get-it/src/util/pubsub.ts

Generic HTTP request library for node, browsers and workers

// Code borrowed from https://github.com/bjoerge/nano-pubsub

import type {PubSub, Subscriber} from 'get-it'

export function createPubSub<Message = void>(): PubSub<Message> {
  const subscribers: {[id: string]: Subscriber<Message>} = Object.create(null)
  let nextId = 0
  function subscribe(subscriber: Subscriber<Message>) {
    const id = nextId++
    subscribers[id] = subscriber
    return function unsubscribe() {
      delete subscribers[id]
    }
  }

  function publish(event: Message) {
    for (const id in subscribers) {
      subscribers[id](event)
    }
  }

  return {
    publish,
    subscribe,
  }
}