Hyperlinkv0.8.0-beta.28

← PubSub

PubSub.isEmptyconsteffect/PubSub.ts:722
<A>(self: PubSub<A>): Effect.Effect<boolean>

Returns true if the Pubsub contains zero elements, false otherwise.

Example (Checking whether a PubSub is empty)

import { Effect, PubSub } from "effect"

const program = Effect.gen(function*() {
  const pubsub = yield* PubSub.bounded<string>(10)

  // Initially empty
  const initiallyEmpty = yield* PubSub.isEmpty(pubsub)
  console.log("Initially empty:", initiallyEmpty) // true

  yield* Effect.scoped(Effect.gen(function*() {
    const subscription = yield* PubSub.subscribe(pubsub)

    // Publish a message for the active subscription
    yield* PubSub.publish(pubsub, "Hello")

    const nowEmpty = yield* PubSub.isEmpty(pubsub)
    console.log("Now empty:", nowEmpty) // false

    yield* PubSub.take(subscription)
  }))
})
predicates
Source effect/PubSub.ts:7221 lines
export const isEmpty = <A>(self: PubSub<A>): Effect.Effect<boolean> => Effect.map(size(self), (size) => size === 0)