B, E2, R2>(
f: (a: A) => Effect<B, E2, R2>
): <E, R>(
self: Effect<A, E, R>
) => Effect<B, E | E2, R | R2>
<B, E2, R2>(f: Effect<B, E2, R2>): <A, E, R>(
self: Effect<A, E, R>
) => Effect<B, E | E2, R | R2>
<A, E, R, B, E2, R2>(
self: Effect<A, E, R>,
f: (a: A) => Effect<B, E2, R2>
): Effect<B, E | E2, R | R2>
<A, E, R, B, E2, R2>(
self: Effect<A, E, R>,
f: Effect<B, E2, R2>
): Effect<B, E | E2, R | R2>
}
self: PubSub<A>(parameter) self: {
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; <…;
}
PubSub<A>.strategy: PubSub.Strategy<A>(property) PubSub<A>.strategy: {
shutdown: Effect.Effect<void>;
handleSurplus: (pubsub: PubSub.Atomic<A>, subscribers: PubSub.Subscribers<A>, elements: Iterable<A>, isShutdown: MutableRef.MutableRef<boolean>) => Effect.Effect<boolean>;
onPubSubEmptySpaceUnsafe: (pubsub: PubSub.Atomic<A>, subscribers: PubSub.Subscribers<A>) => void;
completePollersUnsafe: (pubsub: PubSub.Atomic<A>, subscribers: PubSub.Subscribers<A>, subscription: PubSub.BackingSubscription<A>, pollers: MutableList.MutableList<Deferred.Deferred<A, never>>) => void;
completeSubscribersUnsafe: (pubsub: PubSub.Atomic<A>, subscribers: PubSub.Subscribers<A>) => void;
}
PubSub<in out A>.Strategy<in out A>.shutdown: Effect.Effect<void>(property) PubSub<in out A>.Strategy<in out A>.shutdown: {
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;
}
Describes any finalization logic associated with this strategy.
shutdown),
import EffectEffect.const when: {
<E2 = never, R2 = never>(
condition: Effect<boolean, E2, R2>
): <A, E, R>(
self: Effect<A, E, R>
) => Effect<Option<A>, E | E2, R | R2>
<A, E, R, E2 = never, R2 = never>(
self: Effect<A, E, R>,
condition: Effect<boolean, E2, R2>
): Effect<Option<A>, E | E2, R | R2>
}
self: PubSub<A>(parameter) self: {
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; <…;
}
PubSub<in out A>.shutdownHook: Latch.Latch(property) PubSub<in out A>.shutdownHook: {
open: Effect.Effect<boolean>;
openUnsafe: (this: Latch) => boolean;
release: Effect.Effect<boolean>;
await: Effect.Effect<void>;
close: Effect.Effect<boolean>;
closeUnsafe: (this: Latch) => boolean;
whenOpen: <A, E, R>(self: Effect.Effect<A, E, R>) => Effect.Effect<A, E, R>;
isOpen: (this: Latch) => boolean;
}
Latch.open: Effect.Effect<boolean>(property) Latch.open: {
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;
}
Opens the latch, releasing all fibers waiting on it.
When to use
Use to let current and future waiters continue.
open),
import EffectEffect.const asVoid: <A, E, R>(
self: Effect<A, E, R>
) => Effect<void, E, R>
Maps the success value of an Effect to void, preserving failures.
Example (Discarding success values)
import { Effect } from "effect"
const program = Effect.asVoid(Effect.succeed(42))
Effect.runPromise(program).then(console.log)
// undefined (void)
asVoid
)
}))Referenced by 2 symbols