@efesto-cloud/publisher

Tiny, typed pub/sub primitive for broadcasting events without stored state.

Use Publisher for fire-and-forget events; use @efesto-cloud/observable when you also need to keep the current value.

Installation

pnpm add @efesto-cloud/publisher

Quick Start

import { Publisher } from "@efesto-cloud/publisher";

const bus = new Publisher<[string, number]>();

const off = bus.subscribe((event, code) => {
    console.log(event, code);
});

bus.notify("saved", 200);

off(); // unsubscribe

API

interface IPublisher<ARGS extends unknown[]> {
    size: number;
    subscribe(s: (...args: ARGS) => void): () => void;
    unsubscribe(id: number): void;
    notify(...args: ARGS): void;
    unsubscribeAll(): void;
}

• new Publisher<ARGS>() — typed tuple of event args.
• subscribe(listener) — returns an Unsubscribe function; keep it for cleanup.
• notify(...args) — invoke every subscriber synchronously.
• unsubscribeAll() — clear all listeners (e.g. on dispose).

Rules

• Do not use Publisher as a state container — if you need get/set, use Observable.
• Always keep and call the returned unsubscribe function to avoid leaks.
• Emitted arguments must match the declared tuple type.

Example: typed event bus

type Events = [event: "created" | "deleted", id: string];

const events = new Publisher<Events>();

events.subscribe((event, id) => {
    if (event === "created") console.log("new", id);
});

events.notify("created", "post-123");