effect-io-ai

Package: effect
Module: PubSub

PubSub.remaining

Returns the number of messages currently available in the subscription as an Effect.

When to use

Use when checking a subscription from effectful code and shutdown should interrupt the effect.

Details

The count includes replay-buffered messages. If the subscription has been shut down, the effect interrupts.

Example (Checking remaining messages)

import { Effect, PubSub } from "effect"

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

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

    // Publish some messages
    yield* PubSub.publishAll(pubsub, ["msg1", "msg2", "msg3"])

    // Check how many messages are available
    const count = yield* PubSub.remaining(subscription)
    console.log("Messages available:", count) // 3

    // Take one message
    yield* PubSub.take(subscription)

    const remaining = yield* PubSub.remaining(subscription)
    console.log("Messages remaining:", remaining) // 2
  }))
})

See

• remainingUnsafe for a synchronous check that reports shutdown as Option.none()

Signature

declare const remaining: <A>(self: Subscription<A>) => Effect.Effect<number>

Source

Since v4.0.0