<A>(self: TxPubSub<A>): Effect.Effect<boolean>Checks whether the TxPubSub has no pending messages (all subscriber queues are empty).
Example (Checking whether a pub/sub is empty)
import { Effect, TxPubSub } from "effect"
const program = Effect.gen(function*() {
const hub = yield* TxPubSub.unbounded<number>()
const empty = yield* TxPubSub.isEmpty(hub)
console.log(empty) // true
})export const const isEmpty: <A>(
self: TxPubSub<A>
) => Effect.Effect<boolean>
Checks whether the TxPubSub has no pending messages (all subscriber queues are empty).
Example (Checking whether a pub/sub is empty)
import { Effect, TxPubSub } from "effect"
const program = Effect.gen(function*() {
const hub = yield* TxPubSub.unbounded<number>()
const empty = yield* TxPubSub.isEmpty(hub)
console.log(empty) // true
})
isEmpty = <function (type parameter) A in <A>(self: TxPubSub<A>): Effect.Effect<boolean>A>(self: TxPubSub<A>(parameter) self: {
subscribersRef: TxRef.TxRef<Array<TxQueue.TxQueue<A>>>;
shutdownRef: TxRef.TxRef<boolean>;
strategy: "bounded" | "unbounded" | "dropping" | "sliding";
capacity: number;
toString: () => string;
toJSON: () => unknown;
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 TxPubSub<in out A>A TxPubSub represents a transactional publish/subscribe hub that broadcasts messages
to all current subscribers using Software Transactional Memory (STM) semantics.
Example (Subscribing to a transactional pub/sub)
import { Effect, TxPubSub, TxQueue } from "effect"
const program = Effect.gen(function*() {
const hub = yield* TxPubSub.unbounded<string>()
yield* Effect.scoped(
Effect.gen(function*() {
const sub = yield* TxPubSub.subscribe(hub)
yield* TxPubSub.publish(hub, "hello")
const msg = yield* TxQueue.take(sub)
console.log(msg) // "hello"
})
)
})
TxPubSub<function (type parameter) A in <A>(self: TxPubSub<A>): Effect.Effect<boolean>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<boolean> => 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>
}
const size: <A>(
self: TxPubSub<A>
) => Effect.Effect<number>
Returns the current number of messages across all subscriber queues (the max).
Example (Reading subscriber queue size)
import { Effect, TxPubSub, TxQueue } from "effect"
const program = Effect.gen(function*() {
const hub = yield* TxPubSub.unbounded<number>()
yield* Effect.scoped(
Effect.gen(function*() {
const sub = yield* TxPubSub.subscribe(hub)
yield* TxPubSub.publish(hub, 1)
yield* TxPubSub.publish(hub, 2)
const s = yield* TxPubSub.size(hub)
console.log(s) // 2
})
)
})
size(self: TxPubSub<A>(parameter) self: {
subscribersRef: TxRef.TxRef<Array<TxQueue.TxQueue<A>>>;
shutdownRef: TxRef.TxRef<boolean>;
strategy: "bounded" | "unbounded" | "dropping" | "sliding";
capacity: number;
toString: () => string;
toJSON: () => unknown;
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; <…;
}
s: numbers) => s: numbers === 0)