Super simple es6 class pubsub

simple-pubsub-es6.js

class Publisher {
  constructor() {
    this.subscribers = [];
  }

  addSubscriber(subscriberInstance) {
    this.subscribers.push(subscriberInstance);
  }

  emit(eventName, payload) {
    this.subscribers.forEach(subscriber => {
      if(subscriber.subscriptions[eventName]) {
        subscriber.subscriptions[eventName](payload)
      }
    })
  }
}

class Subscriber {
  constructor() {
    this.subscriptions = {};
  }

  on(eventName, callback) {
    this.subscriptions[eventName] = callback;
  }
}

const publisher = new Publisher();

const subscriber1 = new Subscriber();
const subscriber2 = new Subscriber();

publisher.addSubscriber(subscriber1);
publisher.addSubscriber(subscriber2);

subscriber1.on("event/newNotification", (payload) => {
  console.log("Fired subscriber1! event/newNotification", payload);
});

subscriber2.on("event/newNotification", (payload) => {
  console.log("Fired subscriber2! event/newNotification", payload);
});

publisher.emit('event/newNotification', {
  foo: 'bar',
})